BKI class.pdf

BIRO KLASIFIKASI INDONESIA

GUIDELINES FOR THE CONSTRCTION AND CLASSIFICATION/CERTIFICATION OF FLOATING, PRODUCTION, STRORAGE AND OFFLOADING UNITS

EDITION 2009



EDITION 2009



EDITION 2009


GUIDELINES FOR THE CONSTRUCTION AND CLASSIFICATION/CERTIFICATIO CLASSIFICATION/CERTIFICATION N OF FLOATING, PRODUCTION, STORAGE AND OFFLOADING UNITS

EDITION 2009

ii

Biro Klasifikasi Indonesia

The following Guidelines come into force on 1st April 2009

Reproduction in whole or in part by any means, is subject to the permission in writing by Biro Klasifikasi Indonesia Head Office

Published by : Biro Klasifikasi Indonesia

Table of Contents

iii

Table of Contents

Section 1

General Requirements and Definitions

A.

Application Applicatio n ................................................ ....................... ................................................... .................................................. ................................................. ................................................. .......................... .. 1- 1

B.

Scope/Extent Scope/Ext ent of BKI Surveys Survey s ............................................. .................... ................................................... ..................................................... ................................................ ..................... 1- 1

C.

Other Applicable Applica ble Regulations Regula tions and Guidelines Guidelin es ................................................. ....................... ...................................................... ............................................ ................ 1- 2

D.

Documentation Document ation .................................................. ........................ ................................................... ................................................... .................................................. .......................................... .................. 1- 3

E.

Certification/C Certif ication/Classifi lassification cation ............................................ .................... .................................................... ...................................................... .................................................. .......................... .. 1- 3

F.

Definitions Definit ions ................................................... ......................... .................................................... .................................................... ................................................... ............................................... ...................... 1- 4

Section 2

Surveys for Certification

A.

Surveys Survey s During Fabrication Fabrica tion ................................................. ........................ ................................................... ................................................. ................................................ ......................... 2- 1

B.

Surveys Survey s of Units in Service .................................................... .......................... .................................................. .............................................. ............................................... ......................... 2- 1

C.

Condition Surveys Survey s ................................................ ...................... ................................................... ................................................... ............................................... ....................................... .................. 2- 5

D.

Other Surveys ................................................... ......................... ..................................................... ..................................................... ................................................. ......................................... .................. 2- 6

Section 3

Loads and Load Conditions, Site Environment

A.

Site and Environment Enviro nment Conditions Conditio ns - General Genera l................................................. ....................... ..................................................... ................................................ ..................... 3- 1

B.

Loads to be Considered Consider ed ................................................ ....................... ................................................. .................................................. ................................................ ............................... ......... 3- 1

C.

Load Conditions, Conditio ns, Load Cases ........................................ ................... ................................................. ....................................................... .................................................. ......................... .. 3- 5

D.

Determination Determin ation of Loads .............................................. ...................... ................................................. ................................................ ................................................. ................................... ......... 3- 6

Section 4

Structure

A.

General Design Considerations Conside rations ................................................. ........................ ................................................. .............................................. ............................................ ...................... 4- 1

B.

Allowable Stresses Stress es ............................................... ....................... .................................................. .................................................... ................................................... ...................................... ............. 4- 1

C.

Structural Design of Specific Installations/Components............... ....................... ................ ................ ................ ............... ................ ................. .............. ...... 4- 3

Section 5

Materials and Fabrication, Corrosion Protection

A.

Materials ............................................... ..................... .................................................... .................................................... ................................................. ................................................. ............................... ..... 5- 1

B.

Fabrication Fabrica tion ............................................... ..................... .................................................... .................................................... ................................................... ................................................... .......................... 5- 5

C.

Corrosion Corros ion Protection Protec tion ............................................... ...................... .................................................. ................................................. ................................................. ...................................... ............. 5- 6

Section 6

Subdivision, Stability, Freeboard

A.

General Requirements......... Require ments................................. .................................................. ................................................... ................................................... ................................................ ...................... 6- 1

B.

Documents for Approval Approv al .................................................. ........................ .................................................... .................................................... ................................................... ......................... 6- 1

C.

Watertight Watertig ht Integrity; Integr ity; Freeboard Freeb oard ................................................. ........................ ................................................. .............................................. ............................................ ...................... 6- 1

D.

Intact Stability ................................................ ........................ ................................................. ................................................. ................................................. ............................................... ...................... 6- 1

E.

Subdivision; Subdivis ion; Damage Stability Stabilit y ............................................ ................... ................................................... .................................................... ................................................ ...................... 6- 2

Section 7

Anchoring/Positioning Systems

A.

General Definitions Definit ions and Requirements Require ments ............................................... ...................... ................................................. ................................................. .................................. ......... 7- 1

B.

Materials; Materials ; Fabrication Fabric ation ................................................. ....................... ................................................... ................................................... ................................................. ................................ ......... 7- 2

iv

Table of Contents

C.

Catenary Mooring Systems - Design Considerations and Requirements................ ........................ ................. .................. ................. .......... 7- 2

D.

Single Point Mooring Systems (SPM) ............................................... ................... ...................................................... .................................................... ................................. ....... 7- 5

E.

Dynamic Positioning Position ing (DP) ................................................. ........................ ................................................. ................................................. ................................................ .......................... ... 7- 5

F.

Turret - Active Heading Control ............................................... .................... ..................................................... .................................................... .......................................... ................ 7- 9

Section 8

Lifting Appliances

Section 9

Helicopter Landing Facilities

Section 10

Life Saving Appliances and Equipment/Means of Escape

A.

Means of Escape/Refuge Escape/ Refuge .............................................. ..................... ................................................... ................................................... ................................................ ............................ ..... 10- 1

B.

Life-saving Life-s aving Appliances Applianc es and Equipment Equipmen t............................................. ................. ...................................................... .................................................... ............................... ..... 10- 1

Section 11

Fire Safety

A.

Area Classification Classif ication/Ventilati /Ventilation on ................................................... ........................ ................................................... .............................................. ........................................ .................. 11- 1

B.

Structural Struct ural Fire Protection Protect ion ..................................................... ........................... ...................................................... ...................................................... ............................................ .................. 11- 4

C.

Control Stations, Stations , Fire and Gas Detection Detectio n Systems ..................................................... ......................... ...................................................... ............................... ..... 11- 9

D.

Storage of Gas Bottles ................................................. ........................ ................................................... .................................................. .................................................. .............................. .... 11-10

E.

Fire-Fighting Fire-F ighting Installations Insta llations ............................................ ................... ................................................ ................................................ ................................................ ............................... ........ 11-10

Section 12

Communications Systems

Section 13

Machinery

A.

General Indications; Indicat ions; Scope .............................................. ..................... ................................................... .................................................. ................................................ .......................... .. 13- 1

B.

Internal Intern al Combustion Combust ion Engines; Engine s; Air Compressors Compre ssors.......................... .................................................... ...................................................... .................................... ........ 13- 1

C.

Boilers, Pressure Vessels, Thermal Fluid Systems, Heat Exchangers ............... ....................... ................ ................ ................ .............. ...... 13- 2

D.

Propulsion Propuls ion and Steering Steerin g Systems ........................................ ................ .................................................... ...................................................... ............................................ .................. 13- 2

E.

Pumps, Piping Systems ................................................... .......................... .................................................. .................................................. ................................................... ............................ 13- 2

F.

Inert Gas System ............................................... ....................... .................................................. ................................................... ....................................................... ........................................ .......... 13- 2

G.

Winches, Windlasses, Hoists..................... Hoists.............................................. ................................................. ............................................... ............................................... .......................... .. 13- 3

Section 14

Production/Process Facilities

A.

General Indications Indicat ions ................................................ ...................... .................................................. .................................................. .................................................... .................................... .......... 14- 1

B.

Flare and Cold Vent Systems ................................................... .......................... ................................................. ................................................. ........................................... .................. 14- 2

C.

Production Producti on Sub-systems Sub-sy stems and Components Componen ts ............................................ ..................... .............................................. ........................................... .............................. .......... 14- 2

Section 15

Electrical Installations

A.

General Indications; Indicat ions; Scope .............................................. ..................... ................................................... .................................................. ................................................ .......................... .. 15- 1

B.

Power Supply ................................................ ........................ .................................................. .................................................... ................................................... ........................................... .................. 15- 1

C.

Electrical Electri cal Installations Insta llations/Equipmen /Equipmentt in Hazardous Hazard ous Areas ..................................................... ........................... ................................................. ....................... 15- 1

D.

Dynamic Positioning Positio ning System .............................................. ...................... .................................................... ...................................................... ............................................ .................. 15- 1

Table of Contents

Section 16

Control and Instrumentation

Section 17

Riser System

v

A.

General Indications Indicat ions ................................................... ........................ ................................................... .................................................. .................................................... ................................. ....... 17- 1

B.

Basic Safety Requirements Require ments ............................................... ..................... ................................................... ................................................... .............................................. ........................ .... 17- 1

C.

Control System .................................................... .......................... .................................................... .................................................... .................................................. ..................................... ............. 17- 2

D.

Venting ................................................... ......................... .................................................... .................................................... .................................................... .................................................. ........................ 17- 2

E.

Flexible Risers .................................................. ...................... ...................................................... ..................................................... .............................................. ....................................... .................... 17- 2

F.

Swivels, Connectors Connect ors ...................................................... ............................ .................................................... .................................................. ........................ ............................. ......................... .... 17- 3

G.

Disconnectable Disconn ectable Riser System .................................................. ........................ .................................................... ................................................ .......................................... .................... 17- 3

Section 18

Storage and Offloading Facilities

A.

General Indications Indicat ions ................................................... ........................ ................................................... .................................................. .................................................... ................................. ....... 18- 1

B.

Storage Tanks and Related Spaces ............................................... ....................... ................................................. .............................................. ..................................... ................ 18- 1

C.

Storage Operation Operat ion Facilities Facilit ies ................................................ ....................... .................................................. ................................................ ............................................... ........................ 18- 2

D.

Offloading Offloadin g Facilities ............................................ ..................... ................................................ ................................................ ........................................... ........................................ .................... 18- 2

E.

Mooring of Attending Vessels ............................................. ...................... ................................................ ................................................ .............................................. ....................... 18- 4

F.

Pollution Prevention Preven tion................................................ ....................... ................................................ .............................................. ................................................... ....................................... ........... 18- 4

G.

Storage Storag e and Transport Transp ort of Chemicals Chemical s ................................................ ..................... ..................................................... .................................................... ................................. ....... 18- 4

Appendix A

Formal Safety Assessment

Appendix B

Regulations, Standards and Codes cited

Section 1 – General Requirements and Definitions

A, B

1-1

Section 1 General Requirements and Definitions

A.

existing mooring installation may be certified separately (see sub-Section C.).

Application

These Guidelines are applicable to 1. floating installations intended for production, and possibly also for storage and offloading of hydrocarbons, and for which survey and/or certification by BKI has been requested. The main types of offshore 2. installations under consideration are

units

or

The Guidelines may be applied, in principle, 6. also to existing units, including units not built under surveillance of BKI, e.g. in cases of conversion, condition surveys and (re-) certification.

7. Amendments to these Guidelines shall be applied to existing units, wherever this is considered necessary with a view to their safe operation.

−

ship-type, self-propelled units, anchored or connected to the seabed by an articulated mooring system.

−

ship-type units provided with a dynamical positioning system.

−

barge-type units, anchored or connected to the seabed as described above.

−

semi-submersible-type (column stabilized) units, anchored or provided with a dynamical positioning system.

−

buoy-type units, anchored or connected to the seabed as described above.

−

inspection of materials to be employed.

–

survey of components fabrication.

–

surveillance of installation, tests/trials commissioning on site.

−

regular/periodical operation.

−

certification of any such activity.

−

Other types of installations will be considered on a case to case basis. (Fixed, rigid structures will be subject to Rules for Classification and Construction of Offshore Installations, see C.1. below or equivalent acceptable rules or regulations). The Guidelines refer to installations used for 3. the production of hydrocarbons (crude oil, gas), but may be applied in principle to similar installations serving other purposes, including further processing of hydrocarbons. For substances being stored and conveyed at low temperatures (< 0 °C), special considerations will be necessary.

Facilities connected to and operated together 4. with the production unit are dealt with in so far as necessary regarding testing and other aspects of safe operation of the installation. Certification of such facilities, however, is usually independent of the production unit (see sub-Section E.).

B.

The surveys necessary for certification and 1. continuous re-surveys of an offshore production installation will normally comprise the following activities review of design and calculations/analysis, based on Rules and Guidelines (see C.1.) and/or other existing regulations as agreed upon.

surveys

during

and

service/

(For surveys, see also Section 2). Note:

For the activity of checking the design documentation (drawings, calculations, etc.), in comparison with applicable rules/regulations and standards or codes, and possibly carrying out independent (re-) calculations of certain parts of the installation, often the term "Verification" is used. It will not be used in the following, as it is deemed to be covered by the general terms "Certification" and "Classification"

2.

The mooring/positioning system will usually 5. be included in the certification, as part of the overall installation. However, in particular cases an already

Scope/Extent of BKI Surveys

Safety assessment

BKI will also review, within the certification procedure, safety assessments based on probabilistic methods.

1-2

Section 1 – General Requirements and Definition

Such assessments may be related to the whole production installation or to parts or systems of the unit, and may be prepared for/refer to different stages, e.g.

− –

−

design phase(s), initial service/testing phase (changes, improvements),

major conversions and changes of the operation conditions (including additional structures/ installations in the vicinity of the unit).

C

−

Rules for Non-metallic Material

−

Rules for the Classification and Construction of Offshore Installations (Volume 2, 3, 4 & 5)

−

Rules for Mooring and Loading Installations

−

Rules for Pipelines and Risers

(Details covered by the above Rules will generally not be repeated in these Guidelines. Relevant cross references are made where considered useful).

See Appendix A.

2.

BKI reserve the right to approve designs 3. deviating from these Guidelines and the related Rules, if deemed to be equivalent and suited for the intended service, or alternatively, to impose more stringent requirements should these be deemed to be justified.

Applicable Regulations and associated 2.1 Guidelines issued by National Authorities/ Administrations shall be observed where necessary. If more stringent, statutory regulations take priority over the provisions of these Guidelines. A relevant statement will have to be made either in the Certificate or in other accompanying documentation.

BKI will consider recognizing surveys and/or 4. certificates of other competent and acknowledged institutions in individual cases.

It is assumed that all parties involved in the 5. planning and design, material and components production and installation have the professional qualifications required and suitable facilities/ equipment for fabrication. This will normally be established for critical/safety relevant activities by BKI Audits and certified accordingly. See also Section 5.

BKI's surveys focus on safety and reliability of 6. components and procedures, but do not aim to ensure the efficiency/economical viability of the intended operations, unless BKI's contract is specifically extended to include such additional obligations and statements.

C.

1.

Other Applicable Guidelines

Regulations

and

Statutory requirements

Some of the provisions in these Guidelines 2.2 are based on (and refer to) internationally agreed/adopted IMO Conventions, Resolutions and Codes, the application of which to FPSO units may, however, not always be fully clarified. In such cases agreement may have to be reached with the competent National Administration. Application of statutory requirements will 2.3 generally be compulsory in areas such as

−

unit identification/marking

–

navigational aids, lighting

–

life-saving appliances

–

helicopter operations

–

means of external communication

–

crew number and qualification (manning)

–

pollution prevention/control.

Some of these topics are treated in various sections of these Guidelines, particularly Sections 8 to 12.

BKI Rules

Regarding the design and fabrication of components, such as

−

(steel) structure

–

mooring and anchoring elements

–

piping and machinery items,

relevant (more detailed) BKI Rules may be applied as appropriate, e.g.:

−

Rules for Hull, Volume II (Section 1-3)

–

Rules for Materials, Volume V

–

Rules for Welding, Volume VI

3.

Regulations/codes of practice/guidelines and guidance notes, issued by industrial organizations

Commonly used and internationally acknowledged regulations, codes of practice/guidelines, guidance notes, etc., published by industry institutions and or ganisations such as those listed below, will be accepted for the design review and approval where considered applicable and fitting into the agreed safety concept

−

API (American Petroleum Institute)


D, E

1-3

–

ASME (American Society of Mechanical Engineers)

E.

−

AWS (American Welding Society)

–

IEC (International Electrotechnical Commission)

–

ISO (International Standardization Organization)

–

OCIMF (Oil Companies International Marine Forum).

1. Compliance of an offshore production/ storage unit with these Guidelines and the provisions of the appropriate Rules, or with any other standards and regulations used for the design will be certi fied. The type of unit, location, other installations connected, types of hydrocarbon(s) to be handled and other important conditions of use will also be stated in the certificate.

See also Appendix B.

D.

Documentation

Design and construction particulars are to be 1. submitted (in triplicate) to BKI for approval well ahead of the commencement of manufacture. The documents are generally to include at least the following items

−

general description of the unit installation and its operation conditions; details on the location and environment, including soil properties.

−

drawings, calculations and material specifications as well as welding and NDT procedures and plans, referring to all essential structural, machinery and electrical items, including the anchoring, mooring and hydrocarbons transfer systems and safety-related equipment/measures.

Certification/Classification

During the manufacturing process, individual 2. components will be marked and certified as far as necessary to ensure reliable identification and adequate quality of materials and components employed. This may be achieved by the manufacturer's quality assurance procedures, to be acknowledged and controlled by BKI Audits. However, for critical items, e.g. pressure vessels, BKI reserves the right to carry out surveys and witness tests, supplementing the manufacturer's own quality assurance measures. All activities will be certified accordingly. During fabrication/construction important 3. procedures will be reviewed and new, critical procedures, e.g. welding of high pressure hydrocarbon ser vice pipes, certified.

−

description of transport, offshore assembly and installation procedure(s).

−

safety/risk assessments and analysis.

−

operations manual/instructions 1.

Phases of fabrication/construction will be certified where required, confirming satisfactory performance and results and stating extraordinary events where relevant. (This applies particularly to cases where fabrication is carried out at different places and/or by different manufacturers/contractors).

−

survey and maintenance planning in relation to the intended service life 1.

4.

1

for information and reference purposes

One copy of each approved (stamped) 2. document is returned to the sender. BKI will keep one ap proved copy of all submitted documents in their files at Head Office; another copy will be handed to the Inspection Office in charge.

All documents submitted to and kept by BKI 3. will be treated confidentially.

Manufacturing documentation/quality control 4. records, including the recording of any special occur rences are to be kept and also made available to the attending BKI Surveyor(s) at the manufacturing site(s). The same applies to documents related to maintenance and monitoring procedures, in connection with the surveys carried out by BKI after commissioning, where a classification procedure has been agreed (see E. below).

Certificates with defined period of validity: Classification

Where classification has been agreed, i.e. a 4.1 procedure including periodical surveys by BKI of the installation while in service, in addition to the design review and fabrication surveys, the certificate will be assigned a defined period of validity (normally, five (5) years). The certificate will cease to be valid, if that period expires without the survey(s) due (see Section 2, B.) having been carried out.

The validity of the certificate depends on 4.2 owners or operators having met the following obligations

−

to notify BKI of any damages or incidents having occurred which could impair the safe operation of the system;

−

to inform BKI about any significant modifications and repairs, and to submit the necessary documentation, prior to them being carried out.

1-4


4.3

Character of Class, Notations

4.3.1

Hull

The unit will be assigned the "Character of Class" A100 with additional "Notations" referring to the particular type and use, type of mooring/positioning etc. (see also Section 7). The type of unit may be described, e.g., by FPS

(Floating Production and Storage Unit)

FPSO

(Floating Production, Storage and Offloading Unit)

The notation Oil Tanker may also be included, where the corresponding characteristics are fulfilled. 4.3.2

Machinery

4.3.2.1 The machinery of the unit used for conventional shipboard operations such as propulsion and auxiliary services, including energy supply, will be assigned the Character of Class SM, if complying with the BKI Rules and Regulations, with the corresponding Notations (e.g., for Automation). See Rules for Classification and Surveys, Volume I, Section 2, C.

3.

Loading/Unloading Terminal:

A floating or fixed structure serving as mooring point for the production unit and/or as regular berthing facility for vessels used for the export of the hydrocarbons (see above). 4.

Location:

The offshore site selected for permanent or temporary operation of the production unit. Geographical, geological and oceanographic characteristics of the location must be clearly defined (see Section 3). 5.

Permanent/Temporary Installation:

Permanently installed, in the context of these Guidelines, means intended for at least 5 years of operation at the determined site. In such case, a "design life" shall be defined, which is to be taken into account, e.g. for fatigue calculations of components. Temporarily installed means intended for less than 5 years of operation. For components dimensioned on the basis of statistical values - see Section 3 - a correspondingly shorter design life may be envisaged. This will be noted in the certificate. 6.

4.3.2.2 The machinery installed for process/ production operations, if included in the classification procedure, will be assigned the Character of Class P SM, with possible additional Notations.

F

Anchoring/Positioning System:

The means provided to keep the production unit on the predetermined position under all possible or defined environmental conditions. In the case of single-point mooring (see below), the anchoring system may consist, e.g., of an array of chains/wires and anchors.

F.

Definitions

1.

Authority, Administration:

Specially designed foundations may form part of the anchoring system in certain cases, depending on the sea floor characteristics and loads to be transmitted.

Official (state) body responsible for granting installation and operation permits in the case under consideration.

Single-point Mooring: A mooring system allowing the production unit to weather-vane during all operations and under all environment conditions.

(Two Administrations may be involved where a unit is operated under the flag of a state different from the state responsible for the production location.)

This may be accomplished by connecting the unit to a floating or fixed mooring installation, or by provid ing a turret, i.e. a turn-table-like structure arranged inside the hull of the production unit.

2.1

Dynamic Positioning: A propulsion system used exclusively, or in addition to the anchoring system, to keep the production unit on position.

FPS:

Floating Production and Storage Unit (The reserve buoyancy of a ship or barge type vessel is usually utilised for intermediate storage of produced hydrocarbons, depending on the overall configuration and site conditions). 2.2

FPSO:

Floating Production, Storage and Offloading Unit (Where further transport of the hydrocarbons is carried out by shuttle tankers, a special offloading system or installation will be provided).

7.

Hydrocarbons Transfer/Conveying Systems

Risers: Vertically arranged piping connecting sea bottom pipelines and/or manifolds (PLEM) with the production unit.

Risers may in principle be used for import and for export of the produced media.


Offloading Installation: A system of pipes and flexible hoses, including safety/controlling and metering equipment, used for transfer of hydrocarbons to shuttle tankers.

8.

F

1-5

Area Classification:

The systematic sub-division of a unit exposed to explosion risks, into areas of different hazard levels. (Detail definitions: See Section 11).

Section 2 – Surveys for Certification

A, B

2-1

Section 2 Surveys for Certification

A.

Surveys During Fabrication

For Floating Production, Storage and Off1. loading Units to be certified by BKI, the following surveys will generally be required during the new building or conversion process. Surveyors are to be given access to manufacturing facilities at any time. Essential materials required to conform to 2. the Rules for Materials, Volume V - see Section 5 shall be produced under BKI surveillance as described in the appropriate rules mentioned. Construction of structural parts and 3. fabrication of components shall be carried out according to approved quality assurance procedures, with random detailed inspection and final acceptance by BKI. Where such parts are produced by subcontractors, corresponding certificates will be issued by the BKI Inspection Office(s) in charge.

Regarding particular requirements for the supervision of welding work, see Section 5, B. and Rules quoted there. Surveillance by BKI includes also witnessing 4. of tests and trials, either at the manufacturers works or on board of the production/storage/offloading unit, in order to ascertain proper functioning of the installation. See the following sections regarding specific systems.

B. 1.

Surveys of Units in Service

supervision and survey will be applied and combined, as appropriate

−

continuous control and maintenance by the operator

−

annual surveys by BKI

–

intermediate surveys by BKI

–

special surveys by BKI at 5 years intervals.

An inspection schedule may be agreed upon, which provides for a "Continuous Survey" incorporating the items usually covered by Annual and Special Surveys, and taking advantage of the continuous control by the operator. 1.3 Continuous control (operator): The controlling, monitoring and maintenance service provided by the operator will be accepted as an integral part of the overall inspection schedule, if the operator adheres to the agreed procedure, and provided that all controls, measurements, replacements, repairs, etc. carried out are well documented and capable of being verified by the Surveyor coming on board for a periodical survey. 2.

Annual surveys

2.1

General

Depending on the type of unit and subject to possible additional requirements of the appropriate National Authority/Administration, annual surveys will be carried out, comprising, essentially, a visual inspection, but supported where appropriate by operation testing/checking of

−

the accessible structure (integrity, water tightness; corrosion; bulkhead penetrations, particularly in pump rooms);

−

positioning system, as far as accessible (chains, cables, fairleads etc.);

−

turret installations: control of bearings, swivels, riser supports (see also 4.2.2.3);

−

hydrocarbons transfer system (where possible, witnessing of relevant operations; control of hose markings; testing of hoses and pipes may be required where deemed necessary, and where tests are due according to a fixed schedule);

−

all watertight closures (hatches, watertight doors, ventilator heads etc.);

General indications

1.1 Periodical surveys during the service life of the unit - i.e., surveys at regular intervals - are required where renewal of certificates (Classification) has been agreed (see Section 1, E.4.). These surveys are intended to ensure that the installation continues to comply with the requirements of the Rules and other Rules and Regulations which have been used as a design base.

A detailed inspection schedule will be set up 1.2 in each individual case, depending on the type of installation and the maintenance program provided by the operator. In principle, the following kinds of

2-2

–

2.2


safety equipment, e.g. tank pressure/vacuum relieve valves, flame arrestors, gas detectors etc., control of maintenance documentation.

2.3

B

Fire extinguishing and fire alarm systems

The fire extinguishing equipment will be subjected to the following inspections and tests

Machinery and electrical equipment

−

The machinery, including the electrical equipment, will be subjected to the following surveys and operational checks

checking of the remote shut-down devices for ventilators and other electrical machines, and of the remote control devices for the fuel tanks,

−

checking of all closing arrangements,

–

checking of the fire warning and alarm systems, as well as of the fire extinguishing facilities, such as fire pumps and corresponding piping/hoses, including verification of the last servicing by recognized specialists where provided,

−

checking of the foam fire extinguishing and/or water spraying systems(s),

−

checking of the firemen’s outfit for satisfactory

−

general inspection of the machinery and boiler rooms, including the propulsion system de pending on the type of unit and positioning, the auxiliary engines, fire and explosion sources, and checking of emergency exits as to their free passage,

−

external inspection of boilers, pressure vessels with their appliances and safety devices,

−

positioning system(s): Inspection of winches etc. (Dynamic positioning system: see below),

−

inspection of the remote control, quickclosing/stopping devices and checking of pumps, valves, ventilators, etc.,

−

inspection of tank venting systems, including safety equipment,

−

inspection and checking of the main and auxiliary steering gear, including their appliances and control systems, where relevant,

−

checking of all communication systems between bridge and control, machinery, boiler and steering gear rooms,

−

inspection of the bilge system, including remote control mechanisms and bilge filling level monitor, piping

systems

including

condition and completeness. 2.4

Corrosion protection

The general condition and functioning of 2.4.1 corrosion protection systems will be checked during annual surveys. Where the system provides the possibility of measuring and recording, the corresponding documentation will be revised and/or cross checks made. 2.4.2 For coated tanks, an inspection schedule shall be set up, allowing all such spaces to be sur veyed at least once during a 5 years period. The inspection method (means of access) shall be such that any damages/deterioration of the coating will be detected. Extended surveys and thickness measurements may be required, if the ESP (Enhanced Surveys Procedure) is to be applied (see 4.2.2.2).

−

checking of all pressure gauges,

−

checking of bilge, ballast and stripping pumps for leakages, as far as practicable,

−

checking of equipment related to pollution control/prevention (MARPOL regulations),

−

survey of ventilation and pressurizing systems,

Special equipment such as life saving equipment, cranes etc. will be surveyed according to instructions issued by BKI or by the competent Administration in the individual case.

–

survey of inert gas systems, where applicable,

2.6

–

checking of the main and emergency power supply systems, including the switch-gear and other electrical installations,

−

electrical equipment: Inspection of cabling and cable connections, as well as protective, safety and interlocking devices,

−

checking of the ESD system (s), possibly using simulation routines,

−

production installations: General inspection and review of documentation on regular controls, maintenances and abnormal occurrences.

2.5

Special equipment

Riser system

The risers, as far as accessible, and 2.6.1 particularly the connecting elements on board of the unit, shall be inspected for corrosion and damages, regardless of certification (see Section 17, A.1.). 2.6.2 The control and shut-off systems for the risers shall be checked, e.g. by operation tests, where possible.

Data transfer lines (umbilicals) running parallel or attached to the risers should be included in the inspection in view of possible interaction with the risers. The inspection and maintenance routine of the operator may be accounted for.


For flexible pipes, special inspection 2.6.3 routines shall be followed, as laid down by the manufacturer and the operator and agreed with BKI. 2.7

Intermediate surveys

Depending on the type of unit, and 3.1 particularly for ship type units for which the conventional classification procedure has been adopted, so called "Intermediate Surveys" may have to be carried out. An intermediate survey is an extended annual survey, to be carried out at the date due for the 2. or 3. annual survey within a class period.

Regarding the scope of Intermediate Surveys 3.2 related to conventional ship-type structures and machinery/equipment, reference is made to the Rules for Classification and Surveys, Volume I, Section 3, C.1.2 and Section 4, A.3. Summarizing, the extended surveys refer to

−

ballast tanks (corrosion protection, close-up surveys and thickness measurements, depend ing on the unit's age);

−

crude oil tanks (as above, and tank cleaning and venting installations);

−

machinery and electrical installations: Automation equipment, shafting/lubrication systems, electrical machinery (insulation, earthing/ bonding etc.);

−

2-3

not exceeding 5 years. Upon completion of the sur vey, the (class) certificate of the unit will be issued and will be valid for another 5 years term (class period). See also Section 1, E.4.

Dynamic positioning system

The dynamic positioning system, where provided, shall be checked for operational availability/ functioning of the essential sub-systems, such as position reference, control system, power supply and thruster response. The operator's inspection and testing program may be taken into account, and log book notation regarding disturbances and general performance should be reviewed. 3.

B

inert gas installations, where provided;

Function tests may be demanded. The maintenance and testing schedule of the operator will generally be accounted for when deciding about particular survey and testing requirements.

For production/process machinery and 3.3 installations, including conveying installations (piping systems) and riser system, extended Intermediate Surveys may be defined from case to case, depending on the overall survey plan of the operator. 4.

Special (“Class Renewal“) surveys

4.1

Period definition

Special surveys, also called "Class Renewal 4.1.1 Surveys", are to be carried out at nominal intervals

4.1.2 The Special Survey may be carried out in several parts. The whole survey duration, however, must not exceed 12 months, and the survey must have been completed by the end of the validity period of the certificate (class period). 4.2

Structure (Hull)

4.2.1

General indications

A comprehensive survey of the underwater and above water structure will be carried out at 5 years intervals covering the following aspects

−

overall condition and integrity

–

plate thickness measurements and nondestructive testing according to an approved inspection plan and/or on-the-sport decision where excessive corrosion or damages are found or suspected

−

effectiveness of the corrosion protection system (potential measurements, condition of anodes etc.; see Section 5, C.)

−

marine growth

–

condition (corrosion, wear etc.) of the anchoring system.

Account may be taken of data recorded by instruments installed to monitor structural behavior. Special attention shall be given to areas of stress concentration and of suspected or proven damage, and to areas where repairs have been carried out previously. Diver assistance may be necessary, see 4.2.2 below.

Cleaning and/or uncovering of areas selected for close-up inspection and non-destructive testing may be required. 4.2.2

Ship and barge type units

4.2.2.1 A thorough survey of the ship’s bottom and of attachments such as rudder and thruster installations is in principle to be carried out in dry dock at intervals of 5 years.

Upon special agreement, and subject to the corresponding BKI Rules, every second dry-docking may be substituted by an “In-Water-Survey“, combined with an internal bottom and hull survey including thickness measurements according to a pre-planned schedule (see below). Tanks are to be cleaned and gas-freed for this purpose. See also 2.4.2 above. Regarding the conditions and particular requirements for In-Water Surveys, see the Rules for Classification

2-4


and Surveys, Volume I, Section 3, C.1.7.

4.2.2.2 For tanker-type production units with the Class Notation ESP (Enhanced Survey Procedure), the corresponding survey requirements shall be observed - see the Rules for Classification and Surveys, Volume I, Section 2, C.3.1.7 and Section 4, A. This procedure calls for a pre-planned close-up inspection of tank structures, thickness measurements, tank testing and extended documentation. 4.2.2.3 In case of single-point turret mooring, a comprehensive inspection of the turret structure shall be carried out, including attachments, supports etc. for risers and anchor lines (to be included in the diver inspection in the case mentioned under 4.2.2.1 above, if submerged).

Turret bearings may be required to be opened-up and inspected internally, if this has not been done and properly documented within the operator’s own inspection and maintenance schedule. 4.2.3

Mobile offshore units

In addition to the general requirements see 4.2.1 attention is to be given to internal and secondary structural parts such as bulkheads, tanks, cofferdams, chain lockers, anchor racks and fairleads, helicopter deck and substructures of heavy equipment with respect to fatigue or corrosion damages, or excessive wastage. Selective tank testing may be required, depending on type and condition of the tank. The survey has to be carried out in a sheltered area, preferably in dry-dock, the same exemption being possible as stated under 4.2.2.1. Sea inlets, strainers and underwater propulsion units are to be cleaned and examined.

On column stabilized units, the columns and braces with decks footings shall be examined, where from the interior. Non-destructive required at suspect areas. 4.3

Machinery, equipment

4.3.1

General

connections of and pontoons/ accessible also testing may be

4.3.1.1 An extended examination of machinery spaces and installations as per 2.2 / 2.3 on occasion of the special survey will generally include, as far as applicable

−

close inspection of machinery foundations,

–

opening/internal inspection of boilers, pressure vessels and heat exchangers/thermal oil plants according to approved inspection plans,

−

pressure and operability testing of pipe systems according to an approved inspection plan.

For electrical equipment, see 4.3.2 b elow.

B

4.3.1.2 The detailed special survey procedures may be chosen according to the Rules mentioned under 4.2.2.2, Section 3, C.1.3 - 1.5. 4.3.1.3 Regarding special equipment, see 2.5. Applicable regulations of the appropriate National Authority/Administration are also to be complied with. This could limit the time intervals between retesting, e.g. of pressure relief valves, cranes and lifting devices. 4.3.2

Electrical installations

4.3.2.1 The electrical equipment including the generators, the motors of the essential auxiliary machinery, all switch gear including their protective and interlocking devices, as well as the cable network are to be examined and tested. 4.3.2.2 Where electrical installations, particularly explosion protected machines and apparatus, are situated in spaces in which there is danger of inflammable gas or steam air mixtures, they are to be inspected (see 4.3.3). 4.3.2.3 Fittings and connections on main switch boards, and distribution panels are to be examined, and care is to be taken to see that no circuits are over fused. 4.3.2.4 Cables are to be examined as far as practicable without undue disturbance of fixtures. 4.3.2.5 In addition to the general indications given above, the following details are to be observed

−

all generators are to be run under load, either separately or in parallel; switches and circuit breakers are to be tested.

−

all equipment and circuits are to be inspected for possible development of physical changes or deterioration. The insulation resistance of the circuits is to be measured between conductors and between conductors and ground, and these values are to be compared with those previously measured.

−

electrical auxiliaries installed for vital purposes, generators and motors are to be examined and their prime movers opened for inspection. The insulation resistance of each generator and motor is to be measured.

−

the emergency remote switch-off devices of ventilators, fuel pumps, oil fired installations and similar equipment are to be tested.

4.3.3

Hazardous Areas

Enclosed Hazardous Areas are to be examined and doors and closures in boundary bulkheads verified as effective. Electric lighting, electrical fixtures and instrumentation are to be examined, proven satisfactory for the area classification zone and/or


verified as explosion-proof or intrinsically safe. Ventilating systems including ductwork, fans, intake and exhaust locations for enclosed restricted areas are to be examined, tested and proven satisfactory. The ventilating air alarm systems are to be proven satisfactory.

C

2-5

unit is maintained under all anticipated "single failure" conditions. 4.3.6

Turret turning installation

For electric motors the correct area classification certificates are to be verified.

Where a turret turning installation is provided (see Section 7, F.), the drives shall be closely inspected and opened up if considered necessary, and the relevant power supply and control system checked by function tests.

4.3.4

4.3.7

Riser system

4.3.4.1 If the riser system is included in the classification procedure, the underwater part shall be inspected together with and to a comparable extent as the unit's hull and the mooring system. Special attention is to be given to corrosion and damages (e.g., buckling), and to connecting elements between riser sections and with attached or incorporated components such as buoyancy aids, umbilicals, etc. Note:

As this survey will usually require diver (or ROV) assistance, a detailed inspection schedule has to be set up including statements/procedures regarding diver qualification, communication means, documentation, etc.

4.3.4.2 Inspections carried out by the operator dur ing the class period, including retrieval and overhaul of risers, may be accounted for. Where possible, the BKI surveyor should be called at such occasions, possibly combining this inspection with an annual survey according to 2.6. 4.3.5

4.3.7.1 All fixed and mobile components of the hydrocarbons transfer system shall be examined and tested in accordance with procedures laid down in the detailed maintenance and inspection part of the Operating Manual. Hoses are to be carefully inspected for possible deterioration as well as pressure and vacuum tested. The survey is also to ensure that the pollution prevention requirements are met. 4.3.7.2 Inspections and overhauls carried out recently, e.g. on the occasion of a conversion or major repair, may be credited to the special survey, if acceptable documentation is available and the relevant system or component is obviously in satisfactory, operable condition. 4.3.8

Mobile offshore units

On column stabilized units, bilge and ballast systems shall be thoroughly examined, including opening up of sample valves, cocks etc., and carrying out of essential function tests according to special instructions also incorporated in the Operating Manual.

Dynamic positioning system

On occasion of the special survey, the following checks and tests shall be carried out

−

for class notation DP2 and DP3, verification of redundancy and independence requirements;

−

function tests of alarm system(s) and position reference system(s) (sensors, peripheral equipment);

−

function tests of control alarm systems of all thrusters;

−

tests/surveys of the electrical installations (e.g., power supply) as for other types of consumers (see 4.3.2);

−

Hydrocarbons transfer system

tests of the remote thrust controls.

Details of the testing program will be determined in the individual case, depending on the system configuration. The tests shall cover all operational modes, back-up and manual override systems and shall, in summary, ascertain that the position keeping capability of the

C.

Condition Surveys

Floating production/storage and unloading 1. units for which a certificate is required, and which have not been constructed under surveillance by and in accordance with the Rules and Guidelines of BKI, shall be surveyed as follows. (See also Section 1, A.6.).

Design and fabrication documentation: A 2. complete set of documentation shall be submitted for review by BKI Head Office, covering all important systems described in the previous sections, as far as applicable. Where the available drawings, calculations or certificates are not sufficient for proper appraisal, BKI will carry out, or require to have carried out, relevant investigations (including verification of material properties, where appropriate). A comprehensive survey of the unit, 3. including the anchoring system and comprising drydocking where possible, will be carried out in order to

2-6


–

verify the conformity of all components with the documents submitted, and

−

ascertain the actual condition of all components essential for safe operation

Underwater inspection by divers will usually be required where dry-docking is not possible.

Where structural strength, particularly fatigue investigations have been carried through in connection with the condition survey, the structural details identified as critical shall be carefully checked. Generally, thickness measurements will have to be carried out.

The unit and connected systems will be 4. particularly investigated for corrosion damage and the corrosion protection system checked for proper functioning. Thickness measurements of important structural elements may have to be carried out. Proper functioning and condition of anchor5. ing, mooring, hydrocarbons handling, fire-fighting and other equipment essential for operational safety and reliability may have to be verified by tests, the scope and extent of which will be determined from case to case. Before issuing a certificate for the floating 6. production/storage/offloading unit, BKI will carry out a final survey to ensure that the repairs, which may have been found to be necessary, as well as modifications carried out since the initial (new building) sur veys, have been performed satisfactorily.

3.

D

Damage and repair surveys

3.1 Where damage has occurred to the unit’s hull, machinery, including the electrical plant, the automatic/remote-control systems, etc., the damaged parts are to be made accessible for inspection in such a way that the kind and extent of the damage can be thoroughly examined and ascertained.

The repair measures are to be agreed with 3.2 the Surveyor such as to render possible confirmation of the class, without reservations, upon completion of the repairs. In general, a confirmation of class with recommendations, e.g. in the case of a preliminary repair ("emergency repair"), requires to be approved by BKI Head Office. Surveys conducted in the course of repairs 3.3 are to be based on the latest technical knowledge and instructions by BKI. In particular cases advice is to be obtained from BKI Head Office, especially where doubts exist as to the cause of damage, or the suitability of the repair method. For older units, in the case of repairs and/or 3.4 replacement of parts subject to classification, as a matter of principle, the Construction Rules in force during the period of construction continue to be ap plicable.

However, this does not apply in the case of modifications required to the st ructure or machinery parts in the light of new knowledge gained from recent ex perience and damage analysis, with a view to avoiding recurrence of similar damages. Regarding the materials employed and 3.5 cer tificates required, the requirements for new buildings are applicable (see A.).

D.

Other Surveys 4.

BKI may be called in for survey of a floating 1. production/storage and offloading unit not subject to regular, periodical classification surveys on special occasions, such as

−

damage , e.g. due to collision,

–

conversions and major repairs,

–

change of location/reinstallation.

The extent of the survey will be agreed upon from case to case. In case of classification, where periodical 2. surveys have been agreed upon (see B.), BKI (Head Office) will have to be notified in any of the events listed under 1. (See also Section 1, E. and following paragraphs).

Conversions

In case of major conversions, generally a new (class) certificate will be issued. The procedures regarding materials and components to be used, and regarding fabrication supervision and certification, are as described above and in the preceding sections for new buildings. 5.

Reinstallation, reactivation

For units which have been out of service for a longer period and are required to be re-certified, a comprehensive survey - at least with the scope of a special survey, see B.4. - will be necessary. The survey program will be agreed upon from case to case, de pending on type and age of the unit, and on the time out of service and volume of alterations. The reactivation surveys may be combined with conversion and repair surveys, see above.

Section 3 - Loads and Load Conditions, Site Environment

A, B

3-1

Section 3 Loads and Load Conditions, Site Environment

A.

Site and Environment Conditions -General

A chart and a comprehensive description of 1. the mooring site are to be submitted for the approval procedure, containing data on water depths, tide conditions, wind and waves characteristics, ice, currents, visibility and soil/anchoring conditions. Any other planned or existing installations at or near the envisaged site shall be contained and described in the site plan.

2..

Environmental loads

Where applicable, and depending on the 2.1 location, the loads due to the following influences and load effects shall be taken into account –

wind

–

waves

–

currents

–

green water on deck

–

temperature variations

–

marine growth/fouling

–

ice, snow

–

earthquakes.

2.

It has to be shown that, under the environmental conditions to be expected, water depth(s) and manoeuvring area are adequate to ensure safe operations. 3.

Sea floor/soil investigations shall be adequate to determine the kind of anchoring or foundation and to evaluate the safety of the system. See alsoSection 7. 4.

5.

Sea level

The highest still water level to be used for 5.1 design is defined by the water depth d w at the highest astronomical tide plus water level elevations due to storm surge. The lowest still water level to be used for 5.2 design is defined by the smaller value of either the water depth d w due to the lowest astronomical tide minus a water level decline due to storm surge, as applicable, or the chart datum. B.

Loads to be Considered

1.

Kinds of loads

The following kinds of loads have to be considered –

environmental loads

–

permanent loads

–

functional loads

– –

test loads accidental loads.

Environmental design values are, in 2.2 principle, to be based on statistical data obtained from longterm observations in a statistically valid manner. If sufficiently accurate data are not available, reasonably conservative estimates can be used if approved byBKI. Regarding the calculation of loads resulting 2.3 from waves, currents and wind, acknowledged methods shall be used. See also the Rules for Structures,Volume 2, Section 2, B. Special consideration is to be given to hydrodynamic loads exerted on the structure (e.g., forebody) due to the combined effects of waves and the unit’s motions (see Section 4, C.3.). 2.4

Wind (definitions)

The sustained wind speed us is defined as 2.4.1 the largest 10 minutes mean of wind speed expected within a time period of N = 100 years. The gust wind speed u g is defined as the largest 3 second mean of wind speeds expected within a time period of N = 100 years. The sustained wind speed can be 2.4.2 obtained from the largest 60 minute mean of wind speeds un60max (z 10 ) observed at z = 10 m above the still water level within a period of n years as follows:

3–2


( N = 100 years, ln = natural logarithm). The observation time period of un60max must not be shorter than n = 1 year. The gust wind speed can be obtained from the 2.4.3 largest 60 minute mean of wind speed un60max (z10) observed at z= 10 m above stillwater level within a time period of n years as follows:

The observation time period of un60max must not be shorter than n = 1 year. If observations of un60max (z 10 ), which are 2.4.4 needed to define the sustained wind speed or the gust wind speed from 2.4.2 and 2.4.3, respectively, are scarce or not available, un60max (z 10 ) for n = 1 can be estimated as follows: For sheltered sea conditions: for open sea conditions: for high sea conditions:

27 m/s 30 m/s 35 m/s

Use of sea conditions for design shall be approved by BKI. For N = n, i.e., the considered design period 2.4.5 is equal to the observation period, the formulae given in 2.4.2 and 2.4.3 can be reduced to

For heights z differing from 10 m above the 2.4.6 sea surface, u s or u g can be obtained from

2.5

Sea waves

2.5.1 with

Sea waves may be specified alternatively

–

natural sea state parameters or

–

equivalent design wave parameters

The definition of either set of parameters for any considered application shall be approved by BKI.

Natural sea state parameters are, e.g., the 2.5.2 significant wave height H s, defined as the average of the 1/3 highest wave heights in a record of stationary sea surface elevations, and the characteristic wave period T c, defined as the average time period between successive wave crests in the same record. With these parameters a design wave spectrum shall be defined for deep water waves as follows:

B

with ω = 2 π /T For intermediate water depths, i.e.,

The spectrum shall be modified as follows:

with: γ

= 3,3

b

= 0,07 for ω < 5 . 3 2 / T c

b

= 0,09 for ω > 5 . 3 2 / T c

Definition of design values of H s and T c shall be based on long term observations in a statistically valid manner.

2.5.3 Equivalent design wave parameters are thewave height H and the related wave period T of a single design wave or a regular design wave train, which are used to replace the natural seaway in such a way that its considered effect on the structure is approximately equivalent to the corresponding effect of the natural seaway. For a fully developed wind sea, the equivalent design wave parameters of a single wave may be approximated as follows:

with T 1= 3600 s.

2.5.4 Particle velocities uw and accelerations aw due to waves are related to wave height H, period T and water depth d w. Based on acknowledged standards and text books, a relevant wave theory shall be used to define the design velocity and the design acceleration at the location of the structural element considered. 2.5.5 The effect of wave-current interaction may be taken into account by the vector addition of the respective particle velocities.

Mmmmmmmmmmmmmmmmmmmmmmmmmmm


2.5.6 The concept of an equivalent design wave is not applicable to single-point moored FPSOs. Instead, the natural seaway design condition must be defined.

For "Tsunamis", see 2.12.

2.6

Sea currents

2.6.1 Currents to be considered are sub-surface and near-surface currents.

The definition of a design sea current velocity shall be based on long term observations in a statistically valid manner. If sufficient data are not available, reasonably conservative estimates can be based on the following assumptions. 2.6.2 The velocity u ss of sub-surface currents, such as tidal or thermosaline currents, shall be based on observed values provided by competent institutions, subject to approval by BKI. If no reliable information is available, the velocity profile can be estimated as follows:

where u ss0 is the current velocity at the sea surface, ζ is the vertical coordinate, originating at sea surface(ζ = 0) and pointing downward, and d w is the water depth. 2.6.3 The wind induced near surface current velocity can be estimated as follows:

3-3

Temperature variations may also have to be taken into account in the design of the production / hydrocarbons treatment installations. 2.9

2.5.7

B

Marine growth/fouling

Marine growth may be considerable in some 2.9.1 areas and should be taken into account, e.g., when assessing wave and current loads acting on submerged parts of the installation. Relevant informationshall be submitted to BKI f or verification. Thickness of marine growth should be as2.9.2 sessed according to local experience. If no relevant data are available, a thickness of 50 mm may be chosen for normal climatic conditions. 2.10

Ice, snow (precipitation)

2.10.1 If icing over of parts of or snow accumulation on the structure is possible, the weight of ice or snow shall be added to the permanent loads under operating conditions. 2.10.2 Loads due to ice and/or snow on open decks and external, exposed walls are to be chosen according to indications of independent competent authorities/institutions, valid for the location.

Snow covering can be disregarded for inclined surfaces set at more than 60° to the horizontal, and may be reduced linearly for inclinations between 0 and60°. 2.10.3 Where ice covering is due mainly to sea water spray, it may be taken to decrease linearly to zero from a level corresponding to the highest wave elevation to 60 m above that level. 2.11 Loads due to sea ice

with ζ15 = 15m and uns = 0 for ζ ≥ ζ 15 u s ( z 10) : See 2.4.2. 2.7

Green water on deck

Loads due to green water on deck may be significant, and their effects shall be accounted for in the areas affected. Prediction is possible, at least qualitatively, in connection with the investigation of the unit’s motion behavior (see C.2.2, and Section 4 and 7). 2.8

Temperature influences

Stresses and deformations of the structure or parts of it induced by temperature gradients in the structure shall be added to the permanent load induced stresses and deformations under operating conditions where deemed relevant.

2.11.1 Forces exerted on a structure by sea ice are to be evaluated for their local effect on structural elements and for global effects on the installation as a whole. 2.11.2 Ice loads are to be evaluated for a range of ice structure interactions. The range of interactions is determined by the ice environment in the area of operations and may include

–

p ressure from continuous multiyear level ice

–

c ollision with first and/or multi-year rid ges within the ice field

–

impact by drifting ice floes (see ice or glacial ice) impact by icebergs.

–

first

or

2.11.3 The maximum compressive strength of the ice is to be considered as characteristic of the local loading of the unit’s structure by ice. When selecting

3–4


the appropriate compressive strength, the following factors shall be considered:

B

Functional loads are loads due to normal 4.1 operations, occurring in a variable manner, e.g.

–

temperature or temperature gradient in the ice

–

weight of tools and mobile equipment

–

orientation of the ice crystals

–

–

salinity

weight of hydrocarbons or other liquids in tanks/vessels and pipes of the processing installation

–

total porosity of the ice (brine volume, gas pockets and voids)

–

stores, frequently varying injection liquids, fuel, wastes

–

strain rate

–

loading rate

–

loads from operations of cranes and other conveyance equipment

–

scale effects (size of structure/ice thickness). –

loads from helicopters

–

mooring/fendering loads from vessels serving the installation.

Note:

In most cases "ice-breaking" quality of the installation will not be relevant, and disconnecting will be required for defined ice conditions. 2.12

Earthquakes

For locations where earthquakes may be expected, a so-called "Design Earthquake" shall be defined, using available statistical information. The Design Earthquake shall be taken into account for the design of all elements connected with the sea bottom which may be affected by motions and/or forces resulting from an earthquake (e.g., risers, riser connections). Tsunami-type waves resulting from earthquakes may have to be considered in particular cases; it will be decided from case to case, depending on the probability of occurrence, whether a Tsunami and the resulting motion behavior of the FPSO have to be considered in connection with the design earthquake, or as an accidental load. 3.

Permanent loads

Permanent loads are loads which act 3.1 throughout the lifetime of the installation or during prolonged periods. Such loads may comprise the weight of structures, equipment, permanent ballast, and the effect of hydrostatic pressure exerted on parts of the submerged structure. Permanent loads shall be clearly 3.2 documented and accounted for in the design documentsand calculations. In cases where loads/weights may be acting 3.3 for longer periods but not necessarily at all times (e.g., certain kinds of equipment), both cases - load acting/not acting - may have to be investigated to cover the most unfavorable condition. 4.

Functional loads

transport

ballast

operations,

and

e.g.,

Loads on windlasses etc., exerted by 4.2 mooring lines, shall generally be regarded as functional loads, although mainly due to environmental influence. Regarding permissible stresses, these mooring loads shall be attributed to loading conditions 1 or 2 as applicable (see C. and Section 7). Deck loads, weight of equipment, etc. shall 4.3 be specified by the owner/designer. The specification should also contain indications and limitations with a view to the overall weight of the structure or installation, e.g., in connection with stability requirements. Any such limitations must also be stated in the Operations Manual. The most unfavorable distribution of loads is to be accounted for in the structural analysis. Where no other indications have been made regarding the loading of deck surfaces, the following values may be used as guidance: Crew Spaces, walkways etc.:

5 kN/m2

Work areas:

9 kN/m2

Storage areas: 5.

13 kN/m2

Test loads

Test loads, such as hydraulic test pressure in tanks or pipes, will usually occur only once or a few times during the unit’s life and under controlled (e.g., environmental) conditions. Nevertheless, a test load case may be an important consideration in designing/dimensioning a particular element or system and will usually be associated with other operating (and permanent) loads. See also C.1. below.


6.

Accidental loads

Accidental loads are loads not normally occurring during the installation and operating phases, but which should be taken into account depending on location, operations and possible consequences of failure. Accidental loads within this context may be due to, e.g.: –

collisions (other than normal impacts referred to under 4.1) falling/dropped objects

–

failing crane operations

–

explosions, fire

–

earthquake (exceeding a "design earthquake" that has to be withstood without damage).

Regulations of the competent Authority/ Administration may have to be observed, especially regarding collisions.

C.

Load cond. 1.

"Operating loads"

Load cond. 2.

"Extreme environmental loads"

Load cond. 3.

"Accidental loads"

These load conditions refer to the operation phase; where significant loads are imposed on specific components during other phases (assembly, transportation/towing, sea installation, hydraulic testing, etc.), they have also to be taken into account in the design as an additional load condition or load case. 2.

functional loads (e.g. crane loads, mooring impact, liquids circulating in the treatment production system), where relevant

–

loads exerted on the unit by risers, anchor chains or positioning system, moored vessels etc., under the defined environmental conditions mentioned above, depending on the configuration of the overall installation.

2.2

Limitation of operation:

Three main cases may be distinguished

a.

the unit stays at the location under all occurring environment conditions, and all connections to the sea-floor remain uninterrupted. Certain operations, however, may be restricted or interrupted under defined heavy weather conditions.

b.

the unit remains at the location as above, but critical production/hydrocarbons transfer lines are disconnected, production being shut down.

c.

the unit leaves the location, i.e., total disconnection of any elements linking the installation to the sea floor.

Load Conditions, Load Cases

The load conditions normally to be 1. considered and the kinds of loads to be taken into account for each load condition are listed in Table 3.1. Each of the following load conditions shall cover all possible load cases (load combinations) producing the maximum stress in particular elements of the unit or the most unfavorable situation in particular parts of the hydrocarbon handling/processing installation:

"Operating loads"

3-5

–

mooring

–

C

In any of the three cases, some of the functional loads may continue to be acting. The choice between these alternatives shall be taken in the design procedure as early as possible, and the limiting (critical) environment and motion conditions shall be clearly established by a comprehensive investigation of the behavior of the whole installation (offshore unit and anchoring system). See also Section 4, A.4. and Section 7.

3.


This load condition takes into account the most severe environment state(s) which the unit is intended to endure at the location (see 2.2 above), and any functional loads which are not expressly excluded under these conditions. Generally several load cases will have to be investigated, e.g., different combinations of wind/wave direction and different loading/ballast conditions.

This load condition includes all loads 2.1 occurring during normal operations, i.e.

4.

–

permanent (dead) loads

–

liquids in tanks, stores, etc. (various load cases may have to be considered)

The choice of accident cases and determination of loads for load condition 3 ("Accidental loads") will be considered from case to case.

–

defined, limited environmental loads

"Accidental loads"

5. Operations Manual: Any restrictions / limitations of operations due to environment conditions or other foreseeable influences shall be clearly stated in the Operations Manual (see Section1, D.1).

3–6


Table 3.1

D

Load conditions Kind of load

Load condition

Permanent Functional EnvironEnvironloads loads mental loads mental loads (limited) (extreme) 1

Collision, etc. (accident)

1.

"Operating loads"

X

X

X

(X)

2.


X

(X) 2

–

X

–

X

(X)

X

(X)

X

3. "Accidental loads" 3 1 2 3

–

See 3 See 2.2 and 3 See 4 and B.6.

x = applicable

D.

Determination of Loads

This Guideline is based – explicitly or 1. implicitly – on nominal or design load values (design loads FD) to be used in structural analysis. Design values of permanent loads shall be 2. vectorially added to the design values of other loads as listed in B.1. Design values of environmental and 3. functional loads generally occur at different times. Thus, vectorial superposition of design values of these loads are conservative, and consideration of the influence of the respective random load processes to define design values of superimposed loads is acceptable. The following rule may be applied to stochastically independent design values F Di:

i

= 1,2, ... I, where I is the number of independent design values F Di being considered.

Other superposition principles, especially for nonlinear superposition of correlated random load processes, may be applied upon agreement with BKI.

For permanently installed production units, 4. design values for extreme environmental loads based on a 100-year recurrence period shall generally be used. For temporarily installed units, shorter recurrence periods may be agreed upon. ( See Section 1, F.5). For the purpose of calculations of the 5. anchoring/mooring system, wind and currents may generally be regarded as being constant within one load case analysis. Sea waves impose dynamic, oscillatory loads which may have to be split up into firstorder loads with frequencies corresponding to the wave frequency and second-order loads oscillating with the low drift frequency (see Section 7, C.).

Section 4 - Structure

A, B

4-1

Section 4 Structure A.

General Design Considerations

Note:

In the following only some general remarks will be made regarding the structural design, as well as indications given referring to installations and structural elements peculiar to floating production units.

1. For the design/dimensioning of conventional structural elements of ship- or barge-type production units the Rules for Hull, Volume II may be applied; for semi-submersible-type units the Rules: for Structures, Volume 2, Section 3 and 4; and for Specific Types of Units and Equipment Volume 3, Section 2 and other equivalent code are applicable.

The two Rules mentioned shall generally not be applied simultaneously for the same unit, except whereexplicitly agreed upon with BKI (e.g. regarding materials). 2. FPSO structures shall be designed and constructed using adequate ductile and weldable, approved materials (see Section 5), and with a view to avoiding stress concentrations, complicated weld connections and excessive material thicknesses, as far as possible. 3. In the design of structures and structural elements, consideration should also be given to inspection (accessibility) and maintenance requirements.

A comprehensive investigation of the motion 4. behavior (response) of the unit under the given environmental conditions and anchoring/mooring restraints is to be carried out. The resulting loads/forces shall be accounted for when applying the Rules mentioned above. See also Section 7 and Section 3, C.2. 5. Serviceability and functional considerations may have influence on the structural design. They will generally be specified by the owner/operator of the installation, but will be taken into account in the design review by BKI where relevant from the safety and integrity points of view. 6. Corrosion and wear allowances: Determination of scantlings, using these indications or equivalent design methods, is based on the

supposition that an accepted corrosion protection system is provided (see Section 5).

Adequate corrosion allowances are to be agreed upon, depending on the environmental and operating conditions. The same applies to structural elements prone to wear, e.g. by chafing of cables or chains. For ship-type units, corrosion allowances shall generally correspond to the Rules for Hull, Volume II, Section 3, K., unless environment and inspection conditions require increased values. 7. For structural strength calculations based on a load - allowable stress concept, loads and load conditions according to Section 3 and allowable stresses as defined in B below shall be used.

Where other concepts of strength analysis are used, such as probabilistic or semi-probabilistic methods using characteristic load and resistance values and partial safety factors, agreement with BKI shall be reached in the individual case. 8. For details regarding structural calculations using the Finite Element Method, see the Guidelines for Strength Analysis of Ship Structures with the Finite Element Method (Analysis Techniques Strength). B.

Allowable Stresses

1.

Design concept

When using the conventional deterministic 1.1 dimensioning method normally based on linear elastic theory and global safety factors ("allowable stress design"), the allowable stresses shall be taken as indicated below. The allowable stresses are generally related to the minimum specified yield strength of the material. For materials without a defined yield strength, special agreements will be made. 1.2 The design concept mentioned above is based on the condition :

.

4-2


where

B

such point s corresponds to the required for

σ, τ

stresses resulting from the design loads defined in Section 3.D.

R eH

minimum specified yield strength R eH is not to be taken greater than 0,75 . R m (R m = minimum tensile strength)

γg

global safety factor, see 2.

2.

Safety factors/allowable stresses

In case of undisturbed stress distribution, i.e. 2.1 in girders, frames and other structural components where the distribution and magnitude of stresses is reliably obtained from the calculations mentioned under 1., the safety factors γg may be chosen according to Table 4.1.

"special structural members" (see Section 5) and fatigue considerations (see 2.5 below) are not essential. See also the Guidelines mentioned in A.8. 2.5 Fatigue: The allowable stresses may have to be reduced in case of loadings repeated with considerable frequency (fatigue). The admissible stresses may be obtained according to the indications given in the Rules for Hull, Volume II, Section 20 or for Structures, Volume 2, Section 3.G. See also the Guidelines for Fatigue Strength Analysis of Ship Structures(Analysis Techniques Strength). 2.6 A reduction of admissible stresses may also be necessary

–

in case of unfavorable inspection and testing conditions,

– 2.2 The factors are not applicable to local plate bending under lateral pressure. The total stress, including local plate bending, may reach R eH for load condition 2.

in case of not sufficiently well-known loads, and

–

where the consequences of a possible failure are deemed to be extremely negative.

2.3 In case of predominant compression or plate shear stresses, the possibility of buckling is to be investigated. The corresponding indications in the Rules for Hull, Volume II, Section 3, F. or Rules for Structures, Volume 2, Section 3, F. may be used, depending on the type of unit.

Admissible stresses for elements of special 2.7 purpose installations such as cranes or drilling rigs may be taken according to acknowledged regulations relating to such equipment. The application of such regulations shall be agreed with BKI. The applicability of relevant load conditions, in comparison with those defined in Section 3, shall be carefully checked.

2.4 Where calculations are carried through, e.g. using finite element methods, in order to determine the stress distribution in a more elaborate way, values up to the yield strength may be admitted for loading condition 2, provided that the material employed at

Table 4.1 Global safety factors γg

ect on

- tructure

-

C.

Structural Design of Specific Installations/ Components

elements) may configurations.

1.

Storage tanks

Special consideration has to be given to fatigue, particularly in weld connections.

1.1 Ship- or barge-type units provided with integrated storage tanks are required to comply with the regulations for tankers, being assigned the corresponding "Character of Class"/Class Notations (see Section 1, E.4.). Existing requirements regarding subdivision (tank volume limitations, double hull, etc.) have to be observed.

1.3 Temperature variations may have to be considered in some cases, e .g. in buckling calculations. The extreme possible temperatures of the stored liquids have to be stated. 1.4 Where venting is restricted for operational or safety reasons, the possible maximum gas pressure inside the tank is to be taken into account. In certain cases the Rules for Ship Carrying Liquefied Gases in Bulk, Volume IX, may be applicable.

necessary

for

complicated

2.4 In units (ships) designed for heading into the main wind/wave direction (weather-vaning), areas particularly exposed to hydrodynamic loads (slamming effects, green water on deck) require special consideration and may have to be additionally strengthened. 2.5

1.2 Structural elements of ships (tankers) designed according to the Rules for Hull Volume II, Section 24, shall additionally be checked regarding their resistance to dynamical loads resulting from liquids impact (sloshing, slamming) under the specific motion conditions at the anchoring site (see Sections 3 and 7). Partial filling may produce critical loads even in moderate sea states, i.e. load condition 1. Additional or enlarged structural elements (e.g., swashs bulkheads) may have to be provided.

be

Turret

2.5.1 In case of turret-mooring-type units, the turret and the surrounding hull structure shall be designed with a view to sufficient stiffness (evaluation of deformations), in order to prevent damages of bearings and sealing system, and/or impairment of the turret rotation.

To get a sufficient understanding of the interaction between hull an turret structure, generally a 3dimensional calculation will be required. Particularly, it shall be ensured that –

turret loads will be safely transferred into the supporting hull structure, and

–

stresses in the hull structure, e.g. resulting from longitudinal bending and transverse loads, are conducted around the turret without affecting its operation.

1.5 For the tank deck structure, additional loads from production installations and/or operations on top may have to be accounted for.

2.5.2 The connection of the risers with the turret and possible interactions between the riser system and the turret structure will normally be investigated using a separate calculation model; however, these calculations need to be co-ordinated with the investigations described in 2.5.1. See also Section 17.

Anchoring/mooring and riser suspension structure

2.5.3 Reinforcements and special considerations regarding deformation may be necessary in case of active turning (installation of turret turning drives).

2.

2.1 The forces acting on the special structure (e.g. turret; bow mooring yoke) provided for positioning the unit have to be evaluated for all load conditions and load cases defined in Section 3. Allowable stresses shall be taken as stated above, under B. 2.2 Load cases to be investigated will usually have to include incomplete anchor chain and/or riser arrangements, differing filling states of risers (repair, well-service or re-arranging phases), as well as heeling of the unit (see 3.2 below). 2.3 To get a sufficiently accurate knowledge of the stress distribution, detail investigations (finite

2.6 The material used for the main elements of the mooring structure shall at least correspond to the category prescribed for “Primary structural members” (see Section 5). 2.7 Attachment points for anchoring cables (chains) and mooring lines (hawsers) are generally to be designed according to the relevant Sections in the Rules or Specific Types of Units and equipment (Volume 3, Section 5, B.1.5).

Anchoring structures should be designed 2.8 considering also inspection and repair requirements (see Section 7).

4-4

3.


Production installation - Deck houses, stacks, etc.

3.1 Modules similar to conventional superstructures or deck houses of ships may be designed according to the Rules for Hull, Volume II, Section 16, with due regard to heavy equipment/concentrated loads and possible dynamic loads resulting from liquids in tanks and pipes. 3.2 In connection with the analysis of the unit's motion behavior, the possibility of loads from "green water on deck" acting on superstructures and deckhouses shall be investigated. 3.3 The ability of superstructures and their connections to the main structure (hull) to withstand possible inclinations/heeling shall be proven. The corresponding load cases shall include the maximum heeling angles determined for load condition 2 (Extreme environment condition) and for damaged condition of the unit, load condition 3 (see Section 6). 3.4 Tower- or stack-like structures (e.g., flare stack) may be designed according to appropriate codes or standards1; care has to be taken, however, in com paring the corresponding load conditions/cases with those defined in Section 3, and in taking into account the motion behavior of the unit. 3.5 Thermal loads and strains may have to be considered in the structural design of production installation parts. 3.6 Regarding fire safety and explosion prevention considerations (e.g. area classification, structural fire protection), which may influence structural design, see Section 11.

Corrosive media handled in (parts of) the 3.7 installation should be accounted for in the material selection, where contact with the supporting structure (leakages) can not be excluded.

4.

C

Helicopter landing area

The helicopter landing area ("Helideck") shall 4.1 be dimensioned for the largest helicopter type expected to serve the unit. 4.2 Loads shall be determined according to the most adverse environmental conditions possibly occurring during helicopter transfer operations. This may include conditions worse than those defined for "load condition 1", i.e. beyond ceasing of normal production operations. In any case, the load requirements of Administration regulations valid for the location are to be fulfilled. 4.3 The main load-carrying elements of the helicopter deck, including substructure, shall be considered as "primary structural elements" regarding material selection.

If aluminium is to be used for (parts of) the 4.4 helideck structure, the material shall correspond to the Rules for Materials, Volume V, Section 10, or equivalent material codes. The manufacturer of the deck structure must be qualified for this type of work (particularly, aluminium welding). Fire safety considerations will generally require a fireretardant coating of the aluminium structure. For details of loads (e.g. landing impact) and 4.5 dimensioning see, e.g., the Rules for Specific Types of Units and Equipment, Volume 3, Section 6 or the Rules for Hull, Volume II, Section 7, C. 4.6 Regarding safety considerations other than structural, such as fire safety and lighting, see Section 9 and 10 4.6 Regarding safety considerations other than structural, such as fire safety and lighting, see Section 9 and10.

1 E.g., API SPEC 4F, "Specification for Drilling and Well Servicing Structures"

Section 5 - Materials and Fabrication, Corrosion Protection

A

5-1

Section 5 Materials and Fabrication, Corrosion Protection A.

Materials

2.

1.

Material selection – general

Important structural parts, typical for off 2.1 shore production units and not mentioned in the Rules listed above, should correspond to the "Material Class" indicated in Table 5.4.

Materials used for the structure and 1.1 machinery of offshore production units shall correspond, basically, to the Rules for Materials, Volume V and Rules for Non-Metallic Materials. Further, the following Rules shall be observed: –

for ship-or barge-type units: Rules for Hull Volume II, Section 2.

–

for semi-submersible units: Rules Structures, Volume 2, Section 4.

Categories of structural members

In this context, a definition of the material classes in relation to steel grades and plate thicknesses, taken from the BKI Rules mentioned, is shown in Table 5.3. Typical ship structural members shall be selected according to the Rules for Seagoing Ships (see 1.1 above).

for

Materials for all elements defined in the 1.2 Rules must be supplied by manufacturers approved by BKI.

2.2 Offshore units: According to the definitions given in the Rules for Structures, Volume 2, Section 4, structural members are categorized as f ollows:

–

are members essential to the overall integrity of the structure and which, apart from a high calculated stress level, are exposed to particularly arduous conditions (e.g., stress concentrations or multi-axial stresses due to the geometrical shape of the structural member and/or weld connections, or stresses acting in the through- thickness direction, with large-volume weld connections on the plate surface).

Works approvals by other acknowledged institutions may be accepted from case to case. Structural steel shall be suitable for welding, 1.3 complying with Rules for Materials, Volume V for either normal or higher strength hull structural steel, or equivalent steels as specified in the Rules for Offshore Installations. Steel with a nominal yield point R eH greater than 390 N/mm2 should be avoided in view of possible brittle fracture and fatigue problems. (Hull structural steels: See Table 5.1 for easier reference).

–

If in special cases the application of high 1.5 strength quenched and tempered steels with nominal yield stresses up to 690 N/mm2 is considered, reference shall be made to the Rules for Materials, Volume V, Section 4, D. For units stationed in areas with prolonged 1.6 arctic conditions (temperatures below – 20 °C), the steel selection for the structure above the water line shall be made according to the requirements of the Rules for Hull, Volume II, Section 2, B.3.4 (selection depending on structure category–see 2. below–, design temperature and plate thickness).

Primary structural members are members participating in the overall integrity of the structure or which are important for operational safety and exposed to calculated load stresses comparable to the special structural members, but not to additional straining as mentioned above.

Materials other than specified in the Rules 1.4 mentioned above, the adequacy and applicability of which is proven, may be accepted based on satisfying documentation and/or tests. A selection of acceptable steels is given in Table 5.2.

Special structural members

–

Secondary structural members are all structural members of less significance, exposed to minor stresses only, and not coming under the above categories of "special" and "primary" (e.g. non-structural walls, stairs, pedestals, mountings for pipings and cables, etc.).

These categories correspond, in principle, to the "Structural member categories" defined in the Rules for Hull, Volume II, Section 2, B.

5-2


Table 5.1

A

Hull structural steel according to BKI Rules

Yield strength (min) ReH 2 [N/mm ]

Steel grade

Notched bar impact test Tensile strength Rm 2 [N/mm ]

Elongation (min.) A5 [%]

2

Impact energy Kv Test temper. [°C]

longit. [J]

transv. [J]

Normal strength

KI–A

+ 20

KI–B

– 0

235

KI–D

400 – 490

22

3

–

– 20

KI–E

– 40 Higher strength

(27)

27

20

31

22

34

24

41

27

1

KI–A 32

0

KI–D 32

315

KI–E 32

440 – 590

22

– 20 – 40

KI–F 32

– 60

KI–A 36

0

KI–D 36

355

KI–E 36

490 – 620

21

– 20 – 40

KI–F 36

– 60

KI–A 40

0

KI–D 40

390

KI–E 40

510 – 660

20

KI–F 40

– 20 – 40 – 60

1

In Table 5.2 and 5.3 higher strength steels are designated AH, DH, EH, FH

2

For plate thickness t

3

Supposed min. value, no test required.

≤

50 mm. See referenced rules for greater plate thicknesses.

Section 5 - Materials and Fabrication, Corrosion Protection Table5.2 Structural member category

A

5-3

Selection of suitable steels for plates and sections Steel strength class

Material designation

Nominal tensile 2 strength 2 Rm [N/mm ]

KI–E 32, KI–F 32

440 – 570

KI–E 36, KI–F 36

490 – 630

KI–E 40, KI–F 40

510 – 660

EN 10113-2

S 355 NL

470 – 630

EN 10113-3

S 355 ML

450 – 610

EN 10113-2

S 420 NL

520 – 680

EN 10113-3

S 420 ML

500 – 660

EN 10113-2

S 460 NL

550 – 720

EN 10113-3

S 460 ML

530 – 720

Standard and/or Rules

1

BKI Rules for Materials, Volume V, Section 4, B

Higher strength Special

Normal

BKI Rules for Materials, Volume V, Section 4, B.

400 – 500

EN 10113-2

S 275 NL

370 – 510

EN 10113-3

S 275 ML

360 – 510

As for "Special", and additionally: KI–D 32

440 – 570

KI–D 36

490 – 630

KI–D 40

510 – 660

EN 10025

S355 J2G3, S355 J2G4, S355 K2G3, S355 K2G4

490 – 630

EN 10113-2

S 355 N

470 – 630

EN 10113-3

S 355 M

450 – 610

EN 10113-2

S 420 N

520 – 680

EN 10113-3

S 420 M

500 – 660

EN 10113-2

S 460 N

550 – 720

EN 10113-3

S 460 M

530 – 720


Higher strength

Primary

As for "Special", and additionally:

Normal strength

BKI Rules for Materials, Volume V, Section 4, B

KI–D

400 – 500

EN 10025

S235 J2G3, S235 J2G4,

340 – 470

EN 10025

S275 J2G3, S275 J2G4

410 – 560

EN 10113-2

S 275 N

370 – 510

EN 10113-3

S 275 M

360 – 510

As for "Special" and "Primary", and additionally: Higher

BKI Rules for Materials, Volume V, Section 4, B EN 10025

Secondary

KI–A 32

440 – 570

KI–A 36

490 – 630

KI–A 40

510 – 660

S355 JR, S355 JO

490 – 630

As for " Special " and " Primary ", and additionally: Normal strength


KI–A, KI–B

400 – 500

EN 10025

S235 JRG2, S235 JRO,

340 – 470

EN 10025

S275 JR, S275 JO

410 – 560

1

For high strength quenched and tempered steels for welded structures with nominal yield stresses between 420 and 690 N /mm 2 reference Nis made to the Rules for Materials, Volume V, Section 4, D. 2

Requirements for yield stress (R eH), elongation (A 5) and notch bar impact energy may be taken from the Rules for Materials, Volume V,

5-4 Table5.3

1

Section 5 - Materials and Fabrication, Corrosion Protection 1

Material Classes

Quoted from Rules for Hull, Volume II, Section 2

Table 5.4

Material selection for some typical elements of FPS(O) structures

A

5-4


Table 5.3

A

Material Classes 1 Thickness t [mm] 1

<_ 15

Material Class I II III

A/AH A/AH A/AH

> 15 <_ 20

> 20 <_ 25

> 25 <_ 30

> 30 <_ 35

> 35 <_ 40

> 40 <_ 50

> 50 <_ 100

A/AH

A/AH

A/AH

B/AH

B/AH

D/D

D/DH

D/DH

H

2 E/EH

E/EH

E/EH

E/EH

A/AH B/AH

B/AH D/DH

D/DH D/DH

D/DH E/EH

1Actual thickness of the structural member 2For thicknesses t > 60 mm: E/EH

Quoted from Rules for Hull, Volume II, Section 2

Table 5.4

Material selection for some typical elements of FPS(O) structures Material class (See Table Structural element, type of structure

stress

regular1complicated pattern 2

Production installations (deck houses or modules): II I II

III II III

Turret – Main structural elements – other structural elements

II I

III II

Yoke (bow mooring) – Main load bearing structure – other elements

II I

III II

Offloading installation – Main derrick structure – other elements

II I

III II

Helicopter landing structure – Main load bearing elements (if steel) – other elements

II I

– Main supporting structure (trusses) – Decks – Flare stack (and similar structures)

1Elements/cross sections with easily described (linear) stress distribution 22- or 3- dimensional stress pattern, stress concentrations (notches)

III II


B

5-5

The categories and steel grades of structural 2.3 members are to be determined in the design stage and indicated in the construction documentation presented for approval.

specifications (e.g., OCIMF guides); see also Section 17, E. and 18, D. Suitability for the media to be handled and for the environmental conditions (dynamic loads, deformations) shall be demonstrated.

3.

B.

Fabrication

1.

General requirements

Anchoring/mooring equipment

Elements used for positioning/anchoring and mooring (anchors, chain cables, wire ropes, etc.) shall conform to the requirements of the Rules for Specific Type of Units and Equipment, Volume 3, Section 5 and the Rules for Materials, Volume V, Section 12 to 15. See also Section 7. 4.

Lifting appliances

Materials used for the construction of lifting appliances (cranes, hoists, etc.) shall correspond to the requirements listed in Volume 3, Section 4 of the Rules for Specific Type of Units and Equipment and relevant requirements of the Rules for Materials, Volume V. For standard materials provided, e.g. for existing installations, equivalence with the requirements mentioned above shall be demonstrated. 5.

Production equipment

5.1 Tanks/containments: Integrated or detached tanks or containments shall be constructed using materials adequate for the media to be handled, or suitably protected by coating, cladding etc. In case of tanks integrated into the structure of the unit, weldability and compatibility with the hull structural steel has to be guaranteed. 5.2 Boilers, pressure vessels and similar pressurized equipment shall be made of materials suitable for the service conditions (temperature, pressure etc.) and conform to the relevant BKI Rules or equivalent standards or regulations, e.g., ASME Code.

Regarding materials to be used for sour 5.3 service, see Rules for Machinery Installations, Volume 4, Section 18. Reference is also made to the NACE Standard MR 0175. 6.

Machinery

Machinery components, piping, mechanical and electrical equipment, e.g. in the cargo transfer, energy supply or any other auxiliary installations, shall comply with the applicable BKI Rules (Ships or Offshore Installations) and/or accepted Codes and Standards. 7.

Flexible hoses are to be manufactured and tested in compliance with accepted standards and

Fabrication and manufacturing of all parts 1.1 and installations subject to certification/classification may only be carried out in workshops approved by and under surveillance of BKI. Exceptions or deviations, e.g. in case of standard mass produced elements or components from factories using an approved/certified Quality Assurance system, may be accepted from case to case. Particularly as regards welding, 1.2 manufacturers must be suitably equipped and have at their disposal sufficiently trained and experienced personnel, including qualified supervisors, able to guarantee acceptable quality for all types of welding specified in the design documents. For details, see –

Rules for Welding, Volume VI; and

–

Rules for Structures, Volume 2, Section 4, C.

Internationally recognized codes and regulations, such as the AWS Structural Welding Code, will generally be accepted as basis for fabrication procedures. Tests, such as listed below, shall be carried 1.3 out under the supervision of BKI Surveyors, as specified in the Rules –

(destructive) material tests

–

tolerance and verification tests/measurements

–

function tests

–

load tests

–

non-destructive tests (e.g. weld connections).

Special testing/trials and certification may be required by an Administration for hydrocarbons storage and conveying (loading, unloading) systems, with a view to environment protection. 2.

Welding

Weld joint geometry, preparation, execution 2.1 (welding parameters) and post-weld heat treatment shall conform to the Rule requirements or to acknowledged standards considered equivalent. See Rules for Hull, Volume II, Section 19, and Rules for Structures, Volume 2, Section 4.

5-6


A specification for non-destructive testing of 2.2 weld connections is to be set up and presented to BKI for approval. Any repairs of weld connections found to be 2.3 faulty are to be agreed upon with the BKI Surveyor.

C.

Corrosion Protection

1.

General indications

Corrosion protection measures are to be 1.1 considered as early as possible during planning and design, and the relevant specifications are to be presented to BKI for approval. The influence of adjacent structures and installations, including riser system, shall be taken into account. Protection by coating shall generally be 1.2 provided for sea water ballast tanks, and should preferably be chosen for oil (production storage) tanks in view of the limited efficiency of cathodic protection under the conditions usually encountered on production units. The protection measures for the production 1.3 facilities (tanks/containments, (tanks/containments, pressure vessels, piping systems, etc.) shall be carefully evaluated, depending on the substances handled and the environment / climatic conditions. Special attention is to be paid to possible galvanic corrosion between metals with differing potential. Where the use of inhibitors is considered, 1.4 their compatibility with the substances handled shall be carefully evaluated. evaluated.

For details, e.g. regarding impressed current 1.5 protection, see Rules for Structures, Volume 2, Section 6. Reference may also be made to the Rules for Hull, Volume II, Section 38. 2.

Coatings

For the selection of coatings, the following 2.1 influencing factors shall be considered, i.e.

C

–

aggressiveness (chemical, mechanical) of substances stored/handled

–

filling rates/flow rates/flow path of liquids

–

climatic conditions, conditions, temperature temperature variations variations

–

corrosion potential potential of the coating coating itself.

Surface preparation and conditions 2.2 prevailing during application application shall be according to acknowledged standards, suppliers specification, and the BKI Rules mentioned above (1.5).

The condition of coatings is to be regularly 2.3 controlled, and is subject to periodical surveys for classified units (Reference : Rules for Classification and Surveys, Volume I, Section 3 and 4).

3.

Cathodic protection

Where cathodic protection is intended to be 3.1 provided in storage tanks with varying degrees of filling, it should be considered that this type of corrosion protection is efficient only in presence of a liquid acting as electrolyte. (Cathodic protection may be achieved by sacrificial anodes, impressed current, or a combination of both.)

The system chosen, the material and 3.2 geometrical distribution/arrangement of anodes, the physical and chemical boundary conditions and details of the fastening devices shall be described and the documentation presented for approval. Potential measurements are to be carried out 3.3 after an appropriate period following installation and initial use to establish whether the structure is provided with with the required protection. With impressed current systems, regular 3.4 control measurements and checks are to be carried out according to an approved itinerary.

Section Section 6 - Subdivision, Subdivision, Stability, Stability, Freeboard

A, B, C, D

6-1

Section 6 Subdivision, Stability, Freeboard A.

General Requirements

Stability and freeboard shall satisfy the requirements of the regulations applicable to the type of unit of unit and location in question. Particularly, it has to bedetermined whether the unit is to be regarded as aship a ship or a mobile offshore installation. 1.

– – – – –

flooding openings. seawater ballast system; solid ballast, if any. piping piping systems, systems, including including points points of discharge. intact and damage stability calculations. calculations. information on computer control (hardware/software). cont rol syst ems rel ated ate d to the ite ms list ed above.

2.

For ship-type units guidance is given under C to E below. Depending on the decision of the Administration, such units may be regarded as "special- purpose ships", e.g. with a view to watertight subdivision (see Rules for Hull, Vol. II, Section 29, II C). The arrangement of collision and peak bulkheads may be specially considered, if mooring facilities are provided at the the vessel's end. 3.

For mobile offshore units, e.g. semisubmersibles, the provisions of the IMO "Code for the Construction and Equipment of Mobile Offshore Drilling Units" are applicable. See also Rules for Specific for Specific Type of Units and Equipment, Volume 3, Section 3. 4.

A computer-based stability-control checking system will generally be required.

B.

and

Documents for Approval

C.

Watertight Integrity; Freeboard

1.

Watertight integrity shall generally be achieved according to established shipbuilding practice and has to be in line with the provisions of the International Convention on Load Lines (1966), if applicable. Any external openings necessary during normal operations, below the down-flooding level as defined in the stability calculations, calculations, shall be kept under constant control and be capable of being closed immediately immediately from a central control/operating control/operating station. The number of openings in watertight bulk heads shall be kept as small as possible. Any necessary penetrations shall be designed according to acknowledged standards. Closing appliances for internal openings shall be capable of being operated from a constantly accessible control room (see above) as well as locally from both sides of the bulkhead.

2.

3.

Any doors, hatch-covers, etc., relevant regarding the considerations mentioned above, shall be clearly marked to this effect.

1.

A "Stability Booklet" is to be prepared and submitted for approval, containing all relevant information and instructions related to floatability and stability of the unit, in all modes of operation. The Stability Booklet may be part of the general Operations Manual (see Section 1, D. 1.).

2.

Plans/documents for the following items are to be submitted for approval, apart from the Stability Booklet: –

general general arrangement arrangement and detail detail plans, plans, containing information on the location of control rooms; watertight and weathertight doors and hatches; and hatches; windows, sidescuttles and any other openings, other openings, particularly down-

4. The freeboard shall comply with the provisions of the International Convention on Load Lines(1966), Lines (1966), where applicable to the type of unit, with possible possible modification modificationss due to the damage damage stabilityrequirements stability requirements (see E. below).

D. 1.

Intact Stability

Sufficient stability stability of the production unit has to be demonstrated for all operating and emergency conditions as described in Section 3. In the stability calculations it is usually assumed that the unit is floating free, without restraints restraints from mooring lines lines or

6-2

Section 6 - Subdivision, Stabilit , Freeboard

E

2.

risers. While such restraints will normally have a stabilizing effect, any possible negative influences, e.g. due to asymmetrical/incomplete mooring and riser arrangements, shall be carefully considered.

For ship-type units including storage facilities, considered as new buildings whose delivered onor on or after 6 July 1996 the double - hull requirements according to Regulation 19, Annex I, MARPOL73/78(IMO) have to be observed.

2.

Exemptions regarding a double bottom requirement may be considered for units which will not be able to leave the location with oil storage and fuel tanks (partially) filled.

The intact stability criteria of IMO Intact Stability Code shall generally be observed. For semisubmersible units, see also the IMO Code for Mobile Offshore Drilling Units, and Rules for Specific Type of Units and Equipment, Volume Volume 3, Section 3.

3.

3.

Particularly regarding wind heeling moments and icing, reference is made to the regulations mentioned above. Wind forces may be calculated according to the indications given in Section 3, B. and D. The wind heeling moment curve is to be determined for a sufficient number of heeling angles up to an angle beyond beyond the "second "second intercept" intercept" (crossing (crossing point) point) with the righting moment curve. Wind tunnel tests may be required/recommended in particular particular cases.

In the damaged/flooded condition, considering increased draught, heel and trim, and the heelingeffect heeling effect of wind with a (sustained) speed of 25,8 m/s (50 knots) blowing from any direction, the resulting waterline shall still remain below any opening through which progressive flooding may occur. 4.

Any means provided to counter act heeling, e.g. shifting of water ballast, may not be taken into account when determining the final waterline mentioned above.

4.

For all operating and emergency conditions, the effect of free liquid surfaces in tanks and containments shall be accounted for in the stability calculations. The principle that the number of tanks with partial partial filling filling should be kept at a minimum minimum should always be observed. The tanks/containments which may be filled only partially during normal operations,and those for which partial filling is not allowed forextreme environment conditions or during transit and/or installation operations, shall be clearly stated in the Stability Booklet and Operations Manual. Any anticipated lifting operations using the unit’s own facilities shall be accounted for in the stability calculations, where relevant.

5.

6.

Inclining Test: An inclining test is to be carried out with the unit as near to completion as possible, in order to determine/check determine/check the center(s) of gravity assumed in the calculations. The results shall be recorded in the Stability Booklet, and the necessary corrections made. E. 1.

Subdivision; Damage Stability

The unit shall have a freeboard and shall be subdivided in such a way as to ensure sufficient buoyancy and stability to sustain flooding of com partment partmentss as defined defined in the applicab applicable le regulations. As a minimum requirement, the 1-compartment status is to be achieved (see 6. below).

All structures mounted on deck shall be designed to withstand the maximum angles of inclination of the unit in the damaged condition. See alsoSection also Section 4, C. 5.

6.

Damage assumptions

Any one compartment adjacent to the sea 6.1 shall be considered damaged to the following extent: –

depth of damage ( penetration): 1,5 m

–

vertical extent: From the base line upwards to the uppermost continuous deck.

–

horizontal extent (along hull): Full length of compartment, minimum 3 m. (i.e., in case of bulkheads placed closer than 3 m, two com partments will will be considered considered flooded).

All piping, ducts etc., within the extent 6.2 defined above are to be considered damaged. Effective/positive Effective/positive means of closure are to be provided to preclude to preclude flooding flooding of other compartments. compartments. For column-stabilized column-stabilized (semi-submersible) (semi-submersible) 6.3 units, see also Rules mentioned in A.3. for details regarding damage assumptions, means to ensure watertight integrity, and ballast system.

Section 7 - Anchoring/Positioning Systems

A

7-1

Section 7 Anchoring/Positioning Systems

A.

General Definitions and Requirements

The floating production unit is to be provided with an anchoring/positioning system, or a combination of systems, which ensure(s) station keeping in a safe and controlled manner, either

above.

1.

–

–

2.

under all predictable weather/environment conditions, or within defined sea-state limits. (This requires the possibility of detachment/separation of both the anchoring lines and the riser systems from the unit).

–

–

–

Spread Mooring, i.e. an arrangement of chains/anchor lines and anchors evenly distributed to provide restoring forces practically equal for any direction or displacement. (Usual means of positioning for semi- submersible units). Single Point Mooring, allowing the unit to rotate (‘weather-vane’) around a fixed or buoyant structure, to which it is connected by articulated elements. The mooring is usually arranged at the bow (ship- or barge-type units). Buoyant mooring structures may in turn be anchored by a spread lines system, see above. Turret Mooring: Combination of spread and single point mooring; a turret-like structure integrated into the hull of the unit, allowing non restricted rotation as above. The turret supports the anchor lines and riser system. Dynamic Positioning: Keeping the unit on position by means of thrusters/propellers and a position control and correction system based on hydro-accoustic, micro-wave, strain measurement or other suitable methods. Dynamic positioning may be used alone or assisting anchoring systems as mentioned

Class Notations

The following Class Notations (examples) will be assigned in case of the unit being subject to a classification procedure (see Section 1, E.): –

for units kept on position by a spread anchor line system: "Positioning by Spread Catenary Mooring" (CM)

–

for units connected to a separate, anchored mooring installation (single point mooring; e.g., with yoke): "Positioning by Single Point Mooring" 1 (SPM)

–

for units kept on position by a turret installation forming part of the unit's structure: "Positioning by Turret Mooring" (TM)

–

For units kept on position by thrusters/propellers and a position control and reference system: "Dynamic Positioning" (DP)

Types of positioning

The following means of keeping the unit on the determined position within defined tolerances/deviations may be used, depending on owner’s/operator’s preference, local (environment) conditions including water depth, and type of vessel or unit: –

3.

Note:

The notations given above are somewhat ambiguous: There are designs not correctly described by the a.m. definitions. A turret configuration, e.g., is usually combined with a spread anchor line mooring. 4.

Approval documents

The following documents are to be submitted for approval: –

overall/general description and arrangement of the positioning system, including auxiliary fixed or buoyant structures/installations, if provided.

–

specification of equipment (chains, windlasses, etc.).

–

drawings and structural calculations of auxiliary mooring installations (see above) and connecting elements (yokes, etc.), including particulars on foundations and soil characteristics where sea-bed based structures are provided

1

anchoring/mooring hawsers, anchors,

Regarding certification of a separate mooring structure, see also Section 1, A.5.

7-2

–

–


Analysis of the displacements of the unit and forces exerted on the anchoring/positioning elements under all possible environment and operational conditions. Specification, lay-out and detailed description of the system(s), including power supply, control/monitoring and measuring (position reference) systems, where dynamic positioning is to be provided.

–

Results of model tests, where applicable.

–

System specification and procedures for disconnection and re-connection, in case of disconnectable riser and anchoring elements (see Section 3, C. and 17, G.).

–

General arrangement, components and related calculations of an (active) turret turning installation, if provided (see F.).

B.

Materials; Fabrication

All components of the anchoring/positioning system shall comply with the corresponding BKI Rules (see Section 5) and be supplied with BKI certificates, or certificates considered equivalent in particular cases. 1.

For anchor chains, anchors and related equipment, see Rules for 2.

–

Specific Type of Units and Equipment,

B, C

be reviewed. Function tests will have to be carried out 6. under BKI surveillance, as indicated under the individual headings below. C. Catenary Mooring Systems (CM) – Design Considerations and Requirements

The arrangement of the anchoring system shall be such that 1.

–

interference with the risers is precluded,

–

mooring operations of attending vessels will not be impaired, and

– the product transfer facilities (hoses, etc.), where provided, not endangered. 2.

Inspection/monitoring and maintenance

The anchoring system should be designed 2.1 having in mind also the possibility of/need for inspection and repair, particularly of elements prone to corrosion and abrasion. Corrosion protection and/or regular surveys 2.2 are to be combined in a maintenance procedure, subject to approval by BKI in case of classification, and incorporated in the Operation Manual. See also Section 2.

Volume 3, Section 5 –

Materials, Volume V, Section 12 to 15

Lower grade chain shall not be employed in permanent mooring lines. Steel wire and ropes: See also C.3.3. For power supply, propulsion machinery and electrical installations in connection with positioning, see the relevant material-and fabrication-related instructions given in the Rules for Materials, Volume V and in the Rules for Seagoing Ships or for Offshore Installations.

For mooring systems of floating production 2.3 units, particularly in cases where other - fixed or mobile - installations are stationed nearby, monitoring of the forces in representative mooring lines is recommended, e.g., by strain measurement. These measurements should be supplemented by and correlated with a position monitoring system for the unit (e.g. satellite reference navigation system).

3.

For auxiliary mooring structures not forming part of the unit, the Rules for Structures, Volume 2, shall be applied in case of larger, fixed installations; for loading/unloading terminals, see the Rules for Mooring and Loading Installations. 4.

Fabrication is generally to be carried out under 5. BKI surveillance. For existing installations to be used again, a thorough condition survey will be conducted by BKI, and previous documentation/certification will

3.

Anchor lines

For installations complying with all rule and 3.1 classification requirements regarding design calculations (mooring system analysis), materials, control of corrosion and wear, etc., the safety factors γa shown in Table 7.1 may be used. For all load conditions investigated also the case “one line failed/missing” shall be calculated (see Table 7.1). Under unfavorable conditions, e.g., where a reliable assessment of environment conditions is not possible or regular surveys cannot be guaranteed, the safety factors should be increased.

Section 7 - Anchorin /Positionin S stems

Table 7.1

Safety factors a Method of Analysis

1

Quasi - Static Analysis

Dynamic Analysis

All lines intact

2,0

1,7

One line missing

1,4

1,3

Case

C

7-3

For anchors of special design - high holding 4.3 capacity anchors - tests will be required, proving the values aimed at with a view to the soil conditions to be expected at the installation site. Where anchors are provided which are not 4.4 capable of resisting vertical (lifting) forces, the analysis of the system shall prove that under all loading conditions only horizontal forces will occur at the anchoring points.

1

See 6., below

(γa

= minimum breaking load/maximum calculated force in anchor line)

In anchor lines consisting of different 3.2 components, all connecting elements shall be designed and tested for at least the same ultimate load as the main component (e.g. chain), except for a ‘weak link’ incorporated intentionally in particular cases. This also applies to clump weights and buoys incorporated in the anchor line to influence its restoring characteristics. An additional safety factor of 1,1 is recommended for the connecting elements. Steel wire or fiber rope used for anchoring 3.3 lines shall be of special make, to be agreed upon with BKI. For synthetic fiber ropes, the long-term mechanical and chemical resistance/adequacy shall be proven; relevant test results and investigations shall be presented for information. The elasticity of the rope material shall be taken into account in the calculations of the anchoring system. Steel wire should not be used in portions of the anchor line subject to varying contact with the sea bottom (abrasion/corrosion). All mooring lines shall be subjected to a load 3.4 test after installation. The test load should correspond to the maximum load resulting from the mooring analysis (see 6.), where practicable. 4.

Anchor points

Evidence shall be provided of the adequacy 4.1 and the holding capacity of the anchor type selected, in relation to the seafloor properties prevailing at the anchoring site. A proof load equal to the maximum dynamic (design) load should be applied for at least 15 minutes. The accuracy of positioning of the anchors 4.2 shall be established in the design procedure, depending on length of anchor line, water depth etc. The actual anchor points have to be monitored and documented during installation.

For the pull-out safety, i.e., holding capacity 4.5 divided by maximum (calculated) anchor line force, a minimum value of 2 is recommended. The safety factor may have to be adjusted, depending on anchor type and soil conditions. For anchoring elements suitable for vertical 4.6 traction loads, i.e., piles or gravity-type anchors, see Rules for Structures, Volume 2, Section 7. Load testing after installation: See 3.4. The 4.7 exposure to the test load shall be long enough to make sure that the anchor has s ettled. 5.

Auxiliary equipment

Anchor and anchor line handling equipment, 5.1 such as windlasses and winches, stoppers, fairleads, shall be designed in accordance with good shipbuilding practice and dimensioned in relation to the breaking strength of the anchor lines. See Rules for Specific Type of Units and Equipment, Volume 3, Section 5.C. and Rules for Machinery Installations Volume 4, Section 8. See also Section 13, G. Quick-release connections shall be of a proven 5.2 design and are to be tested in presence of a BKI Surveyor. Failure shall not occur under loads less than 1,5 times the breaking load of the attached anchor line. Safe release must be possible under a load equal to the line load and under all predictable angles of application of the load. In cases where disconnection of the riser and 5.3 anchoring systems is provided (see Section 3, C. and 17, G.), details of the necessary equipment - hoists, actuators, storing facilities, etc. - are to be presented for approval. The parts of the anchoring system remaining on location, including, e.g., buoyancy aids and the related control equipment, will be included in the approval procedure upon special agreement, but should be covered by the submitted documentation at least for information. For ("active") turret turning installations, see 5.4 F below.

7-4


6. Motion and anchoring system 6.1

strength

analysis

of

the

Cases to be considered

A 3-dimensional analysis of the system, 6.1.1 consisting of the moored unit and all anchoring elements contributing to the restriction of motions/displacements (excursions), has to be carried out, considering –

different load conditions and load cases as defined in Section 3, C., including possible variations of draught (empty, ballast, fully loaded unit),

–

a sufficient number of sea states and wind/wave/current directions (see below),

–

constraints imposed by the riser system as well as any other subsea equipment to be installed,

–

attending vessels moored to the unit,

–

the case one anchor line failed or not installed (see 3.1 and 6.2 below),

C

such a way that a failure of any single anchor line will not cause progressive failure of the remaining lines, or riser damage/failure under load conditions where production continues. 6.3

Motion analysis methods

Wave forces acting on a floating vessel positioned by catenary mooring comprise the following three components: –

first-order forces at wave frequencies

–

second-order forces at frequencies lower than wave frequencies

–

steady component of the second-order force, the so-called mean drift force.

To take account of the forces mentioned above, both quasi-static and dynamic approaches are generally used. However, quasi-static analysis methods should be applied only in the early stages of mooring design as approximation, and a dynamic analysis method is generally necessary for final design confirmation and for the fatigue assessment. The method(s) used in the particular case shall be specified in the approval documentation. Note:

The number of cases investigated must be 6.1.2 sufficient to identify maximum forces in the anchor lines and connecting elements, and any other situations considered as critical. Regarding allowed direction of line pull at the anchoring points, see 4. above. The load condition "Extreme environmental 6.1.3 loads" (see Section 3, C.), applied to the investigation of the positioning system, shall usually include two cases: –

100 year return period waves, with associated wind and currents

–

100 year wind, with associated waves and currents.

(See also Section 3, D.4.). The effect of sea swell may have to be considered.

In a quasi-static analysis, the dynamic wave loads are accounted for by statically offsetting the vessel by an appropriately defined wave induced dislocation. Loads induced by vertical fairlead motions and the dynamics of the mooring system itself are neglected. A dynamic analysis accounts for the dynamic response of the mooring system itself. Time-varying effects due to mooring line inertia and damping are included. The time-varying fairlead motions are calculated from the vessel's surge, sway, heave, roll, pitch and yaw motions. Generally, to predict mooring line response, it suffices to account for only the vertical and horizontal fairlead motions in the plane of the mooring line catenary. A dynamic mooring analysis for a ship-shaped production unit must account for the dominant effect of low -frequency motions. Specifically, the analysis needs to consider the following aspects: –

coupled motion equations for surge, sway and yaw

–

adequate formulation of slowly varying wave drift forces

Note:

Steady forces due to wind and current can be computed analytically or obtained from model tests (see 6.6). For tanker based production units, wind and current coefficients documented in "Prediction of Wind and Current Loads on VLCCs, " public domain data compiled by OCIMF, can be used. Additional wind forces due to the presence of process and other equipment can be significant and must be separately determined. 6.2

The anchoring system should be designed in

–

low-frequency damping

–

mooring line dynamics

–

riser effects.

The safety factors to be used for 6.4 dimensioning of the mooring line components are given in Table 7.1, see C.3.


Fatigue analysis: For the important load 6.5 bearing components of the mooring system, generally a fatigue investigation will be required, based on the load history derived from the calculations mentioned above. For fatigue analysis, see Section 4, B.2.5. 6.6 Model tests may be incorporated in the design procedure to supplement or confirm data previously obtained by calculation (e.g., model towing basin experiments, wind tunnel testing).

The results of such tests may be accepted by BKI as part of the design documentation, if the tests are carried out in an acknowledged laboratory, and evidence is provided of the validity of the modeling assumptions and the accuracy of measurements and data evaluation. Special consideration may be given to an 6.7 arrangement where the anchoring system is used in conjunction with thrusters to maintain the unit on position (see E.). Dimensioning of the anchoring elements will be considered from case to case. D.

Single Point Mooring Systems (SPM)

For single point mooring systems (e.g., SALM (Single Anchor Leg Mooring)), a dynamic analysis is required, taking account of the following influences/effects, where relevant:

D, E

7-5

The calculation model used for the final design shall be suitable for revealing : 3.

–

the maximum forces occurring in the system elements as well as the force variation needed for a fatigue analysis, and .

–

the maximum forces occurring in the system elements as well as the force variation needed for a fatigue analysis, and

–

the maximum excursions and rotational movements (in articulations, swivels - control of admissible relative movements).

For the transfer and installation phase, special investigations may be necessary, taking account of the environment conditions to be expected (limiting conditions). See also Rules for Structures, Volume 2, Section 8. 4.

5.

Articulations

1.

–

environment and hydrodynamic forces acting on both, the moored unit and the SPM structure 1

–

interactions between the structures involved (eventually including flexible connecting elements)

–

non-linear effects, e.g., due to buoyancy changes

–

friction effects (articulations).

Depending on the configuration of the system and on the state of design progress (preliminary to final), different calculation methods (frequency domain, time domain) and mathematical models (varying degree of simplification) may be used. The method(s) and model(s) used shall be agreed upon with BKI. For SPM mooring systems the requirements/statements of C.6.1, 6.5 and 6.6 are applicable in principle. 2.

Articulated connections shall be designed with 5.1 a view to maintenance, inspection and repair. Lubrication should be reliable and automatic, as far as possible. Materials for contact surfaces shall be 5.2 carefully selected with a view to corrosion and abrasion properties, and experience gained. Safety factors for design contact pressure and 5.3 allowances for motion range limitation will be considered from case to case. For buoyant structures forming part of the SPM mooring, damage cases (one/two compartments flooded) will generally have to be investigated. See also Rules for Mooring and Loading Installations. 6.

Local hydrodynamic loads (slamming) may have to be accounted for in the structural design. 7.

E.

Dynamic Positioning (DP)

1.

General indications

Note:

Due to the non-redundant configuration, the system integrity depends on the performance of every single element in the mooring force transmission line. Detail design and maintenance/inspections are therefore still more important than in the case of conventionalspread mooring.

Thrusters used as a means of position keeping, 1.1 together with a semi-automatic or automatic positioncontrol and -correction system, should provide a level of safety/reliability at least equivalent to that inherent in conventional mooring equipment.

7-6


For details about dynamic positioning systems, see Rules for Dynamic Positioning Systems.

E

(response analysis). –

proof of the unit's ability of maintaining position after specific single failures. See Section 2.A. of the Rules mentioned under 1.1.

The arrangement and design of the dynamic 1.2 positioning system shall take into consideration, i.e.: –

the type and purpose of the unit

–

–

the environmental conditions and water depth at the operations site

functional block diagrams of the control system(s).

–

the motion restrictions imposed by elements connecting the unit with the sea bottom (i.e. in first line, risers)

functional block diagrams of the position reference system(s) and the environmental sensor(s).

–

wiring diagrams.

–

drawings showing the electrical power supply of all units and the internal power distribution.

–

drawings and descriptions of monitoring functions of control, sensor and reference systems.

–

list of equipment identifying manufacturer, type, type approval number etc.

–

–

the distance and kind of structures/installations in the vicinity

–

the consequences malfunction.

of

system

other

failure

or

1.3 Definitions: A dynamic positioning system is usually composed of the following main subsystems:

–

measuring and sensor system (environment, position and motion reference)

–

control system (evaluation information, thruster activation)

–

propulsion system (position adjustment)

–

power generation

of

sensor

Detailed information on the positioning 1.7 system, its operation, maintenance, safety checks, alarms and contingencies in case of component failure or malfunction shall be contained in a special DP Operation Manual.

2.

As a dynamic positioning system is designed 1.4 to suit a particular unit at a defined location, this restriction will be clearly indicated in the certification or classification documents. All essential 1.5 Control station: data/information about position/heading of the unit, environment conditions, functioning/status of measuring equipment and alarms, status of thrusters, etc., shall be displayed in a separate control station, arranged at a suitable location overlooking the operations and surroundings of the unit. 1.6

Documents for approval

The following documents shall be presented to BKI for approval:

Class Notation

Dynamic positioning installations complying 2.1 with the Rules may be assigned one of the following Notations (additions) to the Character of Class of the vessel or unit: Class Notation DP1 Class Notation DP2 Class Notation DP3 The Class Notations corresponding to DP1 to 2.2 DP3 are associated with different failure modes and degrees of redundancy, DP 1 meaning the lowest, and DP3 the highest grade of sophistication.

–

general description of the system configuration and characteristics, including general arrangement drawings, e.g., control panels, control consoles, location of control station.

For details regarding equipment components and failure suppositions see the Rules mentioned under 1.1 above. In the following, some general requirements are listed and indications given, in addition to the Rules mentioned.

–

thruster characteristics.

3.

–

response of the unit to environment influences, as described under C.6., and to thruster action

Measuring and sensor system

3.1 Definition: The installations/devices referred to under this heading comprise the following items:

Section 7 - Anchoring/Positioning Systems –

position reference/measuring system, indicating at regular intervals the position of the unit in relation to fixed reference points on the seafloor (e.g., beacons) and/or land based reference stations (radar), or satellites; mechanical systems (e.g., taut wire, strain measurement) may be used additionally

–

measuring devices continuously indicating the heading of the unit (usually, gyrocompass)

–

continuous recording of water depth

–

inclination and accelerations measuring devices (roll, pitch, heave), depending on type of unit

–

environmental forces: Wind speed sensors and in particular cases, water velocity (currents) sensors.

Generally, a combination of different 3.2 measuring methods is used for position reference, to ensure an acceptable level of redundancy and reliability. For operations far from land ( radar) stations, DGPS will usually be incorporated in a position reference system. 3.3

Certification, rule applicability

Measuring devices and sensors for which 3.3.1 offshore operation experience is proven will generally not be required to be certified by BKI. However, all equipment forming part of the DP system shall be included in the function testing procedure of the whole system (see 7.). Mechanical, electrical and hydraulic 3.3.2 components of measuring and sensor installations shall comply with Rules for Materials, for Machinery and for Electrical Installations, as far as applicable. Suitability for the particular ocean environment shall be proven. The data transmission frequency of position 3.4 reference measurements shall be sufficient to ensure the reliable functioning of the control system. Acoustic measuring systems shall be designed/ adjusted so that interference with noise/signals from other sources on the unit or neighboring installations will not impair the reliability/operability of the DP system. 3.5

Alarms shall be provided to indicate

–

malfunctioning or breakdown of any single measuring device or sensor,

–

surpassing of allowed range limits.

See also Rules for Electrical Installations, Volume 5, Section 9, and the Rules mentioned under 1.1. above. Where the system design requires redundancy 3.6 of sensors and/or measuring devices, these must be

E

7 -7

fully independent (power supply, data transmission lines, etc.) See Rules mentioned under 1.1 above. 4.

Control system

4.1 Definition: The control system is meant to be a computer or array of computers and interfaces, together with programs, capable of storing and processing the information received from the measuring/sensor system, and deriving there from suitable input for the activation of the thrusters. Furthermore, the system must be capable of controlling the availability/functioning of all components and automatically switching/passing on functions and duties to other (stand by) components in case of failure.

The implied functions of determining the 4.2 unit's actual position and calculating the forces and moments necessary to restore the desired position shall be performed by the computer programs in a stable, convergent manner. This capability, essential for the reliability and efficient of a DP system, shall be confirmed by trials (see 7). Systematic investigations such as failure 4.3 mode and effects analysis should be carried out to determine the viability and reliability of different possible/contemplated system concepts. The corresponding investigation for the concept finally chosen shall be part of the approval documentation. For control/safety systems in general, see also 4.4 Section 8 and Rules for Electrical Installations, Volume 5, Section 9. 4.5

Power supply of the control system: See 6.

Where the degree of redundancy chosen provides for a second (back-up) control system, the power supply of the latter shall be completely independent. 5.

Propulsion system

5.1 Definition: Depending on the type of unit, the propulsion may in principle be effected by

–

fixed propellers (free or ducted; fixed/variable pitch; for ship type units, also transversely arranged tunnel),

–

thrusters (azimuthing unit with gear, usually ducted, sometimes retractable).

Propulsion unit components (propellers, gears, 5.2 couplings, piping) shall generally conform to the relevant BKI Rules (Rules for Materials, Vol. V, Section 11; Rules for Machinery Installations, Volume 4, Sections 5 and 6, or Rules for Machinery Installations, Volume III, Sections 4, 5, 6). See also Section 13, D.

7-8


Where a dynamic positioning installation is 5.3 provided as a sole means for station-keeping, it shall be possible to maintain the position and heading of the unit within the predetermined limits also after failure of any one of the thrusters. Thruster/propulsion control shall generally be 5.4 possible manually as well as incorporated in the computer-based control system (see above). The control mode actually in operation shall be indicated on a separate thruster control panel in the control station(s). The possibility of correcting the heading and 5.5 position of the unit by the combined action of propellers and rudders will generally not be considered as an option within the dynamic positioning concept. The arrangement, design and hydrodynamic 5.6 configuration of the propulsion equipment shall be such that disturbance of the position monitoring (measuring) devices - particularly acoustic systems - is minimized. Special provisions shall be made for propellers 5.7 forming part of the positioning systems, which are also intended for propulsion during transit operations. 6.

Power generation/supply

The electrical power needed for the positioning 6.1 system may be provided by the general power generation system of the unit, or by a separate system. The following requirements are valid for both cases. See also Section 15. Regarding general design and safety 6.2 requirements, reference is made to the relevant BKI Rules (Seagoing Ships: Volume IV, Section 3; Offshore Installations: Volume 5, particularly Sections 3 and 4).

emergency generator).

–

–

–

the total amount of power needed in extreme conditions; the necessary number of generators running, depending on environment conditions; power distribution between positioning system and other users/power needs on board, under normal and under emergency conditions (local selection and limitation); power-related input to the control system (see 4. above), including reaction to component failure/breakdown;

In case of a power supply breakdown, the 6.4 control system shall automatically be supplied by an

system

(battery,

emergency

Redundancy: Regarding availability and 6.5 redundancy requirements for power supply, depending on the Class Notation, see Rules mentioned under 1.1 above. 7.

Testing, trials

Hardware components of the DP system shall 7.1 be tested before being installed, either according to the BKI Rules where they are applicable, or according to an approved test plan. Standard components may be exempted, if testing in a satisfactory manner is incorporated in the production process. Testing of sub-systems shall be carried out 7.2 before installation on board, as far as practicable, by simulation of real operating conditions. This applies also to computers and software. Component and system failures considered in the design procedure are part of the simulation program. Any apparatus/device forming part of the DP 7.3 system installed on board in such a way that it can be affected by vibrations may have to be subjected to a relevant investigation and test. Trials upon completion and installation on 7.4 board shall be carried out in presence of a BKI Surveyor, according to an approved trials plan/program. Acceptance criteria shall be established and agreed upon. The trials program, which may be divided into dockside and on-location testing, shall include verification/testing of the following: –

functioning of the measuring/sensor systems

–

reaction of the control system(s) to specific signals received from the measuring system

–

functioning of alarms and status signals

–

functioning of automatic switch-over and substitution procedures/actions (failures of equipment to be simulated)

–

functioning of all relevant information flow between the control system(s) and the thrusters/propellers

–

position keeping ability of the system after any single failure associated with the assigned Class Notation.

A "Power Management" scheme should be set 6.3 up to determine, i . e., –

supply

E

The propulsion and power supply systems are 7.5 additionally subject to the test procedures prescribed by

Section 7 - Anchorin /Positionin S stems

the BKI Rules for Seagoing Ships, as far as they are not covered by the trials program mentioned above. For tests and surveys, see also Rules for Dynamic Positioning Systems mentioned under 1.1.

2.

Turret - Active Heading Control

1.

General design considerations

Where positioning is effected using a turret installation, it must be decided during the design procedure whether an active turning installation (drives) must be provided to ensure the required heading ("weathervaning") capability of the FPSO unit. Note:

This decision may have to be made at a relatively late stage of design, as it depends on a number of factors, such as turret diameter, bearing configuration, environment forces acting on the unit, tolerances of riser system.

7-9

Structural design

Local forces exerted by the drives shall be taken account of in the structural design of the turret and the adjacent structures of the unit, considering also stiffness requirements/tolerable deformations. See Section 4, C.2.5.

3. F.

F

Mechanical and electrical installation

The machinery components and electrical installation (drive units, gears, power supply, cabling, etc.) shall generally correspond to the requirements of the applicable BKI Rules (Seagoing Ships: Volume III and IV; Offshore Installations: Volume 4 and 5), and/or to acknowledged standards and codes.

The activation of the drives and control of the 4. relative heading shall be effected from the bridge and/or central control station. System details shall be submitted for approval. Testing of the turning installation and control 5. instrumentation is to be carried out under BKI supervision, according to an approved test plan.

Section 8 - Lifting Appliances

8 -1

Section 8 Lifting Appliances 1.

Application/Scope

All lifting appliances, the correct functioning of which may be relevant for the safety of personnel and operations on board, will usually be included in the certification/classification procedure, subject to agreement with the competent Administration. Such appliances may be

Environmental influences on the 3.2 loads, e.g. dynamical effects resulting from ship motions, are generally to be ascertained according to the operating conditions defined in Section 3. However, for liftingappliances special limitations may have to be impos ed in relat ion to sea state/motions of the unit and wind characteristics. Any limitations and instructions for lifting operations shall be clearly stated in the Operating Manual(s).

–

cranes,

–

derricks,

4.

–

hoists (e.g. for riser installation),

Possible influences of lifting operations (heeling moments, changes of vertical centre of gravity) on the stability of a floating unit shall be taken into account in the stability investigations (see Section 6).

– lifts, including their driving/activating machinery and power supply.

Stability

Winches serving the anchoring installation are dealt with in Section 7.

5.

2.

For all materials used for structures and 5.1 equipment of lifting appliances subject to certification, the Rules for Materials, Volume V, shall generally be applied. Exceptions and special agreements for standard components are possible as stated in the Rule mentioned under 3.1 above.

Approval documents

Documents are to be submitted for approval 2.1 as stated in Section 1.D., including information on rated loads, material selection, strength calculations, machinery equipment, rigging and instrumentation. Where standardized equipment is to be used, approval may be based on the specification and complete documentation of the components. In any case, loads exerted by lifting 2.2 appliances on the structure are part of the design documentation to be submitted for approval of the supporting structural parts of the unit.

3.

Load definitions and strength calculations

For definition of loads and for principles and 3.1 requirements regarding strength calculations, see Rules for Specific Type of Units and Equipment. Volume 3, Section 4.

Material and welding

Materials of structural parts connected with the 5.2 structure of the production unit by welding are subject to Rules for Welding, Volume VI in any case, regardless of whether the lifting appliance is included in the certification or not. 6.

Tests and examinations on site

Lifting appliances subject to certification / classification shall be tested (function test, load test) in pres ence of a BKI Surveyor before being put into service. Further periodical tests (and surveys) and tests following repairs or conversions will be defined depending on supervision of the unit in service (classification procedure) by BKI. For details see the Rules for Specific Type of Units and Equipment, Volume 3.

Section 9 - Helicopter Landing Facilities

9-1

Section 9 Helicopter Landing Facilities 1.

Scope, general indications

This guideline provides some general safety 1.1 oriented indications related to helicopter landing facilities. In detail, and particularly regarding size, clearances and approach conditions, marking, lighting and safety equipment, relevant national regulations applicable for the location shall be observed (see 1.3). The helicopter landing area shall be designed 1.2 for the largest helicopter type expected to serve the production unit, and for the landing impact (dynamical) loads considered possible, depending on type/motion characteristics of the unit and environment conditions limiting helicopter service. Regarding safety of helicopter operations, 1.3 attention is drawn to the standards of the International Civil Aviation Organization (ICAO), to the "Memorandum of Understanding" between ICAO and IMO, and to the UK Guidance on relevant standards (e.g., CAA/JAA, CAP 437). 2.

3.

Structure

See Section 4, C.4., and the BKI Rules stated there. Construction material: See 4.1. below. 4.

Fire protection; access

Helicopter decks and their supporting 4.1 structure shall be made of steel or of equivalent fire resistant construction. Helicopter decks arranged directly on top of 4.2 a super-structure shall correspond to an "A60" Class division (see Section 11, B.). Means for a safe drainage of spilled fuel 4.3 shall be provided (see 6.) The helicopter deck shall have at least two 4.4 points of access/escape routes, situated as far apart as possible.

Allocation of the helideck 5.

On offshore production units capable of 2.1 weather-vaning, the helicopter landing area shall be located as far as possible upwind; on ship-type units this usually means a helideck structure on top or to the bow of the accommodation super structure. On production units which cannot turn into 2.2 the wind, e.g. semi-submersible offshore units with spread mooring, the helicopter landing area should be arranged considering –

greatest possible distance from hazardous areas,

–

greatest possible distance from approach obstacles (observing existing regulations, see 1. 1),

–

easy access by personnel,

–

prevailing wind direction.

Where helidecks are located above 2.3 accommodation quarters, structural fire protection requirements must be observed. It is recommended to provide a space with free air circulation between the helideck and the top of the deckhouse serving as living area. See also 4.2.

Fire-fighting equipment

Fire-fighting/-extinguishing equipment shall be provided in accordance with the regulations of the competent Administration. The following indications may serve as guidance: –

Dry powder extinguishers with a total capacity of not less than 45 kg.

–

A suitable foam application system consisting of monitors or branch pipes. The system must be capable of supplying to the points of discharge 6 l/min of foaming agent for at least 5 minutes per each square meter within a circle of diameter D (D is the distance in meters across the main rotor and tail rotor in a fore and aft line of a helicopter with a single main rotor and across both rotors for a tandem rotor helicopter). The operation of the foam system is not to interfere with the simultaneous operation of the fire main.

–

CO2 extinguishers of a total capacity of not less than 18 kg, one of the extinguishers being able to reach the engine area of a helicopter using the platform.

9-2

Section 9 - Helicopter Landing Facilities

–

At least two dual purpose nozzles and hoses sufficient to reach any part of the helicopter deck.

Fire resistant material, as short as possible and protected against damage.

–

At least one fireman’s outfit.

6.

Fuel storage

Electrical fuel pumping units and associated 6.6 control equipment are to be of a type suitable for the location and potential hazard.

The fuel storage areas should be as remote 6.1 as practicable from accommodation spaces, escape routes and embarkation areas, and suitably isolated from areas containing a source of ignition. Containment of fuel spillage and draining to 6.2 a safe location is to be provided for. Tanks and associated equipment are to be 6.3 protected against physical damage and from a fire in an adjacent space or area. Storage tank fuel outlet valves are to permit 6.4 closure from a remote position. The fuel pumping unit is to be connected to 6.5 one tank at a time, and the piping between the tank and the pumping unit is to be of steel or equivalent.

Fuel pumping units should incorporate a device which will prevent over-pressure in the delivery or filling hose. Where portable fuel storage tanks are used, 6.7 special attention is to be given to –

design of the tank for its intended purpose,

–

mounting and securing arrangements,

–

electrical bonding,

–

inspection procedure.

Additional requirements of the competent 6.8 Administration, e.g. regarding fire-extinguishing arrangements for the fuel storage area, may have to be observed.

Section 10 - Life Saving Appliances and Equipment/Means of Escape

A, B

10 - 1

Section 10 Life Saving Appliances and Equipment/Means of Escape

A.

Means of Escape/Refuge

Areas or groups of spaces which are 1. regularly occupied, and accommodation spaces, must have two separate escape routes.

Lifts should not be considered as forming 2. one of the required means of escape.

B.

Life-saving Appliances and Equipment

1.

General

Life-saving appliances and equipment shall 1.1 comply with the relevant applicable international and/or national regulations and shall be suitable for the type and use of the offshore unit. Reference shall be made to the –

IMO Code for the Construction and Equipment of Mobile Offshore Drilling Units ("MODU CODE"),

–

SOLAS 1974, Chapter III.

–

IMO Life-saving Appliances Code

–

BKI Regulations for Life - saving Launching Appliances.

Stairways and ladders shall be so arranged 3. as to provide ready means of escape to the lifeboat and life raft embarkation deck.

Dead-end corridors of more than 7 m in 4. length are not allowed.

Lifeboat embarkation stations and the access 5. routes to them must be sufficiently protected to withstand a fire long enough to enable the crew to abandon the platform or unit.

Escape ways and embarkation areas shall be 6. sufficiently illuminated. Lighting shall be automatically switched to the emergency source of power (see Rules for Electrical Installations, Volume 5, Section 3, D.).

For production units, for which 1.2 certification/classification by BKI has been agreed, life-saving appliances may be included in the certification, upon owner’s request. The following indications may serve as a 1.3 guidance where no other regulations are applicable or available. 2.

Life-saving appliances

Access to and location of the helideck: See 7. Section 9.2.

If not stated otherwise by the competent Administration, each manned unit s hould be provided with at least the following life-saving appliances:

A temporary refuge (shelter) room or several 8. such rooms may be required in particular cases, depending on the assessment of r isks and possibilities of escape. Details regarding, e.g.,

–

one rigid totally enclosed motor-propelled survival craft, on each side of the unit (on ship- type units, and in two locations reasonably apart on other units) of such aggregate capacity as to accommodate all persons on the unit;

–

in addition, rigid or inflatable life raft(s) of such aggregate capacity as will accommodate the total number of persons on board, complying with the applicable regulations (see above);

–

structural fire protection,

–

venting/air supply,

–

communications,

–

first aid facilities and survival equipment

will be determined in the particular case, and will possibly have to be agreed upon with the competent Administration.

10 - 2

Section 10 - Life Savin A

liances and E ui ment/Means of Esca e

B

–

One rescue boat (a lifeboat may be accepted as a rescue boat provided it also complies with the applicable requirements rescue boats);

However, the supporting structure in way of the launching devices, taking into account the forcesfrom the above appliances, is subjected to approval and certification/classification.

–

lifejackets of an approved type for all persons usually present on board of the unit, and, in addition, spare lifejackets for 5 % of that number;

The inspection of the life-saving appliances 3.2 and their launching devices with regards to their proper condition and functioning may be carried out within the scope of the periodical (classification) surveys upon special request (see 1.2).

–

at least eight lifebuoys so distributed as to be readily available on all sides of the installation, and as far as practicable on all open decks extending to the sides.

3.

Approval, tests, surveys

Generally, the dimensioning and testing of 3.1 survival craft with their launching devices and of other life-saving appliances are not part of the certification/classification procedure (see 1.2 above).

Section 11 - Fire Safety

A

11 - 1

Section 11 Fire Safety A.

Area Classification/Ventilation

1.

General remarks

1.1

Scope

Due to the nature and properties of the 1.1.1 substances handled on board of offshore production and storage units, the risk of explosion and/or fire exists, to a varying degree, in various locations of the unit. It is, therefore, necessary to define Hazardous Areas and Non-hazardous Areas ("Area Classification"), and to separate these areas as efficiently as possible. Regarding Control and 1.1.2 requirements, see also Section 16. 1.2

Instrumentation

General arrangement

Depending on the type of unit, the Area 1.2.1 Classification influences the general arrangement of the installations on board. For units capable of "weather-vaning", the principle should be observed that Hazardous Areas are arranged downwind from Non-hazardous Areas. On units, where this possibility does not exist, separation of the areas mentioned, and of the air supply to the related spaces, shall be accomplished as efficiently as possible. In the vertical direction, sufficient separation 1.2.2 of Hazardous and Non-hazardous Areas is to be provided, e.g. accommodation spaces should not be arranged above storage tanks classified as Hazardous Areas or, if this cannot be avoided, separation by a ventilated space shall be provided. See also B. 2.

Definitions

2.1 Hazardous Areas are areas in which flammable, explosive or toxic substances, particularly gas/air mixtures, are normally present or may be present under normal operating conditions. In such areas, special measures are to be taken, such as

2.2 Non-hazardous Areas are all areas not considered hazardous, i.e. areas where a dangerous concentration of substances as described above must not be expected under normal operating conditions.

Due to the confined space available, it may be necessary, also in areas classified as "non-hazardous", to provide measures such as ventilation and/or pressurising, in order to achieve an acceptably low risk level (e.g., in living quarters). 2.3

Degree of enclosure

Enclosed spaces are closed rooms confined by walls/bulk-heads, decks etc., and provided only with the absolutely necessary openings, such as doors, windows, ventilation ducts, etc. Partially enclosed locations are spaces which are not closed on all sides or not closed completely, but where natural ventilation is not ensured. Outdoor locations are areas where natural ventilation is not impeded. 3.

Area classification

3.1

Definitions/principles

For the purpose of selection and installation 3.1.1 of machinery and electrical equipment Hazardous Areas are divided into Zones as follows: Zone 0 in which an ignitable gas/air mixture is continuously present, or considered to be present for long periods. Zone 1 in which an ignitable gas/air mixture is likely to occur. Zone 2 in which an ignitable gas/air mixture is not likely to occur, and if it occurs, it will only exist for a short time.

This area classification is based on normal operating conditions. Other related codes are applicable. The following aspects for the determination 3.1.2 of Hazardous Areas have to be additionally considered

–

explosion-proof equipment (see E. and Section 8)

–

physical properties substances

of

–

ventilation (see 4. below)

–

–

fire-fighting and rescue equipment (see D.)

quantity, pressure and substance(s) released

–

environmental conditions

–

method of ventilation

the

ignitable

temperature

of

11 - 2


As the boundaries of areas often cannot be 3.1.3 definitely stated to cover all possible situations, each individual case has to be considered under the aspect of sound engineering practice. The boundaries of the different Zones may be determined in accordance with relevant recognized standards or codes of practice. It may be seen from the f ollowing examples that classification, e.g. into Zone 1 or 2, often depends on the judgement of prevailing conditions and on the equipment/installations provided, e.g. ventilation arrangement. Personnel safety with respect to toxic 3.1.4 substances (e.g., H2S) is to be considered separately, taking into account also the requirements of the com petent Administration. 3.2

Hazardous Areas, Zone 0

3.2.1

Hazardous Areas, Zone 0 include

–

the internal spaces of closed tanks and pipes (including escape gas outlet pipes),

–

crude oil and gas producing and treating facilities, and

–

any other spaces in which an oil/gas/air mixture is expected to be continuously present or present for long periods.

A spherical space surrounding an escape or 3.2.2 vent gas outlet has to be defined as a Zone 0 area, if gas is released continuously or for extended periods. For the determination of the radius of that spherical space the pressure, properties and quantity of the released substances as well as environmental factors have to be taken into consideration. 3.3

Hazardous Areas, Zone 1

–

A

pits, ducts or similar structures in locations which otherwise would be classed Zone 2, but where the arrangement is such so that dispersion of gas is not ensured, depending on environment conditions.3.4Hazardous Areas, Zone 2

Hazardous Areas, Zone 2 include –

outdoor locations/deck in the crude oil storage area up to a height of 2,4 m above the deck. Where inerting is used for storage tanks, the area classification may be specially considered;

–

locations within 1,5 m from the outdoor areas listed as third and fourth under 3.3 above;

–

enclosed spaces and partially enclosed locations which contain detachable sections of crude oil or gas pipes, where leakage may occur (if such locations are not classed Zone 1);

–

outdoor locations within 3 m from ventilation outlets and from detachable crude oil or gas pipes where leakage may occur (if such locations are not classed Zone 1;

–

air locks between a Zone 1 and a Nonhazardous space;

–

pits, ducts or similar structures in locationswhich otherwise would be classed as nonhazardous areas, but where the arrangement is such that dispersion of gas is not ensured.

3.5 Connections between different zones of Hazardous Areas

Hazardous Areas, Zone 1 include

3.5.1

–

tanks and cofferdams adjacent to crude oil or slop tanks,

–

enclosed and partially enclosed spaces which contain a possible source of release, such as pumps and compressors handling crude oil and gas;

3.5.1.1 Except for compelling operational reasons, access doors or other openings shall neither be provided between a Non-hazardous and a Hazardous Area nor between a Zone 2 and a Zone 1 space.

–

outdoor or partially enclosed locations within 1,5 m from

Where such access doors or other openings are provided, any enclosed space not referred to under 3.3 or 3.4 having a direct access to any Zone 1 or Zone 2 location becomes the same Zone as that location, with the following exceptions.

+ release sources as mentioned above,

3.5.1.2 An enclosed space with direct access to any Zone 1 location can be considered as Zone 2 if

+ safety valves or other outlets possibly releasing gas,

–

the access is fitted with a gas-tight door opening into the Zone 2 space, and

–

ventilation is such that the air flow with the door open is directed from the Zone 2 space into the Zone 1 location, and

–

loss of ventilation is alarmed at a manned station.

+ ventilation outlets of Zone 1 spaces, and + access openings to Zone 1 spaces; –

Access openings

outdoor locations within 1,5 m from vent outlets of crude oil tanks and slop tanks,


3.5.1.3 An enclosed space with direct access to any Zone 2 location is not considered hazardous if

–

–

–

the access is fitted with a self-closing gastight door that opens into the non-hazardous location, and ventilation is such that the air flow with the door open is directed from the non-hazardous space into the Zone 2 location, and loss of ventilation is alarmed at a manned station.

3.5.1.4 An enclosed space with direct access to any Zone 1 location is not considered hazardous if

–

the access is f itted with gas-tight self-closing doors forming an air lock, and

–

the space has ventilation overpressure in relation to the hazardous space, and

–

loss of ventilation overpressure is alarmed at a manned station.

Where in special cases ventilation arrangements of the intended safe space are considered sufficient to prevent any ingress of gas from the Zone 1 location, the two self-closing doors forming an air lock may be replaced by a single self-closing gas-tight door which opens into the non-hazardous location and has no hold-back device. Piping systems shall be designed to preclude 3.5.2 direct communication between Hazardous Areas of different zone classifications and between Hazardous and Non-hazardous Areas. 4.

Ventilation

4.1

General requirements

Attention shall be given to ventilation inlet 4.1.1 and outlet locations and air flow in order to minimize the possibility of cross contamination. Inlets are to be located in Non-hazardous Areas as high and as far away from any Hazardous Area as practicable. The arrangement of ventilation inlet and 4.1.2 outlet openings in an enclosed space shall be such that the entire room is effectively ventilated, giving special consideration to air consumption by and location of the equipment. Each air outlet shall be located in an outdoor 4.1.3 area which, in the absence of the considered outlet, is of the same or lesser hazard than the ventilated space. Ventilation for Hazardous Areas is to be 4.1.4 completely separate from that used for Non hazardous Areas. Adequate discharge of exhaust air under

A

11 - 3

environmental conditions must be aimed at. Where natural ventilation is considered 4.1.5 sufficient, its effectiveness has to be proved. Additionally, the following aspects shall be 4.1.6 considered: –

maintaining of suitable temperatures, supply of fresh air, humidity conditions and acceptable levels of noise

–

thermal insulation

–

air filtration

–

provision of standby equipment.

4.2

Ventilation of Hazardous Areas

Enclosed Hazardous Areas shall be provided 4.2.1 with adequate ventilation with under pressure in relation to an adjacent less hazardous space or Zone. Special consideration shall be given to the location of equipment which may release gas, and to locations where gas may accumulate. 4.2.2 Ducts: Where the inlet duct passes through an area with higher hazard rating, it has to have overpressure in relation to this area. The outlet air from Zone 1 and Zone 2 spaces shall be led in separate ducts to outdoor locations. The internal spaces of such ducts belong to the same Zone as the ventilated space.

For ducts, see also 4.5 and B.4.6. 4.3

Ventilation of Non-hazardous Areas

4.3.1 Enclosed living and working areas are to be maintained under overpressure in relation to adjacent hazardous locations. 4.3.2 Ducts: Where the inlet duct passes through a space rated as Hazardous Area it has to have overpressure in relation to the Hazardous Area. Exceptions may be allowed if the ducts in the Hazardous Area are made gas-tight and are provided with increased wall thicknesses and/or insulation.

For control stations alternative and separate 4.3.3 means of air supply shall be provided; air inlets of the two sources of supply shall be so disposed that the risk of both inlets drawing in smoke or flammable air/gas mixtures simultaneously is minimized. 4.4

Values of air flow rate and overpressure

At least 20 air changes per hour have to be 4.4.1 achieved in spaces of Zone 1, and at least 12 in spaces of Zone 2. During start-up or after shut-down it is necessary either to ensure that the internal atmosphere is not hazardous, or to proceed with prior purging of

11 - 4


sufficient duration. Generally the necessary volume for purging is estimated as at least five times the internal volume of the room and its associated ducts. Where mechanical ventilation is provided for 4.4.2 overpressure, a minimum of 25 Pa (0,25 mbar) with respect to the outer atmosphere shall be maintained at all points inside the space. If there is any air consuming equipment inside the pressurized room, the ventilation flow shall be capable of covering all needs. 4.5

Ducts and shutters

Air ducts have to be made of steel or other 4.5.1 equivalent material, where ‘equivalent material’ means any material which, by itself, or due to insulation provided, has structural properties equivalent to steel at the end of the applicable fire exposure to the standard fire test (e.g., aluminium with appropriate insulation). The ducts have to be protected against corrosion and shall be provided with means for inspection. provided for ventilation of 4.5.2 Ducts accommodation or service spaces and control stations shall generally not pass through working spaces. Ducts provided for ventilation of working areas shall not pass through accommodation or service spaces and control stations. See also B.4.6. The exhaust ducts from galleys shall be 4.5.3 constructed of "A" Class divisions (see B.). Each exhaust duct shall be fitted with –

a grease trap readily removable for cleaning,

–

a fire damper located in the lower end of the duct,

–

an off-switch (actuated from the galley) for the fan, if power ventilation is provided, and

–

fixed means for extinguishing a fire within the duct.

The main inlets and outlets of all ventilation 4.5.4 systems shall be capable of being closed from outside the area being ventilated. Ducts with a sectional area exceeding 750 cm2 and penetrating Class A or B bulkheads and decks are additionally to have fire dampers with melting fuse or plug or other equivalent arrangement. The fire dampers shall close automatically at a temperature above 70°C. In the closed condition fire dampers shall rest firmly and throughout on sealing steel bars and be capable of being arrested. Their position shall be clearly and permanently indicated.

B

B.

Structural Fire Protection

1.

General indications

The terms and definitions used in the 1.1 following correspond to those of Chapter II-2 of SOLAS 74. The requirements of this IMO convention are applicable in principle. Additional requirements of the competent Administration may have to be observed. Some principles on structural fire protection, 1.2 together with particular requirements for offshore production/storage units, are given below. For details see also –

for ship - type units: Rules for Hull, Volume II, Section 22;

–

for offshore installations such as column stabilized units: Rules for Machinery Installations, Volume 4, Section 10.

1.3

In special cases the fire protection arrangements may differ from the regulations of this section, provided that the protection is considered to be equivalent, owing to appropriate measures having been taken.

Type "A", "B" and "C" Class divisions as 1.4 well as the insulation materials, linings, ceilings, surface materials and not readily ignitable deck coverings shall be of approved type. Drawings showing the general arrangement 1.5 and the intended use of all spaces, and containing details on the planned structural fire protection arrangements as well as information about type, manufacturer and existing type approvals are to be submitted for approval. 1.6

Fire and blast walls: See 5.

2.

Materials

The hull, decks, structural bulkheads, super 2.1 structures and mooring structures are to be made of steel (see Section 4 and 5). Other equivalent material (Aluminium alloy suitably insulated) may be approved in particular cases, having in mind the risk of fire. Components made from aluminium alloys 2.2 require special treatment with regard to the mechanical properties of the material in case of temperature increase. In principle, the following is to be observed:


B B

11 - 5 11 - 5

a)

The insulation of "A" or "B" Class divisions shall be such that the temperature of the structural core does not rise more than 200 °C above the ambient temperature at any time during the relevant exposure to the standard fire test.

Accommodation spaces are those used as 4.1.3 public spaces, cabins, offices, hospitals, cinemas, games and hobbies rooms and similar spaces. Public spaces are those portions of the accommodation which are used for halls, dining rooms, lounges, and similar permanently enclosed spaces.

b)

Special attention shall be given to the insulation of aluminium alloy components of columns, stanchions and other structural members required to support helidecks as well as lifeboat and liferaft stowage, launching and embarkation areas, and "A" and "B" Class divisions to ensure that

Stairways are interior stairways, lifts and 4.1.4 escalators (other than those wholly contained within the machinery spaces) and enclosures thereto.

for such members supporting helidecks, lifeboat and liferaft areas and "A" Class divisions, the temperature rise limitation specified in a) above applies at the end of one hour; and

Service spaces (low risk) are lockers, store 4.1.5 rooms and working spaces, in which no flammable materials are stored, drying rooms and laundries.

–

–

for such members required to support "B" Class divisions, the temperature rise limitation specified in a) above applies at the end of half an hour.

Crowns and casings of machinery spaces of 2.3 category A shall be of steel construction adequately insulated, and openings therein, if any, shall be suita bly arranged and protected to prevent the spread of fire.

3.

Terms and definitions

For basic definitions in connection with structural fire protection, such as –

"non-combustible material",

–

"standard fire test",

–

"A Class division", "B Class division",

–

fire zone(s), etc.,

reference is made to the rules and regulations mentioned under 1.1 and 1.2 above. 4.

Structural fire protection requirements

4.1

Definitions of spaces

Control stations are those spaces in which the 4.1.1 unit's radio or main navigating equipment is located, or where the production control is centralized, or where the fire recording or fire control equipment or the dynamical positioning control system is centralized, or where a fire extinguishing system serving various locations or a central ballast control station is situated. In the application of this section, the space where the emergency source of power is located is not considered as being a control station. 4.1.2 Corridors means corridors and lobbies.

In this connection a stairway, which is enclosed only at one level, should be regarded as part of the space from which it is not separated by a fire door.

Machinery spaces of Category A are all 4.1.6 spaces which contain –

internal combustion type machinery used either for main propulsion or other purposes, where such machinery has in the aggregate a total power of not less than 375 kW;

–

any oil-fired boiler or oil fuel units;

–

trunks to such spaces.

Other machinery spaces are all machinery 4.1.7 spaces except those of Category A containing propelling machinery, boilers and other fired process equipment, oil fuel units, steam and internal combustion engines, generators and major electrical machinery, oil filling stations, refrigerating, stabilizing, ventilation and air-conditioning machinery and similar spaces, and trunks to such spaces. Hazardous Areas are all those areas where, 4.1.8 due to the possible presence of a flammable atmosphere arising from the production operations, the use without proper consideration of machinery or electrical equipment may lead to increased fire or explosion hazard. See also A. above. Service spaces (high risk) are lockers, store 4.1.9 rooms and working spaces in which flammable materials are stored, galleys, pantries containing cooking appliances, paint rooms and workshops other than those forming part of the machinery space. 4.1.10 Open decks are open deck spaces, excluding Hazardous Areas. 4.1.11 Sanitary and similar spaces are communal facilities such as showers, baths, lavatories etc., and isolated pantries containing no cooking appliances. Sanitary facilities which serve a space and with access only from that space shall be considered a portion of the space in which they are located.

11 - 6


4.1.12 Crude oil pump room is a space containing crude oil conveying pumps, and includes entrances and trunks leading to such a space. 4.2 Fire integrity of bulkheads, decks and superstructure boundaries

In addition to complying with the specific 4.2.1 Provisions for fire integrity of bulkheads and decks in the detailed regulations mentioned under 1.2, the minimum fire integrity of bulkheads and decks should be as shown in Tables 11.1 and 11.2.

B

4.2.2 Application of the tables 4.2.2.1 Tables 11.1 and 11.2 apply respectively to the bulkheads and decks separating adjacent spaces as defined under 4.1. 4.2.2.2 For determining the appropriate fire integrity standards to be applied to divisions between adjacent spaces, such spaces are classified according to their fire risk: Categories 1 to 12, corresponding to the definitions given in 4.1. The title of each category is intended to be typical rather than restrictive.

Table 11.1 Fire integrity of bulkheads separating adjacent spaces


B

11 - 7

Table 11.2 Fire integrity of decks separating adjacent spaces

4.2.3 Perforations: Where "A" Class divisions are pierced for the passage of electric cables, pipes, trunks, ducts, etc., or for girders, beams or other structural elements, arrangements shall be made to ensure that the fire resistance is not impaired.

4.3

Exterior boundaries of superstructures and 4.2.4 deckhouses enclosing accommodation, including any overhanging decks which support such accommodation, should be constructed to "A-60" standard for the whole of the portion which faces the crude oil storage area (and/or the production area, if this, in exceptional cases, is arranged nearby - see A.1.2 above). On the side and top portions the same applies to the boundary plating for a distance of not less than 3 m from the portions mentioned above. BKI may accept equivalent arrangements.

4.3.2

Arrangement and type of openings

The BKI rules mentioned under 1.2 above 4.3.1 are applicable regarding details, depending on the type of unit. Some important principles are stated below. Doors

4.3.2.1 External doors in superstructures and deckhouses should be constructed to "A-0" Class division and be self-closing, where practicable. 4.3.2.2 No doors shall be arranged in or near superstructure boundaries facing the crude oil storage and production areas, if they would provide access to accommodation and service spaces, or to control stations. Doors leading to other spaces, not having direct connection to spaces as listed above, may be permitted, provided that the boundaries of the spaces are insulated to "A-60" standard.

11 - 8


4.3.2.3 The construction of all doors and frames in Class divisions, including the means of securing them when closed, shall provide resistance to fire as well as to the passage of smoke and flames, as far as practicable, equivalent to that of the bulkheads in which the doors are situated. Such doors and door frames shall be constructed of steel or other equivalent material. 4.3.2.4 Doors in "A" Class divisions must be capable of being opened and closed from each side of the bulkhead by one person only. 4.3.3

4.3.3.2 Skylights for crude oil pump rooms shall be of steel (without glass panes) and shall be capable of being closed from outside the pump room. Corridors

Corridor bulkheads, including doors, should be "A" or "B" Class divisions extending from deck to deck. Where continuous "B" Class ceilings and/or linings are fitted on both sides of the bulkhead, the bulkhead may terminate at the continuous ceiling or lining. Doors of cabins and public spaces in such bulkheads may have a louvre in the lower half. Such openings should not be provided in a door in an "A" or "B" Class division forming a stairway enclosure. For escape ways, see Section 10, A. 4.5

Stairways, elevator trunks

Stairs shall be constructed of steel or equiva4.5.1 lent material. Stairways which penetrate only a single deck shall be protected at least at one level by "A" or "B" Class divisions and self-closing doors so as to limit the rapid spread of fire from one deck to another. Personnel lift trunks should be protected by 4.5.2 "A" Class divisions. Stairways and lift shafts which penetrate 4.5.3 more than a single deck should be surrounded by "A" Class divisions and protected by self-closing doors at all levels. Self-closing doors should not be fitted with hold-back hooks. However, hold-back arrangements incorporating remote release fittings of the fail-safe type may be utilized.

Ventilation ducts

Ducts provided for ventilation of machinery 4.6.1 spaces of Category A and Hazardous Areas shall not pass through accommodation and service spaces or control stations. However, relaxation from this requirement may be permitted provided that –

the ducts are constructed of steel and insulated to "A-60" standard; or

–

the ducts are constructed of steel and fitted with an automatic fire damper close to the boundary penetrated, and insulated to "A-60" standard from the machinery space of Category A to a point at least 5 m beyond the fire damper.

Windows, sidescuttles, skylights

4.3.3.1 Windows and sidescuttles, with the exception of navigating bridge windows, should be of the nonopening type. Navigating bridge windows may be of the opening type, provided the design of such windows would permit rapid closure. Windows and sidescuttles outside Hazardous Areas may be of the opening type, depending on the applicable Administration regulations.

4.4

4.6

B

Ducts provided for ventilation of 4.6.2 accommodation and service spaces or control stations should not pass through machinery spaces of Category A or Hazardous Areas. However, relaxation from this requirement may be permitted provided tile ducts are constructed of steel and an automatic fire damper is fitted close to the boundaries penetrated. 4.7

Fire protection of helidecks: See Section 9, 4.

5.

Fire and blast walls

Where, on open decks, a satisfying 5.1 separation of areas corresponding to different hazard classification or different fire zones cannot be achieved, or where an improved protection of important escape ways is considered necessary, the arrangement of fire or blast walls may be required. A fire wall shall in principle be constructed 5.2 to A-60 standard. The structure shall be adequate to withstand the environment forces and the inclinations/accelerations to be expected at the particular location on the unit. Where the wall is supported by other structures, such as a superstructure or deckhouse, also the connecting elements shall be suitably protected against fire. For the design and construction of blast walls, 5.3 the particular situation (geometrical configuration, nature of explosion source, etc.) shall be evaluated, considering, i.e., –

the "worst case scenario" regarding energy dissipation/occurring pressures, and

–

the kind of installations and structures to be protected.


Control stations

At least one control station, which is to be 1.1 permanently manned, shall be provided in the safe area. Depending on the design of the production/ storage unit, a second control station may be required. The arrangement of the control station(s) is to be determined from case to case. See also Section 14, A. In the control station the following items 1.2 shall be provided a)

means of communication with other stations essential to the safety of the unit;

b)

all the necessary arrangements for the emergency shut-off and remote controlled valves, including riser and offloading line connections, where applicable, referred to in Section 17, C. and Section 18, C. and D.;

c)

arrangements for starting the fire pumps referred to in E.2.;

d)

manual means to set off the general, fire and gas alarms;

e)

means of indicating whether fire doors are closed and whether the bulkhead doors are open or closed;

f)

2.

the fire alarm and gas alarm central consoles, lists and location plans/tables of fire detectors and gas monitoring points, and the control plans. Fire detection and alarm system

Every offshore installation shall be provided 2.1 with an automatic fire detection system for all accommodation and service spaces. Sufficient manual fire alarm stations shall be 2.2 fitted at suitable locations throughout the unit. In the Hazardous Areas referred to under A. 2.3 only alarm loops of a certified safe type may be used. The sensitivity of the detectors, individually 2.4 or in groups, must be capable of being adjusted to the local conditions. With respect to their mode of operation the 2.5 following types of fire detectors have to be provided for the appropriate locations: a)

smoke detectors are to be used for clean areas not associated with flammables, i.e.

11 - 9

accommodation, control rooms, electrical switch gear rooms. Flame detection can be used in addition;

C. Control Stations, Fire and Gas Detection Systems 1.

B

b)

flame detectors shall be used where flames are to be expected to give the first indication of fire, i.e. in hydrocarbon and fuel areas;

c)

thermal detectors are to be used where ambient conditions are not suitable for smoke detectors, i.e. on open deck areas, or as a back-up to flame detectors in high hazard areas;

d)

readily visible manually actuated alarms have be provided in addition for escape routes, corridors, stairways, and at locations from which the fire pumps can be started.

In workshops and spaces in which the smoke 2.6 detectors may be actuated by normal operations, for instance by welding work, such detectors may be switched off while the work is going on. The detectors must be reactivated automatically after a pre- selected time. 2.7

Arrangement of detectors and alarm loops

Every alarm loop shall not cover more than 2.7.1 one fire zone or watertight compartment and, as far as practicable, not more than one deck or a stairway connecting more than two decks. Where there are arrangements for the separate flooding with fire extinguishing media of two or more adjoining spaces, separate alarm loops have also to be provided. For areas provided with automatic pressure 2.7.2 water spray systems, separate alarm loops per section are to be allocated. The number of the detectors referred to in 2.5 2.7.3 shall not exceed 20 per alarm loop. Manually actuated alarms may be incorporated in a loop together with automatic alarms. The arrangement and number of detectors 2.7.4 have to be such that all Hazardous Areas are covered. This applies in particular to control and working spaces. 2.8

Fire alarm central console

The fire alarm central console shall be 2.8.1 located in a permanently attended space (control station). The fire alarm central console shall contain 2.8.2 means of operating a visual and audible signal in case of a responding fire detector, which is to be clearly distinguishable from other signals.

11 - 10


Where it is not ascertainable at the central 2.8.3 console which detector has responded, each individual detector shall be provided with its own visual indication. This indication shall remain active until the alarm has been accepted all the central console. The system shall be self monitoring, i.e. all 2.8.4 faults such as broken wires or short circuits in an alarm loop, loss of voltage, etc. are to be indicated visually and audibly. The fire alarm central console is to be 2.8.5 supplied from two separate power sources. Change over from the main supply to the emergency source shall be automatic. A list or location table showing the 2.8.6 arrangement of detectors has to be provided in the vicinity of the fire alarm central console. If two or more fire detectors are actuated 2.9 simultaneously, appropriate automatic safety functions shall be initiated. 3.

Gas detection and alarm system

A fixed automatic flammable gas detection 3.1 and alarm system is to be provided. It is to be so arranged as to monitor continuously all areas where an accumulation of gases may be expected to occur, and be capable of indicating at the control station(s) by audible and visual means the presence and location of an accumulation of gas. At least two portable gas monitoring devices 3.2 are to be provided, each capable of accurately measuring a concentration of flammable gas. The gas and fire detection system shall be 3.3 designed in such a way that it can be tested without interrupting the normal activities on the unit. The gas alarm central console is to be located 3.4 in a permanently attended space (e.g., control station). It shall be possible to identify the detector giving alarm on the control panel. 3.5

Alarm and automatic safety functions

The detection system shall initiate an alarm in 3.5.1 the control station before the gas concentration reaches dangerous limits. At a concentration of 20 % of the LEL an audible and visual alarm shall be initiated in the control station. The detection system shall automatically 3.5.2 activate the safety system before the concentration of gases reaches the explosive limit. At a maximum of 60 % LEL automatic safety functions shall be activated.

4.

D, E

Calibration and testing

4.1 Means shall be provided whereby operational personnel may readily check on the accuracy of gas percentage readings and the response of fire detectors. 4.2 Provision shall be made to enable the fixed system to be tested without disruption of the normal routine. D.

Storage of Gas Bottles

Special areas are to be provided for the storage of acetylene, oxygen and other gas cylinders which might be a source of or contribute to a fire. 1.

2. Where two or more cylinders of each gas are intended to be carried in enclosed spaces, separatededicated storage rooms are to be provided for eachgas. 3. Gas bottles storage rooms are to be constructed of steel, and be well ventilated and accessible from safe areas. (For storage of CO 2 gas containers, see E.3.2).

E.

Fire-Fighting Installations

1.

General indications

The kind of fire extinction equipment which 1.1 may be used in the different typical areas of a floating production/storage unit may be chosen according to the relevant requirements for Seagoing Ships (Volume III, Section 12, Table 12.1) or for Offshore Installations (Volume 4, Section 10, Table 10.3), depending on the type of unit. National regulations may have to be observed. Where systems of the same type are used in 1.2 different areas, the total quantity of fire-fighting medium to be kept available on board shall be determined from case to case, depending on the connecting piping/transport facilities, and on the evaluation of fire risk in the areas concerned. Plans and documents containing details 1.3 (type, manufacturer, number, location) of the fire fighting equipment are to be submitted to BKI for approval.


Testing of fire-fighting equipment and drills 1.4 should be possible without impairment or interruption of other (normal) operations on board of the unit. In the following, some general requirements 1.5 are listed. For details, see Rules for Machinery Installations, Volume 4, Section 10, C. – F., as applicable. Gas-based fire fighting agents other than CO2 1.6 may be considered, if proof of their successful and safe use can be furnished. 2.

Water-based fire-fighting systems

2.1

Fire pumps

2.1.1 At least two fire pumps driven independently of the main power source have to be provided. At least one of the pumps is to be dedicated to fire fighting duties only. 2.1.2 The pumps, their power supply and the associated pipes and valves are to be so arranged that a fire in any fire zone does not involve the failure of all the fire pumps. 2.1.3 Fire water pumps shall start automatically when there is a pressure drop in the firewater main. 2.2

Fire mains

2.2.1

A fixed fire main shall be provided.

2.3

2.2.3 With the required fire pumps operating simultaneously, the pressure maintained in the fire mains shall be adequate for the safe and efficient operation of all equipment supplied therefrom. 2.2.4 The fire main is to be routed clear of Hazardous Areas as far as practicable and be arranged in such a manner as to make maximum use of any shielding or physical protection afforded by the structure of the unit. 2.2.5 The fire main shall be provided with isolating valves located so as to permit optimum utilization in the event of physical damage to any part of the main. 2.2.6 The fire main shall not have connections other than for fire-fighting purposes. 2.2.7 All practical precautions should be taken to protect the fire main against freezing, in order to have water readily available. or oil processing facilities and storage areas which

11 - 11

Deluge systems

Gas or oil processing facilities and storage areas which require water protection may be covered by automatically or manually operated deluge systems and/or monitors. Where deluge systems are installed, the requirements as per Section 10, C.3.1 of the Rules mentioned in 1.5 apply. 2.4

Automatic sprinkler systems

Every normally manned production/storage 2.4.1 unit shall be provided with an automatic sprinkler system for the accommodation spaces. The pressure water tank and sprinkler pump 2.4.2 are to be located in a safe area outside the spaces to be protected. The system is normally to be supplied by a 2.4.3 pressurized fresh water system, capable, once actuated, of operating automatically and efficiently for 4 hours. In the event of a pressure drop in the system, 2.4.4 a pressure water pump used solely for this purpose shall start up automatically before the pressure water tank has been exhausted. A changeover arrangement to a fire water 2.4.5 main shall be provided. 2.5

2.2.2 The diameter of the fire main and service pipes shall be sufficient for the effective distribution of the maximum required discharge from the required fire pumps operating simultaneously.

E

Monitors, hydrants, hoses and nozzles

The unit shall be equipped with a sufficient 2.5.1 number of strategically located monitors, hydrants, hose stations and fire hose reels. Monitors (for water or foam) shall be 2.5.2 provided to cover the Hazardous Areas of Zones 1 and 2 in open air areas. The capacity and number of the monitors is to be sufficient to deliver at least 6 l /m2/min at a nozzle pressure of 5 bar. Each monitor shall be capable of discharging under jet and spray conditions. Hydrants are to be so distributed, that at least 2.5.3 two water jets not emanating from the same hydrant can reach any point of the unit which would normally be accessible to the crew. One jet may be delivered by a single length of hose and the second by a joint hose length of not more than 30 m. Fire hoses shall be of an approved type and 2.5.4 be sufficient in length to project a jet of water to any of the spaces in which they may be required to be used. Their maximum length should not exceed 15 m. Every fire hose shall be provided with a dual purpose

11 - 12


nozzle and the necessary couplings, and together with any necessary fittings and tools be kept ready for use in conspicuous positions near the water service hydrants or connections. 2.5.5 Nozzles shall comply with the following requirements:

–

–

standard nozzle sizes should be 12 mm, 16 mm and 19 mm or as near thereto as possible. Under special circumstances the use of larger nozzles may be considered. for accommodation and service spaces, a nozzle size greater than 12 mm need not be used.

E

solution to the monitors and foam applicators at a rate which shall be at least the greater of the following quantities, but not less than 1250 l /min: a)

0,6 l /min per square meter of the total area to be protected

b)

1,5 l /min per square meter of a circular area with the radius of 75 % of the nominal length of throw of the largest monitor provided.

The supply of foam concentrate is to be 3.1.8 sufficient for at least 30 minutes of operation of the system at maximum capacity as specified in 3.1.7.

for machinery and exterior locations, the nozzle size shall be 19 mm.

Foam monitors are to be so arranged that the 3.1.9 protected area can be covered from at least two monitors, which shall as far as practicable be located opposite to each other.

3. Foam or gas based fixed fire-fighting systems

3.1.10 Foam hydrants are to be so arranged that any part of the protected area can be reached with at least one foam applicator and hose.

–

3.1

Foam systems

3.1.1 Permanently installed foam systems may be used in open air areas, such as the helicopter landing deck, and in machinery spaces as well as crude oil pump rooms.

(For helidecks, see also Section 9, 4.). 3.1.2 Only approved foam concentrates are to be used. The systems must be protected against freezing. 3.1.3 High expansion foam systems for the protection of enclosed spaces are to be so designed that the largest space to be protected can be filled with foam at the rate of at least 1 m depth per minute without allowance for machinery and equipment. The supply of foam solution shall be sufficient to fill completely at least 5 times the largest space to be protected. The expansion ratio of the foam shall not exceed 1000:1.

One foam hydrant is to be arranged at the access to any area to be protected. The total of foam applicators available shall not be less than four. 3.1.11 Foam storage tanks, associated pumps, proportioners and controls shall be located in a safe area not likely to be cut off in the event of a fire in a protected area. 3.1.12 The operation of the foam system shall not impair the simultaneous use of any water fire fighting installation required by the applicable rules and regulations. 3.2

CO2 systems

Permanently installed CO2 systems may be 3.2.1 used in enclosed spaces, except accommodations. The system is to be arranged for manual 3.2.2 initiation of release only.

3.1.4 The foam generator with tanks, pipe system, ducts etc. is to be permanently installed and shall be capable to attain full foam production within 2 minutes after fire alarm.

CO2 cylinders, associated pressure 3.2.3 components and piping shall be approved in respect of materials, design and manufacture. Special attention is to be paid to the risk of icing of quick-flooding lines.

3.1.5 The foam generator with equipment is to be placed in a safe area, separated from areas to be protected. If there is no access from the open deck, two separate means of access are to be provided.

The pipes for conveying the gas shall be 3.2.4 provided with control valves so marked as to indicate clearly the compartments to which the pipes are led.

3.1.6 If low expansion foam is used, the system is to be so designed, that the largest area over which fuel can spread, can be covered within 5 minutes with a 150 mm thick layer of foam. The expansion ratio must not exceed 12:1.

Fixed low-expansion foam systems for use in 3.1.7 exterior locations shall be capable of supplying foam

Gas cylinder storage rooms or areas shall be 3.2.5 situated at a safe and readily accessible position and be effectively ventilated. Any entrance to storage rooms should preferably be from the open air and in any case shall be independent of the protected space. Access doors shall be gastight and open outward. Bulkheads and decks, which form the boundaries of such rooms, shall be gastight and adequately insulated to prevent an excessive rise in temperature in


the room. Any of' the boundaries which are contiguous with the protected space are to be A-60 Class division. 3.2.6 Means shall be provided for automatically giving audible and visual warning of the release of CO2 gas into any space to which personnel normally have access. The alarm shall operate for a suitable period before the gas is released.

4.

details regarding fittings, pipe 3.2.8 For connections, delivery rates, warning signs etc. See Rules for Machinery Installations, Volume 4, Section 10, D.2.

11 - 13

Portable and mobile fire extinguisher

Water, dry powder, CO2 or foam may be used as extinguishing agents for the portable and mobile fire extinguishers to be provided in accordance with the Rules and possibly with additional National regulations. Detail requirements may be gathered from Rules for Machinery Installations, Volume 4, Section 10, E.1.

5. 3.2.7 Means shall be provided for stopping all ventilation fans and closing openings serving the protected spaces, before the medium is released.

E

Firemen's outfit

The firemen's outfit may be chosen according to the Rules for Machinery Installations, Volume 4, Section 10, E.2.

The regulations of the competent Administration may have to be observed.

Section 12 - Communications Systems

12 - 1

Section 12 Communications Systems 1.

Internal communications

An internal communication system is to be 1.1 provided between all stations, rooms and working places. In case of failure of the main power supply, the communication system is to be switched automatically to the emergency power supply. A public address system is required which 1.2 can be operated from important locations, including the bridge. The public address system shall be audible throughout the accommodation area, at the normal working places and operating locations such as the control station(s). For details, see Rules for Electrical Installations, Volume 5, Section 9, B.

2.

External communications

External communication systems, such as radio and navigation equipment, are subject to the regulations of the competent National Administration and are generally not covered by the BKI Certification or Classification procedure. However, equipment com ponents may be checked/judged by BKI as to their adequacy and reliability upon special request.

Section 13 – Machinery

A, B

13-1

Section 13 Machinery

A.

General Indications; Scope

B.

This section covers machinery items serving 1. as auxiliary equipment on board of production units; "auxiliary" meaning, in this context, any machinery not serving directly the hydrocarbons production. Machinery installations used for the production process are dealt with in Section 14. 2. For details about machinery systems commonly used on ships, see also Rules for Machinery Installations, Volume III.

For machinery systems aboard mobile 3. offshore units, such as column-stabilized units, see also Rules for Machinery Installations , Volume 4. 4. Machinery essential for the safety of operations shall be of an approved design and produced by recognized manufacturers operating a certified quality control system.

Standard equipment produced in series under a certified QA system and/or conforming to an internationally recognized code may be accepted, subject to a survey and certification procedure to be agreed from case to case. 5. For area classification (definition Hazardous/Non-hazardous Areas) see Section 11.

of

Power supply and electrical systems/ 6. installations: see Section 15; control and instrumentation: see Section 16.

Internal Combustion Engines; Air Compressors

Combustion engines shall be of an approved 1. type, adequate for continuous use under the ambient conditions prevailing at the site where the offshore unit is intended to operate. For gas compressors, see Section 14.

Internal combustion engines and air 2. compressors should be arranged in Non-hazardous Areas, as far as possible. The installation in Zone 2 of Hazardous Areas may be permitted under defined conditions. Documents for approval: See the 3. requirements in the Rules mentioned under A.2 and 3. Seagoing Ships: Volume III, Section 2; Offshore Installations: Volume 4, Section 3. 4.

Engines using process gas

Where internal combustion engines and/or 4.1 air compressors are to be fuelled by gas from the production process, the suitability of the engine(s) for operation with the particular type of gas shall be demonstrated, e.g. by tests at the manufacturers. In principle, the relevant requirements of the 4.2 IMO IGC Code, Chapter 16, "Use of Cargo as Fuel" and Rules for Liquefied Gas in Bulk, Volume IX may be applied.

Drives for turret turning installation: see 7. Section 7, F.

Special arrangements may be necessary to 4.3 provide adequate ventilation in the engine room, depending also on the type of fuel gas used. Gas detectors and alarms are generally required.

8. In the following, indications are given regarding important safety principles as well as particular items and conditions relevant for offshore production units.

4.4 The arrangement and specifications of the gas conditioning equipment (compressors, coolers, piping etc.) shall be presented with the approval documentation (see also E below).

The documentation shall include information about all safety-related measures, devices and instruments. Suitable measures are to be taken to prevent 4.5 fuel gas from entering the compressed air starting system and crank case. The crank case shall generally be provided with gas detectors.

13-2


Combustion engines and air compressors 5. shall generally be manufactured and tested under supervision of a BKI Surveyor. For series production equipment special arrangements may be considered.

C.

Boilers, Pressure Vessels, Thermal Fluid Systems, Heat Exchangers

1. All pressure vessels, i.e. systems in which pressures greater or less than atmospheric pressure

C, D, E, F

For design details see Rules for Hull, 4. Volume II, Section 14 for rudders, and Rules for Machinery Installation, Volume III, Section 4 - 6 f or propellers, couplings, gears and Rules f or Machinery Installation, Volume 4, Sections 5 and 6. Copper alloys for propellers: See Rules for Materials, Volume V, Section 16. Tests/trials shall be carried out under 5. supervision of BKI as indicated in the rules mentioned above.

may exist during their operation, shall be of an approved design and manufactured and tested under supervision of BKI.

Pressure vessels are required to also comply 2. with the applicable statutory requirements of the unit’s country of registration. 3. For the design, construction and testing of pressure vessels the following rules and regulations are applicable:

Seagoing Ships:

Volume III, Section 7 - 9

Offshore Installations:

Volume 4, Section 12

Designs according to acknowledged codes may be accepted. For boilers to be fuelled also with gas from 4. the production process (dual-fuel boilers), special precautions will be necessary such as automatic take over of the liquid fuel burner and gas supply shut-

down under defined conditions. The system specification will be considered and approved from case to case. Regarding gas supply, see B.4.4 above.

D.

Propulsion and Steering Systems

1. All propulsion machinery and steering systems, including shafting arrangement, are to be of

an approved design and to be constructed under supervision of BKI, using materials according to the Rules. 2. Documents for approval: Drawings showing the general arrangement of the propulsion and steering installations, and documentation about types of propulsion elements and related equipment, including shafting, couplings, bearings etc., and about manufacturers as well as materials to be used, are to be submitted for approval.

For propulsion systems used f or positioning of 3. the unit, see also Section 7, E.

E.

Pumps, Piping Systems

Pumps and connected piping shall conform to the Rules for Machinery Installations, Volume III, Section 11, or to the Rules for Machinery Installations, Volume 4, Section 13, or to equivalent, recognized codes/standards, such as API, ASME, ANSI, ASTM, NACE, ISO, SNI. 1.

2.

For gas compressors, see Section 14, C.

Wherever possible, pipes carrying flammable 3. or toxic substances shall not be led through areas defined as non-hazardous. Where this can not be avoided, special precautions - e.g. arrangement of ventilated ducts - must be taken. See also Section 11. Drainage of all piping systems shall be 4. designed to meet the relevant pollution prevention requirements of the National Regulations. See also MARPOL 73/78. Where pipes belonging to auxiliary systems 5. are connected or may be in connection with piping of the production system(s), the requirements of Section 14 will generally apply.

F.

Inert Gas System

Where inert gas is used on board of a 1. production/storage unit, e.g. for inerting the atmosphere in storage tanks, Rules for Inert Gas Systems for Tankers shall be applied (see the Rules for Machinery Installations, Volume III, Section 15, D). In case of classification, the Class Notation INERT may be assigned. In the following, some general provisions are quoted for easier reference.


2. Storage tanks: Floating oil storage units of 20.000 dwt and above and storage units equipped with a tank washing system are to be equipped with a permanently installed inert gas system in accordance with the Rules mentioned in 1. (Section 15, D.). 3.

Double hull spaces

On floating oil storage units required to be 3.1 fitted with inert gas systems, suitable connections for the supply of inert gas shall be provided for double hull spaces. Where necessary, fixed purge pipes arranged such as to take into account the configuration of these spaces shall be fitted. 3.2 Where such spaces are connected to a permanently fitted inert gas distribution system, suitable means (e.g. a second water seal and check valve) shall be provided to prevent flammable vapors entering the double hull space.

Where no permanent distribution system is 3.3 installed, a sufficient number of means for connecting to these spaces shall be provided on the inert gas main. 4.

General design requirements

G

13-3

It must be possible to purge empty tanks 4.5 with inert gas in order to reduce the hydro-carbon content to less than 2% by volume as to ensure subsequent safe ventilation. 4.6 Under normal operating conditions, i.e. when tanks are either full, partly filled, or being filled with inert gas, it must be possible to maintain positive pressure in the tanks.

Gas discharge openings for tank purging 4.7 must be arranged in suitable locations on deck. The free area of the vent openings shall be so designed that an exit velocity of at least 20 m/s is maintained if 3 cargo tanks are purged simultaneously. 4.8 The system must be capable of delivering inert gas at a rate of at least 125 % of the total discharge capacity of the cargo pumps.

The oxygen content of the inert gas 4.9 produced shall not exceed 5 % by volume under any operating conditions of the system. Means are to be provided to stabilize the 4.10 operation of the system after start-up. The system shall ensure that the gas volume 4.11 specified in 4.8 is available during discharge. At other times, a sufficient quantity of gas in accordance with 4.6 shall be permanently available.

The room containing the inert gas generating 4.1 equipment is to be considered as a Category A machinery space.

4.12 Parts of the inert gas system which come into contact with the corrosive vapors and/or liquids from the inert gases must be resistant to these or are to be protected by suitable coatings.

4.2 The inert gas system shall be capable of supplying a low-oxygen gas or gas mixture in order to achieve an inerted atmosphere in cargo tanks and slop tanks.

4.13 The Operation Manual shall contain instructions for the operation and maintenance of the inert gas system, together with notices about health hazards and safety regulations for the prevention of accidents.

Inert gas may be produced by one or more 4.3 main or auxiliary boilers, by one or more inert gas generators, by other sources, or by any combination of these.

In normal operation, the inert gas system 4.4 shall prevent air from flowing into the tanks and shall maintain the oxygen content of the tank atmosphere at less than 8 % by volume. Provision shall, however, be made for ventil ating the tanks when access is required. See also Section 18, B.

G.

Winches, Windlasses, Hoists

Windlasses, hoists, etc. serving the anchoring or mooring system and hydrocarbons or provisions transfer installations are generally subject to the certification procedure. Documentation about type, manufacturer etc. shall be submitted for approval. Details: See Rules for Specific Type of Units and Equipment, Volume 3, Section 5.C, and Rules for Machinery Installations, Volume 4, Section 8. See also Section 7, C.5. of this Guidelines.

Section 14 – Production/Process Facilities

A

14 - 1

Section 14 Production/Process Facilities A.

(see Section 3).

General Indications

Components of the hydrocarbons production 1. installation will usually be chosen according to operator specifications and acknowledged standards, and ordered/purchased from manufacturers operating an appropriate certified (ISO 9000 or equivalent) quality system. The production installation shall be comply with Government Regulation, in addition subject to review & survey by BKI for safety aspects, within the classification/certification procedure, as follows. 2. Approval Documents: Plans/documentation shall be submitted for approval, including the following items:

All materials used for system components 4. shall correspond to Rules for Materials, Volume V or equivalent regulations/standards, and be suitable for the envisaged environment and substances to be handled. 5. All means and possibilities leading to shutdown/interruption of the production process, or partsof it, and any possible cases of emergency shall be pr es en te d to BK I for co ns id er at io n Th is as well as routine maintenance procedures, shall be clearly defined and described in the Operating Manual(s), with reference, where applicable, to the defined load conditions (see Section 3, C.).

See also Section 11, Section 16 and Section 17, C. –

general arrangement, including indication of hazard areas;

–

listing of all systems related to production processes, with type designation of components, main dimensions and masses;

–

schemes of piping and electrical/electronic connections between systems and components; process flow diagrams, piping and instrumentation diagrams, electrical single line diagrams, schematic/principal wiring diagrams;

–

process shut-down system(s);

–

plans and specifications of safety equipment (sensors/detectors, alarms etc.);

–

use of hydrocarbons generation on board;

for

For the case of disconnectable risers, see Section 17, G. 6. General Arrangement: Production facilities should be arranged as far as possible separated and "downwind" from accommodation and service areas. Where this principle can not be adhered to in an optimal way, consideration will be given to alternative protection measures such as the provision of fire rated walls and supporting steelwork/floors.

Pressurization, closures, escape ways, fire-fightingand life-saving equipment and any other safety measures shall be described and presented to BKI for approval. All safety-related information shall be clearlydocumented in the Operating Manual and displayed in instruction posters on board. (See also Section 10and 11).

power/heat

–

storage and conveyance of substances (e.g., chemicals) used in the production process;

–

safety plans and equipment (escape ways etc.);

–

location and outfit of control station(s).

See also Section 11 and 16. 3. It shall be demonstrated, by acceptable reference or tests, that systems and equipment used for the production process are suitable for the envisaged marine environment, i.e. climatic conditions and motions (inclinations, accelerations) to be expected

7. Control station: A control station for the central monitoring and control of all production and storage related systems shall be arranged in a nonhazardous area location. The systems mentioned shall particularly include fire and gas detection as well as emergency shut-down procedures. See also Section 11, C. and Section 16.

Co-ordination of information with other control stations, if provided, shall be carefully considered and agreed upon with BKI. The foundations/securing of all system 8. components shall be designed taking into account the actual masses and motion characteristics (see 3 above). See also Section 4, C.3.

14 - 2

Section 14 - Production/Process Facilities

9. For storage of chemicals (hazardous) products, see Section 18, G.

and

other

10. Where classification by BKI i.e. design appraisal and survey during construction and commissioning, followed by periodical surveys of the unit and re-certification have been agreed upon, any changes or amendments in the configuration of the system(s) shall be notified to BKI, providing the necessary documentation for approval. Major damages shall also be communicated to BKI, and routine repairs and maintenance work shall be clearly documented in the log-book or diaries. See also Section 2, D.

5.

B, C, E

Cold Vents

The arrangement and geometrical configuration of vents not normally to be ignited are to be presented for approval. Where accidental ignition can not be completely excluded, means for flame detection and for extinguishing the flare shall be provided. Adequate facilities shall be provided for draining and collection of liquids accumulating in the venting system.

C.

Production Sub-systems and Components

1.

For production sub-systems, such as

–

gas separation system

–

dehydration system

The flare installation shall be arranged outside of and as distant as possible from Hazardous Areas. On offshore units capable of changing the heading ("weather-vaning"), the flare installation shall be placed at the farthest down-wind end. On units not offering this possibility, the flare may have to be placed on a cantilever structure with sufficient outreach.

–

oil heating system

–

seawater cooling system

–

seawater treatment system

–

seawater injection system

–

coalescer system

–

drainage system,

Flares should be designed according to 2. acknowledged standards. National regulations may have to be observed.

the design specifications and lists of components and manufacturers shall be submitted to BKI f or approval and/or information, depending on the scope of the agreed certification. In the design, the general requirements and safety considerations according to A. and to Section 16 shall be observed.

B.

Flare and Cold Vent Systems

1.

For flares and cold vents, see also Rules for Machinery Installations, Volume 4, Section 11.

The predicted motions of the unit shall be 3. taken into account in the structural design. See also Section 4, C.3.3 and Section 7, C.6.

4. Heat protection shielding and/or selection of heat-resistant material may be necessary for parts of the flare structure and for adjacent installations.

A heat radiation investigation will generally be required, which may be carried through using relevant acknowledged oil industry standards (see, e.g. API RP521). Regarding admissible radiation levels, National Regulations have to be observed.

For typical components such as listed in 2. Table 14.1, Rules for Seagoing Ships, Volume III and IV or Rules for Offshore Installations, Volume 4 and 5 should be observed, where applicable. Generally, designs and manufacture according to internationally acknowledged standards and codes (some of which are listed in the table) will be accepted.

For pumping and piping (sub-)systems, 3. including those necessary for conveying crude oil to storage tanks, the Rules mentioned above may be applied (see also A.2.). Components designed and manufactured according to acknowledged standards and codes will generally be accepted. (See also Section 13, E.).

C.

Production Sub-systems and Component

B.

Flare and Cold Vent Systems

The flare installation shall be arranged 6. outside of and as distant as possible from Hazardous Areas. On offshore units capable of changing the heading ("weather-vaning"), the flare installation shall be placed at the farthest down-wind end. On units not offering this possibility, the flare may have to be placed on a cantilever structure with sufficient outreach.

Flares should be designed according to acknowledged standards. National regulations may have to be observed. 7.

For flares and cold vents, see also Rules for Machinery Installations, Volume 4, Section 11.

The predicted motions of the unit shall be 8. taken into account in the structural design. See also Section 4, C.3.3 and Section 7, C.6.

9. Heat protection shielding and/or selection of heat-resistant material may be necessary for parts of the flare structure and for adjacent installations.

A heat radiation investigation will generally be required, which may be carried through using relevant acknowledged oil industry standards (see, e.g. API RP521). Regarding admissible radiation levels, National Regulations have to be observed.

Section 14 – Production/Process Facilities

C

14 - 3

Table 14.1 Production system components/Rules, Standards, Codes *

BKI RULES Component

Standard, Code

Ships

Offshore Units

Boilers

Volume III, Section 7 I

Volume 4, Section 12a

ASME, Section I (Power Boilers) ASME, Section IV ( Heating Boilers) BS 1113 (Water Tube Steam Gen. Plants) BS 2790 (Shell Boilers of Weld Constr.)

Combustion Engines

Volume III, Section 2

Volume 4, Section 3

NFPA No. 37 (Stationary Comb. Eng.and Gas Turb.)

Compressors (Air)


Volume 4, Section 3

API 672 (Packaged, Integrally Greared Centrif. Air Compr. for Petrol., Chem. and Gas Industry Serv.)

Compressors (Gas)

–

–

Gas/oil firing equipment


Volume 4, Section 12d

Gas turbines

Volume III, Section 3 II

Volume 4, Section 4

API 616 (Gas Turb.f.Pet.Chem.and Gas Serv.)

Gears, couplings


Volume 4, Section 5

API 671 (Special Purp. Coupl f. Pet. Chem and Gas Industry Serv.)

Volume 4, Section 12c

API 661 (Air Cool. Heat Exch. f. Gen. Ref. Serv.)

Heat exchangers

API 617 (Centrif. Compr.rf fPet, Chem.and Gas Serv.) API 618 (Recipr.Compr.f. Pet, Chem and Gas Serv) API 619 (Positive Displacement Compressor)

Pressure vessels (unfired)


Volume 4, Section 12c

ASME, Section VIII (Div. 1 - 3) (Pressure Vessel) BS 5500 (Unfired Fus. Weld. Pressure Vessel)

Pumps, Pipe systems



API 610 (Centr. Pumps f. Gen. Ref. Serv.)

Separators, Scrubbers

–

–

Tanks/vessels (atmospheric)



Thermal oil systems

Volume III, Section 7 II

Volume 4, Section 12b

API RP14C (RP for Analysis, Design, Install. and Testing of Basic Surf. Syst. f. Offsh. Prod. Platf.) API RP521 (RP for Pressure Relieving and Depressur. Syst.)

API 12F (Shop Weld. Tanks f. Storage of Prod.Liquid) API 650 (Weld. Steel Tanks f. Oil Storage) BS 2654 (Vert. Steel Weld. Storage Tanks)

API Spec. 6A (Wellhead. and Christmas Tree Equipment) Wellhead equipment

–

–

* National Regulation, Related API and Other Recognized Code

API Spec. 16 A (Specif. for Drill Through Equipment)

Section 15 – Electrical Installations

A, B, C, D

15-1

Section 15 Electrical Installations

A.

General Indications; Scope

Electrical installations are to be designed 1. and fabricated according to the Rules for Electrical Installations, Volume IV as far as applicable, or accord ing to the Rules for Electrical Installations, Volume 5, depending on the type of unit. Additional indications for production units are given in the following. Except where specified otherwise in the Rules 2. mentioned above, electrical equipment con forming to an applicable, internationally recognized standard, e.g. IEC publications, will generally be accepted within the plan approval procedure. National regulations may have to be observed additionally. Materials used for electrical equipment shall 3. be adequate for the marine environment and for the specific (e.g. corrosive) influences prevailing on board the type of unit in question.

B.

Power Supply

1.

Main power supply

The arrangement for the main power supply shall in principle comply with the Rules for Electrical Installations , Volume 5, Section 3, C.

2.

The arrangement for the emergency power supply shall in principle comply with the Rules for Electrical Installations, Volume 5, Section 3, D. Details regarding the emergency power supply will be agreed in the individual case. For systems that need to be operable after shutdown of process facilities special arrangements may be required, e.g. uninterruptible power supply (UPS).

C.

Electrical equipment to be installed on board 4. production and/or storage units shall be adequate for the motions and vibrations to be expected under the given site conditions. Adequacy may have to be demonstrated by tests. (Minimum requirements: See Rules for Electrical Installations, Volume 5, Section 1, E.). 5. Documents for approval: Regarding the documents to be submitted for approval, see Rules for Electrical Installations, Volume 5, Section 1, C.

The system plans and calculations listed in the Rules shall include the electrical installation in the production and storage areas.

Emergency power supply

Electrical Installations/Equipment in Hazardous Areas

Electrical equipment and wiring installed in 1. Hazardous Areas shall be limited to a minimum necessary for operational purposes. It shall be suitable for the particular Hazardous Area zone and comply with Rules for Electrical Installations, Volume 5, Section 13. For Hazardous Area classification, see Section 11. In case of exceptional conditions where the 2. explosion hazard may accidentally extend outside the Hazardous Areas, arrangements are to be provided for a selective disconnection or shutdown of all equipment that may cause an explosion.

(Exception: Ex-protected electrical equipment, capable of operating during an unusual situation.)

D.

Dynamic Positioning System

See Section 7, E. and the Rules for Dynamic Positioning System.

Section 16 – Control and Instrumentation

16-1

Section 16 Control and Instrumentation

1.

Scope

The following requirements and indications apply to all areas and systems of the unit, which in other respect are treated in the different Sections of this Guidelines. 2.

Control station

A control station for the central monitoring and control of all production, storage and offloading related systems should be provided in a Nonhazardous Area location. The control and monitoring includes

− –

fire and gas detection systems and the emergency shutdown system.

(See Section 14, A.7.) 3.

Approval documents

The following documents are to be submitted to BKI for approval, if applicable

−

functional design specifications,

–

software design specification,

–

software documentation (special agreement between system designer and BKI),

−

P&I diagrams,

–

cause and effect charts,

–

loop diagrams,

–

process operation systems, incl. those for remote operation on other units or installations, where applicable,

−

earthing layout,

–

process shutdown system,

–

fire and gas detection system (see also Section 11),

−

fire extinguishing systems (see also Section 11).

which an accumulation of flammable gas may be expected to occur. For more detailed requirements, see Section 11, C. and the Rules referenced there. A fixed fire detection system shall be provided in all accommodation and service spaces. 4.2

4.2.1 Devices to initiate automatic shutdown actions depending on an abnormal process situation or the detection of fire/gas should be provided. Facilities for manual release of the ESD action have to be in-stalled in the control station and at strategic positions. The manually operated ESD function should as far as possible be arranged independent of the automatically operated ESD system. 4.2.2 Initiation of an ESD is to activate audible and visual alarms at main control points. 4.2.3 Alarms are to be displayed in such a way that the location and the source of initiation of the ESD or the equipment effecting an ESD can be readily identified at the control station.

The ESD system including sensors, actuators 4.2.4 and their associated connections and circuits are to be arranged independently of other monitoring control and alarm systems. Total shutdown of the whole FPSO should 4.2.5 be provi ded only, if the safety int egrity of unit can not be maintained otherwise. Special agreement is necessary in such a case. 4.3

System requirements

4.1

Gas and fire detection system

A fixed gas detection system shall be provided to monitor continuously all enclosed areas of the unit in

Process operation system (Distributed Control System, DCS)

Process operation systems shall not interfere with safety related systems (see also 5.1). However, a data transfer from the safety related system to an operational system may be accepted on a case to case basis. 4.4

4.

Emergency shutdown system (ESD)

Public address system

A public address system is to be installed capable of reaching all operating areas at any time in which personnel may be permanently or occasionally present. The system may be accepted as a general alarm

16-2

Section 16 – Control and Instrumentation

facility. For detail requirements see Rules for Electrical Installations , Volume 5, Section 9, B. See also Section 12 of this Guidelines. 4.5

Crude oil storage

For high level alarm in crude oil storage tanks, see Section 18, C. 5.

System aspects

All safety related systems should generally be 5.1 independent from each other and from operational systems. A combination of different systems (e.g., fire and gas detection) is to be specially agreed. Smaller computer based safety systems may be integrated in one common hardware after detailed examination by BKI. This may apply to fire and gas detection systems.

The design should be based on the EMC 5.2 (Electromagnetic Compatibility) Directive 89/ 336. A simple EMC test on site, e.g. a test with local radio, is recommended near safety re lated electronic equipment.

All above mentioned safety related systems 5.3 shall be connected to a monitored UPS. Alarms are to be displayed in such a way that 5.4 location and source of initiation can be readily identified at the central control station. (See also Section 11, C.) If computer based systems are provided, the 5.5 safety integrity according to an international standard, e.g. IEC 61508, should be investigated for the particular application. Measures to fulfill the requirements of the standard should be listed and submitted to BKI.

Depending on the safety integrity level of the system, an examination of hard- and software may be required in addition to the document approval. 6.

Installation requirements

A separated instrument earthing may be required in addition to the protection earthing of the electrical installation.

Section 17 - Riser System

A, B

17 - 1

Section 17 Riser System

A. 1.

General Indications

Where the risers are connected with the 1.2 production/storage unit through a turret, the fixed portion of the riser system within the turret will be considered as part of the production installation in any case and therefore included in its certification. For active turning (drives) of the turret, see Section 7, F. Approval documentation

The documents to be submitted for approval shall include, i.e., information, specifications, calculations etc. regarding the following items: –

Investigation of motions/displacements, including risk of collisions or interference with other structures or elements (see B.)

–

Materials and ancillary equipment used

–

Installation procedures

–

Testing and maintenance procedures.

–

Corrosion protection measures.

Classification

The riser system including umbilicals, if 1.1 provided, will generally be regarded as essential part of the production installation, and included in the overall certification procedure. Where a separate certificate is required in particular cases, the safety assessment of the riser system is nevertheless to be carried out in conjunction with the survey of the entire unit and installation, according to the following indications and requirements.

2.

–

Overall system configuration (riser type(s), general arrangement, dimensions, combination with lines/cables for other purposes than conveying of produced media (e.g., umbilicals), segmentation, points of connection/disconnection etc.)

3.

Other BKI rules/regulations

Regarding materials, welding, corrosion protection, installation and testing, control and monitoring, see also Rules for Subsea Pipelines and Risers. Regarding flexible pipes, see Guidelines for the Design, Manufacture and Installation of Unbonded Flexible Pipe for Subsea Pipelines and Risers.

4.

Other recognized regulations and codes

Within the approval and certification procedure, BKI will usually recognize as valid design basis national or internationally acknowledged codes and standards such as –

API RP 2RD (Design of Risers for Floating Production Systems and Tension Leg Platforms)

– API RP 17A (Recommended Practice for Design and Operation of Subsea Production Systems)

–

Riser support details

– API RP 17B (Recommended Practice for Flexible Pipe).

–

Swivels and similar connections with piping on board

B.

–

Tensioning system, where provided

–

Essential data about the media to be conveyed (pressures, temperature, flow characteristicsetc.)

–

Control and shut-down elements and procedures, ESD system (see also Section 14 and 16)

–

Strength and fatigue calculations (details see under B. below)

–

Leak detection measures

Basic Safety Requirements

(Strength, Motions) The (rigid or flexible) riser(s) - free span 1. between sea-bed connecting point and connector(s) on board of the production unit - shall be analyzed for stresses and deformations/displacements under the influences of environmental forces and of the motions of the floating unit as described in Section 6 (mooring analysis). Additional loads (e.g., loads due to installation, pretensioning, vortex shedding, marine growth) may have to be taken into account. A fatigue assessment will generally be required.

17 - 2


2.

The analysis of motions/displacements shall ensure that the riser(s) will not come in contact with parts of the mooring system or any other elements belonging to the production unit. The case "one mooring line failed" – see Section 7, C.6. – shall be included in this investigation. Where contact between risers and other lines or components can not be excluded, suitable protective measures must be provided. 3.

Where detachment (disconnection) of the risers' lower part from the unit is planned under defined weather conditions (see Section 3, C.2.), the separation procedure shall also be analyzed to ensure that the connecting elements will not be damaged. See G. below. 4.

Where the upper part of the riser(s) is fixed in a turret, the combined system is to be investigated regarding possible interactions between risers and turret structure - see also Section 4, C.2. The investigation may have to cover thermal expansion and buckling phenomena, depending on the type of connections. 5.

C, D, E

between control station and bridge control room as regards motions of the unit and relevant operating limits for the riser system (see also Section 7). 2.

The following details shall be submitted to BKI for information and approval –

kind of data to be monitored (tensions, angles, valve or actuator position, etc.)

–

location and types of sensors

–

method(s) and means of data transmission

–

safety/redundancy considerations and logic.

3.

Shut-off valves shall be arranged at locations of the riser(s) where interruption of flow and possibly disconnection of the line is desired and/or required. The shut-off system and specification of components shall be presented for approval. The requirements of API RP14C (Recommended Practice for Analysis, Design, I nstallation and Testing of Basic Surface Safety Systems for Offshore Production Platforms) or of an equivalent acknowledged standard shall be complied with.

Corrosion protection 4.

The riser system is to be suitably protected 5.1 against corrosion by both, external (environmental) influences and internal corrosive action. A careful evaluation of the substances to be conveyed, including flow characteristics and temperatures, will be necessary for material selection and decision on coating/internal liners. External corrosion protection should be 5.2 combined for risers and the anchoring system, if arranged in close vicinity. Special consideration shall be given to the corrosion protection in the splash zone, particularly in way of clamps and attachments (coating, corrosion allowance). See also Section 5, C. 6. Abrasion, wear: Depending on external contact conditions and on the transported media, abrasion may have to be considered when determining the wall thickness and material quality. 7.

For surveys/inspection of risers in service, see Section 2, B.

C.

Control System

The riser system shall be controlled/ 1. monitored from the main control station on the production/storage unit. Suitable connection/communication shall be established

Shut-off valves should be operable from a station near to the location where the risers come on board, and also from the control station. The current status shall be clearly visible on the control panels. Regarding requirements for control systems and instrumentation, see also Section 16. 5.

6.

For disconnect able risers see F below.

D.

Venting

Adequate venting is to be provided where risers pass through closed spaces, e.g. inside of a turret structure. See also Section 11. The air change rate should be 6, as a minimum.

E.

Flexible Risers

Flexible risers or riser sections shall be of a 1. proven design and make, or else their suitability be demonstrated by tests. Design, fabrication and testing shall conform to the BKI Guidelines for the Design, Manufacture and Installation of Unbonded Flexible Pipe for Subsea Pipelines and Risers, or to an acknowledged code or standard, such as API RP17B ("Recommended Practice for Flexible Pipe") and API SPEC 17J ("Specification for Unbonded Flexible Pipe”).


F, G

17 - 3

Equipment and elements used for supporting, 2. anchoring and stabilizing flexible riser lines (buoys/weights, chains, cables etc.) shall in principle conform to the requirements for anchoring equipment (see Section 7).

G.

Disconnectable Riser System

1.

Scope; general requirements

F.

–

normal production and associated operations are interrupted,

–

the unit is disconnected from the risers and the anchoring system, and leaves the location.

Swivels, Connectors

The connection elements of the risers with the 1. fixed transfer lines on board (swivels) shall be of proven design. New designs shall undergo a test procedure to be agreed upon (see 5. below). The pressure-subjected parts of a swivel shall be designed and fabricated in accordance with a recognized pressure vessel code. (See also Rules for Machinery Installations Volume III, Section 8 and Section 11, D. and U.)

The bearings and sealing systems shall be 2. designed for the forces and pressures acting under operating conditions. Standard elements may be used if their satisfactory behavior under similar conditions can be proven. Due attention shall be paid to the selection of materials (e.g., corrosion risk).

Pressurized swivels shall be arranged/supported 3. such that external loads resulting from connected piping, sea water (impact) etc. are minimized.

Leakage control, inspection, maintenance, 4. repair and renewal procedures shall be established and laid down in the Operations Manual. Additional requirements of the National Regulation have to be observed.

A testing program shall be set up, including 5. pressure tests as well as dynamic tests to verify the rotational and bending design capabilities of the connecting element under design pressure conditions. Type-tested components may be accepted where proof is furnished regarding comparable applications.

Connectors/swivels serving the transmission of 6. electrical signals shall comply with the general requirements of Section 15.

Apart from – unprecedented – emergency 1.1 situations there may be foreseen and planned cases/ events (e.g. extreme weather conditions; modifications in the riser system), where

(See Section 3, C.). Procedures shall be available, suitably documented (Operating Manual etc.) and introduced, indicating in an inequivocable way –

the prescribed sequence of actions/steps,

–

the responsibilities of involved personnel,

–

the required communications / flow of information,

–

training schedules and drills.

Shut-down of production processes and 1.2 hydrocarbons flow, as well as emptying of tanks/vessels, where necessary, and purging of flow lines and risers shall be indicated by suitable measuring and control equipment in the control station(s) and shall be acknowledged before the disconnection procedures are started. Disconnection of risers shall be completed, 1.3 placing the riser head(s) in a safe position where the following operations cannot cause damage, before the disconnection of the unit from the anchoring/positioning system is initiated. The lower part of the riser system, remaining 1.4 connected to the sea bed installation, shall be capable of resisting the extreme environment conditions determined according to the indications in Section 2. Relevant calculations shall be presented for approval, depending on the scope of certification (see A.1.). Note:

Where a retractable - e.g., buoy type - riser support platform is provided, the submersion under the sea surface shall be such that wave action and possiblesea traffic/ship operations cannot endanger the installation part remaining on the location.

Disconnection systems shall be redundant, 1.5 with power supply from different sources, one of which should be independent from the unit’s main supply net.

17 - 4

Section 17 - Riser S stem

Disconnection should be effected from a 1.6 central control station or from the bridge, and in constant audio-visual contact with the local control station near the connection point, if provided. Where an additional possibility of disconnection is provided at this location, it is to be ensured that –

clearly defined procedures exist regarding priorities/take-over of operations, and

–

the local control station is sufficiently protected against environmental impact (safety of attending personnel).

2.

Approval of system(s) and components

For new designs, apart from the system/plan 2.1 approval by BKI Head Office, prototype testing will usually be required under conditions representing as realistically as possible the expected on-site conditions. In case of proven systems, 2.2 evidence/references shall be provided, showing that the disconnecting arrangement has been used under comparable conditions.

3.

G

Function tests, maintenance

Upon installation of the production unit at the 3.1 location, and before starting of normal operations, function tests shall be carried out for the disconnecting/connecting systems provided (see 1.5, 1.6). The test procedure shall be agreed upon in the individual case. National Regulation should be applied. The ability of the system to disconnect the 3.2 risers - and possibly the anchoring elements - shall be demonstrated under sea-state conditions worse than those defined as limiting conditions in the Operating Manual (e.g., for characteristic wave heights one meter higher). The operability of the disconnecting 3.3 system(s) shall be safeguarded by a suitable maintenance and testing schedule, to be approved by BKI in case of classification.

Section 18 - Storage and Offloading Facilities

A, B

18 - 1

Section 18 Storage and Offloading Facilities

A.

General Indications

1.

The arrangement and structural details of storage tanks shall conform to the requirements listed under B. Components of the hydrocarbons storage and offloading installation, other than structural, shall generally be chosen in compliance with Rules for Machinery Installations, Volume III, Section 15, and Rules for Electrical Volume IV, Section 15, as far as applicable. 2.

subject, however, to agreement from case to case. 2.

Structure

The tank structure shall be designed according to the principles listed in Section 4 for ship-type units. For the detail design, the BKI Rules for Seagoing Ship are applicable, with due consideration of the motion behavior of the unit in the anchored condition, i.e. dynamical loads. 3.

Corrosion protection

Complementary, acknowledged Codes and Standards may be used upon agreement with BKI.

A suitable corrosion protection system is to be provided for all tank spaces. For crude oil and ballast tanks preference should be given to coating.

Regarding documents for approval, material 3. selection, safety measures, etc., the provisions under Section 14, A. are applicable, in principle, also to storage and offloading facilities.

See also Section 5, C.

B.

Storage Tanks and Related Spaces

1.

General arrangement

The arrangement of storage tanks is to comply, 1.1 in principle, with the requirements of the Rules for Hull, Volume II, Section 24; except that the prosions requiring accommodation spaces, control stations and service spaces to be arranged "aft of the cargo tank area" do not apply. Crude oil storage tanks, integrated into the 1.2 structure of the offshore unit, are to be separated from machinery spaces and other spaces with similar risk of ignition, drinking water tanks and from accommodations, by cofferdams. Regarding pollution prevention considerations 1.3 (tank sizes, double hull, segregation requirements, etc.) the provision of the MARPOL 73/78 convention will generally have to be taken into account, depending on the decision of the competent Administration. See also Section 6, E.2. Regarding the arrangement of crude oil pump 1.4 rooms, fuel oil tanks and water ballast tanks, the provision of the Rules mentioned under 1.1 (Section 24, A.4.3) shall be applied in principle, the details being

4.

Venting

Tanks used for storage of substances from 4.1 which flammable gases may evaporate shall be equipped with suitable installations for venting/gas freeing. All vents are to be equipped with appropriate flame arrestors. Details of the venting installation, e.g. regarding the arrangement of inlet and outlet openings and exhaust velocity: See Rules for Machinery Installations, Volume III, Section 15, B.5. Crude oil pump rooms and ballast pump 4.2 rooms located in the oil storage area are to be ventilated by mechanically driven extraction fans. For details of the ventilation system, see the Rules mentioned above. Provision must be made for venting of ballast 4.3 tanks, pipe tunnels, cofferdams, double hull spaces and similar spaces. Forced ventilation may be required where exhaust ducts from spaces as per 4.2 are led through the spaces listed above. 5.

Inspection and maintenance

Tank structures shall be provided with adequate means, including suitable access possibilities, facilitating inspection and maintenance.

18 - 2


Attention is drawn to the requirements of the ESP scheme ("Enhanced Surveys Procedure") which may be applicable. See also Section 2, B. Accident prevention measures according to the requirements of the competent Administration may have to be observed. Smaller, detached tanks for the storage of 6. special products, e.g. for use in the utilities systems, shall be designed for the maximum pressures and temperatures to be expected, and their foundations/ connection with the structure of the unit shall be capable of resisting the motions and forces occurring at the particular location. For substances requiring a second barrier, either a double-walled tank or drip trays of sufficient volume shall be provided.

5.

C, D

Tank filling level control

Crude oil tanks shall be fitted with a level gauging device of an approved type. In addition a high level alarm should be provided, which is released when the tank is filled to about 98 % of its volume. See also the Rules mentioned above, Section 15, B.7. 6.

Fire and explosion prevention

See Sections 11 and 15, as well as Rules for Machinery, Volume III, Sections 12 and 15, B.9. and 10. and Rules for Electrical Installations, Volume IV, Section 15.

D.

Offloading Facilities

1.

C.

Storage Operation Facilities

1.

Crude oil pump and piping system

For the crude oil pumping and conveying 1.1 system, the provisions of the Rules for Machinery Installations, Volume III, Section 15, B. are generally applicable. Regarding dimensioning and materials of pipes, reference is made to Section 11 of the same Rules. See also Section 13, E. of this Guidelines. Where submerged ("deep well") pumps are 1.2 used, instead of pumps arranged in a pump room, the system and arrangement will be specially considered regarding safety and reliability aspects such as –

power supply/cable connections,

–

inspection/maintenance procedures,

–

venting/explosion protection of well and ducts, if any.

2.

Bilge and ballast systems

For the bilge pumping and ballasting installations, Section 15, B. of the Rules mentioned under 1. above is also applicable, with possible modifications due to deviations regarding in the general arrangement of spaces, to be agreed upon in the individual case. 3.

Inerting system

See Section 13, F. and the Rules mentioned above. 4.

Tank cleaning equipment

See Rules for Machinery Installations, Volume III, Section 15, B.8.

Offloading of hydrocarbons treated on board of the production unit may be carried out using a subsea pipeline or (shuttle) tankers. In the former case, for the export risers necessary for connecting with the pipeline the provisions of Section 17 apply in principle. For pumping facilities, see C. 1. above and 10. 2.

In case of offloading systems connecting the unit temporarily with a tanker, the limiting environment conditions for offloading operations shall be defined and clearly stated in the Operations Manual (see also E. below). The offloading system shall be designed and installed so as to allow, and safely endure, the expected relative motions between the units. Investigations regarding the motions of the units and the loads and deformations/movements of the connecting elements will generally be required. 3.

Note:

The transfer lines shall not be designed to serve at the same time as mooring connection (see E); but they shall be capable of enduring any forces and deformations which inevitably ensue due to relative movements between the production unit and the shuttle tanker. 4.

Materials shall be selected with due regard for the chemical and physical properties of the media to be conveyed. In the Operations Manual, reference shall be made, additionally, to critical items/locations (corrosion, wear, etc) and checks to be made. See also Section 5. Automatic shut-down is to be provided for the 5. case of line failure or loss of pressure in the transfer line. It must further be possible to operate (open/close) the valves in the offloading line from a

Section 18 - Storage and Offloading Facilities control station located near and with unobstructed view at the connection line. Possible pressure variations (surge) due to 6. normal operations or in unusual/emergency situations have to be considered when dimensioning the components of the transfer system. Thermal expansion shall be taken into account 7. in the design of piping and their connections to the structure. Where the build-up of wax or hydrates cannot 8. be excluded, the need for pigging has to be taken into consideration.

D

18 - 3

Design/reliability of end connections: Unless 9.2.2 favorable experience has been gained with similar hose connections successfully employed in comparable systems, investigations – including (model) tests – may be required to prove the suitability and fatigue strength of the configuration proposed. The conditions to be expected, regarding forces and pressures acting, motions/deformations imposed, temperatures prevailing, etc. are to be simulated as realistically as possible. Initial testing of hoses and hose connections is 9.3 to be carried out in the presence of a BKI Surveyor. For flexible hoses, instructions shall be 9.4 contained in the Operations Manual regarding, e.g.,

9.

Flexible hoses

–

maintenance and replacement schedules,

9.1

Applicable regulations

–

regular testing,

–

storage (while not in use).

Flexible hoses used for the offloading 9.1.1 operations shall in principle correspond to the requirements outlined in Section 17, E. See also the BKI Guidelines for the Design, Manufacture and Installation of Unbonded Flexible Pipe for Subsea Pipelines and Risers and Rules for Mooring and Loading Installations, Section 8. Other applicable Codes and Standards may be 9.1.2 accepted as a basis for the design and specification of system components from case to case. Reference is made, e.g., to the OCIMF (Oil Companies International Marine Forum) publications, "Buoy Mooring Hose Guide" and "Hose Standards". 9.2

Design requirements

For the design and/or selection of hoses used 9.2.1 in cargo transfer lines, the following considerations may have to be taken into account: –

Employment/destination, e.g. fully submerged, constantly filled; floating or suspended in air, filled temporarily only

–

Pressure conditions and variations

–

Forces and bending moments, curvatures imposed (fatigue considerations) – see 3. above

–

Temperature conditions (air, sea, crude oil)

–

Separation from other lines/elements

–

Flow characteristics (velocity, temperature, etc.; abrasion)

–

Insulation and flotation aids

–

Inspection and replacement procedures (see 9.5 below).

schedule

/

9.5 Weak Link: A "weak link" concept may be adopted in cases where a defined failure point in the hose line is considered to be justified for safety reasons. The design and material selection of such an element require careful evaluation and control. It must be ensured that offloading is interrupted and the line(s) shut off before disconnecting of the offloading line. 10.

Pumping facilities

For general design requirements, see C.1. above. Pumping operations shall be controllable also from the control station overlooking the offloading installation (see 5. above). 11.

Swivels and flexible joints

Offloading line connections allowing one or 11.1 more degrees of rotation should be of a proven design. New designs shall undergo a test procedure to be agreed upon (see 11.3 below). The pressure-subjected parts of a swivel shall be designed and fabricated in accordance with a recognized pressure vessel code. (See also Rules for Machinery Installations, Volume III Section 8 and Section 11, D. and U.) The bearings and sealing system shall be 11.2 designed for the forces and pressures acting under operating conditions. Standard elements may be used if their satisfactory behavior under similar conditions can be proven. Due attention shall be paid to the selection of materials (e.g., corrosion risk). Rotating and flexible joints will have to be 11.3 shop-tested according to a program to be prepared from case to case. Type-tested components may be

18 - 4


accepted where proof comparable applications.

is

furnished

regarding

Leakage control, inspection, maintenance, 11.4 repair and renewal procedures shall be established and laid down in the Operations Manual.

F.

E, F, G

Pollution Prevention

The MARPOL 73/78 Convention is applicable in principle. Details of the offloading system and arrangements may have to be agreed upon with the competent Administration. 1.

2.

E.

Mooring of Attending Vessels

Supervision/control of mooring operations shall be possible from the unit's bridge and from a control station located at a suitable place, e.g. on deck. The control station should be identical with that provided for the offloading procedures (see D. above). 1.

2.

The mooring system shall be designed for the maximum loads occurring in load condition 1 (Operating loads – limited environmental loads) according to Section 3, C. However, securing/storing of mooring equipment elements while not in use shall be effected so that they safely withstand extreme environmental conditions and associated motions of the production/storage unit. Note: Depending on site conditions and production schedules, the "limiting environmental loads" (sea state) defined for production and for offloading (mooring of attending tankers) may differ. 3.

Conventional mooring equipment such as hawsers and shackles may be selected according to accepted standards and specifications. Safety factors may be adjusted, depending on the redundancy of the arrangement and its flexibility (e.g., use of compensators). A safety factor of 2,5 (definition: See Section 7, C.) is considered adequate for initial design. Machinery serving mooring operations, such as windlasses -– where provided on board of the unit – should be designed with special consideration of the service and maintenance conditions to be expected (see also Section 13, G.). 4.

Elements provided for fastening/securing or 5. leading mooring lines shall be designed and arranged with due consideration of all the geometrical configurations and the maximum relative motions as well as dynamic forces possibly occurring during offloading operations. Strength shall generally be based on the breaking load of the relevant cable (see Section 4, C.2.).

It is recommended to carry out an investigation regarding the possibilities and consequences of failures (failure mode analysis), as a measure assisting in the design of leakage control and spillage prevention facilities. A "Safety Management Plan" should be set3. up (and will possibly be required by the Administration), covering also the safety measures related to the offloading operations. See also Rules for Classification and Survey, Volume 1, Section 1, D.4.

G.

Storage and Transport of Chemicals

1.

Facilities/compartments used for the storage of chemicals and substances related to the production installation shall be contained in the documentation to be presented for approval (Section 14, A.2.). The IMO/SOLAS Dangerous Goods Code (IMDG Code, Reg. 54) should generally be applied. National regulations may have to be observed additionally. 2.

Precautions such as

–

coating of tanks/walls and pipes,

–

venting,

–

control of atmospheric conditions, concentration measurements,

–

access warnings, etc.

gas

are to be taken depending on the kind of substance and of storage (bulk, packaged). The corresponding measures are generally subject to approval. Where substances used in the production 3. process are conveyed on board by pipes, the requirements regarding ventilation etc. according to Section 11, A.4. may have to be applied. The statement under F.3. above applies also to storage and handling of chemicals and similar hazardous substances.

A

endix A - Formal Safet Assessment

A-1

Appendix A Formal Safety Assessment

1.

Scope/Application

1.1

Introductory remarks

Formal Safety Assessments (FSA) are 1.1.1 increasingly being applied to safety and reliability investigations of offshore installations, supplementing conventional design procedures based on rules/ regulations, guidelines, codes and standards. Some national Administrations even require or strongly recommend the use/application of FSA to certain types of installations, at least with relation to personnel safety. The rules and survey activities/duties of a Classification Society cover both, personnel safety and reliability of systems and components; considering the additional task of checking and auditing management systems (ISM, introduced in shipping operations), it is evident that a Classification Society is active in, and prepared to deal with all aspects to which a FSA may be related.

subject, and authors of this kind of investigations are supposed to be acquainted with handling them. 1.3

Application

FSA may be applied to offshore 1.3.1 installations to differing extents, for example: –

to the whole arrangement of structures and installations at an offshore production site, including supply and products transport operations;

–

to the whole of a floating production/storage unit, including positioning and riser systems;

–

to parts, systems or components of a FPSO.

BKI will consider and decide in the particular case, whether and to which extent the FSA satisfiesor substitutes the Rules. The corresponding decision as to the r equirements of national R egulations is generally up to the competent Administration.

Safety assessment techniques may be used 1.1.2 under the following aspects:

FSA may be applied to all phases during 1.3.2 thelifetime of an offshore installation, such as:

–

–

design phase(s) (including concept/definition phase),

–

init ia l serv ice/ te st in g ph ase (dec is io n on improvements, changes),

–

design/preparation phase for major operational changes and conversions (including changes/additions to surrounding structures installations),

Vi ew of th e designe r:

To assist designers and their clients in deciding on design alternatives, with a view to optimum reliability of systems and processes; even where statistical data on failure rates etc. are still scarce or incomplete, comparative risk and reliability analyses for alternative solutions/arrangements may be valuable. –

View of the Classifi cation Society:

To supplement/assist conventional R ule based c ertification/c lassification design assessment procedures, particularly where the existing rules/regulations, guidelines and standards do not adequately cover the installations or components to be certified. 1. 2

Scope

It is the intention of this Appendix to the BKI FPSO Guidelines to inform the designer and/or operator about the r ole and involvement of BKI in this kind of investigations, and about the relationship / interdependence between FSA and the conventional documentation to be submitted for approval and certification. It is not intended to present a comprehensivereview of FSA techniques, such as the "Safety Case Concept", Risk Analysis methods etc., as there is sufficient literature available on this

(A change of location and production site is in most cases considered to constitute a fundamental redesign and start of a different unit/installation, to be certified a new). 2.

Definitions

(In the following, definitions will only be given to the extent necessary for the understanding and interpretation of this Appendix. It is assumed that users/designers preparing FSAs are acquainted with the terminology – see also 1.2. In case of deviating definitions, agreement with BKI shall be sought.) 2.1 Audit: A systematic and independent examination, by writing and/or interrogation, to determine whether the management activities of the audited entity comply with planned arrangements,

A-2

Appendix A - Formal Safety Assessment

and whether these arrangements are effective and suitableto achieve the agreed or prescribed objectives.

satisfactory performanceof all it’s critical elements as defined. 3. Procedures

system, plant, 2.2 Critical element:Any structure, component, equipment, procedure, etc., which has been identified as essential to the safety of operations and/or integrity of the unit.

3.1

2.3 Failure: Loss of function, or malfunction, of a system or component.

The method of safety assessment used shall be described and/or the standard or code from which it is derived shall be stated. Approval by BKI of the application in the particular case should be sought as earlyas possible. 3.2

2.4 Hazard, Hazardous Situation: A situation or development with potential for an accident causing human injury, or damage to the installation/unit or to the environment. Hazards may be predictable / foreseeable (e.g., environment, weather), or unpredictable (e.g., gas leak).

a)

b)

The term is used with two

the whole arrangement of structures, units, sea floor equipment and foundations, connection lines, etc., at a production site. a system or plant located on board an offshore unit, serving a defined purpose.

A written 2.6 Performance Standard: description or statement, expressed in qualitative or quantitative terms, of the performance (capabilities, qualification) required/expected of a critical element, or of a person or procedure. Performance standards are used as a basis for controlling, inspecting, auditing and verification activities during the lifetime of the installation or unit.

2.7 Risk: The probability, in quantitative terms, that a defined hazard will develop into an undesired event (accident, fire, component failure, etc.). The probability may be related to a specified time interval, or linked to defined conditions. "Risk" is sometimes also defined as the probability that an undesired event will occur, multiplied by the (quantified) consequences of that event.

2.8 Unit: The floating production/storage unit (vessel, semi-submersible, etc.), including positioning, riser, offloading systems, etc. 2.9 Verification: An independent and comprehensive examination of the safety assessments carried out to ensure the safety and integrity of the unit or installation and the

Definition of extent/scope

The scope of the safety assessment, i.e. the installation or part of the installation (e.g., system) to which it refers, shall be clearly defined. Any relation to similar assessments of other parts or systems of theinstallation shall be stated. 3.3

2.5 Installation: meanings:

Method of assessment

Identification of hazards

All hazards as well as the "undesired 3.3.1 events" which may result therefrom, considered meaningful regarding the safety/integrity of the installation or unit, are to be identified. 3.3.2 Hazards and hazardous situations may arise in different fields of activity and operation, such as

–

well servicing and control (including diver, R emotely O perated Vehicle (ROV) operations),

–

control/changes/repair of riser and piping systems,

–

production processes,

–

storage operations, including inerting,

–

supply, lifting, personnel transfer operations,

–

cru de oil offl oad ing ope rati ons, includ ing mooring of vessels.

3.3.3 Hazards and undesired events may also be classified according to their appearance and nature:

Structure (hull): –

d egradation (corrosion, wear, fatigue, etc.),

–

sudden damage (collision/impact, explosion, extreme weather conditions), with possible consequent failure on a larger scale: Loss of stability, floatability, integrity.

Process, auxiliary machinery instrumentation installations:

and

control

Appendix A - Formal Safety Assessment

–

degradation (as above), leading to leaks and fire/explosion/intoxication accidents, and/or to malfunction,

–

incidents/malfunction due to human error or

–

leaks/spillage, line damage due to collision, falling objects,

–

damages due to environment al f orces.

3.4 Identification of critical elements and failure modes

All elements/components, the failure or 3.4.1 malfunction of which is considered to be critical for the safety/integrity of the unit or installation, shall be identified and systematically listed or grouped according to systems and sub-systems. A relation shall be established between 3.4.2 elements identified as critical and the hazards accordingto 3.3 above. For each critical element the possible 3.4.3 failure modes (type/character of failure) shall be identified.

3.5 Ranking and evaluation of hazards and undesired events

The hazards identified as stated above, and 3.5.1 the undesired events which may result, shall be evaluated and classified according to their probability (frequency) of occurrence and the probable consequences if the undesired event occurs. 3.6

Risk analysis

A formal, quantitative risk analysis/ 3.6.1 assessment shall be carried out, based on the information received from the investigations described under 3.3 to 3.5 above. The results of this analysis are used to make various decisions, including –

alternative arrangements or component selection, where unacceptable risks have been identified;

–

additional or alternative preventive and/or protective systems, devices or measures;

–

structure and details management sytems.

of

the

safety

A-3

The analysis methods (mathematical 3.6.2 models) used and the consequences derived from the analysis shall be clearly stated and are subject to approval by BKI w ithin the certification procedure(see 1. above). 3.7 Performance standards - definition, compliance

For the critical elements identified 3.7.1 according to 3.4 the "performance standards" (see 2.6) shall bedefined. Comparing the results of the hazards ranking and the acceptance criteria ( see 3.5) with the risk analysis, it shall be ascertained whether the performance standards are met and may be excepted to be fulfilled throughout the following service period(s), subject to compliance with the maintenance and inspection arrangements prepared for the unit/installation (see 4). 3.7.2 Within the certification/classification proce dure, BKI w ill check whether the performance standards of the elements investigated, as defined, are inline with the objectives of the applicable r ules provide an equivalent level of safety. and 4.

Maintenance and inspection procedures

The operator will be responsible for 4.1 setting up maintenance plans and inspection procedures to ensure that the unit/installation, and particularly the critical elements referred to under 2 and 3 above, aremaintained in a condition satisfying the defined performance standards. Where the inspections reveal 4.2 components or systems that do not fulfill the requirements, either due to original deficiencies or to deterioration, remedialmeasures have to be taken. If it is evident or suspected that the original design is not satisfactory, a new safety assessment may be required, taking into account the experience gained during the past service period. The scope of the assessment will depend on the extent of the deficiencies found, i.e. on possible connections/interdependence between the deficient component or system and other systems. 4.3

BKI involvement

In the case of continuing involvement with 4.3.1 the unit, i.e., in case of classification, it is the duty and responsibility of BKI to ascertain the extent to which the inspection and maintenance provisions of the operator can be accounted for in the scheme of (periodical and extraordinary) surveys carried out by the Classification Society (see Section 14 of these Guidelines). BKI reserves the right to cross check findings of operator inspections and recordings by

A-4

A

endix A - Formal Safet Assessment

inspections of BKI Surveyors. A combined (joint) inspection/survey 4.3.2 scheme may be agreed between owner/operator and BKI . The auditing and checking of 4.3.3 management systems (e.g., ISM) may be part of the tasks conferred to BKI.

4.4

Major changes, conversions

In case of system changes, conversions, important additions, major repairs, etc., new or additional safety assessments shall generally be carried out, considering the experience gained since the design phase, and the reasons which made the changes necessary or advisable.

Appendix B - Regulations, Standards and Codes cited

Chapter 6 B-1

Appendix B Regulations, Standards and Codes cited

Reg./Stand./Code

Title

Page

–

1 – 2 / 13 – 2

Drilling and Well Servicing Structures

4–4

RP for Pressure Relieving and Depressurizing Systems

14 – 2

API

(generally)

API

Spec. 4E

API

RP 521

API

672

Packaged, Integrally Geared Centrif Air Compr. for Petrol., Chem. and Gas Industry Serv.)

14 – 3

API

617

Centrifug. Compressors for General Refinery Services

14 – 3

API

618

Reciprocal Compressors for General Refinery Services

14 – 3

API

619

Positive Displacement Compressors

14 – 3

API

616

Type H Industr. Combust. Gas Turbines for Refinery Services

14 – 3

API

671

Special Purpose Couplings for Refinery Services

14 – 3

API

661

Air Cooled Heat Exchangers for Gen. Refinery Services

14 – 3

API

610

Centrifugal Pumps for Gen. Refinery Services

14 – 3

API

12 F

Shop Welded Tanks for Oil Storage

14 – 3

API

650

Welded Steel Tanks for Oil Storage

14 – 3

API

Spec. 6A

Wellhead and Christmas Tree Equipment

14 – 3

API

Spec. 16A

Specif. for Drill Through Equipment

14 – 3

API

RP 57

Offshore Well Compl., Servicing, Workover and Plug- and Abandoment. Oper.

14 – 3

API

RP 2RD

Design of Risers for Floating Production Systems and Tens. Leg. Platf.

17 – 1

API

RP 17A

RP for Design and Operation of Subsea Production Systems

17 – 1

API

RP 17B

RP for Flexible Pipes

17 – 1 / 17 – 2

API

RP 14C

RP for Analysis, Design, Install. and Testing of Basic Surface Systems for Offshore Production Platf.

17 – 2

API

SP 17J

Spec. for Unbonded Flexible Pipes

17 – 3

ANSI

(gen.)

13 – 2

ASME

(gen.)

1 – 2 / 13 – 2

ASME

(gen.)

5–5

ASME

Sect. I (Power Boilers); Sect. IV (Heating Boilers)

ASTM

(gen.)

AWS

(gen.)

14 – 3 13 – 2

Structural Welding Code

1–3/5–5

B–2 B-2

Appendix B - Regulations, Standards and Codes Appendix B - Regulations, Standards and Codes

Reg./Stand./Code

Title

Page

BS 1113

Water Tube Steam Generating Plant

14–3

BS 2790

Shell Boilers of Welded Construction

14–3

BS 2654

Vertical Steel Welded Storage Tanks

14–3

BS 5500

Unfired Fusion Welded Pressure Vessels

14–3

CAA (UK)

CAP 437 (Offshore Helicopter Landing Areas)

9–1

EMC Dir. 89/336

EMC Directive 89/336

EN 10025

Hot rolled products of non-alloy structural steels

5–3

EN 10113

Hot rolled products in weldable fine grain structural steels

5–3

ICAO (gen.)

15–2

9–1

IEC (gen.)

1–3/15–1

IEC 61508

Functional safety of electrical/electronic/programmable electronic safety related systems

IMO-Modu Code

Code for the Construction and Equipment of Mobile Offshore Drilling Units

IMO-LLC

International Convention on Load Lines (1966)

6–1

IMO-Res. A 749

Intact stability criteria (1993)

6–2

IMO-MARPOL

MARPOL 73/78, Annex I

IMO-IGC Code

International Gas Carrier Code

IMO-SOLAS

International Convention for the Safety of Life at Sea (1974) + Amendments/Protocols

IMO-Res. A689 (17)

Recommendation on Testing of Life-Saving Appliances

IMO-ISM Code

(Res. A647 [16], A680 [17], A741 [18]) International Management Code for the Safe Operation of Ships and Pollution Prevention

ISO (gen.) ISO 9000–9003

16–2 6–1/6–2/ 10–2

3–2 6–2/13–2/ 18–1/18–4/ 13–1 10–2/11–4/ 18–4 10–2 Appendix A 1–3/13–2

Quality Management and Quality Assurance Standards

14–1

BKI class.pdf

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