Arc Flash Awareness NFPA 70E
Michael White Shermco Industries, Inc.
Hazards of Electricity
An Illustrative Story
A 400 Amp, 480-volt Automatic Transfer Switch A Critical Hospital Life-Safety Circuit A Simple Task to Modify the Controls An Experienced Electrical Worker July 18, 1984
Typical Transfer Switch
The Result
More…
Electrical Safety Statistics Average of 4,000 non-disabling and 3,600 disabling electrical contact injuries annually in the United States One person is electrocuted in the workplace every day Electrocutions are the 4th leading cause of fatalities. Over 2,000 workers are sent to burn centers each year with electrical-related burn injuries
Lethal Voltages
>600,
<100,
11%
5%
100 250,
250 600, 45%
39%
Costs Of An Electrical Fatality
$1,300,000 estimated direct costs
3RD INT’L CONFERENCE ON ELECTRICAL INJURY
Lost production Cost of personnel away from job Increases in Workman ’s Comp Increases in insurance costs OSHA fines Litigation
Costs Of An Electrical Fatality
Add:
Pain and suffering of employee Loss to family dependents • Financial and emotional
Total direct and indirect costs estimated at $3,900,00 to $10,400,00 per incident • DR. MARY CAPPELLI-SCHELLPFEFFER
Injury Costs Can Last A Lifetime A study of one utility revealed these costs of a survivable serious electrical injury Immediate direct costs…… $250,000 Direct costs after year 1 ….. $1.3 million Indirect costs ……………… $11.24 million Total ….. $12.8 million*
*1991 dollars. Equivalent in 2003 dollars is $17.4 million – “Facts on Electrical Incident & Injury Costs”, Lanny Floyd II, 11th Annual IEEE Electrical Safety Workshop
Arc-Flash Fatality
On Nov. 24, 1997, employees removed safety guards from energized electrical conductors in the cubicle. Physical evidence indicates that it was likely that part of one of the safety guards touched the energized conductors, causing an electrical explosion with a 26- foot fireball.
After The Arc
Arc-Flash Fatality
Proposed penalties of $455,000 against Western Resources at its Lawrence, Kan., Energy Center
“Management showed a lack of concern about taking the required safety precautions that might have prevented this triple tragedy,” said OSHA Administrator Charles N. Jeffress.
Hazards of an Arc Flash
Toxic Gasses
Rapidly Expanding Vaporized Metal and Air Visible and Invisible Light
Heat Data Curable burn Skin cell death Tin Gasoline Aluminum Copper Carbon steel Sun’s surface Arc flash
145o F 200o F 450o F 800o F 1,200o F 1,981o F 2,700o F 9,000o F 35,000o F
480V Arc Flash in Real Time
480V Arc Flash Slow Motion
141.5db@2ft. >2160lbs/sq.ft. >2250C/4370F
500C/1220F
>2250C/ 4370F
Components of Hazard Analysis Determine the Flash Protection Boundary (FPB) Shock Approach Boundaries
Calculate incident energy
Limited Restricted Prohibited Using IEEE 1584 or NFPA 70E Tables 130.7
Perform a PPE Assessment
Approach Boundaries – NFPA 70E
Flash Protection Boundary
Incident energy
Total heat from arc
Incident Energy at the Working Distance
Arc Flash Boundary
FPB Equal to on-set of second degree burn Severe and possible fatal thermal burns if unprotected
MCC
Never Think, “It will only take a second”
The Six Steps 1. 2. 3. 4. 5. 6.
Determine if work is performed within the Flash Protection Boundary Gather the information Perform an Arc Flash Study Choose the proper PPE Mark your equipment Train your workers
Gathering Data
System single line
Utility short circuit data
Study operating conditions, such as Normal operation; Loops closed; Transformers in parallel; Dual Feeds
Find details on transformers, buses, substations, and feeder cables
Modification of Switching Procedures
Evaluation of Site
The NFPA 70E-2004
OSHA And The NFPA
The NFPA develops consensus standards
NATIONAL ELECTRIC CODE – NFPA 70 ELECTRICAL EQUIPMENT MAINTENANCE – 70B ELECTRICAL SAFETY REQUIREMENTS FOR EMPLOYEE WORKPLACES – 70E
OSHA issues regulations
They are Federal law 29CFR (CODE OF FEDERAL REGULATIONS)1910
OSHA And The NFPA
OSHA has members on the NFPA 70E Committee
Ensures it stays consistent with regulations
70E is updated every three years OSHA tells us what, the 70E tells us how OSHA has been citing the 70E in court
The NFPA 70E Hazard / Risk Categories
NFPA 70E Tables
Use Tables 130.7 in 70E as long as incident energy values are under arc energy listed in Table notes
<40 cal/cm2
Article 130.7(C)(9)(a).
……”For tasks not listed or for power systems with greater the assumed short -circuit current capacity or with longer than the assumed fault clearing times, a flash hazard analysis shall be required….”
NFPA 70E Tables
Select Hazard/Risk Category from Table 130.7(C)(9)(a)
Select recommended PPE from Table 130.7(C)(10)
Verify choices by reviewing Table 130.7(C)(11) • ATPV is minimum for Hazard/Risk Category
PPE Levels – NFPA 70E 2004 0 cal/cm2 < 1.2 2 3.9 1.2 cal/cm 2 7.9 4.0 cal/cm 2 24.9 8.0 cal/cm 2 39.9 25.0 cal/cm 2 >40.0 cal/cm
Level 0 Level 1 Level 2 Level 3 Level 4 NO ACCESS
Hot Enough? • 1.0 cal/cm2 is amount of heat produce by a cigarette lighter on finger tip for 1 second
Proper PPE
This hazard risk category represents tasks that pose the greatest risk. Use when incident energy is between 25.1 and 40 cal/cm2 .
Would you use this on a class 0,1,2,3?
Knowing how to use your PPE
Mark Your Equipment
Effect on Workers Two workers had 2nd and 3rd degree burns on +60% of their bodies. One of the workers was placed in a druginduced coma for over 60 days. The supervisor initially had minor injuries. He has suffered long-term effects including neurological problems. Three families will never be the same again.
Optional Equipment Marking
Questions?
Michael White Shermco Industries Phone: 888-SHERMCO