NFPA 70E - Maine Water Utilities Association – · PDF fileElectrical Safety Statistics...
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NFPA 70E Presented by: Joe Bergan Occupational Safety Engineer
Transcript of NFPA 70E - Maine Water Utilities Association – · PDF fileElectrical Safety Statistics...
NFPA 70E
Presented by:Joe BerganOccupational Safety Engineer
Electrical Safety StatisticsAverage of 4,000 non-disabling and 3,600 disabling electrical contact injuries annually in the United StatesOne person is electrocuted in the workplace every dayElectrocutions were the fourth leading cause of traumatic occupational fatalities.Over 2,000 workers are sent to burn centers each year with electrical-related burn injuries
Presenter
Presentation Notes
- Non-disabling = lost time; disabling = cannot work in same capacity again - Covers shock only. There are 10-15 people sent to the hospital each day with arc flash injuries. It does not cover near misses. - When you look at the Department of Labor statistics they appeared to be nondescript. There are several issues that are not addressed by statistics. - The statistics only address electrical shock. They do not address arc flash and arc blast. At this time, there is no statistical data are available for arc flash and arc blast. There is a foundation in the Chicago area that has a grant to compile this information. This is data will not be available for at least two more years. The point is that the statistics are artificially low and do not truly represent the dangers that are present in electricity workplace. The arc flash and arc blast hazard has become a important focus in Part 2 of 70E. - There are approximately 400 electrocutions per year in the workplace. This statistic may seem reasonable to some people, but it breaks down that each and every day someone is electrocuted in the United States in the workplace. This statistic does not include arc flash and arc blast incidence. - The statistics also do not include near misses. The ratio is typically 1000 near misses to a OSHA recordable injury. If your company had a system to identify near misses , it could be valuable information to critique and modify the Company’s electrical safety program policies, procedures, and work practices. - Last bullet: “sent to burn centers” indicates extensive, traumatic burns (2nd degree burns on 50% of body). This statistic is from Dr. Mary Capelli
Electrical Hazards
Electrical ShockArc-FlashArc-BlastFallsFire
Electrical Shock = Current Flow through the Body
Three major factors in electrical shock incidents:
The Path that current takes through the body The amount of current that flows through the body The amount of time that current flows through the body
Electrical Shock Review
Sensation of pain .4maPainful at levels above 2maMuscle Contraction and Pain 3ma“Let Go” Threshold above 9maRespiratory Paralysis 30-75maHeart Fibrillation 100-200maTissue and organs burn 1,500ma
Electrical Arc
Copper Vapor:Solid to VaporExpands by67,000 times
Intense Light
Hot Air-Rapid Expansion
35,000 °F
Pressure Waves
Sound Waves
Molten Metal
Shrapnel
Presenter
Presentation Notes
- When an electric arc occurs, various hazards can result: Pressure Waves (Result of super heating of air & metal vapors) Sound Waves Molten Metal (Result from high temperatures) Copper Vapor (Result from high temperatures) Intense Light Shrapnel Burns This is a simplified model of an arcing fault occurrence. The arcing fault can be between one phase to ground or neutral or phase to phase or three phase. A phase to ground or phase to phase arcing fault can quickly escalate into a three phase arcing fault due to the expansive cloud of copper vapor which can engulf all phase conductors . The chain of events during an arcing fault can be extremely rapid. The incident can be so rapid that the human system (eyes, optic nerves, brain, etc.) is incapable of observing and recalling the event in detail. The event occurs too fast. The test video footage captured by normal speed and high speed devices will illustrate this. The magnitude of an arcing fault is subject to many variables and therefore is unpredictable. Sustainable arcing faults in equipment may vary from approximately a minimum of 38% (L-G) to 89% (3 phase) (SPD). This phenomenon can occur when an arcing fault is initiated accidentally by a worker. The consequences to the worker can be catastrophic.
Arc Flash Hazards
Arc temperatures are extremely highAt the point of contact, 35,000ºF, easily achievableIn the workers ambient space, 15,000ºF, easily achievableThe result is a conductive plasma fireball made of vaporized and molten metals
Arc Flash Hazards
Second degree burn threshold is:80 ºC / 175 ºF (0.1 sec),2nd degreeThird degree burn threshold is:96 ºC / 205 ºF (0.1 sec), 3rd degreeThe results of Arc Flash exposure are 2nd
degree burns (curable), 3rd degree burns (incurable) & damage to the eyes
Arc Blast Hazards
Extreme pressure from expansion of vaporizing metals and super heated airWhen water vaporizes is expands by a factor of 1,670When copper vaporizes is expands by a factor of 67,000An Arc Blast is comparable to a C4 explosion, or a hand grenade
15,000 Volt Electrical Incident
Job assignment
Perform preventive maintenance for food processing plant emergency power system.Perform work on a holiday weekend.Record data on performance of system.
Scope of job
Work to be performed on Memorial Day morning. Start work at 7:00 AM and finish at 11:00 AM.Open 15 KV switch to start emergency generator.Run generator for 3 hours under load to test reliability of system. Record ampere, water temperature, and oil pressure on generator.
Personnel
Electrical supervisor, electrician, and technician.All workers had minimum of 5 years of experience.All workers had performed this type of work in the past.
Effect on workers
Two workers had 2nd and 3rd degree burns on 60% of their bodies.One of the workers was placed in a drug induced coma for over 60 days.The third worker had initial minor injuries. He has suffered long term effects including neurological problems.Three families will never be the same again.
Post evaluation
No hazard analysis.Workers could not cite the three hazards in the workplace.Workers were not properly trained.Workers were wearing polyblend clothing. All three workers were within the flash protection boundary.
End results
Lost three longterm employeesOSHA citationand fineNegative publicityLitigation
480 Volt Electrical Incident
Company Information
In business for 9 years3 employees at the job site; 15 total in the CompanyOSHA History: No history with OSHA, had never been inspected.OSHA Recordkeeping: Only minor incidents, no lost time.
Work to be Conducted
Removal of an existing 3 phase 480 volt circuit breaker and hardware (fingers, contacts) from a 1,000 amp 3 phase 480 volt Main Distribution Panel.
Incident Information
PPE was limited to one pair of Class 1 electrical gloves and one pair of leather insulated glove protectors for both workers.
Incident Information
The Foreman dropped his screwdriver and proceeded to get another one.
The Owner’s pliers began to lose their grip on the “finger” and he expressed the need to hurry up to the foremen.
CRITICAL CHOICE
Something Went Wrong
Effects of the Incident
Both men were seriously burned and were transported by Helicopter and Ambulance to the Burn Center.
Effects of the Incident
Owner had 1st 2nd and 3rd degree burns and was hospitalized for 6 weeks with several months of physical and psychological therapy.Journeyman also suffered 1st 2nd & 3rd degree burns but very limited.
~
OSHA Requirements ~
Electrical Safety in the Workplace
Presenter
Presentation Notes
Approximate Timing: 45 minutes on slides Point out excerpts from OSHA 1910 Subpart S and 1926 Subpart K found in the back of the workbook.
29 CFR 1910.333(a)(1)Live parts to which an employee may be exposed shall be deenergized before the employee works on or near them, unless the employer can demonstrate that deenergizing introduces additional or increased hazards or is infeasible due to equipment design or operational limitations.
NOTES
Interruption of life support equipment Deactivation of emergency alarm systemsShutdown of hazardous location ventilation equipment
NOTES Continued
Testing of electrical circuits that can only be performed energized
Integral part of a continuous industrial process (chemical plant)
ALL OTHER WORK DEENERGIZED
OSHA Methods of Enforcement
The General Duty Clause - Requires workplaces free from recognized hazards
Recognized hazard in the industry
NFPA 70E is an industry standard
OSHA General Industry Electrical Regulations
29 CFR 1910 Subpart S - Electrical1910.302-1910.308 Installation Requirements1910.331 Safety Related Work Practices1910.332 Training1910.333 Lockout/Tagout1910.335 Use of Protective Equipment
Presenter
Presentation Notes
Installation Requirements are from the NEC The next four items are from Part 2 of the old edition of 70E
~ Working On or Near Live Parts
Electrical Safety in the Workplace
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Presentation Notes
Approximate Timing: 15 minutes on slides 1-6 45 minutes on activity 4.1 40 minutes on slides 8-20 45 minutes on activity 4.2 10 minutes on slides 22-28 Article 130 Definitions of working on and working near: Article 100, page 18
NFPA 70E Qualified Person
One who has the skills and knowledge related to the construction and operation of the electrical equipment and installations and has received safety training on the hazards involved.
Presenter
Presentation Notes
130.1(A), page 24 110.6(D)(1)(a), page 17 110.8, page 18
NFPA 70E Requirements for Working on or Near Live Parts
Complete Energized Electrical Work PermitPerform Hazard/Risk AnalysisSelect Personal Protective EquipmentEnsure task-specific trainingConduct a job briefing
Presenter
Presentation Notes
130.1, page 23 Energized Electrical Work Permit: 130.1(A), page 24 Hazard/Risk: 130.2; 130.3, pages 24-25 PPE: 130.3(B), page 25; 130.7, page 28 Training: 110.6, page 17 Job briefing: 110.7(G), page 17; 130.1(A)(2)(10), page 24 Review Annex J and Annex I h/o 4.0.1 h/o 4.0.2 or in standard
Energized Electrical Work Permit
Requires written authorizationRequires the worker to:
Identify and understand the hazardsBe a qualified personUse proper PPERestrict access to unqualified personsComplete a job briefing
Presenter
Presentation Notes
Answer Slide – Do not print in Participant Workbook Summary of key points in activity; use after discussing activity Energized Electrical Work Permit identifies the hazards 130.1(A), page 24
Hazard/Risk Analysis
Establish Shock Protection Boundary Conduct Flash Hazard AnalysisEstablish Flash Protection Boundary Select Personal Protective Equipment
Presenter
Presentation Notes
Shock Protection Boundary: 130.2, page 24 Flash Hazard Analysis: 130.3, page 25 PPE: 130.3(B), page 25; 130.7, page 28
Distance Boundaries
Two types include:Approach Boundaries - used to reduce shock hazardFlash Protection Boundaries - used to reduce arc flash hazards and may reduce arc blast hazards
Approach Boundary to Live Parts
Limited (42 in)
Restricted (12 in)
Prohibited (1 in)
System Voltage = 480 v
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Presentation Notes
130.2, page 24; Table 130.2(C), page 25
Limited Approach BoundaryOuter-most boundaryMay be crossed only by qualified personMay not be crossed by unqualified persons unless escorted by a qualified person
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Presentation Notes
130.2(D)(1), page 24; 130.2(D)(2), page 25
Restricted Approach BoundaryMiddle boundaryReserved for qualified personsShock-protection techniques and safety equipment are required
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Presentation Notes
130.2(C), page 24 Shock protection techniques, i.e. not wearing conductive articles Safety equipment, i.e. PPE and insulated tools
Prohibited Approach BoundaryClosest boundaryReserved for qualified personsRequires same protection as direct contact with a live part
Presenter
Presentation Notes
Article 100, page 14 130.2(D), page 24
Flash Protection Boundary: Burns
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Presentation Notes
Curable burn is roughly the same as a second-degree burn – See Ray Jones book, pg 26
Flash Protection Boundaries
Methods to determine Flash Protection Boundaries using NFPA 70E
Default or TablesCalculations
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Presentation Notes
130.3(A), page 25 70E committee permits calculations, but does not endorse any particular calculations
Job BriefingSection 110.7(G) requires a job briefing before:
Starting each jobAny change in scope of a job
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Presentation Notes
110.7(G)(1), page 17 Annex I, page 112 New in 2004 Sample came from Chevron and DuPont
Personal Protective Equipment
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Presentation Notes
Included in photo: Flash or switching suit and hood, v-rated tools and gloves, protective blankets, voltage tester, safety glasses
What is PPE?
Protective scheme for electrical hazardsDesigned to protect specific areas of the body
Head, face, neck, chinEye protectionBody protectionHand and arm protection Foot and leg protection
Presenter
Presentation Notes
Articles 110, 120, 130 130.7(C)(1) through 130.7(C)(7), page 28
Levels of ExposureCalculated
Incident EnergyHazard Risk
CategoryMinimum
ATPV Rating
Up to 1.2 Cal/Cm2
1.2 to 4 Cal/Cm2
4.1 to 8 Cal/Cm2
8.1 to 25 Cal/Cm2
25.1 to 40 Cal/Cm2
Over 40 Cal/Cm2
Category 0
Category 1
Category 2
Category 3
Category 4
(N/A)
4
8
25
40
No Category – Not Permitted
Presenter
Presentation Notes
Very important slide – Use to explain Table 130.7(C)(11), page 34 Give examples of each Over 40 Cal/CM2 - Don’t want to be there; can’t adequately be protected 1.2 Cal is level of 2nd degree burn. This slide shows the range for each Category, for example, if your calculation is 3.7, it is a Category 1
Basic Rules of PPE
LayeringOuter layersUnder layers
CoverageFitMaintenance of equipment
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Presentation Notes
130.7(C)(12), page 32 130.7(C)(16), page 35 Under layers – no polyester shirt underneath Coverage – no exposed skin Temperature is cut approximately in half with each layer. A typical 7-10 Cal flash at two feet is 400-500 degrees (on shirt); through shirt to t-shirt it becomes 250 degrees; through t-shirt to skin, it becomes 125 degrees.
Clothing Characteristics
MeltingFlammabilityNot permitted
Presenter
Presentation Notes
130.7(C)(9), page29 130.7(C)(14), page 34 130.7(C)(15), page 35 Melting – spandex, polyester melts at 180 degrees Flammability – cotton ignites at 400 degrees, depending on weight
Program Analysis
Electrical Safety is a four step analysis process
Establish electrically safe workProvide trainingPlan the workUse Personal Protective Equipment where applicable
NFPA 70
2002 NEC Arc FlashHazard Marking
Requirement
Section 110.16 Flash Protection
240 volt Live Panel Board
Program SummaryFirst, identify and recognize the hazardsWork Deenergized!!!Identify the affected partiesProvide awareness training for unqualified peopleProvide protective schemes and training for qualified peopleWritten documentation is the key
Presenter
Presentation Notes
These are the basics of an electrical safety program. Written documentation: - as a record - for OSHA - for analysis of program - to help enhance program in the future
Questions?????????
Comments……………
Concerns……………..
