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ARC FLASH SAFETY
ARC FLASH SAFETY
OSHA Cited Violations: FY 2010
OSHA Cited Violations: FY 2010
OSHA Violations FY 2010
OSHA Violations FY 2010
OSHA Violations FY 2011
OSHA Violations FY 2011
Electrical Hazards
Electrical Hazards
Arc Flash Defined
Arc Flash Defined
Arc Flash
Arc Flash
Arc Flash Hazards
Arc Flash Hazards
Causes of Arc Flash
Causes of Arc Flash
Causes of Arc Flash
Causes of Arc Flash
Causes of Arc Flash
Causes of Arc Flash
Arc Blast
Arc Blast
Arc Blast Hazards
Arc Blast Hazards
Electrical System Susceptibility
Electrical System Susceptibility
Arc Flash Energy Released
Arc Flash Energy Released
Possible “Traps”
Possible “Traps”
Current/Reaction Chart
Current/Reaction Chart
Need for an Arc Flash Study
Need for an Arc Flash Study
Arc Flash Study
Arc Flash Study
Arc Flash Study
Arc Flash Study
Aids to Safe Operations
Aids to Safe Operations
Arc Flash Hazard Analysis
Arc Flash Hazard Analysis
Safe Distance Calculations
Safe Distance Calculations
Arc Flash Boundaries
Arc Flash Boundaries
Flash Protection Boundary
Flash Protection Boundary
PPE Based on Incident Energy Preplan
PPE Based on Incident Energy Preplan
PPE by Hazard Risk Category
PPE by Hazard Risk Category
Definitions
Definitions
E
E
Power Formula
Power Formula
Horsepower and Watts
Horsepower and Watts
Qualified Person
Qualified Person
Types of Damage
Types of Damage
Caution
Caution
Signage
Signage
Hazard Preplan
Hazard Preplan
Safety Precautions: PPE
Safety Precautions: PPE
PPE
PPE
Match PPE to Task
Match PPE to Task
Match PPE to Task
Match PPE to Task
Match PPE to Task
Match PPE to Task
Tools
Tools
Safety
Safety
Safe Work Practices
Safe Work Practices
Avoiding Arc Flash
Avoiding Arc Flash
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Some Questions OSHA will Ask
Summary
Summary
Bibliography
Bibliography
????? Questions & Answers
????? Questions & Answers

Презентация: «ARC Flash Safety». Автор: jeburd. Файл: «ARC Flash Safety.ppt». Размер zip-архива: 1320 КБ.

ARC Flash Safety

содержание презентации «ARC Flash Safety.ppt»
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1 ARC FLASH SAFETY

ARC FLASH SAFETY

29 CFR 1910.303 29 CFR 1910.305 29 CFR 1926.400-449,Subpart K NFPA 70E

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Bureau of Workers’ Comp PA Training for Health & Safety (PATHS)

2 OSHA Cited Violations: FY 2010

OSHA Cited Violations: FY 2010

OSHA has long understood the importance of safety in this area and tracks electrical violations OSHA Most Cited Violations (2010) Electrical-General Requirements (1910.303): 2,770 Lock-out/Tag-out (1910.147): 3,531

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3 OSHA Violations FY 2010

OSHA Violations FY 2010

1926.400-449, Subpart K 404(f)(6) Grounding path 473 404(b)(1)(i) Ground fault protection 338 405(g)(2)(iv) Flexible cords-strain relief 277 416(e)(1) Worn/frayed cords or Cables 256 403(b)(2) Equipment installation and use 241

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4 OSHA Violations FY 2011

OSHA Violations FY 2011

1910.147 Lock-out/Tag-out 3,639 1910.305 Electrical-wiring Methods 3,584 1910.303 Electrical-General Requirements 2,863

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5 Electrical Hazards

Electrical Hazards

Shock Electrocution: 4th leading cause of industrial fatalities Fires Burns Arc Flash Arc Blast

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6 Arc Flash Defined

Arc Flash Defined

Electrical work may cause injury or death One severe occurrence is the Arc Flash event “Arc Flash: an electrical discharge that uses the air as a conductor, exploding from a high voltage source to another conductor or ground nearby. The release can be 5,000oF or hotter, melting nearby metals and damaging the electric circuits involved. The brightness, heat and force of the arc flash can cause damage to the human body.” Tyler Lacoma, eHow Contributor, http://www.ehow.com/about_5110071_definition-arc-flash.html

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7 Arc Flash

Arc Flash

Hazards resulting from arch flash: Heat Shrapnel Pressure Sound Intense light UV IR

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8 Arc Flash Hazards

Arc Flash Hazards

Statistics:* 5 to 10 such serious arc flashes a day occur in the United States Result: 1 to 2 fatalities Although protective clothing exists, there is no guarantee against such severe energy releases *Dr. Mary Capelli-Schellpfeffer, “Arc Flash Presentation,” as quoted in eHow.com facts, May 30, 2012

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9 Causes of Arc Flash

Causes of Arc Flash

Overloading/overheating of circuits Damaged circuit breakers Over-fusing Wiring in a non workman -like manner Faulty electrical panels

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10 Causes of Arc Flash

Causes of Arc Flash

System overload Incorrect wire gauge for system requirements

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11 Causes of Arc Flash

Causes of Arc Flash

Faulty panels or overloading panels

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12 Arc Blast

Arc Blast

Accompanies the flash Intense radiant heat released Nearby surfaces (persons and objects) absorb and are instantly heated to vaporizing temperatures

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13 Arc Blast Hazards

Arc Blast Hazards

Serious situations!!

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14 Electrical System Susceptibility

Electrical System Susceptibility

System Hazard Less then 120V Arc flash highly improbable 480V electrical Sufficient capacity to cause services Above 600V Medium-voltage with higher energy/potential for an arc flash event http://en.wikipedia.org/wiki/Arc_flash

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15 Arc Flash Energy Released

Arc Flash Energy Released

Per Wikipedia Example: single phase-to-phase fault on 480V system with 20,000 amps of fault current Resulting power is 9.6 MW If fault lasts 10 cycles at 60Hz, resulting energy would be 1.6 megajoules Comparison: TNT releases 2,175 J/g or more when detonated. This fault is equal to 380 grams (about 0.8 pounds) of TNT !!! http://en.wikipedia.org/wiki/Arc_flash

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16 Possible “Traps”

Possible “Traps”

Beware of a “profusion of electrical confusion”

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17 Current/Reaction Chart

Current/Reaction Chart

Current Reaction Below 1 milliampere Generally not perceptible. 1 milliampere Faint tingle. 5 milliampere Slight shock. Not painful-disturbing. Average person can let go. Strong involuntary reactions can lead to other injuries. 6-25 milliamperes Painful shock. Loss of muscular control. (women) 9-30 milliamperes Freezing current (“let-go” range). Person can not let go but can be thrown from the current if extensor muscles are stimulated. 50-150 milliamperes Extreme pain, respiratory arrest, severe muscular contractions. Death is possible 1,000-4,300 Rhythmic pumping action of heart ceases. Muscular milliamperes contraction and nerve damage occur; death likely. 10,000 milliamperes Cardiac arrest, severe burns; death probable.

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OSHA Training Institute, “Construction Focus Four: Electrocution Hazards,” April, 2011

18 Need for an Arc Flash Study

Need for an Arc Flash Study

Numerous inherent dangers when working around electrical systems Safety from arc flash should include an Arc Flash Study Done prior to conducting work on hazardous locations

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19 Arc Flash Study

Arc Flash Study

Study components per IEEE 1584: Data Collection (steps 1 & 2) System diagrams Modes of operation scenarios Analysis (steps 3-7) Determination of bolted fault currents Protective devices recommended Document system voltages & classes of equipment Determine working distance from arc flash source

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20 Arc Flash Study

Arc Flash Study

Arc Flash Hazard Analysis (Steps 8 & 9) Incident energy determination (Energy needed for an arc flash to cause second-degree burns) Flash protection boundaries (Distance where the second-degree burns are caused, or where the incident energy is 1.2 calories per centimeter squared or 1.2 cal/cm2) Both may be calculated using NFPA or IEEE equations Diane Bonder, eHow Contributor

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21 Aids to Safe Operations

Aids to Safe Operations

NFPA 70E-2004 Standard for Electrical Safety Requirements for Employee Workplaces IEEE 1584 Guide for Arc Flash Hazard Calculations

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22 Arc Flash Hazard Analysis

Arc Flash Hazard Analysis

Results aid in determining:

Proper PPE, distance-dependent from possible threat: - Shirts - Pants - Underwear - Goggles - Gloves

- Hard hats - Shields, face and neck - Heating protection - Shoes

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23 Safe Distance Calculations

Safe Distance Calculations

Used to determine safe distances and PPE Variables taken into account: Voltage Working distance Clearing time Grounding Gap between conductors Bolted fault current

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24 Arc Flash Boundaries

Arc Flash Boundaries

“Distance from an arc flash within which an unprotected person has a 50% chance of receiving a second degree burn”

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25 Flash Protection Boundary

Flash Protection Boundary

Arc flash hazard is based on: Fault current Arcing time Distance Preplanning your facility will enhance the safety of your staff

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26 PPE Based on Incident Energy Preplan

PPE Based on Incident Energy Preplan

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27 PPE by Hazard Risk Category

PPE by Hazard Risk Category

Findings compared to table which indicates arc thermal performance of clothing Dangers above a 4 is prohibited “No Safe PPE Exists Energized Work Prohibited”

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28 Definitions

Definitions

Voltage (E): electromotive force (emf) that forces electrons to flow through a circuit measured in Volts (V) Current (I): the number of electrons that flow past a point in a circuit in one second measured in Amperes or Amps (A) Resistance (R): the opposition to current flow in a circuit that contains only resistance and is measured in ohms

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29 E

E

I

R

Ohm’s Law

Relationship between E, I, R “One volt of electromotive force will force one ampere of current to flow through one ohm of resistance”

By knowing 2 of these variables, the other can be calculated!

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30 Power Formula

Power Formula

Power: the rate at which work is done and is measured in Watts (W) (E x I)=Watts So Power is equal to P= E x I Power can be measured in the thousands of watts per hour and reads as KWH or kilowatthours

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31 Horsepower and Watts

Horsepower and Watts

Horsepower is the unit of measure for mechanical energy 746 Watts = 1 Horsepower (hp) or P = E x I Flow of Amps= E/R Additional information

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32 Qualified Person

Qualified Person

Qualified Person: One who has received training in and has demonstrated skills and knowledge in the construction and operation of electric equipment and installations and the hazards involved OSHA defines these as specially trained to work on live electrical equipment Unqualified Person: per 1910.332(b)(2) must still be trained in safe electrical practices for their support jobs (painters, cleaners as examples)

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33 Types of Damage

Types of Damage

Fully understand the hazards related to these activities If possible, review case histories of your industry to devise safe operations

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34 Caution

Caution

Abide by distances determined by NFPA or IEEE NO SHORT CUTS!!!

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35 Signage

Signage

Ensure signage fits hazard and conforms to regulatory requirements

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36 Hazard Preplan

Hazard Preplan

Use checklists to preplan equipment needs when performing service or maintenance Label systems for future maintenance and arc flash studies

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37 Safety Precautions: PPE

Safety Precautions: PPE

PPE should fit the requirements of the job Specific level of PPE is required

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38 PPE

PPE

Tests for arc rating of PPE Found in ASTM F1506 “Standard Performance Specifications for Flame Resistant Textile Materials for Wearing Apparel for Use by Electrical Workers Exposed to Momentary Electric Arc and Related Thermal Hazards”

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39 Match PPE to Task

Match PPE to Task

Level 2 Protective Coverall

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40 Match PPE to Task

Match PPE to Task

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41 Match PPE to Task

Match PPE to Task

Prepare for the possible!

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42 Tools

Tools

Support equipment rated for the task Tools properly insulated Correct support equipment for the job

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43 Safety

Safety

Robotic removal or disengagement devices can do much to maximize personnel safety Also: Draw-out circuit breakers on a life bus Remote racking

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44 Safe Work Practices

Safe Work Practices

Lock-out/Tag-out: Make sure you’re wearing the proper PPE for this job also

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45 Avoiding Arc Flash

Avoiding Arc Flash

Assign qualified person Conduct system analysis to determine arc flash hazard When working, secure all power and enact Lock- out/Tag-out Proper tools and PPE rated for the job Assign electrical safety program manager familiar with codes Properly maintain system and components Apply warning labels

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46 Some Questions OSHA will Ask

Some Questions OSHA will Ask

From EHSToday, March 13, 2008 (and still timely), Kenneth Cybart: OSHA’s goal: for employers to identify all electrical hazards, potential and actual Analyze workplace for shock and arc flash hazards, set safe protection boundaries and define required PPE Circuit or equipment description at job location? Written description, drawing Detailed job description of work?

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47 Some Questions OSHA will Ask

Some Questions OSHA will Ask

Can the fact that the equipment cannot be de-energized or job be deferred be justified? 1910.333(a)(1) Live parts must be de-energized before employee works on/near them Less than 50 volts to ground need not be de-energized if there will be no increased exposure to electrical burns or to explosion due to electric arcs However, never work on live circuits unless absolutely necessary

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48 Some Questions OSHA will Ask

Some Questions OSHA will Ask

Live circuit work necessary? OSHA 1910.33(a)(2): Safety-related work practices required NFPA 70E Article 110.8(B)(1): Electrical Hazard Analysis required before work performed on live equipment operating at 50 volts and higher Other questions to ask: - Safe work procedures? Detailed work procedure established? Will it be used? Job briefing checklist performed?

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49 Some Questions OSHA will Ask

Some Questions OSHA will Ask

Was job briefing given to those doing the job? Proper management approval obtained? NFPA 70E annexes to assist your program: Annex Topic E Electrical Safety Programs F Hazard Risk Evaluation Procedures I Job Briefing Checklists J Energized Work Permits

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50 Some Questions OSHA will Ask

Some Questions OSHA will Ask

Electrical safety analyses performed? Arc flash hazard analysis performed? Flash protection boundaries established? Other potential electrical hazards identified? Proper insulated tools and equipment used? Necessary PPE determined? Insulated blankets/sheeting used to cover all live parts?

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51 Some Questions OSHA will Ask

Some Questions OSHA will Ask

OSHA: Every employer shall furnish a place of employment free from recognized hazards…causing or likely to cause death or serious physical harm… NFPA 70E: Employers to conduct an electrical hazard assessment to include a hazard analysis for shock and arc flash before performing work on live equipment operating at 50 volts and higher Review the following when creating your program: OSHA 1910.132 and 1910.333(a)(1)(i) as well as 1910.269(a)(2)(iii)

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52 Summary

Summary

Appreciate the severe consequences which are possible when working with electrical systems Fully plan the job; know and enact safeguards Match the required PPE and equipment to the task Consider possible emergency response needs for yourself and your team and include in your plan Conduct the job safely Restore safely GET HOME SAFELY!!!

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53 Bibliography

Bibliography

http://en.wikipedia.org/wiki/Arc_flash Tyler Lacoma, eHow Contributor, http://www.ehow.com/about_5110071_definition-arc-flash.html Dr. Mary Capelli-Schellpfeffer, “Arc Flash Presentation,” as quoted in eHow.com facts, May 30, 2012 Diane Bonder, eHow Contributor OSHA Training Institute, “Construction Focus Four: Electrocution Hazards,” April, 2011 http://ehstoday.com/construction/ehs_imp_79112

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54 ????? Questions & Answers

????? Questions & Answers

Questions

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