INJURY PREVENTIONARC FLASH

REGIONAL SAFETY MEETING

Arc Flash & Arc Blast

• Arc Flash – electrical short circuit

that occurs when air flashes from

an exposed live conductor, to

either another conductor or to

ground.

• Arc Blast – pressure wave caused

by the arc flash

Arc Flash/Blast

• Concentrated energy explodes

outward

• High intensity flash

• Temperatures can reach 35,000

(skin ignites 480)

• Pressure wave can reach

200lbs/sq. inch

• Vaporizes conductors and

copper with exploding particles.

SEVERITY FACTORS

Arc Flash Effects

• Severe burns

• Broken bones

• Vision damage

• Hearing loss

• Brain/internal injuries

• Punctures and lacerations

• Death

SCOPE OF THE PROBLEM

• Each year, MSHA identifies about 100 injuries as “non-contact electric arc burns”

• 55% are in bituminous coal

• 84% are on systems of 600V or less

MSHA DATA

Causes of Arc Flash

• Improper training

• Improper work procedures

• Dropped tools

• Accidental contact with electrical

systems

• Installation failure

• Improper Design/Repair

• Voltage testing with inappropriate

equipment

Causes of Arc Flash (cont.)

• Buildup of dust, corrosion

on insulating surfaces

• Lack of maintenance

• Sparks produced during

racking of breakers,

replacement of fuses and

closing into faulty lines.

• Over confidence

Resource Documents

MSHA 75 and 77

All power circuits and electrical equipment shall be deenergized before work is done on such circuits and equipment, except when necessary for trouble shooting or testing.

Trouble shooting and Testing

• Only low and medium voltage circuits

• Purpose is to determine voltage and current

• Qualified person with protective gloves

ARC FLASH PREVENTION

The best way to prevent arc flash incidents is to DE-ENERGIZE and LOCK/TAG circuits before beginning work.

How is your Lock out program?

If we are Locking out properly, then when do we have exposure/risk?

• Trouble shooting and testing

• Removing covers, doors and lids with energized parts.

• Inadequate Barriers between circuits.

Energized Work Approval

• Description of the task to be performed• Justification for energized work• Job specific hazards• PPE

Can be verbal or written (AMS Operator) Adds accountability/ Helps define SAFE

PERSONAL PROTECTIVE EQUIPMENT

Low/Medium rated Gloves

• Can use dry Leather work gloves in Good Condition

• Over 120 volts systems must be intrinsically safe

What is a Calorie?

IEEE Standard 1584

Systems rated below 240 V to ground and below about 400A (125kVA) are not considered ARC FLASH Hazards.

These systems still present a SHOCK Hazard.

Arc-Rated FR Clothing & PPE

• Layering

– Outer layers must be flame resistant

– Under layers must be non-melting

• Coverage – Clothing must cover potentially exposed areas (wrist, neck)

• Care & Maintenance

– Inspect before use

– Launder according to mfg’s instructions

PPE - Hazard Risk Category 00-1.2 cal/cm2

• 100% cotton long sleeve shirt• Long pants• Safety glasses• Hearing protection• Leather and insulated gloves (as

required)• Leather work boots

PPE - Hazard Risk Category 11.2 - 4 cal/cm2

• 4+ cal long sleeve shirt & long pants (or) coveralls

• Hardhat• Safety glasses• Arc rated faceshield• Hearing protection (inserts)• VR gloves• Leather gloves• Leather work boots

PPE - Hazard Risk Category 24 - 8 cal/cm2

• 8+ cal long sleeve shirt & long pants (or) coveralls

• Hardhat

• Safety glasses

• Arc rated faceshield

• Hearing protection (inserts)

• VR gloves

• Leather work boots

PPE - Hazard Risk Category 38 - 25 cal/cm2

• 25+ flashsuit w/ hood over long sleeve shirt and long pants

• Safety glasses• Arc rated faceshield• Hearing protection (inserts)• VR gloves• Leather gloves• Leather work boots

PPE - Hazard Risk Category 425 - 40 cal/cm2

• 40+ flashsuit w/ hood over FR long sleeve shirt and long pants

• Safety glasses

• Arc rated faceshield

• Hearing protection (inserts)

• VR gloves

• Leather gloves

• Leather work boots

BEST PRACTICES

Analyze your ELECTRICAL System

Low arc flash circuit breakers

Current Limiting Fuses

Equipment Design

VOLT METER- SWITCHES TO PROPER VOLTAGE

Label Hazard/PPE Requirements

Make Lock Out Easy

Use Good Safety Practices

Summary

• Lock and Tag Program

• Identify activities with exposure

• Determine potential of injury

• Look for alternative methods

• Put administrative controls in place

• Train and provide appropriate PPE

• Evaluate the effectiveness of your process

SafetyShare.org disclaimer

from SafetyShare.org41

Material presented on the National Mining Association's SafetyShare.org website is intended for information purposes only and does not constitute advice. The National Mining Association tries to provide content that is true and accurate as of the date of writing; however, we give no assurance or warranty regarding the accuracy, timeliness, or applicability of any of the contents. Visitors to the SafetyShare.org website should not act upon the website's content or information without first seeking appropriate professional advice.

The National Mining Association accepts no responsibility for and excludes all liability in connection with browsing this website, use of information or downloading any materials from it, including but not limited to any liability for errors, inaccuracies, omissions, or misleading statements. The information at this website might include opinions or views which, unless expressly stated otherwise, are not necessarily those of the National Mining Association or any associated company or any person in relation to whom they would have any liability or responsibility.