INJURY PREVENTION ARC 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 cal/cm 2 100% cotton long sleeve shirt Long pants Safety glasses Hearing protection Leather and insulated gloves (as required) Leather work boots

PPE - Hazard Risk Category cal/cm 2 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 cal/cm 2 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 cal/cm 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 cal/cm 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

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