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 0
0-1.2 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 1
1.2 - 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 2
4 - 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 3
8 - 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 4
25 - 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
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