Page 34 - Occupational Health & Safety, June 2017

ELECTRICAL SAFETY
The Importance of Arc Flash Mitigation
De-energizing equipment does not absolve the facility from the responsibility of performing an arc flash analysis or providing the necessary PPE.
BY ANTONY C. PARSONS
lent.” When applied to electrical workplace safety, arc flash mitigation involves taking steps to mini- mize the level of hazard and/or the risk associated with an arc flash event.
ANSI Z10-2012, Occupational Health and Safety Management Systems, included a hierarchy of arc flash mitigation controls, as shown below:
Hazard: a source of possible injury or damage to health. Risk: a combination of the likelihood of occurrence of injury or damage to health and the severity of injury or damage to health that results from a hazard.
PPE is often mistakenly viewed as the “solution” to arc flash hazards. The reality is that even when PPE is properly selected, it does not guarantee freedom from injury. NFPA 70E only makes the claim that injuries sustained during an arc flash event would be “reduced” and “survivable” due to mitigating effects of arc-rated PPE.
An effective safety program does not settle for “sur- vivable” injuries; instead, the most effective arc flash safety programs look to incorporate “safety by design,” primarily through application of engineering controls. Though not as effective as substitution or elimination, the goal of engineering controls is to reduce the degree of hazard. Administrative controls and warnings are less effective because they rely on workers following proper procedures and safe work practices. The engi- neering controls covered in this article will either:
1) Reduce arc flash energy to a level where per- mitted tasks can be performed, or
2) Locatetheworkersothathe/sheisnotsubject to harm.
Arc flash reduction systems do not eliminate the electric shock hazard of working on or inside ener- gized equipment. The amount of arc flash energy re- duction will be determined by an engineering analy- sis. The goal of reducing arc flash energy levels is to reduce the severity of the potential arc flash hazards to which a worker may be exposed. PPE is still re- quired when an arc flash energy reduction system is employed, but the level of PPE may be reduced.
While arc flash mitigation has always been a good
30 Occupational Health & Safety | JUNE 2017
www.ohsonline.com
While the threat of shock and electrocu- tion from inadvertent contact with en- ergized parts has long been recognized, the arc flash and arc blast hazards have only fairly recently been incorporated into the elec- trical safety standards. The Occupational Safety and Health Administration (OSHA) enforces electrical workplace safety standards outlined in the National Fire Protection Association’s NFPA 70E: Standard for Electrical Safety in the Workplace®.
Basic compliance with NFPA 70E-2015 Edition guidelines can be established with a five-step process: Step 1: Develop and audit an Electrical Safe Work
Practices (ESWP) policy.
Step 2: Conduct an electrical system study to de-
termine the present degree of arc flash hazards and label the equipment.
Step 3: Ensure adequate supplies of personal pro- tective equipment (PPE).
Step 4: Conduct regular safety training and em- ployee assessments.
Step 5: Maintain all electrical distribution system components.
Companies can take additional steps to reduce the potential for an arc flash. The remainder of this article will focus on mitigating arc flash hazards, specifically engineering controls.
What is Arc Flash Mitigation?
According to Webster’s dictionary, mitigation is defined as “to make milder, less severe or less vio-
SCHNEIDER ELECTRIC