As a certified OSHA Outreach Instructor, a segment I cover in the ten-hour for industry course is Arc Flash & Arc Blast Prevention and Protection. The National Fire Protection Association (NFPA) section 70E regulations state that: anyone exposed to electrical hazards must receive on the job or classroom training in the prevention and protection from arc flash and arc blast hazards every three years or if it is shown through actions that re-training is required.
Many industrial facilities require their electrical workers and facility maintenance workers to take this training annually. Electrical wiring methods, general electrical requirements, and lockout/tagout are consistently in OSHA’s top 10 citations. Furthermore, electrical deaths continue to be in OSHA’s Fatal Four for causes of deaths and injuries in the American workplace.
Proper Protection is Key
To begin this segment, I show the students a series of arc flash and arc blast demonstration videos. They show the power, impact, and potential for injury or death should a blast occur. If a student wasn’t paying attention before, they certainly are now. The importance of proper training on arc flash and arc blast cannot be underestimated.
You may be thinking, so if the situation in the video were to happen to me or my workers, how do we protect ourselves? Personal Protective Equipment (PPE) is assigned an arc rating, measured in Cal/cm2. These Cal ratings are defined by the exposure to arc flash or arc blast. As the combination of voltage and amperage increase, so does the risk of an explosive force.
NFPA 70E then defined four hazard risk categories that correlate to arc ratings. Each category from 1-4 has a higher minimum standard for the protective gear that must be worn. As the hazard risk categories increase, so does the level of protection that must be provided by the employer. Hand protection consists of voltage rated gloves and protector. These gloves require mandatory re-inspection every six months. Currently, at a minimum, flame resistant attire is mandated when any exposure will exceed 50 volts!
It is impossible to define the category of exposure from an open circuit panel without doing an arc hazard assessment. This is a calculation that includes the age and condition of the electrical service equipment along with the voltage and amperage. NFPA regulations require that any non-residential structure have the hazard risk calculation for any electrical exposure and that the panel or equipment be properly labeled with the energy calculation, PPE required and that the boundary area is clearly marked. The electrical law of physics shows that electricity will pass through the air attempting to find ground. It can pass through human tissue, and can even contain the explosive force of a military hand grenade!
Prevent Exposure to Electrical Hazards
I finish this segment of the training course by covering the various effects of a blast or flash on humans, the best practices for avoiding exposure to the hazard, and some of the recent incidents that have been reported to OSHA. I also emphasize that the key to arc flash prevention is dependent on a complete lockout/tagout program to de-energize any equipment prior to exposure to the electrical hazard. It’s interesting to note that even most licensed, experienced electricians come away from this course with new safety knowledge that they take back with them on the job.
Are you wearing the proper PPE to protect from electrical hazards at your facility? When was it last inspected?