Arc Flash Hazard Mitigation
Arc flash hazard mitigation involves taking steps to minimize the level of hazards within your facility in the event of an arc flash. PPE is sometimes thought of as the solution to injury, but this will not guarantee someone will be injury-free in an arc flash. It is important to consider the safety within your facility from an engineering standpoint to ensure the lowest risk for all workers.
How is Mitigation Done?
Mitigation is done by taking a very close look at your circuit breakers and fuses or conducting an over-current protection device coordination study. IEEE 242-1986 – Recommended Practice for Protection and Coordination of Industrial and Commercial Power Systems (The Buff book) serves as the basis for protection co-ordination studies. e-Hazard is capable of providing these studies in any of three major software packages used in the U.S.
The primary goal is to reduce incident energy, or the amount of energy generated by an arc flash. Incident energy is proportional to arcing time and the use of “faster-acting” devices is critical, as this can clear arcing currents faster and ultimately reduce the overall incident energy from an arc flash.
A coordination study will also review your settings so that the most optimal settings can be rolled out within your facility. Once the coordination study is done, the outcome will determine whether minor settings adjustments can lower incident energy levels. The two examples above can make a very large impact and, in some cases, potentially bring a PPE Category 4 arc flash hazard down to PPE category 2, a very significant improvement.
Why is Mitigation so Important?
Mitigation is done to reduce the risk of exposure to an arc flash, ensuring that worker safety is your first priority. Although NFPA 70E and OSHA have rules that prohibit energized work, one must first be able to establish that a circuit is de-energized, and this requires that a worker approach the circuit and verify it. Until it is proven de-energized, one must assume it is still energized and wear full PPE.