PPE is the last line of defense when it comes to arc flash mitigation, according to the hierarchy of hazard mitigation. Appropriate PPE selection is important to prevent introducing new risks to workers on job sites.
Safe PPE Selection
In order to select PPE, you first need to have an incident energy study on your workplace. PPE levels are determined based on the incident energy levels of the equipment being worked on, so you can not appropriately select PPE without an incident energy study. CSA-Z462 has a table that matches types of PPE to arc flash incident energy levels. This table is an excellent guide to use when selecting your PPE.
I personally do not recommend doing work on anything with an incident energy level higher than 40 cal per square centimeter: when incident energy is that high, you should figure out a way to reduce the incident energy level before assigning any work. All PPE should be appropriately labelled so that you know what is acceptable to wear for the present work conditions. At minimum, when working on a system with an arc flash risk, you should be wearing arc rated long sleeve shirts, pants, and undergarments, insulated leather or rubber gloves and boots, eye, face, and ear protection, and a hard hat.
Other Factors that Influence PPE Selection
Other factors to consider when selecting PPE include the working environment and the amount of time it will take to complete the job. Higher levels of incident energy require more bulky PPE. Bulky arc flash suits can impede a worker’s vision, hearing, and mobility. The large, sealed, bulky clothing is cumbersome and also gets hot quickly, which causes increased levels of fatigue. All of these things can lead to new risks that might actually increase the danger to workers on site, which is the opposite of what arc flash mitigation techniques are supposed to do!
One last thing to be sure of is that your PPE is in good repair. Old, worn out PPE full of holes won’t protect you in the event of an arc flash incident, and should not be worn by anyone.
Sometimes it is necessary to do work in heavy, uncomfortable PPE.
When this is the case, it is important that jobs be planned appropriately to reduce risk involved. If fatigue is an issue, schedule multiple people working on the same job in short shifts as opposed to having one person doing all of the work. The buddy system (having at least two people working on the same job) also has the added benefit of safety: the second person can immediately respond if something goes wrong while the first person is working.
You can also assess the functions of the equipment being worked on to see if you can’t reschedule work for a period when the equipment can be de-energized, avoiding the need for the bigger arc flash suits.
Worker training is very important. The NFPA notes that many workers who suffer electrical injury have insufficient training and do not properly use their PPE. Training personnel to appropriately assess hazards and risks is very important because these hazards and risks influence the level of PPE required for a job. All workers should be properly trained in the use of all PPE required for a job: if you aren’t using the PPE properly, then it won’t protect you. Once again, this goes against our goal of arc flash mitigation!
When selecting PPE, you need to know the incident energy on the equipment you are working on. You then need to make sure the labels on your PPE are appropriate for the work and that your PPE is in good repair. When doing energized work, first try to reduce the incident energy levels to avoid having to wear the bulkier PPE. If that isn’t possible, have multiple people working in short shifts to avoid fatigue, or reschedule to a time when you can de-energize the system. Make sure that all employees are trained in the selection and use of PPE.
Stay safe, and as always, thanks for reading!
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