Personal Protective Equipment for arc flash hazards can be a confusing topic. Maintenance departments often have more questions than answers. What category do we need? What type of PPE is involved? Where does it apply? When is it required? Where do we purchase it? How do we know we are doing this right? I get these questions and more in my training sessions. This week’s article will attempt to answer these questions, and hopefully clear up any confusion about arc flash PPE by answering five basic questions.
Thousands of arc flash events occur every year. In many cases, the worker walks away unharmed, but all too often the worker is severely injured or killed. Arc Flash PPE is designed to protect the worker from catastrophic injury and death and driven by OSHA requirements to provide workers with protective equipment for the risks they undertake on the job. OSHA requires employers to provide workers with protection for all recognized hazards, not just electrical. For arc flash hazards, arc-rated PPE meets this requirement.
Arc Flash PPE consists of protection for the entire body. Any portion of the body that might be exposed to an arc flash is to be protected with clothing or equipment that meets or exceeds the incident energy at the equipment. The primary function of arc-rated clothing is to protect the worker from severe burns resulting from the super-heated air. All arc-rated clothing is flame resistant, which means it self-extinguishes once the source of the fire is removed.
Head, face, and neck protection consist of a hard hat, face shield, balaclava, hearing and eye protection, or an arc flash suit hood. All head, face, and neck protection are arc rated just like the clothing. Hand protection can be in the form of voltage-rated gloves designed to protect against shock or arc-rated gloves.
Take note that arc-rated gloves typically do not provide shock protection.
Arc-rated PPE is to be worn anytime the worker is within the arc flash boundary and there are exposed live electrical conductors present. The arc flash boundary can be found on a compliant arc flash label on the front of the equipment. If there is no arc flash label, the worker must reference NFPA 70E Table 130.7(C)(15)(a) for AC systems and NFPA 70E Table 130.7(C)(15)(b) for DC systems. These tables provide the Hazard Risk Category and Arc Flash Boundary based on the ratings of the equipment and the task being performed. Take note that these tables apply only if the available fault current and clearing times are within the table’s parameters.
Arc Flash PPE is to be worn anytime the worker is engaged in live electrical work within the arc flash boundary while electrical conductors are exposed.
Live electrical work includes the following:
• Voltage testing (This includes testing for the absence of voltage during LOTO procedures.)
• Diagnostic testing
• Opening MCC or disconnect doors
• Removing and replacing panel covers
• Removing and/or replacing breakers
• Removing and/or replacing fuses
• Interacting with the equipment in a way that increases risk of an arcing event
• Working in a live situation while assuming it is de-energized
As always, we encourage workers to engage in de-energized work whenever possible. This eliminates the risk and the requirements to wear arc flash PPE.
As long as the worker is wearing arc-rated PPE that covers all exposed parts of the body and the PPE is rated at or higher than the incident energy of the equipment, it doesn’t matter how the worker does it. However, most arc flash PPE programs fall into one of two strategies.
1) The worker wears arc-rated clothing as a uniform. The advantage of this method is that the worker is protected to a certain level during the entire workday making it more convenient and often easier to comply.
2) The worker wears the PPE only when engaged in live electrical work. This usually means that the worker has an arc-rated coverall that is used as needed.
Your program should be predicated on how often your workers engage in live electrical work, the tasks they typically perform, their qualification level, and the condition of the equipment. Communication and planning should be undertaken before deciding which plan works best for you.