Arc Flash Clothing Requirements
NFPA 70E requires that all electrical workers who operate within the Flash Protection Boundary must wear Arc Flash Clothing and understand arc flash clothing requirements. Arc flash, however, can take place and result in injury or death even when there are no energized electrical parts. NFPA 70E Table 130.7 lists the appropriate level of PPE for use when encountering harzardous electrical areas.
Deciding on the appropriate level of Arc Flash Clothing is very important. This is because too little Arc Flash Clothing exposes a worker to potentially lethal injury. On the other hand, high levels of Arc Flash Clothing are extremely bulky, and may restrict vision and movement, increasing the chance of an accident as well as increasing work time and difficulty.
The types of Arc Flash Clothing or personal protective equipment (PPE) required for working on energized electrical equipment and Arc Flash Clothing Requirements have been defined in NFPA 70E and CSA Z462 and is described in the following categories. Each category is further defined by other NFPA standards with respect to the functionality of each type of PPE.
NFPA 70E defines five risk/hazard categories which determine the proper level of Arc Flash Clothing for a given task. The Arc Flash Clothing Requirements table below lists Arc Flash Clothing required at each level. The risk level for a given task is determined either by conducting an arc hazard analysis or by consulting NFPA 70E Table 3-3.9.1, which lists hazard categories for a wide range of tasks.
Cal/cm2 are the units of incident energy that the PPE can withstand. Note that a hard hat with full-face shield and the appropriate gloves are also required by arc flash clothing requirements/p>
The Category 4 PPE is not intended to protect under all conditions but rather only up to a limit of 40 Cal/cm2. Many arc flashes produce energy far in excess of 40 Cal/cm2 with energy values in the hundreds of Cal/cm2.
Arc Flash Clothing Requirements provide protection for only the effects arc flash heat but not arc blast pressure that accompanies the arc flash. This pressure wave and explosive material includes flying shrapnel and molten metal.
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