Step 3 is by far the most important step! There a 4 steps to a basic risk assessment: Trying to figure out when arc flash PPE should be worn is not as straight forward as you might think.īut I’ve got a nice way you can approach it. Not every garment will pass both so remember this one thing.Īll arc rated clothing is flame resistant but not all flame resistant clothing is arc rated. Then once it passes that test it can be sent to see if it passes the AR tests (from ASTMF 1506). In order to even send a material to be tested for an arc rating, it must first meet the requirements of FR clothing standard (ASTM D-6413). What’s the Difference Between AR & FR?Īll arc rated garments are flame-resistant, in fact, that’s the barrier to entry. It’s the amount of incident energy that would result in a 50% chance that breakopen occurs. The breakopen threshold energy (EBT) is similar to the ATPV… What is EBT Rating?Īnother factor in performance testing your arc flash gear is determining when it will break open.īreak open is defined as a hole that’s either has an area of 16 mm2 or an opening of 25 mm in length. This means the skin under your clothing is exposed to about 1.2 cal/cm2. Well… now there is a 50% chance that you will experience the onset of a second-degree burn. So… let’s say you are in an arc flash that is has an incident energy of 8 cal/cm2.Īnd you are wearing clothing that is rated 8 cal/cm2 (because the ATPV was 8). Yup, sounds crazy but this is how it works. The value is determined by the amount of incident energy required to transfer enough heat through the material to create a 50% probability that the person wearing the ppe will experience the onset of a second degree burn. The arc thermal performance value (ATPV) is the material’s ability to withstand the incident energy. We call that the arc flash incident energy. When you are performance testing arc flash apparel you expose the material to a certain amount of heat energy. Usually, it’s the arc thermal performance value or ATPV Rating. Whichever one comes first dictates the number that goes on the equipment’s tag. ASTM F2178/F2178M (arc rated face shields)ĭuring the testing, there are two things that can happen that determine the results of the test and therefore determine the arc rating.Īt certain incident energy, you will either reach the material’s Arc Thermal Performance Value or its Breakopen Threshold Energy.This depends on the type of personal protective equipment you are trying to get rated.Įach type of protection has its own standard (or standards) for testing that it must meet. You can accomplish this by sending it for laboratory testing.īasically, they blow up the clothing or equipment in a lab and see if it passes the test. In order to determine arc flash PPE, you will need to know the arc flash rating of a given material. If the arc rating is low, is PPE still required? Let’s just say we worked it out and it was 3.7 cal/cm2.Īs long as your arc flash gear had a arc rating higher than 3.7 cal/cm2 then you will be protected from the arc flash. You would be exposed to a certain amount of heat energy. So let’s say you are standing in front of 30 amp disconnect (600 volts) and an arc flash occurs. Typically, it’s measured in calories per square centimeter (cal/cm2). Incident energy is the amount of heat energy produced by the arc flash explosion. In order to understand the arc rating, you first need to understand what it is correlated to… There are many ways to achieve arc flash protection, but quite often your only option will be to use electrical arc flash PPE.Įnsuring you are covered head to toe with equipment that is properly rated is paramount to your safety. Using PPE to Protect Yourself from an Arc Flash. Primarily, arc flash PPE is divided into the following subgroups:Īll arc flash apparel and equipment must be given a specific arc rating to ensure that it meets or exceeds the hazard levels present where the work is to be performed. Arc flash personal protective equipment (PPE) is a combination of clothing and safety equipment worn for protection from arc flash and shock hazards by a person performing electrical work.
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