The intense energy and very short duration of an electrical arc flash represents a very unique exposureComplying with NFPA E and following these three steps will greatly reduce your chances of injury due to electrical arc flash.
Workers are assumed safe if the arc rating of their clothing (or ATPV value) exceeds the electric arc incident energy as calculated in the worst case scenario of a risk assessmentMaterials or assemblies are given an ATPV value, expressed in kilojoules per square metre (kJ m), which can be converted into the familiar cal cm.
A common question in arc flash clothing protection is whether an ATPV value or an Ebt value is better protection for FRCLets start by defining these two values and seeing what each actually meansFirst, its important to understand that the arc rating of a fabric is either an ATPV (Arc Thermal Performance Value) or an Ebt (Energy breakopen threshold).
Cal cm² is a rating for what level of incident energy we might expect should an arc flash occur and is directly related to equipmentATPV and EBT are values given to FR fabrics that tell us, when exposed to incident energy, how that fabric will perform and what
ATPV vsEBT The question often arises as to whether an Arc Thermal Performance Value (ATPV) or an Energy Breakopen Threshold (EBT) is better protection in a garment systemWhen ASTM F FM (The Standard Test Method for Determining the Arc Rating of Materials for Clothing) was in development, we quickly recognized that some materials allow skin burn prediction to be reached
Arc rated rain gear testing is very similar to arc flash clothing but must also meet the requirements of the ASTM F specification which calls for the material to be exposed to twice the arc rating to ensure no melting or dripping will occur.
Which is Better The question often arises as to whether an Arc Thermal Performance Value (ATPV) or an Energy Breakopen Threshold (EBT) is better protection in a garment system.When ASTM F FM (the Standard Test Method for Determining the Arc Rating of Materials for Clothing) was in development, we quickly recognized that some materials reach the skin burn prediction threshold (also