The arc flash fire is the most possible harmful reason to the electric workers. Because the temperature of arc happening point is 35000 F, which is 4 times of the sun surface temperature. The around materials will be gasify or burning out. If the workers’ clothing be burned, the workers will be scald.
At present, the arc proof test standard mainly include the EN and America standards.
The EN standard: put 4 pieces fabric under the arc reaction and check the result. The test condition is, voltage 400V, arc flash fire time 500ms, top electrode is made of aluminium, the bottom electrode is made of copper. The interspace is 30mm, the distance between the test sample and the electrode is 300mm.
The requires of the EN standard for the finished clothing is: the style can not hinder the action. It should be long sleeve to protective the body. The button and the zipper can operate after the arc flash fire. The thread, accessories, button and the zipper can’t do further harmful to human. The metal accessories should be covered by fabric and the nonmetal accessories can exposed.
The America standard tested from the flame retardant property, weight, tear strength, tensile strength, washing color fastness, shrinkage and the ATPV. And the ATPV is test from the 21 pcs fabric sample.
America standard requires for the clothing, the thread, accessories, button and the zipper can’t do further harmful to human. The FR thread can’t be melt under the test of 260℃(191A). If the accessories of the clothing may be heat transfer and molten, the accessories should be covered by the fabric and no contact to skin.