Effect of ARC electrode geometry and distance on FR fabric protection properties against second degree skin burn

Abstract

The results of experimental arc testing of Arc Rated FR fabric with three different geometrical arc electrode arrangements is presented and discussed. The testing was done using: a) “open air” apparatus for fabric panel test methods ASTM F1959 and IEC 61482-1-1 with vertical butted arc electrodes in open air; b) “box” apparatus for test method IEC 61482-1-2 with vertical butted arc electrodes placed in a box; c) nonstandard “ejected arc” apparatus with parallel horizontal arc electrodes in open air. FR treated Cotton fabric was used to evaluate the difference of protective properties for the three geometries and arc current levels of 2, 4, 8, 12, and 16 kilo amperes for each of geometries (as possible). Distance between fabric and arc electrodes was 18 inches and an arc gap was 12 inches except box test. A strong difference of a second degree skin burn threshold for tested FR fabric was demonstrated among different geometries and upon current level within the same geometry. Inverse power function represents Time-Current Curve (TCC) second degree skin burn threshold for the fabric. Knowledge of electrode configuration is required and has to be taken in consideration for proper electric arc protection. ATPV alone does not provide adequate protective for all arc configurations.