The effects of sweat and layering clothing in field use of arc-rated garments has been questioned with little research.
This study aimed to formulate a conclusion on the effects of sweat and the impact of layering materials by compiling previous work and continuing to evaluate the effects of moisture on protection values of arc-rated materials using testing to the ASTM F1959 standard.
This article explores how moisture affects the protection level of clothing or PPE when faced with arc flash, examines the effects for single-versus double-layer systems, and seeks to determine whether a worker is better off wearing arc-resistant rainwear rather than getting wet in the rain.
Before an industrial flame-resistant (FR), arc-rated (AR) product goes to market, rigorous large-scale arc flash testing occurs to determine whether the product is compliant. In the case of arc flash protective clothing, compliance is determined through both small-scale methods (e.g., vertical flame testing to ASTM D6413 as well as physical tests for strength, colorfastness and dimensional change) and large-scale arc flash testing (ASTM F1959, 2014). The output of arc flash testing is a rating, or a protection value, reported in kW/m2 [cal/cm2]. This rating, when tested to ASTM F1959 per ASTM F1506, is then only assigned to materials that do not ignite and continue to burn for longer than 5 seconds, and that show no propensity for melting and dripping (ASTM F1506, 2017); these are the criteria required to pass the test for a material to be assigned with an arc rating for use in industry. Testing to ASTM F1959 is performed after three wash cycles and one drying cycle. These attributes in a material are important in FR clothing, as clothing ignition increases body burn, and melting and dripping in testing indicate that in a field exposure a material would melt and drip, causing significant burn injury (Choudhury, 2017).