Key Takeaways

  • 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).

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