Arc Rating Variability and Repeatability: Why Does Fabric Arc Rating Vary and Which Value is Correct?

Variability in arc ratings of fabrics poses challenges for end users, manufacturers and test laboratories. In this paper a test laboratory, a manufacturer, and a large US electric utility partnered and performed repeat tests on fabrics to study variability in arc ratings. The work included cross-referencing data from testing performed on control fabrics and comparison of results from different laboratories. The results help gain an understanding of factors that influence arc rating to improve test methods and standards, guide users to select appropriate PPE to match their hazards and enable manufacturers to validate claims on their products. Lastly, the paper gives recommendations to end users regarding best practices to accommodate arc rating variability in their programs.