Questioning whether or not your non-flame resistant (non-FR base layer counts towards a system arc rating? This blog post gives you the answer and helps you determine the proper garments to wear as a base layer when calculating a layered arc rating.
The answer is no – a non-FR base layer does not count toward an arc rating. Learn why as VP of Technical, Scott Margolin explains the importance of only wearing arc rated clothing when layering. This video also includes footage of the risk associated with combining FR and non-FR for layering purposes.
The Risk of Non-FR Base Layers Explained
The simple explanation for why a non-FR base layer is not counted toward a layered arc rating is that ASTM F1959 – the Standard Test Method for Determining the Arc Rating of Materials for Clothing – states that in order to count towards a system arc rating, the garments involved in layering must have arc ratings. You can only get an arc rating on a flame resistant (FR) fabric. This means that before a garment can even be considered part of a system arc rating, the fabric must be FR (uses ASTM D6413, “the Vertical Flame Test.” ) and tested for its arc rating as determined by ASTM F1959.
FR base layers provide an added level of protection in the event the thermal hazard exceeds the level of protection provided by the outer layer. For more information on the best practices for layering, visit our blog post, “Base Layer Basics.”
What to Avoid Wearing
Understanding the risks you and your colleagues face when mixing FR and non-FR layers of clothing together is key to ensuring your safety on the job. Tyndale’s blog post on, “What Should I Wear Under My FRC?” is a great starting point to learn what industry standards say about undershirts, what your options are for base layers or undershirts, and video footage of what happens when someone wears a non-FR base layer.
In summary, non-FR base layers do not count toward system arc ratings, while AR / FR base layers do.