A flash session on the expo floor Tuesday at Safety 2017 focused on the science behind flame-resistant clothing. Speaker Scott P. Francis told attendees to beware of simple terms.

He said for flame-resistant, arc flash PPE, words like 88/12, inherent, certified do not tell you anything about specific fabric or fabric manufacture. It’s important to know what fabric your garment is made from and who makes the fabric, Francis said. “Fabrics perform very different so you should know the specifics on protection, comfort and value.”

What is inherent, when it comes to FR fabrics, he asked the audience. “There is no consensus on whether fabrics are inherent or not,” he said. “There is simply no substitute for a wear-test consensus. The AR/FR clothing cannot protect if it’s not worn.”

He also stressed that comfort equals protection, but comfort is inherently subjective. “It is not linked to weight across fiber types, and it’s not linked to weight within fiber type until there is more than 30 percent data available.” He said wear tests are the only way to judge a fabric for comfort, quality and protection. Francis also mentioned that you should account for shrinkage over type.

Another topic he briefly discussed was heat stress. He said heat stress and comfort are totally different. “No single layer, breathable woven or knit fabric, whether it’s FR or not, causes heat illness,” Francis said. “Don’t confuse the two. They are two separate issues.”