Do Zippers and Buttons Factor into Ebt Ratings?

Thanks to everyone who submitted questions to be answered in our FR FAQ series. The question we’re answering today was submitted by Charlie S. from Pennsylvania, who asks:

What effect do zippers and buttons have on arc ratings, specifically break open ratings?

As you may know, there are two ways to determine an arc rating as specified in ASTM F1959, the Standard Test Method for Determining the Arc Rating of Materials for Clothing:

  • Arc Thermal Performance Value (ATPV)
  • Energy to Break Open Threshold (Ebt)

There is no difference in the protection provided; whether the arc rating is ATPV or Ebt, you are protected from second degree burn at or below the arc rating of the fabric. The only difference is whether the fabric allows a burn through it (ATPV) or a hole in it (Ebt).

Focusing on Energy to Break Open Threshold (Ebt), let’s listen in as Tyndale’s Vice President of Technical, Scott Margolin, addresses Charlie’s question:

As Scott shares, ASTM F1959 is performed using fabric panels. Zippers and/or buttons are not included on those fabric panels because it is a fabric-specific test. That said, a standard rating of break open (Ebt) does not factor in zippers or buttons. The test is merely looking at how much energy the fabric can withstand before it gets a hole in it (Ebt) or burn through it (ATPV).

There is a different test where a half manikin is put within the same arc apparatus as the fabric panels and testers look for whether the buttons or zipper tapes break open at or below the arc rating of the fabric. Within this test, it’s possible to visually confirm, but not quantify, that buttons, zippers, and other closures do not cause break open below the arc rating of the fabric.

If you have other questions, feel free to email or add your question to the comments section at the bottom of this page. If you’re not sure if we’ve answered your question, use the “Search Our Blog” search bar to type in a key word(s) related to your question. Chances are, we have something on the subject but if not, we would be happy to get back to you and may even cover it in an upcoming post.

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