Fire-Proofing Structural Steel

Q: Since our last survey we were introduced to an epoxy based intumescent fire proofing product to repair damaged areas of vermiculite fireproofing on our structural steel that had bare areas from years of wear. Two weeks-ago we had a “mock” survey by my corporate representative and while he seemed to like the application process, he is not sure that we could pass our survey when the real surveyors come. He suggested that we think about having it repaired with the vermiculite product. What do you think? Any help would be greatly appreciated.

A: This issue is not clearly understood among the different AHJs, let alone their surveyors. I can say that many surveyors would not know what they are looking at if you had mixed fire-proofing products on the same piece of structural steel.

But, to be sure, your representative who conducted the mock survey is correct: You cannot mix and match different types of fire-proofing material to repair missing fire-proofing on structural members of your building. While you will not find a specific code or standard that says this, it is an interpretation of the UL listings for fire-proofing structural members of the building. Simply stated; There is no UL listing that allows you to mix different UL listed products to form a contiguous fire-proofing protection on the structural member. If there is, I have not seen or heard about it.

So, heed the advice from your mock surveyor and only put back the same type of fire-proofing material that was originally applied. Sounds to me, that your mock surveyor should be a real surveyor for CMS or one of the accreditation organizations. He seems to know what he is looking at.