Ask the Expert Question-and-Answer Archive

by Ron Joseph

October, 2004

Intumescent Paint Coating

Q. We are constructing an office building in VT. The steel structure will be installed in January, and must be 2 hour rated. Winter conditions will prevent applying water based products, such as spray-on fireproofing and joint compound, without tenting and heating. Is it possible to paint the steel with intumescent paint in the shop prior to errection? Have you ever heard of this being done? Would the bolts have to be painted in the field? Thank you for your help.

Thanks for your question. I'm not an expert on iintumescent paints although I am familiar with them and suggest that you get advice either from the coating manufacturer or from the folks at UL that qualify the products for their fire ratings. In general, I assume that you can paint the steel in the fabrication shop prior to shipping it to the site; however, you would need to insure that material handling procedures minimize damage to the coating. You will also need to specify a repair procedure for those sections that are unavoidably damaged during shipping and erection. The bolts would need to be coated after they have been installed, because if they are coated in the fabrication shop the coating will be damaged during assembly of the structures.

Please confirm my suggestions with your coating supplier before going ahead with the painting.

Best wishes,

Ron Joseph