There is a company called Technical Fiber Products in New York (a division of a British firm) that sells intumescent panels that can be used in composites products. Their web site is www.techfibres.com.
Good luck.
If I remember correctly, there are two or three ASTM standards that address this topic to one degree or another. I no longer have access to the ASTM books, so I can't look them up for you, but check your closest engineering library or maybe find something online. I have painted epoxy/fiberglass...
