Database of publications held in the former Fire Research Information Service at NIST's Building & Fire Research Laboratory (BFRL).
First, try searching on Google Patents. Once you find a relevant patent, you can easily find more by looking at the patent citations, similar documents, and by clicking on the 'find prior art' link.
You might also want to try this Quickstart Patent Search invented by a WPI alum that is a very good complement to the Google Patents search.