Ms. Kerry J. Smith, CIH Dear Ms. Smith, Your question on gas piping in a hood was referred to me. I recommend you review NFPA 54-2002, National Fuel Gas Code for information on the materials requirements, installation, and testing of gas piping systems in buildings. This correspondence is not a Formal Interpretation issued pursuant to NFPA Regulations. Any opinion expressed is the personal opinion of the author, and does not necessarily represent the official position of the NFPA or its Technical Committees. In addition, this correspondence is neither intended, nor should be relied upon, to provide professional consultation services. Very truly yours, Theodore C. Lemoff Staff Liaison