The April 2013 issue of The Construction Specifier included a technical feature by J.W. Mollohan, CSI, CCPR, CEP, LEED GA, entitled, “Exterior Wall Assemblies: Are You Getting What You Specified?” We received the following letter from Cliff Black, a CSI member and a building envelope product manager for Firestone Building Products.
I am writing in regard to the article on exterior wall assemblies. I agree with the author the issue is certainly a challenging one for the design and specifying community. I would like to cite the bracketed statement at the top of page 57, which states, “buildings of two stories or more.” This appears to be taken in the context of the design of National Fire Protection Association (NFPA) 285, Standard Fire Test Method for Evaluation of Fire Propagation Characteristics of Exterior Non-load-bearing Wall Assemblies Containing Combustible Components, addressing multi-story fire propagation.
However, the International Building Code (IBC) 2603.5 states NFPA 285 is required for buildings of any height for Types I through IV construction incorporating combustible plastic insulation in the exterior wall assembly. IBC Chapter 14 (“Exterior Walls”) calls for differing requirements for water-resistant barriers (WRBs) and various combustible claddings, qualified by height.
In this case, I believe the statement should read “buildings of any height,” rather than “buildings of two stories or more.”
Mr. Mollohan replied to Mr. Black, and has allowed us to share it with other readers of the magazine:
Good catch, Clint! You are absolutely correct that one must be familiar with multiple chapters of the IBC to determine whether an NFPA 285 test is required. My error, and your correction, illustrates the difficulty of this provision. I am attaching an adaptation of a flow chart originally created by Barbara Horwitz-Bennett of DuPont Building Innovations for guidance to interested readers: