Chapter 26 of the IBC 2006 building code requires foam insulations used inside the building weather barrier to be protected by a thermal barrier. The code defines thermal barriers as 1/2 inch thick gypsum wallboard or equivalent to limit the temperature rise to prevent ignition of the foam insulation for 15 minutes. Providing a continuous thermal barrier is sometimes difficult. The plane of the interior face of exterior walls is often interrupted by columns, beams, girts, and other obstacles.
Recently a contractor, through a substitution process, introduced us to Staycell 255 manufactured by Preferred Solutions, Inc. This polyurethane spray foam product can be installed on the building interior and left exposed. No need for a thermal barrier. The product was tested according to UL 1715 full-scale room fire test to meet an alternative compliance permitted by the IBC. The product can be applied up to 4 inches thick on walls and 8 inches thick on ceilings.
This product will provide an efficient solution for insulating the inside face of precast concrete exterior wall panels. The closed cell foam insulation will also serve as an air barrier and will serve as a vapor retarder when installed at least 2.5 inches thick.