A fire contained within a room can spread into void spaces in the walls and ceiling through penetrations in the material that lines the compartment. Few studies have looked at how a room and contents fire transitions to a structural fire. One of the active areas of fire research is the coupling of the fire to the structure. Lightweight wood frame construction represents the majority of residential construction in the U.S. The construction details and choice of materials will affect the overall fire resistance of the structure. Because of the relative lack of knowledge on the fire penetration into wall spaces, this research examined how fire might penetrate into the void spaces of wood framed structures.
In the U.S.A., a critical barrier to the penetration of hot gas products into void spaces is provided by the gypsum-board skin of the compartment. For most compartments, there are many penetrations within the compartment’s gypsum-board skin. Common potential access points include security system wiring (e.q. smoke detectors and cameras), ventilation fixtures, light switches, and electrical outlets among others. A hole in the gypsum may create opportunities for void space ignition. One of the purposes of this work is to develop a small scale testing system to characterize fire driven flow and heat transfer into a void space. With such an apparatus, one can rapidly identify materials that are prone to igniting for a given leakage geometry and fire size. Common materials found in void spaces include wooden structural members, plywood/oriented strand board, a variety of insulation types, and vapor barriers. This study discusses the characteristics of the small scale experimental system and preliminary tests on a range of void space construction materials.