Fire resistance of wood truss floor assemblies

This paper presents and discusses the factors that affect the fire resistance performance of lightweight wood truss floor assemblies protected with two layers of Type X gypsum board ceiling finishes. Fifteen full-scale fire resistance floor experiments were conducted using the CAN/ULC S-101 fire resistance standard which is similar to the ASTM E119. Parameters investigated in this study include the effects of insulation installation in floor cavity, insulation type, wood truss spacing, resilient channel installation, resilient channel spacing, wood truss width, wood truss chord orientation, wood truss web type, wood truss connection type and adding concrete topping above the sub-floor. The impact of these parameters on the fire resistance performance of the wood truss floor assemblies is discussed. The fire resistance of wood truss floors appears to be essentially governed by the wood trusses\u2019 spacing for direct application of gypsum board to wood truss framing, insulation type and resilient channel installation and spacing. Other parameters are of secondary importance.Peer reviewed: YesNRC publication: Ye