Fire Safety of Wood Floor Assembly: Model and Full-scale Test

IRG/WP 07-20375

H Takeda

The present paper describes the model for the prediction of fire safety of wood floor assemblies. The model includes heat transfer model for the calculation of the flow of heat in floor assembly and structural model for the analysis of the mechanical performance of wood joists. The floor assemblies considered in this paper are constructed with nominal 2x10 (38x241mm) wood joists lined by Type X (or Type C) gypsum board (12.7mm or 15.9mm thickness, one layer or two layers) as a ceiling membrane, and 15.9mm thick plywood as a sub-floor. The heat transfer model employed two-dimensional heat conduction equation to predict the temperatures in the ceiling (gypsum board), wood joists and sub-floor (plywood) in the floor assembly, when the ceiling is exposed to fire. The structural model, using the temperature distribution in the joists predicted from the heat transfer model, calculated strength of the joists and deflection of joists based on the modulus of elasticity, moment of inertia and rigidity of joists to examine the mechanical performance of floor / ceiling assemblies. The results from the computer model were compared to the results from the full-scale tests. Reasonably good agreement was observed between the results from the model and those from the tests.

Keywords: simulation model; fire safety; wood floor assembly; heat transfer; mechanical strength; char formation

Conference: 07-10-29/11-02 Taipei, Taiwan

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