Measurement of thermophysical properties of fire testing materials

An unsteady heat flux method was used to determine the thermophysical prope rties of Polymethyl methacrylate (PMMA) and cellulose, both of which are co mmonly used as standard sample materials in flame spread tests. The analysi s is based on an analytical solution to a heat conduction equation with per iodic heat flux. The effective thermal conductivity and diffusivity for a p acked bed of each sample material were simultaneously determined from the a mplitude and phase delay of the temperature response for periodic heat flux . Experiments were performed for a range of heating rates, particle sizes a nd apparent densities. The variation in thermophysical properties with temp erature was obtained, and the effects of pyrolysis for cellulose, and phase transition for PMMA, on the thermophysical properties of these materials w ere investigated.