Properties of tropically sourced timber subjected to elevated temperature

Char layer is an important parameter for the fire-resistance design of timber. The char-layer insulates the inner layer (core) from high temperature to prevent further damage due to fire. This paper assesses the post-fire properties of tropical solid and laminated timber originating from Indonesia. The species are white teak, bayur, rajumas, and sengon. The timber was exposed to fire at time interval of 30, 45, and 60 min. The temperature growth was set according to ISO 834 standard heating curve. The result shows that the average of charring rate of species with greater density and longer time of exposure is smaller than that of species with smaller density and shorter time of exposure. The charring rate of tropical solid and glulam timber has a linear inverse relationship to the density at each time of exposure. The average experimental data linear regression suggests that tropically sourced timber with a density of more than 400 kg/m³ meets the charring rate of European standard. However, all experimental results agree with the Australian standard. Furthermore, according to post-fire mechanical properties examination, the solid timber core shows increased strength after fire; meanwhile, a strength decrease exists in glulam core.