Experimental study on fire performance of cross laminated timber structure exposed to compartment fire

To investigate the contribution of combustible cross laminated timber (CLT) to the fire load of CLT compartment and the dynamic impact of CLT lay-up for fire under the compartment fire, four CLT compartment fire tests with different fire areas on the inner surface and different CLT lay-ups were carried out. The area of the directly fired CLT accounted for 0%, 19.8%, 36.4% and 87.6% of the inner surface of the CLT compartment, respectively. Fire dynamic model for the CLT compartment considering fall-off of the charred layers was proposed based on the two-zone fire model. CLT compartment fire tests were analyzed and simulated, and the effectiveness and limitations of the two-zone model used in the analysis of CLT compartment fire were discussed. The tests results show that the fire area of CLT has a significant influence on the development and heat release of compartment fire. The combustibility of CLT significantly increases the burning rate and the heat release rate of the fire. Whether the charred layers fall off has a significant impact on the fire development. Randomness is found in terms of both time and area of the fall-off of charred layers. The thinner the CLT single layer is, the earlier the charred layers fall off. The two-zone model that considering CLT combustion and fall-off of the charred layers can simulate the air temperature of the CLT compartment fire to a certain extent, but the fire temperature predicted by the two-zone model in the cooling phase is always lower than the test temperature.