Prediction of fire exposure and characterization of the burning behavior of wood for the design of a heavy timber "fireproof building" under localized fire scenario

Prediction of fire exposure due to a localized fire scenario and measurement of material properties of wood for the fire safety design of a large timber-based railway station as a "Fire-proof Building" is reported. The current Japanese building regulation for "Fire-proof buildings" requires autonomous extinction of fire before the collapse of any of load-bearing members due to fire anticipating the difficulty in the availability of fire fighting at the event of a post-earthquake fire. The building featuring long span heavy timber arches supported by steel trusses was designed and finally approved as the first timber-based "Fire-proof building" within this Japanese building regulation framework assuming local ignition on load-bearing member. The study consists of the prediction of the fire exposure of load bearing timber members due to train fires, investigation of the possibility of autonomous extinction at different levels of external heating with bench-scale test apparatuses and evaluation of the influence of design features and configurations on the burning behavior using an intermediate scale radiant panel. The Japanese Cedar was found to be self-extinguishable under only limited level of fire exposure and some design details originally proposed by the architect were found to lead to an uncontrolled burning of the timber components. The building design was coordinated to reduce the fire exposure to the load bearing timber members within the extent allowing the autonomous extinction. The study presents basic framework for the further development of the fire safety design and material properties for timber-based "Fireproof buildings".