Performance of burning and strength of wood against low radiation: Fundamental research for promotion of gymnasiums with roofs supported by wooden beams

In this study, the ignitability tests and cone calorimeter tests at the incident heat fluxes of less than 20 kW/m² for 20~30 minutes were conducted. The results indicated the wood were not ignited below 13 kWAm². And the fire was put out automatically even if the wood had been ignited. But the darkening was observed on the surface of the samples even if the samples were not ignited and the temperature at the depth of 5mm from the bottom of the char layer in some of the test samples reached more than 180C. Therefore the static bending tests and impact tests for the wood exposed to the temperature at 120C,150C or 180C for 20 minutes were carried out to investigate the thermal degradation characteristics of wood, in consequence, the structural performance of wood would be recovered when the wood samples were cooled down later after they had been exposed to the temperature at 120C or 150C.