Experimental study on heat release rate measurement in tunnel fires

摘要

Knowledge about the heat release rate (HRR) is essential for studying tunnel fires. The standard method in ISO 9705 is widely applied to calculate the HRR of combustion by measuring the consumption of oxygen in a fire. However, the studies of HRR measurement in full-scale tunnel fires are rare because of the complication and costs of large experiments. This paper presents a system based on the principle of oxygen consumption calorimetry for the measurement of HRR and total heat release (THR) of full-scale fires in tunnels. A total of 22 fire experiments are performed in a large-scale ventilated testing metro tunnel with dimension of 100.0 m x 5.5 m x 5.5 m to validate the reliability and effectiveness of this system. Firstly, four oil spray fire tests are conducted with nozzle flow of 106 L/h at (1 +/- 0.1) MW HRR to calibrate the instrumentation. Then, 18 full-scale fire tests using square diesel pools at five sizes (0.5, 1.0, 2.5, and 5.0 m(2)) and wood cribs as fire sources are carried out for the measurement of HRR and THR. Results provided by the comparison between the measured HRR and THR values of the fire tests and the theoretically calculated ones show that our system works effectively in the HRR measurement of full-scale fires in tunnels.