For gas explosion accidents occurring in buildings, the explosion characteristics may be affected by the presence of the equipment and furniture, and the temperature produced by the vented explosion threatens the safety of surrounding personal and buildings. To investigate the internal overpressure and external temperature behaviors, explosion venting tests of methane-air mixtures were conducted in a self-designed 4.5-m3 square chamber, by changing the solid obstacles, ignition positions, and initial turbulence levels. The results showed that P 1 is generated due to the venting rate exceeding the volume growth rate of products after vent opening; with increasing flame propagation, flame front increases and more folds are present on the surface during venting, when the rate of combustion product exceeds the venting rate again , then P 2 forms. Ignition position and obstacles have little effect on P 1 , but affect the Helmholtz oscillation and high-frequency pressure oscillation (P 4). Front ignition leads to the longest duration of Helmholtz oscillation and central ignition results in the largest P 4. In the presence of obstacles, P 4 is eliminated and strengthened in the cases of rear and front ignitions, respectively. P 4 decreases and then increases as a function of the number of obstacles. Front ignition leads to the lowest temperature peak, rear and central ignition results in the same temperature peak. The length of the high-temperature field is the shortest under four obstacles and front ignition, respectively. Under strong initial turbulence, the overpressure peak, length and duration of the high-temperature field are the largest. [ABSTRACT FROM AUTHOR]