An experimental apparatus was set up to demonstrate the effect of size on methane-air mixture explosions in spherical vessels connected with pipes. Two spherical vessels and pipes were used to constitute different-sized linked vessels. In this paper, gas explosions and explosion suppression were studied. Under the condition of the vessel size being changed and the pipe length not being changed, the maximum explosion pressure is almost constant, while the maximum explosion pressure rising rate decreases with increasing vessel diameter. A larger vessel with a longer pipe will lead to a safer explosion environment. When a large spherical vessel is connected, there exists a certain length to keep the pipe terminus safer. However, for a small spherical vessel, the pipe terminus becomes more dangerous with increasing pipe length. When wire-mesh is added between the pipe and spherical vessel, the maximum explosion rising rate in a small vessel decreases much more than without wire-mesh. However, for a large vessel, the change of the maximum explosion rising rate is not clear. Generally speaking, wire-mesh has a positive effect on explosion suppression in a vessel; however, in a pipe terminus, it has only a positive influence when a small spherical vessel is connected. The conclusions provide an important reference for the safety design of explosion venting and explosion resistance. (C) 2017 Elsevier Ltd. All rights reserved.