Abstract: An explosion relief valve for a confined space, more particularly for the crankcase of an internal combustion engine, includes a seat (1) which may be fitted into a boundary wall (3) of the space to be protected, a spring-loaded closure plate (4) cooperating with the valve seat, at least one flame barrier (9) having low pressure resistance in the gas path leading through the valve, preferably consisting of sheet-metal strips stacked one above another transversely to the throughflow direction of the gas, which sheet-metal strips are provided preferably at least over part of their width with irregular corrugations, and at least one other perforated wall (11, 12) in the gas path of expanded metal.