This document specifies tests and requirements for the pressure relief valve (PRV), a compressed gaseous hydrogen (CGH2) and hydrogen/natural gas blend fuel system component intended for use on the types of motor vehicles defined in ISO3833 . It is applicable to vehicles using CGH2 in accordance with ISO14687‑1 or ISO14687‑2 and hydrogen/natural gas blend using natural gas in accordance with ISO15403‑1 and ISO/TR15403‑2 . It is not applicable to the following: liquefied hydrogen (LH2) fuel system components; fuel containers; stationary gas engines; container mounting hardware; electronic fuel management; refuelling receptacles; fuel cell vehicles. NOTE1 It is recognized that miscellaneous components not specifically covered herein can be examined to meet the criteria of this document and tested according to the appropriate functional tests. NOTE2 All references to pressure in this document are considered gauge pressures unless otherwise specified.