ISO 12619-9:2017 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 ISO 3833.

It is applicable to vehicles using CGH₂ in accordance with ISO 14687-1 or ISO 14687-2 and hydrogen/natural gas blend using natural gas in accordance with ISO 15403-1 and ISO/TR 15403-2. It is not applicable to the following:

a) liquefied hydrogen (LH₂) fuel system components;

b) fuel containers;

c) stationary gas engines;

d) container mounting hardware;

e) electronic fuel management;

f) refuelling receptacles;

g) fuel cell vehicles.

NOTE 1 It is recognized that miscellaneous components not specifically covered herein can be examined to meet the criteria of ISO 12619-9:2017 and tested according to the appropriate functional tests.

NOTE 2 All references to pressure in ISO 12619-9:2017 are considered gauge pressures unless otherwise specified.