ISO 12619-4:2016 specifies general requirements and definitions of compressed gaseous hydrogen (CGH2) and hydrogen/natural gas blends fuel system components, intended for use on the types of motor vehicles defined in ISO 3833. It also provides general design principles and specifies requirements for instructions and markings.

It is applicable to vehicles using compressed gaseous hydrogen (CGH2) in accordance with ISO 14687‑1 or ISO 14687‑2 and hydrogen/natural gas blends 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 located upstream of, and including, the vaporizer;

b) fuel containers;

c) stationary gas engines;

d) container mounting hardware;

e) electronic fuel management;

f) refuelling receptacles.