ISO 15500-1:2015 specifies general requirements and definitions of compressed natural gas fuel system components, intended for use on the types of motor vehicles as defined in ISO 3833. It also provides general design principles, and specifies requirements for instructions and marking.
This part of ISO 15500 is applicable to vehicles (mono-fuel, bi-fuel, or dual-fuel applications) using natural gas in accordance with ISO 15403‑1. It is not applicable to the following:
a) liquefied natural gas (LNG) 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.
NOTE 1 It is recognized that miscellaneous components not specifically covered herein can be examined to meet the criteria of this part of ISO 15500 and tested according to the appropriate functional tests.
NOTE 2 All references to pressure in this part of ISO 15500 are to be considered gauge pressures unless otherwise specified.
NOTE 3 This part of ISO 15500 is based upon a service pressure for natural gas as fuel of 20 MPa [200 bar] settled at 15 °C. Other service pressures can be accommodated by adjusting the pressure by the appropriate factor (ratio). For example, a 25 MPa (250 bar) service pressure system will require pressures to be multiplied by 1,25.
 1 bar = 0,1 MPa = 105 Pa; 1 MPa = 1 N/mm2