You will need to comply with this standard if you intend to install a natural gas system into a heavy vehicle.
This standard specifies requirements for natural gas (NG) fuel systems for engines mounted on motor vehicles, either for the propulsion of the vehicles or for driving some auxiliary function. It provides requirements for the design and construction of component parts, and for their installation in vehicles, and for tests, commissioning, and periodic inspection. It applies to all vehicle types, e.g. rigid chassis, articulated chassis and semitrailers.
You will need to comply with the version of this standard that was current at the time when the NG system was installed in your vehicle.
