This document specifies general requirements and definitions of liquefied 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.nd edition 2021-06 Road vehicles — Liquefied natural gas (LNG) fuel system components — Part 1: General requirements and definitions Véhicules routiers — équipements pour véhicules utilisant le gaz naturel liquéfié (GNL) comme combustible — Partie 1: Exigences générales et définitions Reference number ISO 12614-1:2021(E) ？ ISO 2021 ISO 12614-1:2021(E) COPYRIGHT PROTECTED DOCUMENT ？ ISO