This document specifies the technical requirements to minimise the hazards listed in Clause 4 which can arise during the commissioning, operation and maintenance of nitrogen or oxygen units when carried out in accordance with the specifications given by the manufacturer or his authorised representative. It also takes into account some performance requirements recognised as essential by authorities, aircraft and ground support equipment (GSE), manufacturers as well as airlines and handling agencies.This document applies to:-all types of mobile nitrogen units and oxygen units with transportable gas cylinders interchangeable for filling purposes;-equipment to be carried with other GSE or vehicles, e.g. skid mounted units,intended for the manual refill of gaseous nitrogen or oxygen on aircraft (Examples see Annex A).NOTEGenerally oxygen units are used under aircraft maintenance conditions, not under commercial servicing conditions.This document does not establish requirements for noise and vibration.Noise and vibration are dealt with respectively in EN 1915 4 and EN 1915 3.This document does not deal with hazards in respect to a standard automotive chassis and from other vehicles on the apron.This Part of EN 12312 is not applicable to nitrogen or oxygen units which are manufactured before the date of publication of this document by CEN.This part of EN 12312 is intended to be used in conjunction with EN 1915-1, EN 1915-2, EN 1915-3 (for vehicles) and EN 1915-4.