This International Standard specifies the functional requirements for a self-propelled potable-water vehicle capable of servicing all aircraft commonly in service in civil air transport. It is not intended to specify equipment design but rather to highlight certain criteria that are known to be essential for efficient operation in the civil airline environment. In all cases this International Standard should be applied with due reference to national regulations on sanitation that may be applicable in the area in which it is proposed that the vehicle will be used. To avoid any accidental contamination, the unit should only be used to supply aircraft with potable water.