This document specifies the design, testing and marking requirements for caps and plugs used to form a pressure tight seal with liquefied petroleum gas (LPG) cylinder valves and pressure vessel valves. Sealing caps and plugs provide an additional seal for self-closing and manually operated valves. Dust caps or plugs and tamper evident seals that do not form an additional seal as part of their design are excluded from the scope of this document. Cylinder valve caps and plugs can be used with valves for liquid and vapour manufactured in accordance with EN ISO 14245 and EN ISO 15995. Pressure vessel valve caps and plugs can be used with valves for liquid and vapour manufactured in accordance with EN 13175. Occasional liquid withdrawal valve caps and plugs are excluded from the scope of this document. Reusable and single use sealing caps and plugs are included in this document. This document does not exclude the use of other designs that provide an equivalent level of safety. NOTE The term pressure vessel does not include LPG tank vehicles, also called road tankers , in CEN/TC 286 standards.