This International Standard specifies the requirements and test methods for mechanical fittings intended to join plastic pressure piping systems including transition fittings to metal pipes for the following: — supply of gaseous fuels (GAS); — supply of water for human consumption (W), including raw water prior to treatment and for the supply of water for general purpose, as well as underground drainage and sewerage under pressure (P); — supply of water for irrigation (I); — industrial applications (IS). This International Standard is applicable only to mechanical fittings with operating-temperature and pressure limits as indicated in the relevant systems standards. NOTE A list of International Standard for plastic pipes for which mechanical fittings can be used can be found in Annex A. Flanges are not covered by this International Standard. Mechanical fittings for hot and cold water systems inside buildings, as well as for district heating applications, are not covered by this International Standard.