ISO 22391-3:2007 specifies the characteristics of fittings for piping systems made from polyethylene of raised temperature resistance (PE-RT), intended to be used for hot and cold water installations within buildings for the conveyance of water -- whether or not the water is intended for human consumption (domestic systems) or heating systems -- under the design pressures and temperatures appropriate to the class of application according to ISO 22391-1.
It covers a range of service conditions (classes of application), design pressures and pipe dimension classes, and also specifies test parameters and test methods. When used in conjunction with the other parts of ISO 22391, it is applicable to fittings made from PE-RT, as well as to those made from other materials, intended to be fitted to pipes conforming to ISO 22391-2 for hot and cold water installations, the joints of which are in accordance with ISO 22391-5.
ISO 22391-3:2006 is applicable to the following types of fitting: mechanical fittings; socket fusion fitting; electrofusion fittings; fittings with incorporated inserts.
It is not applicable for values of design temperature, maximum design temperature or malfunction temperature in excess of those specified in ISO 22391-1.