This International Standard specifies two methods for assessing the effects of heating on injection-moulded thermoplastics pipe fittings — method A, using an air oven, and method B, using a liquid bath. In case of disagreement, method A is the reference method. This International Standard is applicable to cement-welded fittings as well as to flanged fittings and fittings incorporating elastomeric seals and to fittings consisting of the assembly of several moulded parts (e.g. union connectors). It is applicable to both pressure and non-pressure fittings.