This standard specifies the hot oven test method for evaluating the mass of PVC-U, PVC-C, ABS and ASA pipe fittings for injection molding. This method is suitable for pressure and non-pressure pipe fittings, pipe fittings with resilience sealing rings, and pipe fittings with flange and injection molded parts. By heating the specimen in an air circulation oven at 150 ° C for a period of time, observing its internal stress, cold or unmelted parts, weld joint mass, etc., detecting defects such as cracking, bubbles, delamination, etc., and measuring the incidence of their occurrence. This test method can reveal potential defects in the production process of pipe fittings and improve the quality control level of pipe fittings.