This standard covers ac single- or three-phase propeller type ventilating fans, such as exhaust fans, wall fans, window fans, gable-end fans, port-hole fans, bulk-head fans, kitchen fans and dark room fans for use at voltages not exceeding 250 V single-phase or 440 V three-phase, and their associated speed regulators, if any. It does not cover indirectly driven fans.
IS 2312-1967 history
1967IS 2312-1967 Specification for propeller type AC ventilators