This specification applies to the supply, primarily on the basis of performance, of baking insulating and impregnating varnishes suitable for the brushing, spraying, dipping or vacuum impregnation of direct current or alternating current machinery, and telecommunication equipment. Varnishes meeting this specification will be suitable for use at the maximum temperature permitted for Classes A, E and B materials but they will not necessarily be suitable for operation at the maximum temperature permissible for Class F materials.