States and defines the principal performance characteristics of microwave ovens and describes the standard methods for measuring these characteristics. Applies to appliances for heating food and beverages, by electromagnetic energy (microwaves) in one or more of the I.S.M. frequency bands between 300 MHz and 30 GHz, for household use. Also applies to combination microwave oven when used in the microwave generating mode only. Coverage includes external dimensions, usable cavity volume, heating performance, cooking performance and defrosting performance. Also includes detailed definitions and diagrams.