In many cities today there are local ordinances specifying maximum allowable sound levels at commercial
and residential property lines. Consequently, the sound energy radiated from transformers has become a
factor of increasing importance to the neighboring residential areas. It is therefore appropriate that a good
understanding of sound power radiation and its measurement principles be developed for appropriately
specifying sound levels in transformers. An understanding of these principles can be helpful in minimizing
community complaints regarding the present and future installations of transformers.