Noise Abatement From Large Size Electric Generators

Abstract

Growing environmental sound concerns and recognition that lengthy unprotected exposure to high industrial noise levels can be detrimental to man have resulted in increased attention to reducing industrial noise. In the United States, it is required by law that all turbomachinery manufacturers must provide acoustic guarantees to their customers. For instance, for majority of generators, the near field sound pressure level is usually guaranteed not to exceed 85 dBA. To accomplish this goal, a number of methods of noise reduction have been developed in power industry. As one of the most practical and cost-effective solutions, acoustic blankets have been designed and tested for using on large size electric generators to efficiently reduce their sound pressure levels. This work has successfully demonstrated the potential of acoustic blankets for improve the passive acoustic transmission characteristics from generators. The acoustic data obtained from a field test have shown that the blankets can reduce the overall sound pressure level from large size generators about 4 to 6 dBA.