Turbomachinery Noise Rating
An expression of the noise rating of a machine is an important part of its performance specification. Precautions should be taken, however, to make sure that the noise emission specification keeps the true objective in mind, and is neither too stringent nor too lenient. It is a costly mistake to demand more detailed information and more noise reduction than is necessary, but the reverse is also true. Therefore it is important to know when to require octave band or third octave band data, instead of overall A-Weighted levels, and when to request a firm sound guarantee instead of estimated noise emission levels.
Diehl, George M. (1976). Turbomachinery Noise Rating. Texas A&M University. Gas Turbine Laboratories. Available electronically from