Frank H. Brittain
Bechtel Corp., P.O. Box 193965, San Francisco, CA 94119
Predicting operational noise levels is an essential part of designing an industrial facility. Community noise levels are usually predicted for environmental assessment and licensing. In-plant noise levels are predicted, both to evaluate occupational noise exposure and as an input to modeling of community noise predictions. Predictions are used to evaluate the effect of various combinations of low-noise equipment and add-on noise controls. Prediction are also used to evaluate the effects of different operating and atmospheric conditions. This paper shows how a noise model can be structured, and then modified in an iterative process of developing a practical and cost effective approach to noise control. Alternate approaches to performing the necessary calculations on a computer are reviewed. This paper describes various classical techniques for estimating source strength and directivity, indoor and outdoor propagation, as well as the noise reduction of prospective noise controls. Some limitations of these classical techniques are identified.