Noise distribution and reduction in industrial enclosures

Abstract

Noise is one of the main emission factors in industry, and a tendency of production progress is such that further increase in noise emission should be expected. In practice, various methods for noise reduction at its propagation path are used such as reduction of the reflected energy fractions, and proofing of a certain zone with a screen. Both acoustic designing of rooms and noise reduction, require the data on acoustic characteristics of materials and constructions, and sound power of sound sources. Methods of determination of these characteristics are based on the measurements carried out in special rooms with specified acoustic properties—reverberation, ‘‘dead’’ and ‘‘half-dead’’ rooms. Such rooms are also used for other purposes, for example, for generating sound fields of high levels with special uniformity of frequency and spatial spectra needs when testing instrumentation and response constructions for acoustic strength. At present, several methods of representation of the sound field in rooms have been developed: An energy method, a method of acoustic mirages, and a wave theory. In practice, the most widely used method is the energy method which has been considerably modified in this report.