Noise control in the 1990's: A consultant's view

Abstract

The acoustical consultant working with both manufacturers and users of industrial machinery must become thoroughly conversant with the client's equipment or facility and then, and only then, can he take the responsibility for recommending process changes and equipment modifications that will result in noise control. Notwithstanding advances in the analytical and instrumentation areas related to noise propagation and transmission, the methods of noise control other than source modification are, in general, similar to, or the same, as those used in the two preceding decades. Some new hardware has become available including noise cancellation equipment. However, no new theories of noise control have appeared, and the materials and hardware available for noise control have changed little over this period. Some proprietary flow control technology is just now appearing. In general, however, improvements in older materials and systems has simplified the use of existing technology. Industries in the chemical process and utility field still depend on passive “silencers” and insulating jacketing to achieve noise control. Active noise control methods are still mostly confined to experimental work. The use of modern instrumentation has simplified the identification of internal equipment sources. The characteristics of today's methods, materials, and equipment are reviewed along with the expected results. It remains the consultant's responsibility to integrate the noise control measures into the equipment, system, or process without adverse effects on the operation. Several examples from industrial applications will be described.