The Accuracy of Noise Measurements on Machine Tools under Practical Conditions

Summary

The maximum level of noise in workshops which can be tolerated by a responsible society must be such that the risk of damage to hearing is minimal. In order that this level is not exceeded the additive effect of several or many sources of noise in a relatively confined space must be taken into account and the acceptable level of noise from each machine tool is somewhat less than that for the workshop as a whole. The level of acceptance which, at the present time, is most commonly demanded by customers is about 83 dB(A). Since most machine tools produce noise at about this level the difference between acceptance and non-acceptance is slight so that it is important that the measurement of noise under practical workshop conditions is as accurate as possible.

Some of the factors which may influence the accuracy of noise measurement in practice are the instrumentation used, the method of measurement, the conditions of operation of the machine under test, the environment in which tests are carried out, the size of the machine relative to the size of the workshop, and so on. It is the purpose of this paper to discuss the influence of such factors so that makers and users of machine tools will be able to make proper assessments of measured noise levels.