The development of a procedure to ensure effective auditory warning signals

One of the inevitable consequences of the increasing power of mining equipment has been a progressive increase in the noise generated. Although a great deal has been written on the occupational health implications of industrial noise, much less attention has been given to the safety problems which may arise if background noise levels obscure warning signals. This article describes a procedure developed by the Institute of Occupational Medicine (IOM) which enables the objective assessment of the effectiveness of warning signals in noisy environments. The procedure is based on a computer program which takes account of the loudness and frequency of both back ground noise and signal as well as the hearing ability of the workforce. Assessment of the effects of hearing defenders on the audibility of signals can also be carried out. In addition to describing the basis and development of the procedure, three examples of its use in improving signal effectiveness are also reported. 1 ref., 7 figs.