Estimation and reduction of risk to hearing: the background and a case study

For noise exposure varying in both level and duration, current noise criteria are inadequate but, by adapting methods presently available, an equivalent continuous level can be calculated from which the risk to hearing can be assessed. The predicted effects on hearing compare favourably with measured values. These methods are used to predict an 'acceptable' noise limit for the variable noise environment on the agricultural tractor. Methods of noise reduction for the tractor are outlined along with other approaches to hearing preservation.