Australia Model Code of Practice Managing Noise and Preventing Hearing Loss at Work 4.1: Carry out a noise assessment once hazardous noise is identified unless exposure can be brought below the standard immediately, to identify workers at risk, the sources and processes causing it, the controls needed and the effectiveness of existing controls; measurement may be unnecessary for a single machine with manufacturer data but is needed for variable exposures

What does 4.1 require?

A risk assessment is not mandatory for noise under the WHS Regulations, but it is usually the best way to decide what controls to apply, showing how severe a risk is, whether existing controls work, what action to take and how urgently, for both physical and psychosocial risks; where a hazard's risks and controls are already well known, formal assessment can be skipped and the controls simply implemented. Where hazardous noise has been identified, the PCBU should assess the risks by conducting a noise assessment unless exposures can be reduced below the standard at once. The assessment identifies which workers are at risk of hearing loss, which sources and processes cause the risk, what noise controls could be implemented, and whether existing controls are effective. Measurement is not always necessary: a single machine with manufacturer noise data operated in a known way can be assessed without it, while variable noise over a shift or workers moving in and out of noisy areas call for measurement.