A noise survey is not a one-off exercise. Like all risk assessments, the findings remain valid only as long as the conditions on which they were based remain unchanged. If anything significant changes in your workplace that could affect noise levels or worker exposure, the survey should be reviewed and updated.

The most obvious trigger for a repeat survey is the introduction of new machinery or equipment. Different machines generate different noise signatures, and a new piece of equipment — even one replacing an older machine performing the same function — may generate more or less noise than its predecessor. Similarly, changes to production processes, changes to the layout of the workplace, or increases in the volume or pace of production can all affect noise exposure levels.

Changes in working patterns are another important trigger. If workers who were previously spending limited time in noisy areas are now spending more of their working day there, their personal exposure may have increased significantly — even if the noise levels in those areas have not changed. The exposure calculation takes both level and duration into account.

Even without specific triggers, it is good practice to review your noise assessment periodically. Many businesses choose to carry out a formal noise survey every three to five years as a matter of routine, or more frequently in higher-risk environments. This ensures that the assessment remains current and that any gradual changes — for example, machinery becoming noisier as it ages — are captured.

It is also worth noting that if a noise-induced hearing loss claim is made against your business at some point in the future, the currency and thoroughness of your noise monitoring records will be an important part of your defence. A business that can demonstrate a history of regular, competent noise monitoring and appropriate action taken on the findings is in a fundamentally stronger position than one that cannot.

LESH can help you establish a noise monitoring programme that keeps your assessment current and ensures you are always meeting your legal obligations. As part of a retained health and safety service, we can manage this process for you.