Phoenix Journal · LEV & Air Quality
Noise-induced hearing loss is one of the most common occupational diseases, and one of the most preventable. The damage is permanent, it builds slowly, and by the time a worker notices it, it cannot be undone. The regulations turn that risk into three numbers, and those numbers tell you exactly when to act.
The Control of Noise at Work Regulations 2005 set daily exposure thresholds measured over an eight-hour day and written as LEP,d. The lower exposure action value is 80 dB(A), with a peak of 135 dB(C). The upper exposure action value is 85 dB(A), peak 137 dB(C). The exposure limit value, which must not be exceeded, is 87 dB(A), peak 140 dB(C). Reach the lower value and you must assess the risk, inform and train staff, and make hearing protection available on request. Reach the upper value and you must reduce exposure by other means, mark hearing protection zones, enforce protection use and provide health surveillance.
A crucial detail catches people out: the action values are judged on the noise reaching the worker without hearing protection, but the 87 dB limit is judged with protection taken into account. Because the decibel scale is logarithmic, every three-decibel rise roughly doubles the sound energy, which is why the small-looking jump from 80 to 85 is a big real-world change.
The stakes are not abstract. Noise-induced hearing loss is among the most common occupational diseases in the world, it is irreversible, and it often arrives alongside persistent tinnitus that never fully goes away. Because the harm is cumulative and painless until it is permanent, the person losing their hearing is usually the last to notice. Where daily exposure varies a lot across the week, the regulations allow a weekly average, LEP,w, to be used instead of the daily figure, but only genuinely, not as a way to bury consistently loud days inside quieter ones. There is no fixed statutory interval for reviewing a noise assessment, but one must be reviewed whenever it may no longer be valid, and an assessment more than a couple of years old with no record of review tends to be treated by inspectors as insufficient.
Measure it properly
The single most common mistake is to point a meter at a machine, read 83 decibels, and conclude you are between the action values. The regulations are about a worker's personal daily dose, not an instantaneous reading at one spot. A person moving between a loud grinder, a quieter bench and a break area has an exposure that depends on how long they spend where, so it must be worked out over the day, not snapshotted. The HSE offers a rough field check: if you have to shout to be heard by someone two metres away for much of the day, exposure is probably around or above 85 dB(A).
Getting the assessment right is not box-ticking. The HSE reported in 2025 that most noise control reports it reviewed were unsatisfactory, and the commonest failing was jumping straight from measurement to issuing earplugs, with no evidence that quieter equipment or engineering controls had been considered first.
Hearing protection has its place, but it protects only the person wearing it, only when worn correctly, and only if it suits the noise. Treating it as the first answer rather than the last is both poor practice and, where controls were reasonably practicable, a breach of the regulations.
The right order
Cutting noise properly means working from the source outward, which is simply the hierarchy of control applied to sound. Can the noisy process be eliminated or done a quieter way? Can you buy or specify quieter machines, since purchasing policy is one of the most powerful long-term levers? Can you damp panels, fit silencers, isolate vibrating equipment on mounts, or enclose the loudest machine? Can you move people away from it or rotate tasks so no one takes the whole dose? Only when those are exhausted does hearing protection become the sensible residual control rather than a substitute for doing the job.
The same trap twice
The tools that make workshops loud are often the same ones that shake: grinders, breakers, sanders and impact tools. That means the worker at risk of hearing loss is frequently the same worker at risk of another slow, permanent injury, and the two are easy to assess together. It is worth reading about hand-arm vibration, the slow injury sites ignore, because it follows the identical pattern: a gradual, irreversible harm from everyday tools, managed by controlling the source and limiting exposure time rather than hoping the body copes. Tackle the noisy, shaky processes at the root and you cut two risks with one decision.
Questions
They are daily noise exposure thresholds. At 80 dB(A) you must assess the risk, inform and train staff and offer hearing protection. At 85 dB(A) you must reduce exposure by other controls, mark hearing protection zones and provide health surveillance. 87 dB(A) is a limit that must not be exceeded, measured with hearing protection taken into account.
No. Hearing protection is the last line, not the first. It protects only the wearer, only when worn correctly and only if suited to the noise. The regulations require you to reduce noise by engineering and organisational controls where reasonably practicable before relying on protection, and jumping straight to earplugs is a common breach.
A proper assessment measures each worker's daily exposure over the day, not a single meter reading. As a rough guide, if people have to shout to be heard two metres apart for much of the day, exposure is likely around or above the upper action value and needs controlling.
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