Noise exposure calculator

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Enter the noisy tasks and how long each lasts, and get the daily personal exposure against the action and limit values in the Control of Noise at Work Regulations 2005.

How daily noise exposure is worked out

Noise adds up on a logarithmic scale, so you cannot average decibels. The daily figure, L_EP,d, is the level that would give the same total energy if it were constant over an eight-hour day: 10 × log₁₀( Σ (t_i ÷ 8) × 10^L_i/10 ). The practical consequence: 3 dB louder means half the time for the same dose. Two hours at 100 dB is the same exposure as an hour at 103 dB or eight hours at 94.

The three thresholds

The Control of Noise at Work Regulations 2005 set a lower exposure action value of 80 dB(A) - provide hearing protection on request, and information and training; an upper action value of 85 dB(A) - reduce noise at source where practicable, mark hearing protection zones, make protection compulsory, and provide health surveillance; and an exposure limit value of 87 dB(A) that must not be exceeded at the ear once hearing protection is taken into account. There are matching peak values (135, 137 and 140 dB(C)) for impulsive noise such as nail guns and cartridge tools.

What a noise assessment needs

A competent person's estimate of who is exposed to what, based on measurements or reliable published figures like the ones pre-filled here; the controls chosen, starting with quieter methods and equipment; and the hearing protection selected against the actual levels, not a default foam plug. A protector with the wrong SNR can under-protect on a breaker and over-protect (isolating people from warnings) on general site noise. The toolbox talk on noise is the usual way to get the information across.

Typical construction levels

Disc cutters and scabblers sit around 110 dB(A), breakers around 105, grinders and chop saws around 100, plant cabs with the door open around 85, and general site background in the low 80s. At 110 dB the upper action value is reached in under five minutes, which is why cutting tasks dominate the day's dose even when they are short.

FAQs

What is the noise exposure limit at work in the UK?

The exposure limit value is 87 dB(A) daily or weekly personal exposure, measured at the ear with hearing protection taken into account. The action values that trigger duties are 80 dB(A) (lower) and 85 dB(A) (upper).

At what noise level is hearing protection mandatory?

At or above the upper exposure action value of 85 dB(A) daily exposure, or a peak of 137 dB(C). Between 80 and 85 dB(A) it must be made available but is not legally compulsory.

How long can you use a disc cutter without hearing protection?

At around 110 dB(A), the upper action value of 85 dB(A) is reached in roughly four to five minutes. In practice any disc cutting needs hearing protection from the first cut.

Do I need a noise assessment on a construction site?

Yes, if anyone is likely to be exposed at or above the lower action value of 80 dB(A), which covers almost every site using power tools or plant. The assessment must be done by a competent person and reviewed when the work changes.

Get the documents ready-made

Put the numbers into a proper noise assessment and a toolbox talk. The occupational health templates include a noise risk assessment and hearing protection zone record; the Toolbox Talks Library has the noise talk ready to deliver.

General guidance only. This article explains how the rules generally work in UK construction. It is not advice for your specific site, task or project, and it is not legal advice. Your own risk assessment, method statement and arrangements must be prepared and checked by a competent person for the actual work being done.