UK Workplace Noise Exposure Limits: Action Values and What They Mean for Employers

The Control of Noise at Work Regulations 2005 set three noise limits at work that trigger employer duties. But the numbers alone — 80, 85, 87 dB(A) — do not tell you what to actually do. Each threshold triggers a different set of obligations, and the practical difference between them matters.

This guide breaks down the three noise limits at work, explains what each one means in real terms, what employer duties it triggers, and what LEP,d and LCpeak actually measure.

This guide covers the noise exposure framework under UK regulations. It is not legal advice. If you need to determine whether your workplace crosses a specific threshold, get a competent assessment.

What LEP,d and LCpeak mean

Before the thresholds make sense, you need to understand the two measures the regulations use:

LEP,d (daily personal noise exposure) — the average noise level a worker is exposed to over an 8-hour working day. This is not the loudest moment. It is the time-weighted average that accounts for both noise level and duration. A worker exposed to 90 dB(A) for 2 hours and quiet conditions for 6 hours has a lower LEP,d than a worker exposed to 85 dB(A) for all 8 hours.

LCpeak (peak sound pressure) — the highest instantaneous noise level, regardless of duration. This captures sudden impact events: cartridge tools, hammering, pressure releases, dropped metal. A single loud event can breach the peak action values even if the average exposure is low.

The regulations assess both measures independently. You could be below the daily average threshold but above the peak threshold — or the reverse. Both trigger duties.

LEP,w (weekly average) — an alternative to daily averaging. Useful when exposure varies significantly from day to day. The same thresholds apply, but averaged over a working week instead of a single day.

To estimate LEP,d from multiple noise sources and durations, use the free Noise Exposure Calculator.

The three thresholds and what each one triggers

Lower exposure action values: 80 dB(A) / 135 dB(C)

This is the entry point. If any worker's daily exposure reaches 80 dB(A), or peak exposure reaches 135 dB(C), you must:

• Carry out a risk assessment — identify who is exposed, estimate exposure levels, and determine what action is needed (Regulation 5)
• Make hearing protection available to any worker who requests it — not mandatory yet, but you must provide it if asked (Regulation 7)
• Provide information and training on noise risks, the hearing protection available, how to use it, and how to spot signs of hearing damage (Regulation 10)

In practical terms, 80 dB(A) is roughly equivalent to standing next to a busy road or operating a domestic vacuum cleaner. In a workshop or factory, most powered machinery and many hand tools will exceed this level.

Upper exposure action values: 85 dB(A) / 137 dB(C)

This threshold brings significantly stronger duties:

• Reduce noise exposure through control measures following the hierarchy: eliminate, substitute, engineer, administer, protect (Regulation 6)
• Ensure hearing protection is worn — it is no longer optional. You must provide it and ensure workers use it (Regulation 7)
• Designate hearing protection zones — areas where exposure reaches or exceeds these values must be marked with signage, and everyone entering must wear hearing protection (Regulation 7). Use the free Hearing Protection Zone Checklist to check your zones meet the requirements.
• Arrange health surveillance — audiometric testing for workers regularly exposed at or above these values (Regulation 9)

The 5 dB difference between 80 and 85 dB(A) is not small. The decibel scale is logarithmic — 85 dB(A) represents roughly three times the sound energy of 80 dB(A). The jump in employer duties reflects the corresponding increase in hearing damage risk.

Exposure limit value: 87 dB(A) / 140 dB(C)

This is the absolute ceiling. No worker may be exposed above this level, taking hearing protection into account. Key points:

• The 87 dB(A) limit includes the effect of hearing protection — unlike the action values, which are measured without protection. If your workplace is at 92 dB(A) and hearing protection reduces exposure by 10 dB, the effective exposure is 82 dB(A) — below the limit.
• If exposure exceeds the limit, you must take immediate action to bring it below 87 dB(A) and identify why the limit was breached (Regulation 6)
• This is the only threshold that accounts for hearing protection. The lower and upper action values are assessed on unprotected exposure.

How to tell which noise limits at work your workplace reaches

A rough guide based on common workplace scenarios:

Scenario	Typical level	Likely threshold
Normal office conversation	60-65 dB(A)	Below all action values
Open-plan office near printers	65-70 dB(A)	Below all action values
Busy workshop with hand tools	80-90 dB(A)	Lower or upper action values
Circular saw, angle grinder	90-100 dB(A)	Upper action values or limit
Pneumatic drill, impact wrench	95-110 dB(A)	Upper action values and potentially limit
Cartridge-operated tool (peak)	130-140 dB(C) peak	Peak action values or limit

These are indicative. Actual exposure depends on the specific equipment, operating conditions, distance, duration, and workspace acoustics. Do not use this table as a substitute for a proper exposure estimate or measurement.

The "3 dB rule" and why exposure duration matters

Noise exposure is a combination of level and time. Halving the exposure time is equivalent to reducing the noise level by 3 dB. This means:

• 88 dB(A) for 4 hours = 85 dB(A) for 8 hours (same LEP,d)
• 91 dB(A) for 2 hours = 85 dB(A) for 8 hours
• 94 dB(A) for 1 hour = 85 dB(A) for 8 hours

This trade-off is why time-limited exposure (job rotation, scheduling) can be a valid control measure — but only within limits. Reducing exposure time does not eliminate risk; it reduces the daily average.

What to do at each threshold — a practical summary

At 80 dB(A) or above:

1. Complete a noise risk assessment — see How to Complete a Noise Risk Assessment, or start with the free Noise Risk Assessment Starter Template
2. Make hearing protection available on request
3. Train workers on noise risks

At 85 dB(A) or above (add to the above): 4. Implement noise controls — follow the hierarchy, not just hearing protection 5. Require hearing protection in affected areas 6. Mark hearing protection zones with signage 7. Set up audiometric health surveillance for exposed workers

At 87 dB(A) or above (with protection): 8. Take immediate corrective action 9. Investigate the cause and prevent recurrence

Health surveillance: what audiometry involves

When workers are regularly exposed at or above 85 dB(A), health surveillance under Regulation 9 means audiometric testing:

• Baseline test when the worker first enters a noisy role — this establishes their starting hearing level
• Follow-up tests at regular intervals — typically annually for the first two years, then at intervals determined by your occupational health provider
• Action on findings — if a test shows hearing deterioration, you must review controls, consider whether the worker can continue in their current role, and ensure the assessment is still valid

The operational difficulty is not arranging the first test. It is tracking who is due, recording results, acting on changes, and maintaining the programme over years. This is where most small employers lose track.

Common mistakes with exposure thresholds

• Ignoring peak noise — focusing only on daily average exposure and missing short, high-level events that breach peak action values
• Assuming hearing protection solves everything — protection reduces effective exposure, but the lower and upper action values are assessed without protection. You still need controls.
• Not reassessing after changes — new equipment, altered layouts, or different processes can shift exposure levels across thresholds
• Treating the levels as targets — 80 and 85 dB(A) are not safe levels. They are triggers for employer duties. The aim is to reduce exposure as far as reasonably practicable, not just to stay below a line.

Connecting thresholds to compliance workflow

The exposure thresholds determine what you must do. The ongoing compliance work — assessment records, control measure reviews, PPE issue logs, audiometry tracking, review schedules — determines whether you can prove you did it.

For the full regulatory framework behind these thresholds, see UK Noise at Work Regulations: The Complete Employer Guide.

Sources

• The Control of Noise at Work Regulations 2005 — legislation.gov.uk
• Noise at work: regulations — HSE
• Noise at work: employers' responsibilities — HSE
• L108: Controlling Noise at Work (3rd edition, 2021) — HSE