Workplace noise guidance · Article

Understanding Noise Action Values

Workplace noise action values are based on personal exposure over time — not on a single instantaneous sound-level reading. This guide explains the lower exposure action value, the upper exposure action value, the exposure limit value and the associated peak sound pressure values, and how they translate into day-to-day decisions for UK employers.

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What are workplace noise action values?

Workplace noise action values are reference levels of personal noise exposure set out in the Control of Noise at Work Regulations 2005. They are not simple room-noise thresholds. Each value relates to daily or weekly personal noise exposure — a combination of the noise level at the ear and the duration over which a worker is exposed.

Different action values trigger different employer duties. Reaching the lower exposure action value engages information, instruction, training and the availability of hearing protection. Reaching the upper exposure action value engages further duties to reduce exposure, ensure hearing protection is worn where required and consider zones and health surveillance. Exceeding the exposure limit value is not permitted.

Because exposure is a function of both level and time, action values must be interpreted within the full workplace context — tasks performed, shift patterns, worker movement, and the distribution of noise across the working day.

Lower exposure action value

The Lower Exposure Action Value

Daily or weekly personal exposure

80 dB(A) LEX,8h

135 dB(C) peak

Trigger for hearing protection availability on request, information, instruction and training, and a suitable noise risk assessment.

Practical employer duties

Make hearing protection available on request.
Provide information, instruction and training.
Carry out and review a suitable risk assessment.
Review controls and look for further reductions.

Reaching the lower action value does not mean 80 dB(A) is automatically “safe”. It is a regulatory trigger, not a clinical threshold; susceptibility and peak noise vary.

Upper exposure action value

The Upper Exposure Action Value

Daily or weekly personal exposure

85 dB(A) LEX,8h

137 dB(C) peak

Trigger for reducing exposure so far as reasonably practicable, providing and enforcing hearing protection, hearing protection zones and consideration of health surveillance.

Practical employer duties

Reduce exposure so far as reasonably practicable.
Provide suitable hearing protection and ensure its use.
Designate hearing protection zones where required.
Consider audiometric health surveillance.
Provide training, supervision and review of controls.

Exposure limit value

The Exposure Limit Value

Daily or weekly personal exposure

87 dB(A) LEX,8h

140 dB(C) peak

Employees must not be exposed above this value. Hearing protection attenuation may be taken into account for this comparison only.

Important considerations

Real-world attenuation is rarely as high as datasheet values.
Fit, condition and consistent use are essential.
The limit does not remove the duty to reduce noise at source.
Exceedance requires immediate corrective action and review.

Not room thresholds

Why 80, 85 and 87 dB(A) are not simple room limits

Each value describes personal exposure at the ear over a working day or week — not a fixed sound level in a particular room. A workshop can read 85 dB(A) at one machine without every worker in the building being at the upper action value, and a quieter room can still contain workers whose personal exposure exceeds an action value because of where else they work during the day.

Exposure is influenced by task duration, worker movement between areas, short loud tasks combining with quieter periods, shift length and overtime. A single machine-side reading cannot determine full-shift exposure, and different employees in the same workplace can have very different personal exposure.

For the calculations and interpretation behind these values, see noise exposure assessment.

Understanding dB(A)

dB(A) refers to A-weighted sound pressure level — a frequency weighting that emphasises the parts of the audible spectrum to which human hearing is broadly more sensitive at moderate levels. It is the standard weighting used for general occupational noise exposure assessment.

The decibel scale is logarithmic. A small numerical increase represents a substantial change in sound energy: an increase of around 3 dB roughly doubles sound energy, and an increase of 10 dB is perceived as approximately a doubling of loudness. Because of this, the difference between 80 and 87 dB(A) is far greater than the numbers suggest at first sight.

Peak noise

Understanding dB(C) and peak noise

C-weighting is used for peak sound pressure because it is better suited to the low-frequency content of impulsive and impact noise. Peak values capture brief but intense events that an average dB(A) figure can hide entirely.

Typical sources include hammering, metal-on-metal impacts, press operations, pneumatic tools, cartridge-operated tools and air-blast cleaning. A workplace with a moderate daily average can still present a significant peak-noise risk, which is why peak values are assessed and reported independently of LEX,8h.

LEX,8h

What LEX,8h means

LEX,8h is the daily personal noise exposure level expressed in dB(A), normalised to a notional eight-hour working day. It combines the equivalent continuous sound level of each task with the duration of that task across the shift, producing a single figure that can be compared with the action and limit values.

Normalisation to eight hours means that shorter or longer shifts need careful interpretation. Two hours at a high level and six hours of quiet work are not equivalent to eight hours at the average — duration weighting and logarithmic combination both matter. LEX,8h is a calculated quantity, not the value shown on a live sound-level meter. See noise exposure assessment for how this is interpreted in practice.

Daily versus weekly

Daily versus weekly exposure

Weekly personal noise exposure (LEX,40h) may be relevant where day-to-day exposure varies markedly — for example, where a worker performs a noisy task one day per week and quieter work on the others. The Regulations set conditions on when weekly averaging may be used and how it must be documented.

Weekly averaging is not a mechanism for disregarding an unusually loud day, and it does not displace the peak sound pressure action values. Peak exposure still requires independent consideration regardless of any weekly average.

Combining tasks

How different tasks combine

A typical shift includes several different activities. Each contributes to total daily exposure in proportion to its sound energy and duration.

Operating machinery for an extended period
Quieter assembly or inspection work
Cleaning and housekeeping tasks
Loading, unloading and materials handling
Short high-noise tasks such as cutting or grinding

These contributions cannot simply be averaged arithmetically; they combine on an energy basis weighted by duration.

Logarithmic scale

Why decibels cannot be averaged in the ordinary way

Decibels use a logarithmic scale, so an arithmetic mean of decibel values is generally misleading. Combining the contributions of several tasks requires the underlying sound energies — weighted by duration — to be summed before being converted back into a dB(A) value.

In practice this is done either by suitable instrumentation such as integrating sound-level meters and dosimeters, or by professional exposure calculations following BS EN ISO 9612 methodology.

Spot measurements

Action values and spot measurements

Spot measurements have a clear role — screening for noisy areas, identifying significant sources, and planning more detailed monitoring. They are not, however, a substitute for an exposure assessment.

A reading at one moment, at one position, cannot determine personal exposure across a shift because it does not capture task duration or worker movement. See workplace noise monitoring for how spot, area and task measurements are integrated into a defensible exposure picture.

Personal dosimetry

Action values and personal dosimetry

Personal noise dosimetry is well suited to mobile workers, variable tasks, changing locations and shifts where area measurements alone cannot reasonably represent personal exposure. A body-worn dosimeter records sound at the worker over the full shift.

Dosimetry results require interpretation: activity records, shift-pattern context and identification of incidental noise such as deliberate tapping or fall events all matter. See personal noise dosimetry for typical scope and methodology.

Hearing protection

Action values and hearing protection

At the lower exposure action value, hearing protection must be made available on request. At the upper exposure action value, suitable hearing protection must be provided and its use ensured where exposure cannot otherwise be reduced. Hearing protection zones may be required where the conditions for use are met.

Selection should reflect actual exposure — neither underprotecting nor overprotecting the worker. Excessive attenuation can isolate workers from warnings and communication. Attenuation is not subtracted when deciding whether action values are reached; it may be considered only for the comparison against the 87 dB(A) exposure limit value. See hearing protection assessment for selection, fit and review.

Duties at each value

What employer duties change at each value?

Lower action value

80 dB(A) · 135 dB(C)

Information, instruction and training.
Hearing protection available on request.
Suitable risk assessment and review.

Upper action value

85 dB(A) · 137 dB(C)

Reduce exposure so far as reasonably practicable.
Provide and enforce suitable protection where required.
Hearing protection zones where appropriate.
Consider audiometric health surveillance.

Exposure limit value

87 dB(A) · 140 dB(C)

Must not be exceeded.
Immediate corrective action if exceeded.
Review controls and reasons for exceedance.

Common misunderstandings

“The meter showed 84 dB, so no action is needed.”
“85 dB is always safe.”
“87 dB is the point where hearing protection starts.”
“Hearing protection means the action values no longer apply.”
“One worker’s result represents everyone.”
“A short measurement is enough to determine LEX,8h.”
“Weekly exposure can always replace daily exposure.”
“Peak noise is already covered by the daily average value.”

Practical workflow

Practical interpretation workflow

1Identify noisy tasks and the workers who perform them.
2Understand the duration of each task across the shift.
3Collect representative noise measurements at the ear.
4Use personal noise dosimetry where exposure varies.
5Calculate daily (LEX,8h) or weekly (LEX,40h) exposure.
6Assess peak sound pressure (LCpeak) independently.
7Compare results against the action and limit values.
8Identify the duties triggered by the resulting exposure.
9Implement controls following the control hierarchy.
10Review after machinery, layout or process changes.

Worked scenarios

Worked practical scenarios

These qualitative examples illustrate how exposure interpretation differs by role. They do not produce exposure values without site-specific measurement and assessment.

Fixed machine operator

Operates a single production machine for most of the shift with limited movement and a predictable noise profile.

Additional information needed: Representative task measurement at the ear position, accurate task duration and confirmation that operating conditions are typical.

Mobile maintenance engineer

Moves between plant rooms, workshops and production lines, with short bursts of high-level work using power tools.

Additional information needed: Full-shift personal dosimetry with an activity log so different tasks and locations can be interpreted in context.

Warehouse worker — intermittent impacts

Picking, loading and unloading with occasional impact noise from pallets, racking and dropped loads.

Additional information needed: Combined area and personal measurement, with peak sound pressure captured separately from the daily average.

Multi-task production worker

Rotates through several stations during the shift, with different noise levels at each.

Additional information needed: Task-based measurement for each station and accurate task durations, combined into a single LEX,8h.

Construction worker — short power-tool tasks

Short duration high-level work with concrete saws, breakers or grinders, mixed with quieter activity.

Additional information needed: Task-based measurement, careful task timing and explicit peak sound pressure assessment.

How we can help

How Workplace Noise Surveys can help

Workplace noise surveys

Site-wide surveys interpreting area, task and worker exposure against UK action values.

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Workplace noise monitoring

Representative occupational noise measurement across operations and tasks.

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Noise exposure assessment

Daily LEX,8h and weekly LEX,40h calculation and interpretation.

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Personal noise dosimetry

Full-shift dosimetry for mobile, multi-task and variable-exposure roles.

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Hearing protection assessment

Selection, attenuation, fit, compatibility and review of hearing protection.

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Factory noise surveys

Production-line, machinery and process noise assessment for manufacturing.

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Occupational hygiene noise services

Integrated occupational hygiene support across survey, dosimetry and control review.

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Related guidance & services

Related guidance and services

Workplace Noise Resources

UK workplace noise knowledge centre and category index.

Noise at Work Regulations Explained

Practical walk-through of the 2005 Regulations and employer duties.

Noise at Work Regulations

Primary UK regulatory service and compliance overview.

Noise Exposure Assessment

LEX,8h and weekly exposure interpretation against action values.

Workplace Noise Monitoring

Representative occupational noise monitoring across operations.

Personal Noise Dosimetry

Worker dosimetry for mobile, multi-task and shift-based roles.

Hearing Protection Assessment

Hearing protection selection, attenuation, fit and use.

Workplace Noise Surveys

Site-wide workplace noise survey scope and methodology.

Occupational Hygiene Noise Services

Occupational hygiene support across the noise programme.

Article disclaimer

This article provides general UK occupational-noise guidance. It is not legal advice. Actual employer duties depend on the work, the exposure and the risk at each workplace. Competent site-specific assessment may be required to establish compliance with the Control of Noise at Work Regulations 2005.

FAQs

Frequently asked questions

What is the lower exposure action value?

The lower exposure action value is a daily or weekly personal noise exposure of 80 dB(A) LEX,8h, with an associated peak sound pressure of 135 dB(C). At or above this value, employers should make hearing protection available on request and provide noise information, instruction and training, supported by a suitable risk assessment.

What is the upper exposure action value?

The upper exposure action value is a daily or weekly personal noise exposure of 85 dB(A) LEX,8h, with a peak sound pressure of 137 dB(C). At or above this value, employers must reduce exposure so far as reasonably practicable, provide hearing protection and ensure it is used, designate hearing protection zones where appropriate and consider health surveillance.

What is the workplace noise exposure limit value?

The exposure limit value is 87 dB(A) LEX,8h with a peak sound pressure of 140 dB(C). Employees must not be exposed above this value. The limit-value comparison may take into account the noise reduction provided by hearing protection actually worn, provided that protection is suitable, correctly fitted and consistently used.

Is 85 dB(A) always unsafe?

An instantaneous sound-level reading of 85 dB(A) is not in itself the upper action value. The action value relates to daily or weekly personal noise exposure (LEX,8h or LEX,40h) — a combination of level and duration. A short period at 85 dB(A) followed by quieter work will give a different daily exposure than a full shift at 85 dB(A). Professional interpretation is required.

Is 80 dB(A) always safe?

No. The lower exposure action value of 80 dB(A) LEX,8h is a regulatory trigger, not a clinical safety threshold. Susceptibility varies between individuals, peak noise may pose risk regardless of average exposure, and noise can interfere with audible warnings and safety-critical communication. Exposure should be controlled so far as reasonably practicable even where action values are not reached.

Are action values based on one sound-level reading?

No. Action values are based on personal noise exposure assessed over the working day or week, not on a single instantaneous measurement. Spot readings can help identify noisy sources and plan further work, but cannot on their own determine LEX,8h. Representative measurement and an understanding of task duration are needed.

What does LEX,8h mean?

LEX,8h is the daily personal noise exposure level expressed in dB(A), normalised to a notional eight-hour working day. It combines the equivalent continuous sound level of each task with the duration of that task so different roles and shifts can be compared on a common basis against the action and limit values.

What are the peak noise action values?

The peak sound pressure action values are 135 dB(C) at the lower exposure action value, 137 dB(C) at the upper exposure action value and 140 dB(C) at the exposure limit value. Peak values are assessed separately from average daily exposure because brief impulsive noise can cause hearing damage that average dB(A) does not reflect.

Can hearing protection be deducted from action-value exposure?

No. Action-value comparisons are made on exposure at the ear without considering hearing protection. Hearing protection attenuation may only be taken into account when comparing exposure against the exposure limit value of 87 dB(A), and only where protection is suitable, in good condition, correctly fitted and consistently worn.

When can weekly exposure be used?

Weekly personal noise exposure (LEX,40h) may be used in place of daily exposure where exposure varies markedly from day to day, subject to the conditions in the Control of Noise at Work Regulations 2005. It is not a means of disregarding unusually loud days, and peak sound pressure action values continue to apply regardless of any weekly averaging.

Can a phone app determine daily noise exposure?

No. Phone sound-level apps are not a substitute for a competent workplace noise assessment. They use uncalibrated microphones, have limited dynamic range and lack the frequency-weighting and peak detection performance needed to produce defensible LEX,8h or peak sound pressure values. They should not be relied upon to demonstrate compliance with action or limit values.

Do different workers in the same area have the same exposure?

Not necessarily. Two workers in the same area may have very different daily personal noise exposure depending on the tasks they perform, how long they spend near the noisiest sources, how often they move around the workplace and how their shift patterns differ. Personal dosimetry is often required to characterise exposure for mobile or multi-task roles.

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Need Help Interpreting Workplace Noise Action Values?

Workplace Noise Surveys provides independent UK occupational noise assessment, personal dosimetry and hearing-protection review interpreted against the 80, 85 and 87 dB(A) action and limit values.

Contact our team Noise Exposure Assessment

info@workplacenoisesurvey.co.uk 01322 555566