Construction site noise assessment requirements: regulations and action levels

The regulations and action levels

The Control of Noise at Work Regulations 2005 set three levels of noise exposure that trigger specific employer duties:

• Lower exposure action value: A daily or weekly personal noise exposure of 80 dB(A), or a peak sound pressure of 135 dB(C). At this level, employers must carry out a risk assessment, make hearing protection available, and provide information and training.
• Upper exposure action value: 85 dB(A) daily/weekly average, or 137 dB(C) peak. At this level, employers must reduce exposure to as low as reasonably practicable, ensure hearing protection is worn, designate hearing protection zones, and provide health surveillance.
• Exposure limit value: 87 dB(A) daily/weekly average, or 140 dB(C) peak, measured at the ear taking account of hearing protection. This must not be exceeded under any circumstances.

To put these numbers in context: a normal conversation is about 60 dB(A). A diesel generator at 7 metres is about 80 dB(A). An angle grinder is typically 95-105 dB(A). A pneumatic breaker can exceed 110 dB(A). On most construction sites, multiple activities will exceed the lower action value, and many will exceed the upper action value.

The daily exposure is an average over the working day. A worker who uses an angle grinder for 2 hours and does quieter work for the remaining 6 hours has a lower daily exposure than one who grinds all day. But 2 hours of grinding at 100 dB(A) can still give a daily exposure above 85 dB(A), triggering upper action value duties.

Carrying out a noise assessment

A noise assessment is required whenever workers are likely to be exposed at or above the lower action value. For construction, this means virtually every project. The assessment should:

1. Identify noise sources: List every activity and piece of equipment that generates significant noise. Equipment manufacturers should provide noise data in the user manual, but actual site conditions often differ from manufacturer's figures.
2. Measure noise levels: Use a calibrated sound level meter or personal noise dosimeters to measure actual exposure. Spot measurements with a sound level meter give the noise level at a specific time and place. Dosimeters worn by workers give a personal daily exposure reading.
3. Identify who is exposed: Not just the operator but anyone working nearby. On construction sites, noise from one activity often affects workers across a wide area.
4. Assess daily exposure: Combine the noise levels with the duration of exposure to calculate the daily personal noise exposure (LEP,d) for each worker or group of similar workers.
5. Identify controls: Based on the exposure levels, determine what controls are needed to reduce exposure.

The assessment must be carried out by a competent person. This does not require a specific qualification, but the person must understand noise measurement, exposure calculation, and the relevant control measures. Many employers use occupational hygienists or specialist noise consultants, particularly for complex assessments.

Noise control measures

The hierarchy of control applies to noise just as it does to any other hazard:

• Elimination: Can the noisy process be avoided? For example, using hydraulic splitters instead of pneumatic breakers for demolition, or pre-fabricating components off-site to reduce on-site cutting.
• Substitution: Replace noisy equipment with quieter alternatives. Modern diamond-blade saws are quieter than older abrasive disc cutters. Electric tools are generally quieter than pneumatic equivalents.
• Engineering controls: Acoustic enclosures around generators and compressors. Damping materials on vibrating surfaces. Silencers on pneumatic tools. These reduce noise at source.
• Administrative controls: Limit the time workers spend in noisy areas. Schedule noisy work when fewer workers are present. Rotate tasks to reduce individual exposure.
• Hearing protection: Ear defenders or ear plugs as a last line of defence. Hearing protection must be appropriate to the noise level and must be properly fitted. Over-protection (using very high-attenuation hearing protection in moderate noise) is also a problem, as it can prevent workers hearing warnings and alarms.

Hearing protection zones

Where the upper action value (85 dB(A)) is exceeded, the employer must designate hearing protection zones. These are areas of the site where hearing protection must be worn by everyone, regardless of their role or the duration of their visit. The requirements are:

• The zone must be clearly marked with signage showing the hearing protection symbol.
• Entry to the zone without hearing protection is not permitted.
• The zone boundary should be set where noise levels drop to below 85 dB(A). In practice, this often means a radius around the noisy activity.
• The requirement applies to everyone: workers, supervisors, visitors, and inspectors.

On construction sites, hearing protection zones move as activities move. The piling rig that created a zone on the east side of the site this week will create a zone on the west side next week. Site supervisors need to ensure that zone signage moves with the activity and that all workers in the area are informed.

Including noise-related information in your site induction helps ensure that every worker arriving on site understands where hearing protection zones are, what the signage means, and what hearing protection to use.

Health surveillance

Health surveillance (audiometric testing) is required for workers regularly exposed above the upper action value of 85 dB(A), or for any worker exposed to noise who is known to be at increased risk of hearing damage.

The programme typically involves:

• A baseline audiometry test when the worker first joins or is first exposed to noise above the action value.
• Regular follow-up tests, usually annually for the first two years and then at intervals determined by the occupational health provider (often every three years if results are stable).
• Referral to an occupational health professional if any deterioration in hearing is detected.

For construction employers with workers who move between sites, maintaining a consistent health surveillance programme can be challenging. The worker may be on one project for three months, then another for six months, with different principal contractors and different health surveillance arrangements. The employer (the company that directly employs the worker) is responsible for ensuring their workers receive health surveillance, regardless of which site they are working on.

Record keeping

Noise assessments must be recorded and kept up to date. There is no prescribed retention period for noise assessments, but good practice is to keep them for the duration of the project plus at least three years.

Health surveillance records have a longer retention requirement. HSE recommends keeping audiometric records for as long as the individual is under health surveillance and for at least 40 years after the last entry, consistent with records for other occupational health exposures. This is because noise-induced hearing loss is cumulative and may not become apparent until years after the exposure.

Records should include:

• The noise assessment itself: sources identified, measurements taken, exposures calculated, controls recommended.
• Details of hearing protection zones: where they are, what PPE is required.
• Training records: who was informed about noise risks and when.
• Health surveillance results: individual audiometry records linked to each worker.
• Equipment maintenance records: evidence that noise control measures (silencers, enclosures) are maintained.

Storing these records against individual worker profiles in a centralised system ensures they are accessible for as long as they are needed. AttendIQ stores compliance documents and health records against each worker's profile, making it straightforward to maintain the long-term records that noise regulations require.