Noise at Work Risk Assessments Explained
The aim of our articles are to break down acoustic design concepts and terminology as simply as possible, without going too far into the mathematics and every nitty gritty technicality, that acoustic consultants usually love to get stuck into.
So please, if you’re an architect, contractor, developer, planner… or really anyone who occasionally needs to dabble in acoustic design and assessments… then read on…
Got a question?
Is there an acoustic, noise, or vibration related topic or problem that you would like explained? Send us an email and one of our acoustic consultants will write an article about it.
The Control of Noise at Work Regulations
The ‘Control of Noise at Work Regulations 2005’ (‘the NAW Regulations’) sets out the legal requirements in respect of protecting employees against risks to their health and safety arising from exposure to noise whilst at work. The aim of the NAW Regulations is to protect workers from suffering long term hearing damage and tinnitus as a result of prolonged exposure to high noise levels in the workplace.
What are my duties as an Employer?
The NAW Regulations apply to all workplaces and mean that employers are legally obliged to risk assess the exposure of their employees’ exposure to noise within the working environment. The employer must employ appropriate control measures to reduce noise exposure where necessary.
Regulation 5 of the NAW Regulations states that a detailed Noise at Work Risk Assessment (the purpose of this document) must be undertaken if an employee is likely to be exposed to noise at or above lower exposure action values. This may occur if a workplace is considered to be noisier than everyday life.
Noise Exposure Action Values/Limits
In accordance with Regulation 4 of the NAW Regulations, a set of noise exposure action values are set which relate to the average levels of noise exposure over a working day or week, and the peak sound pressure exposure to which employees are exposed to in a working day. In summary:
• ‘exposure action values’ are the levels of exposure to noise at which employees can be exposed to, but employers are required to take certain actions to mitigate this risk, including the provision of hearing protection; and
• ‘exposure limit values’ are the levels of noise exposure at which an employee must not be exposed to, after taking into account the noise reduction provided by personal hearing protection.
As per Regulation 4, the following exposure action and limit values are defined:
Table 1 – Definition of the exposure action and limit values
Actions Required if Thresholds Exceeded
Lower Exposure Action Value(LEAV)
· a daily personal exposure level (LEP,d)1 of 80 dB(A).
· a peak sound pressure level (LCPeak) of 135 dB(C).
(these limits do not account for hearing protection)
In the first instance, the employer should explore other methods of reducing noise levels to as low a level as is reasonably practicable. If the LEAV is still exceeded, then hearing protection is recommended and the employer must provide personal hearing protectors upon the request of any employee in this exposure category (though it must not be compulsory for the employee to wear them unless they are in a designated Hearing Protection Zone (HPZ).
The employer must also provide ‘information, instruction, and training’ to employees who are exposed to above the LEAV.
Upper Exposure Action Value(UEAV)
· a daily personal exposure level (LEP,d)1 of 85 dB(A).
· a peak sound pressure level (LCPeak) of 137 dB(C).
(these limits do not account for hearing protection)
The employer shall reduce exposure to as low a level as is reasonably practicable by establishing and implementing a programme of organisational and technical measures, excluding the provision of personal hearing protectors, which is appropriate to the activity (see following subsections).If the UEAV is still exceeded, then hearing protection is compulsory to employees in this exposure category and must be supplied by the employer. If a particular area is above the UEAV, then this area must be designated as a HPZ. The employers must ensure that affected employees or employees entering the HPZ use hearing protection, who also have a duty to protect themselves.
Exposure Limit Value (ELV)
· a daily personal exposure level (LEP,d)1 of 87 dB(A).
· a peak sound pressure level (LCPeak) of 140 dB(C).
(the effect of personal hearing protection is accounted for in these limits)
Employees must not be permitted to be exposed above the exposure limits (after accounting for the noise reduction provided by personal hearing protection).
Action must be taken immediately to reduce exposure if this limit has been exceeded. The employer must review the programme of control measures, considering the technical and organisational controls, the adequacy of any hearing protection supplied and systems in place that ensures noise-control measures and hearing protection are properly used and maintained.
1 These limits can also apply to a weekly personal exposure level (LEP,w)
2 It may be necessary to conduct ongoing health surveillance for the exceedance of the LEAV and UEAV.
What do these action values mean? How do I mitigate noise?
In summary, if the noise exposure action values are exceeded then the employer may be required to
- reduce the noise exposure that produces these risks to as low a level as is reasonably practicable by either
- reducing noise at source, i.e. by using quieter equipment, a different process, engineering controls, etc.;
- reducing noise levels in the facility, i.e. through sound absorption, keeping noisy machinery away from quieter areas, screens, barriers, or enclosures; and/or
- implementing organisational measures which reduce the length of time that employees are exposed to noise, i.e. turning off equipment when not in use, introducing job rotation so employees are doing a mixture of noise and quiet tasks rather than spending all day working with high noise level equipment;
- provide employees with hearing protection if the noise exposure cannot be reduced enough by the aforementioned measures and the noise levels remain above the exposure action values;
- provide employees with information, instruction, and training on noise in the workplace; and
- carry out health surveillance where there is a risk because of exposure to loud noise.
Paragraph 66 of Regulation 6 of the NAW Regulations indicates that the employer should generally be seeking to reduce the risk of noise exposure irrespective of whether any exposure action values are exceeded. It may also be necessary to carry out ongoing reviews to the risk assessment at set periods, or when circumstances change.
Organisational and Technical Measures of Noise Reduction
Regulation 6 of the NAW Regulations indicates that “the employer shall ensure that risk from the exposure of his employees to noise is either eliminated at source or, where this is not reasonably practicable, reduced to as low a level as is reasonably practicable….. If any employee is likely to be exposed to noise at or above an upper exposure action value, the employer shall reduce exposure to as low a level as is reasonably practicable by establishing and implementing a programme of organisational and technical measures, excluding the provision of personal hearing protectors, which is appropriate to the activity.” The table below provides examples of such measures.
Table 2: Methods of controlling noise through organisational and technical measures
Reduce noise levels at source
Reduce noise propagation throughout the workplace
Personal Hearing Protection
After the measures with Regulation 6 (summarised in the previous subsection) have been explored, the next step is to consider providing personal hearing protection.
Regulation 7 of the NAW Regulations indicate that hearing protection is compulsory for employees exposed to levels above the upper exposure action value (UEAV), though this is not compulsory during the quieter times of the day or if the employee is in a quiet area. It is also compulsory for any employee entering a Hearing Protection Zone (HPZ).
Hearing protection is not compulsory for employees exposed to levels below the UEAV. It is not beneficial to enforce employees to wear hearing protection when not necessary, as this can lead to isolation, decreased communication, uncomfortable working conditions and a decreased ability to hear alarms and sirens.
It is also not strictly beneficial to use hearing protectors which overprotect, for the reasons above. The main aim of hearing protection is to reduce noise levels at the ear to below at least the UEAV (85 dB(A)), but they should be avoided if they reduce noise levels to below 70 dB(A).
The table below shows the ‘single number rating’ (SNR) protection factor that is likely to be suitable for different levels of noise. The SNR value is typically stated with the hearing protection device. This is based upon the information in the NAW Regulations, and in BS EN 458:2004: Hearing protectors.
Table 3: Required protection factors for hearing protection
A-Weighted Noise Level (dB(A)) 1
Select a protector with an SNR of…
85 – 90
90 – 95
20 – 30
95 – 100
25 – 35
100 – 105
1 Based on instantaneous noise levels, not the daily personal noise exposure.
– Higher levels of protection can be achieved through dual protection, i.e. wearing ear-muffs over ear-plugs.
There are several other factors that influence the choice of which type of hearing protector an employee may wish to use, as outlined in Part 5 of the NAW Regulations, which also state that “wherever possible the employer should make more than one type of protector available (making sure that each is suitable for the noise and jobs to be done) to allow the user a personal choice”.
Employees are often reluctant to use hearing protection, are forgetful, or do not apply protection correctly. A programme of monitoring, supervision, warning notices, instruction, and training is needed to ensure they are used. It is also important that a system of maintenance is employed, to ensure that the hearing protection maintains its level of noise reduction and does not become defective over time.
Hearing Protection Zones (HPZ)
Regulation 7 of the NAW Regulations indicates If any area in the workplace is likely to be exposed to noise levels at or above the upper exposure action value (UEAV) then the employer must ensure that:
• the area is designated a Hearing Protection Zone (HPZ);
• the area is demarcated and identified by means of the sign specified for the purpose of indicating that ear protection must be worn;
• access to the area is restricted where this is practicable and the risk from exposure justifies it; and
• no employee enters that area unless that employee is wearing personal hearing protectors, so far as is reasonably practicable.
The boundaries of HPZs should be considered carefully, i.e. they should avoid overlapping commonly used walkways and should not extend further than is necessary to protect people carrying out their normal work. In situations where the boundaries of a zone cannot be marked, then attaching hearing protection zone signs to specific tools is an appropriate alternative.
Information, Instruction, and Training
Regulation 10 of the NAW Regulations indicates that the employer must provide ‘information, instruction, and training’ to employees who are exposed to above the LEAV. It is important for the employer to tell employees:
• their likely level of noise exposure and the health risk this carries;
• what the employer is doing to control risks and exposure to noise;
• when and how the employee can obtain hearing protection and when they should use it;
• how the employee should be using hearing protection and noise control equipment in the correct way to minimize their risk, and how they can identify and report defects;
• what the employees’ duties are under the NAW Regulations; and
• how the employer is providing a health surveillance system; and
• what symptoms of hearing damage the employee should look out for, and to whom and how they should report this.
This information, instruction, and training can be provided in any way, providing the employee can find it easy to understand. The HSE’s ‘Noise: Don’t lose your hearing!’ pocked card can be handed out to supplement this.
It is also a requirement to discuss the risk assessment and all plans relating to controlling noise exposure with a trade union-appointed safety representative, or for groups of workers not covered by this, an elected employee representative.
Regulation 9 of the NAW Regulations state that there is significant evidence which links the regular exposure to noise levels above the exposure action values to long term health risks and hearing damage. Therefore, the employer should provide health surveillance to:
• all employees who are regularly exposed to noise levels above the upper exposure action values (UEAV); or
• employees who are occasionally exposed above the UEAV, or who are exposed between the lower (LEAV) and upper (UEAV) thresholds but who are known to be particularly sensitive to noise, i.e. from medical history, audiometric testing or a history of noise exposure at previous jobs, or a family history of early-onset deafness.
Health surveillance is a programme of health checks which usually involves regular hearing checks (audiometric testing), keeping health records, and referring employees to a doctor if/when hearing damage is identified. It is useful in waring employees if they exhibit early signs of hearing damage to give the opportunity to do something to prevent the damage from getting worse. It is also effective for the employer to identify whether noise control measures are working.
Surveillance can be introduced at any time for existing employees and should be introduced straightaway for new employees, to allow a baseline to be taken. Annual checks for the first two years (followed by three-yearly checks after this unless a problem is detected or the risk of hearing damage is high) should be conducted by someone with appropriate training, with the whole surveillance programme under the control of an occupational health professional.
Regulation 5 of the NAW Regulations indicate that the employer should implement an ongoing control programme in managing noise exposure risks. It may be necessary to review and produce an updated risk assessment when circumstances change, for example, if:
• circumstances change in the workplace, i.e. new equipment is installed, older machinery ceases to be used, shift patterns are changed, any reason that employees’ level of noise exposure may have changed;
• noise control measures have been implemented since the previous assessment and the impact on employees’ exposure needs to be re-assessed;
• the employer becomes aware of improved working methods and noise-control techniques that are new to the industry and could be applied to the workplace;
• control measures that could not be implemented at the time of the original assessment become more viable to do so, i.e. because of new technology or reduced costs; and/or
• continued health surveillance shows that employees’ hearing is being damaged, suggesting that noise control methods are not being properly implemented or are not effective enough.
The NAW Regulations indicate that even if none of the points above are true, the assessment should still be reviewed at least every two years.
I hope you enjoyed this
short rather long article, and keep an eye out for more articles on the common questions that I get asked by clients in my job as an acoustic consultant. Feel free to connect and message me through LinkedIn, send me an email at firstname.lastname@example.org, or through our Contact Us page.
Noise survey reports, acoustic surveys and noise assessments at a competitive price, to the highest quality. Noise surveys to BS8233, BS4142, BB93, BS5528, ProPG, BS7445, NPPF…