Managing the risk of noise exposure

High levels of noise exposure can be very dangerous and lead to noise-induced hearing loss, tinnitus, and other forms of long-term hearing damage. For this reason, employers must be sure to measure their employees’ exposure to noise, and put measures in place to prevent them from being exposed to dangerous noise levels.

In this article, we will look at noise exposure levels, estimating noise exposure, and some of the measures that an employer can take to limit its employees’ exposure to noise.

How is noise measured?

Before looking at how to measure and control hazardous noise exposure, it is important to understand how noise is measured.

Noise is measured in decibels (dB), which is a measure of how intense a sound is. The decibel scale is a little unusual because the sensitivity of the ear allows us to hear an extremely large range of sounds, so an increase of 10dB is actually a 10x increase in intensity.

For example, general city traffic is around 70dB, which is 10x louder than the noise of a normal conversation, which is around 60dB.

For more information on decibels and how loud certain common sounds are, click here to view our knowledge bank article on measuring noise levels.

How is noise exposure measured?

An employee’s occupational noise exposure is usually measured in LEP,d, which represents the daily ‘dose’ of noise they are exposed to (normalised to an 8 hour day). It is calculated by combining information on how loud the various noises that a person is exposed to in a working day are, and how long they are exposed to each of them for.

For example, all three of the following exposures have an LEP,d of 80 dB:

• 80 dB for 8 hours.
• 89 dB for 1 hour.
• 92 dB for 30 minutes.

How do you measure noise exposure?

Employers must measure the noise level that their employees are exposed to in order to assess whether noise levels are sufficiently controlled, and whether they are compliant with the Control of Noise Regulations 2005.

There are several ways to obtain a worker's LEP,d (daily noise exposure level), including:

• Using a sound level meter to measure the LAeq (average sound level measurement) at each working location, and then finding out how long the worker spends at each location.
• Mounting a noise dosimeter to the worker's shoulder, which will measure their individual noise exposure for the full working shift.
• Using data provided by a tool’s manufacturer to determine how much noise it produces, and finding out how long the worker spends using the tool.

A determination of the likely peak sound pressure levels, (LCPEAK), to which workers are exposed should also be measured.

For those employees whose daily exposure to loud noise varies significantly, their weekly noise exposure (LEP,w) should be calculated instead.

Once the relevant information has been gathered, an employee’s LEP,d or LEP,w can be calculated using the exposure calculators and ready reckoners provided on the Health and Safety Executive (HSE) website.

What are the noise action levels?

The Control of Noise at Work Regulations outline several exposure action values and an exposure limit value. 

• An exposure action value is a level of noise at which certain action must be taken. 
• The exposure limit value is the level of noise at the ear above which an employee must not be exposed.

These values are as follows:

An employer may need to take several steps depending on the level of noise that an employee is exposed to:

Above the lower exposure action value

• Perform a risk assessment that identifies those risks associated with noise in the workplace.
• Provide suitable hearing protection to employees who wish to use it, but they are not required to enforce its use.
• Provide employees with suitable information, instruction and training on the current noise levels in the workplace, and the risks associated with it.

Above the upper exposure action value

• Reduce noise exposure levels as far as is reasonably practicable (without using hearing protection).
• Provide employees with suitable hearing protection where noise levels cannot be sufficiently controlled in any other way.
• Measure the noise levels throughout the workplace and mark those areas with high levels of noise as hearing protection zones, in which the use of hearing protection is required and enforced.
• Provide those employees that work in hearing protection zones with regular hearing/audiometric tests.

Above the exposure limit value

It is illegal for employees to be exposed to noise levels that exceed the exposure limit value. However, they can work in areas that are louder than this value, as long as an employer can prove that they have provided suitable hearing protection that reduces an employee’s individual exposure to a level below the exposure limit value.

How can you reduce noise exposure?

When considering ways to reduce noise and noise exposure, a hierarchy of control methods should be followed:

1. First, think about how to remove the source of noise altogether. For example, a noisy machine could be moved so it cannot be heard by workers.
2. If this is not possible, consider using quieter equipment or a different, quieter process.
3. Next, ensure that equipment is well maintained so that it continues to be effective and as quiet as possible. 
4. If noise elimination is not possible, consider designing and laying out the workplace to create quiet workstations.
5. Use absorbent screens, barriers and enclosures to surround noisy equipment.
6. Limit the time people spend in noisy areas.
7. Provide employees with personal hearing protection.

What is personal hearing protection?

Hearing protectors, such as ear defenders and earplugs, should only be considered as a last resort. This is because it relies on an employee remembering to use it, and using it correctly, to be effective.

We will look at three of the most common forms of hearing protection below, but it is advisable to seek specialist help when choosing ear protection.

Ear defenders

Ear defenders should totally cover a person’s ears, fit tightly and have no gaps around the seals. Care should be taken when using them to ensure that hair, jewellery, glasses, hats and other equipment do not interfere with the seal, which can significantly reduce their effectiveness.

Earplugs

Earplugs go inside the ear canal, not just across it, which can make them very effective at limiting noise exposure. However, they can pose a hygiene risk if not used correctly.

A person should always clear their hands before they fit earplugs, and avoid sharing them with anyone else. They should also use them in accordance with the manufacturer’s instructions, as some earplugs can be washed and reused, while others are single-use only.

Semi-inserts/canal caps

These forms of hearing protection are held in or across the ear canal by a band. They are similar to earplugs, so the same general guidance should be applied when using semi-inserts.

They should also be regularly checked to ensure that the band has retained its tension, and is able to keep the caps securely in place.

For more information on noise, consider taking our RoSPA assured Noise Awareness training course:

Noise Awareness