Noise - Stage 2: Assess health risks

How do I assess the risks?

The risk assessment is to help you decide how to ensure the health and safety of your workers who are exposed to noise. It should:

• identify where there might be a risk from noise;
• clarify who is likely to be affected;
• contain a reasonable estimate of your employees' exposures;
• identify what you need to do to comply with the law (eg are additional control measures needed, and if so, where and what); and
• identify any workers who need health surveillance.

You will need to be in a position to show that your estimate of employees' exposure reflects reality. The estimate needs to take account of the work, the way that it is done and typical variation from one day to the next.

• How do I get started?

Do I need to measure my employees' exposure to noise?

You should be able to do a basic risk assessment without the need for measurement. In many cases this will enable you to decide whether exposures are likely to exceed the exposure action values and allow you to plan and prioritise your control actions effectively. Table 1 may help you to estimate exposures.

It is quite common for people to use the ‘one and two metre' rules to indicate whether there is a potential noise problem:

• Two-metre rule: If you have to raise your voice (or repeat yourself to someone who is standing two metres away) then the noise level is likely to be above 85 dB.
• One-metre rule: If speech is difficult at a distance of just one metre then the noise level could be 90 dB or more.

Alternatively, you may choose to use manufacturer's noise data or to have actual measurements taken as a basis for estimating exposures. A detailed exposure assessment may help you to:

• decide which control actions might be most effective and practicable in reducing noise exposure;
• be more certain whether exposures are likely to exceed the action or limit values; and
• check whether your controls are effective.

The regulations require you take reasonably practicable steps to control noise. In many cases you will not need a detailed assessment to identify which steps to take initially.

Estimating exposure - typical noise levels

• Estimating exposure

Table 1 Some typical noise levels for a range of construction-related processes. Actual levels can vary and may increase if the process takes place where there are ‘reflective' surfaces, eg the basement of a building

Process		Noise level
Working with concrete: chipping, drilling, floor finishing, grinding etc	Typical	85-90 dB
Labouring	General work	84 dB
	Shuttering	91 dB
	Shovelling hardcore	94 dB
	Concrete pour	97 dB
	Digging/scabbling	100 dB
Driving machines or vehicles	Typical	85-90 dB
Carpentry	Typical	92 dB
Angle grinding/cutting	Typical	90-110 dB
Piling	Machine operator	85 dB
	Piling worker	100 dB

Exposure depends on a combination of noise level and exposure time. Be wary about just relying on self-reported estimates of exposure because these are unlikely to be accurate. Observe the work; it is just as easy to over as well as underestimate exposure. Take account of background noise which may add to your workers' exposures, eg construction work near a high-speed road.

You may find it useful to observe work activities, measure the exposure time over part of a day and then use the information to estimate exposure for a full shift. If an employee is exposed to noise from more than one tool or work process during a typical day, you will need to collect information about the likely noise level(s) and exposure time for each source.

Once you have collected relevant noise data and exposure times you may find it helpful to use an exposure calculator to assess each employee's daily exposure.

How can tool and machine manufacturers and suppliers help?

The Supply of Machinery (Safety) Regulations 1992 (as amended) require manufacturers and suppliers to design equipment that will minimise noise risks. Equipment should be CE-marked to show that it complies with these requirements, and health and safety information should feature in the instructions that are supplied with a machine. This should include:

• information on safe use and, where necessary, training requirements;
• information on how to maintain the equipment;
• a statement of the noise emission (where the equipment noise level exceeds 70 dB at the operator position), together with information on the test method.

Manufacturer's information can indicate whether further assessment and action might be required. However, general data is unlikely to fully represent the actual conditions of use.