The Control of Noise

Noise is a part of life, but for some people in certain industries, loud noise can be a daily occurrence which can cause long-term damage. Permanent hearing damage results when the noise is too high, goes on for too long or too often. But at what noise level does the law state that you must wear ear protection?

The risk from noise at work is indicated by the daily personal noise exposure level, or LEP,d - the total noise dose permitted in the working day. This calculation takes into account the average levels of noise and time spent in the affected area.

The sound levels workers are exposed to might vary, and their day may be made up of periods at different levels but their exposure level is expressed as the equivalent steady level that would give the same dose over eight hours. Where noise exposure varies from day-to-day, an employer can use weekly personal noise exposure levels in place of daily ones.

Some examples of common workplace noises are shown below:

Very high-level sound such as explosions, gunfire and some machinery may pose a risk of instantaneous damage even when the sound is infrequent or very short duration. This risk is assessed against the C-weighted peak level of the sound - which measures peak, impact or explosive noises².

The General Application Regulations 2007, Chapter 1 of Part 5: Control of Noise at Work gives action and limit values for the above risks, which are trigger points for action to commence to protect employees.

The action values take no account of hearing protection use, but the limit values do take account of the attenuation of any hearing protection used.

It's also worth noting that every 3 decibel increase in noise doubles the risk due to the way noise is measured using a logarithmic scale.

Actions when at or above the lower action value:

• Conduct a noise risk assessment
• Provide staff training on the risks and how to keep safe
• Implement controls to reduce the level and duration of exposures
• Consult with staff on workplace changes
• Make hearing protection available

Additional actions when above the upper action value:

• Produce an action plan of control measures that details the how, when and who is responsible
• Mark out areas where exposures are likely to exceed the upper action values as hearing protection zones. Hearing protection must be worn in these zones
• Provide regular health surveillance to employees at risk (this would usually include everyone regularly exposed above the upper action value)

The limit value - if it is exceeded, you must prevent any reoccurrence immediately.