Causation and Noise Immission Level


In Noise-induced hearing loss claims it is not uncommon for instructing Solicitors to ask the acoustic expert to comment on whether the Claimant’s noise exposure with the Defendant(s) would have had the potential to cause hearing loss.

However, instructing parties ought to be aware that Causation of noise-induced hearing loss in an individual is a matter for the opinion of a medical expert rather than an acoustic expert.

In recent years, medical experts, when diagnosing noise-induced hearing loss, attach significance to a Claimant’s likely lifetime noise ‘dose’, which is represented by the noise immission level (NIL), when it reaches 100 dB, or 90 dB (in association with certain audiometric criteria).

Medical experts base this assessment on proposals made in an article by Coles, Lutman and Buffin which was published in 2000 entitled “’Guidelines on the diagnosis of noise-induced hearing loss for medicolegal purposes”.

The noise immission level is defined in BS 5330:1976 and in the NPL tables.  It is a measure of lifetime noise ‘dose’ and is dependent on the average daily personal noise exposure level, LEP,d , and the number of years of exposure at that level.  So for instance, if a Claimant was exposed to an average daily noise exposure of 90 dB for 10 years, his component NIL would be 100 dB.

Sometimes instructing parties may ask an acoustic expert whether the Claimant’s noise exposure in terms of the noise immission level amounts to a breach of duty, having regard to the standards prevailing at the time. However, we are not aware of any guidance, standard or regulation that indicates a breach of duty associated with the lifetime noise immission level.

Reference to specific points in the article by Coles et al may be useful to our instructing parties.

If you want to know more about causation and noise immission levels, please contact [email protected] or on 01530 412777.

As always, if you have any issues associated with noise or vibration please contact the relevant experts at Finch Consulting.

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