Noise at Work

The ear is a complex organ that consists of three anatomically separate portions: the outer ear which is irregularly shaped piece of cartilage covered by skin, which acts like a radar dish collecting sound-waves. The inner ear consists of the cochlea; a liquid filled hairy tube coiled like a snail shell, the sound wave is transmitted to brain by the auditory nerve. The middle ear lies entirely within the temporal bone inside the skull, known as the external auditory canal covered in fine hairs and protective a fluid (ear-wax).

The Noise at Work Regulations 1989 lays down a framework of duties covering the assessment and control of noise hazards. They set three action levels; the first action level is 85dB(A) for continuous daily exposure, the second is 90dB(A) for continuous daily exposure. The third defined level is a peak action level of 200 pascals and is likely to be linked with sudden noises such as shooting guns and loud explosive noises.

Auditory effects of Noise - noise induced deafness causes damage to the hair cells and nerves in the inner ear and are referred to a sensor neural hearing loss. It can be caused by disease and infection but nearly all noise induced hearing loss is of this type. There are various ways of limiting or controlling noise; these include:

The reduction of noise at source - remedial measures can be taken to avoid impacts - including the introduction of rubber stops or plastic coatings, and by stopping components rattling together: adding silencers at air exhausts and jets, low noise air nozzles.

Enclosing the source of the noise - enclosing the noise source can reduce noise levels considerably by adding a suitable noise enclosure or hood for a certain piece of machinery.

Issuing ear protection to employees - health and safety legislation states that personal protective equipment (PPE) must always be used as a last resort after all other methods of control have been exhausted and must be compatible, comfortable and effective. PPE should be offered by the employer at 85dB(A) and its use is compulsory at 90dB(A).

Measuring hearing loss by using audiometery - the method tests an individual's hearing over a range of frequencies. It can be used to detect deterioration in the hearing of an individual. However, it only concentrates on an individual and not the noisy workplace.

Non-auditory noise controls - it is recommended that controls be implemented after conducting a general noise assessment: by reducing noise exposure either at source or by the introduction of hearing protection will go some of the way to reduce the risks of non-auditory health effects. However, many of these effects have been documented at levels well below those set in the current Regulations.

Cardiovascular - where it is suspected that an individual may be experiencing cardiovascular health effects, they should be referred to the organisation's Occupational Health Department or be encouraged to make an appointment with their general practitioner or nurse. Health surveillance should be established for these individuals, so that their blood pressure and blood lipid content can be monitored on a regular basis.

Reproduction and development - Under no circumstances should expectant mothers be exposed to daily noise levels of more than 85dB(A) or to frequencies below 500Hz. The information about damage that may be caused to the hearing of the foetus should be disseminated to all women within the workplace.

Produced by the GMB, London Region,
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