CONSCIOUS of the impending Control of Noise at Work Regulations, contractor Laing O'Rourke joined forces with 3M, a leading manufacturer of hearing protection equipment, to conduct a survey of noise levels on site.
The results give clear indications of the sort of action most contractors should be taking. Together, the companies carried out a series of noise assessment on 10 Laing O'Rourke sites over a three-month period. The surveys gathered data on:
The levels and type of noise generated by typical construction tasks and tools
Who was most likely to be exposed to high or continued levels of noise
Whether processes or procedures could be improved or introduced to reduce noise at source
Which hearing defenders provided sufficient protection to comply with the new exposure action levels
The time taken for noise exposure to reach these action levels.
The survey found that during normal site conditions, operatives were typically exposed to noise levels of around 82 dB.
The use of equipment such as power saws increased the levels to approximately 109 dB. Since noise 'dosage' is measured according to the amount of time a person is exposed to a given noise intensity, this means that, at 109 dB, it takes only a minute's work with a power saw to reach the upper action level.
Action to reduce the exposure to noise generated by hand-tools is limited by the fact that the user is in immediate proximity to the noise source. Personal hearing protection is therefore always critical. 3M's survey looked at noise levels across a range of frequencies. 'Whether noise is of a high or low frequency is of particular impor tance when trying to control the risk of hearing damage, ' says 3M occupational health and environmental safety product manager Vikki Nash.
The choice of hearing protection equipment is important here, as different types can filter out different frequencies to varying degrees.
The survey also looked at the ergonomic aspects of hearing protection and found that even if workers are aware of the impor tance of wearing the equipment, equipment that is uncomfortable, tricky or time consuming to fit will not encourage use. For instance, standard disposable earplugs, which are typically provided, often take longer to roll and install correctly than the time of the individual noise exposure itself, whereas a more practical solution would be banded ear plugs or helmet mounted ear muffs, which require minimal fitting.
3M and Laing O'Rourke are cont inuing to collaborate on further studies to evaluate the use of a range of personal protective equipment.