Exposure to hazardous, excessive levels of noise at work has increased substantially over the past 50 years and it is thought that 1.3 million workers in the UK are exposed to noise levels over 90 dB which lead to industrial deafness, as a direct consequence. Concerned organisations like The Trades Union Congress (TUC) have suggested that there are new work environment and occupational categories to seriously consider, which may create further risks to hearing, such as call centres and motorcycle couriers.
It was recently estimated that there are over 26 thousand occupational motorcyclists in the UK, over 90 per cent comprising couriers, dispatch riders, police motorcyclists, paramedics and journalists. Occupational motorcyclists, as a distinct group, can be exposed to very high levels of aeroacoustic noise generated around their helmets and are thus, at risk of developing noise induced hearing loss.
A study showed that noise levels in excess of 105 dB were recorded for motorcycles travelling at 70 mph, the maximum UK motorway speed limit. Professional racers often travel at speeds in the region of 150 mph+ and police motorcyclists regularly travel at over the maximum speed limit when attending emergencies.
Occupational motorcyclists were found to have LEP,d’s above the second action level of the Noise at Work Regulations 1989. Lep’d is a measure of exposure calculated upon both sound pressure level and duration of the noise exposure.
The primary noise source was found to originate in the base of helmet between the chin bar and the neck of the rider. The use of a proprietary neck seal reduced inner helmet noise levels by around 4dB at 70mph+. The neck seal was difficult to fit and on a number of occasions the wind pulled it from the helmet. These disadvantages may make this means of noise reduction is unlikely to be used consistently in practice and thus, ineffective in helping to reduce the risk of hearing damage.
The value of conventional hearing protectors in the reduction of noise exposure of motorcyclists is likely to be limited due to the high level of low frequency noise generated by wind turbulence and the impediment they create to the effective use of radio communications. Practicable and efficient methods for the control of noise in this occupational environment are therefore, needed to be researched further.