Anyone who has ever read a medical report in a noise induced hearing loss case will be familiar with the medical expert commenting on whether a claimant has a history of riding a motorbike. So motorcycle use might be considered a relevant feature of a claim.
Whilst occasional, intermittent use may be ignored, in cases where there is more significant use of motorcycles, how much effect does this actually have?
‘Noise Induced Hearing Loss in Motorcyclists’
Expert engineers sometimes use a paper called Noise Induced Hearing Loss In Motorcyclists by Harvey and others. It was a paper written for the Association for European Transport in 2002, and so was designed to consider occupational exposure for motorcyclists. The paper notes that there were a handful of studies which have given a variety potentially high noise levels for motorcyclists.
The paper sought to undertake a range of testing of motorcycle noise exposure. Examples of occupational use such as pizza delivery drivers and police motorcyclists were given. It does also considers recreational use. It cites one claim where a police motorcyclist had a NIHL case successfully settled.
Measurements were taken of the noise levels within a motorcyclist’s helmet. Since a sound meter cannot fit inside a motorcycle helmet, a referenced recording was used whilst a motorcyclist rode along a flat section of public road.
The rider shouted out the speed at which he was travelling. A number of runs were made using different type of helmets (open face and closed) with speeds ranging from 50 to 120 kph. Both wet and dry conditions were tested. Measurements were taken with visor positions both up and down. A 600 cc motorcycle was used.
The results make interesting reading.
If the weather conditions were wet or dry makes quite a difference. Wet conditions were about 5 – 8 dB louder than dry conditions. At lower speeds there was little difference between open and closed face helmets, though there was at higher speeds. Unsurprisingly, across the board, higher speeds resulted in higher levels of noise exposure.
As a sample of some of the results:
At 50 kph (a little over 30 mph) in dry conditions, noise levels were around 81 – 83 dB, depending on helmet and visor position. In wet conditions at the same speed, the noise levels were between about 85 – 90 dB.
At 80 kph (about 50 mph) in dry conditions, the noise levels were between about 85 – 90 dB. In wet conditions at the same speed, the levels were about 92 – 95 dB.
At 120 kph (about 75 mph) in dry conditions, the noise levels varied between about 95 – 102 dB. In wet conditions the measurements were between about 101 – 107 dB.
The report considers the resulting daily noise exposure for an example police motorcyclist. If three hours were spent at 120 kph, plus three hours at 90 kph and two hours at 60 kph, this would result in a daily noise level of about 103 dB (A) lep,d. Whilst an eight-hour shift spent wholly riding the motorcycle might seem unlikely in practice, even if those durations were cut in half, this would result in a daily noise exposure of about 100 dB (A) lep,d.
Occasional exposure (measured in days or weeks or even months) is unlikely to make a great deal of difference to the overall picture of an individual’s hearing. However, if there is a claimant with a significant level of motorcycle use (perhaps in an occupational setting) then this could be sufficient to be a relevant feature and could be enough to influence an individual’s Noise Immission Level (NIL) and so any resulting apportionment.
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