|'The world's finest ear defender against noise at work and recreation'
Hearing loss caused by exposure to noise at work continues to be a significant occupational disease. Recent research estimates that 170,000 people in the UK suffer deafness, tinnitus or other ear conditions as a result of exposure to excessive noise at work.
Currently (under the Noise at Work Regulations 2006) the first action level is a daily personal noise exposure of 80 dB(A) and a peak value of 112 pascals, the second action level is a daily personal noise exposure of 85 dB(A), and the peak action level is a peak sound pressure of 140 pascals.
The limit value will take into account the reduction afforded by hearing protection.
The 'Real World' Attenuation of Hearing Protectors
(testing both muffs and disposable ear plugs)
This research does not apply to custom moulded earplugs, which are equally as effective in the real world as they are in the laboratory.
"It has long been felt that, due to a number of variables between the industrial (real world) situation and the test conditions, that workers do not get the level of protection suggested by the standard data test.
The Health and Safety Executive sponsored this research project to establish the level of protection actually achieved by workers wearing such protectors in industry and to compare these 'real world' results with the test data."
"The testing of hearing protection in laboratory conditions tends to give an unrealistically high estimate of their performance as the subjects are usually familiar with the objectives of the test and are given precise instructions on the fitting of the device. Also the protector is usually new, the subjects do not wear spectacles, and care is taken to ensure that beards or long hair do not impair the effectiveness of the device."
A number of muffs and disposable ear plugs were tested and "in general, there is a degradation in mean attenuation and an increase in the standard deviation associated with all the protectors when the 'field' data is compared with that quoted by the manufacturers."
The report concluded that, for muffs, "the degradation in performance is slightly more severe at the higher frequencies and that the average overall reduction is about 5 dB(A)," and that "for plugs the degradation in performance is more uniform across the whole range of frequencies giving a reduction in overall attenuation of approximately 7-15 dB(A)."
There are several reasons to explain the poorer protection in the real world of hearing protectors, including,
The report concluded that "the field performance of hearing protectors is markedly less than that which is predicted from the manufacturer's specification of their performance."