Hearing Protection
Question: How do we work out what level of ear protection is needed for any given noise level? i.e. if we have a peek DB level of 98DB what SNR ear defenders should we be looking for?
Answer: I’m afraid it’s not as simple as that, as to match the hearing protection to the noise measured, you need to know frequencies as well as decibels. Next to the SNR number on the packet it will give high, medium and low frequency attenuation (noise reduction), but better still is the full octave band information, usually in tiny print on a leaflet inside the packet.
For example, E.A.R. UltraFit has an SNR number of 32, and gives 33 d(B) attenuation in the high frequencies, 28 in the medium, and only 25 in the low frequencies. If you had an overall reading of 111 d(B)A over 8 hours, and you wore these hearing protectors, you would expect it to take the level down to 79d(B), well below the action levels. However, if you had only low frequency noise, it would only attenuate those by 25 d(B), allowing for 86d(B) of noise to affect the hearing, which is above the second action level.
You also need to look at exposure averaged over an 8 hour reference period, not just the peeks – a 5 minutes peek of 100d(B) in an otherwise quite day may not require HP to be worn.
The easiest way is to let a qualified ‘competent person’ do the survey and the calculations, and from that recommend the correct HP! If you wish to do it yourself, then a good meter with a computer programme to download into is essential, as this will work out the correct PPE based on all the frequencies, not just H, M and L.
A: To ensure a good level of noise attenuation, you would need an octave band breakdown on the noise, to check that the hearing protection selected gives sufficient attenuation at the relevant frequencies. Unfortunately, not all noise meters can do this, and not all suppliers give information on attenuation across the frequency range.
A quicker method is to subtract the SNR for the hearing protection (given in most PPE catalogues) from the dB(A) reading, which will give an idea of the noise level at the ear. A result of over 80 means the protection level is likely to be insufficient, but a result of under 70 means the protection level could be too high (which leads to people taking the hearing protection off in order to hear conversation, machine alarms etc).
A: You could have a look at the new ARCO catalogue Page 451 onwards, and this will give them all the advice they need.
A: I have attached some information from the HSE that will help with the selection of hearing protection. Please to download the document please click here
A: The rule of thumb is to reduce sound to 70 db at the ear. Therefore a SNR of 28 db should suffice, however I would recommend an independent noise survey be carried out.
If you purchase 3M ear protection regularly through Arco then this can sometimes be available F.O.C. we have just had one carried out at Hallam’s and they offer a good support service.
A: My advice would be to work with Earsoft a manufacturer of ear protection or Arco who are distributor of PPE and ask them to get a representative out to demonstrate and also supply samples , Earsoft have a extensive range .
