HEARING PROTECTION ASSESSMENT TOOL
Essential for workplace noise assessments.
Can be used to assess whether hearing protection is suitable for the type of noise risk in an area.
All you need is the average dB(C) noise levels from your noise assessment and the SNR from the hearing protector.
How to use the hearing protection assessment tool
You just need two pieces of information, the noise level in the workplace from your noise assessment and the SNR of the hearing protector.
1) Workplace noise level from the noise assessment
You ideally want the average dB(C) level, that is not the peak dB(C) or the average dB(A). Your noise assessment should have the average dB(C) levels but if it doesn’t, use the average dB(A) as they are close enough.
Do not use the peak noise though as that will send you awry - don’t use the loudest noise level seen, always use the average.
2) The protector’s SNR level
All hearing protection will have a certified SNR figure, this is the Single Number Rating and is how many decibels it knocks off the noise.
Plug both these into the spaces in this form and it will tell you the expected level under the protector, adding in the HSE’s recommended 4dB for slightly incorrect wearing.
Hearing Protection Suitability
Strongest is not best in hearing protection
Hearing protection manufacturers often base their marketing on how strong the hearing protection is but this is usually misleading as ‘best’ is not synonymous with ‘strongest’ when it comes to ear plugs and ear muffs.
Many types of hearing protection have noise reduction abilities of 30dB or more but almost no workplace actually needs this level of protection.
Problems with over-protection, hearing protection which is too strong.
People become isolated as it makes things too quiet.
They put the plugs in loosely or off-set the muffs so they are not quite over the ear to let more noise through.
Some experienced people use the noise a machine makes to tell them it is working properly. Too-strong protection stops this.
The employer ends up with a bigger risk as hearing protection is not being worn properly and the liability remains for the employer, and the money they do spend on it is pretty much wasted.
What is the ideal result to aim for?
If your result is 70 to 79 dB that is perfect. The magic ideal number is about 75 dB.
If your result is 80 to 82 dB then technically that is OK but I would urge you to get slightly stronger protectors as it’s getting close to the limits.
If your result is 65 to 69 dB that is OK, especially if you have varying noise levels and the protector is perfect for other jobs or tools.
If your result is 64 dB or lower that is considered to be too strong.
If your result is 83 dB or over then that is too weak.
Technically levels under the protector of 83 and 84 dB are kind of OK but personally I see it as a big ‘no’ as it is getting far too close to the limit. Just a small variation in the noise or in incorrect use could leave people at risk.
The HSE have some info on it here as well: