How to choose the right hearing protection
Getting the right hearing protection is important and it is more complex than buying the strongest you can find.
Key points on how to choose the right hearing protection
Do not over-protect, stronger attenuating hearing protection is not always better and often leads to a higher risk.
The simplest method is to use the SNR level of the hearing protection.
You also need the average dB(C) level for your noise - note, that is not the average dB(A) or the peak dB(C).
Ideally, aim for 70 to 79 dB under the protector.
The HSE’s L108 Controlling Noise at Work (Third Edition) contains guidance on assessing hearing protection, as does their website.
This page on hearing protection allows you to check what noise level a hearing protector’s SNR is good for, or allows you to enter your noise level and it will give you a list of suitable hearing protectors.
Make sure any hearing protection is certified to EN352.
A need for hearing protection is a common outcome of a noise assessment or a noise survey. Although it is technically at the bottom of the ‘hierarchy of controls’ whereby companies need to eliminate noise risk first, then control it by some other organisational means if possible, often hearing protection is either the only practical outcome or is needed as a temporary interim measure.
Hearing protection needs to be ‘just right’, so not too weak meaning people are still at risk, but also not too strong so people become isolated.
Key point: Never choose hearing protection on the basis that ‘stronger is better’.
How to check hearing protection is suitable for the noise risk
So employers have to make sure hearing protection is correct for their noise risk and there is a nice simple way to do this. All hearing protection has an SNR figure, the Single Number Rating, which is the number of decibels it reduces the noise levels by.
(As an aside, our American brethren use NRR, not SNR and the two are not the same - you cannot used NRR here in the UK, if you see anything saying NRR, ignore it, it is for people who think spraying cheese out of a can is normal).
The easy way to assess hearing protection suitability
There is a page on this site specifically about hearing protection which has a few tools you can use.
For one tool you can enter your average dB(C) noise level and the protector’s SNR in there and it will tell you if it is OK.
There is a table of hearing protection SNR and the type of noise level it is suitable for.
If you don’t have a specific hearing protector in mind, you can enter your noise level and it will give you a list of hearing protectors which are suitable for your noise risk.
The mildly more complicated way
To calculate it manually, all you need to do is take the average dB(C) noise level which your noise assessment should give you, and subtract the hearing protector’s SNR from it. Then, add 4 back to it to allow for some slightly incorrect use, and the answer is the sound level people should be experiencing under the hearing protection. As an example:
A Laser Lite plug has an SNR of 35. (And appalling spelling).
The dB(C) result in the noise assessment for the job in question is 95 dB(C).
The calculation is 95-35, giving 60dB.
Add 4dB to account for real-world usage so we get a result of 64dB, that’s what people experience.
Don’t use peak dB(C)
Do not use the peak dB(C) figure as that almost always comes out as the hearing protection being insufficient, you want the average dB(C) level. A noise assessment done by a good professional should have given you that figure.
If you don’t have it you could use the average dB(A) figure but that is generating room for error and is best avoided as average dB(A) and dB(C) are often not the same. As noise gets into the important levels which concern us they are however often fairly close though. It’s not an ideal route but better than nothing.
What is a good noise level under the hearing protection?
You should aim for around 70 to 78 dB under the protector - that’s the noise people actually hear.
81 to 84 dB is a level I don’t personally like hearing protection as that is far too close to the limits for my liking - if there are no better options then OK, but I would avoid it unless you have absolutely no other options.
79 to 80 dB is technically OK but I would steer clear of that personally as it is getting too close to the upper noise limit where hearing starts to be damaged - someone wearing it slightly incorrectly could easily then be at risk.
65 to 69 dB is again OK. The HSE class that as a little too strong but if it is good for other risks within the company then it is fine. As a guide, this is about the noise level of an office so not horrendously quiet - your production staff would just be a the same noise level as your office staff.
64 dB and below is too strong and should be avoided. People tend to not put plugs in properly or off-set ear muffs to let more noise through as they can’t hear what’s going on. They are then at risk and the employer is wasting money on hearing protection that’s not actually doing a lot.
Link: HSE on hearing protection should not reduce noise levels below 70 dB(A).
As another rough guide:
Other methods of calculation
There are two other ways of doing the same thing as above, HML and Octave Band. Noise assessors love Octave Band but I’ll let you into a secret, it makes pretty much no difference over using the simple SNR apart from some very specific circumstances. 99% of the time the Octave Band route gives exactly the same answer as the SNR one, and when it doesn’t it is still within a dB or so.
HML is in the middle, a bit more complicated than SNR, less complicated than Octave Band.
As someone reading this is presumably not a noise nerd with far better things to do with their day I have deliberately not delved into the edge-cases where Octave Band or HML may be more suitable as that will confuse things, just use SNR. The HSE list it in L108 as one of the three acceptable ways to assess hearing protection suitability so if it is acceptable in there, go for it.
Make sure the hearing protection is properly certified
This means making sure it is certified to EN352. A lot of listings for no-brand protection on places like Amazon do fudge this so these are best avoided. If it only says ‘workplace noise’ in a listing without giving any proof of certification to EN352, avoid it,
FAQ: Choosing the right hearing protection
Can we play it safe and just buy the strongest hearing protection?
No, hearing protection which is too strong introduces its own risks, hearing protection needs to be strong enough but not too much.
Can we use NRR to check if hearing protection is good enough?
No. I am talking about the UK here so the Control of Noise at Work Regulations 2005 and the HSE’s L108, Controlling Noise at Work (Third Edition) document, and these require the use of SNR, HML or Octave Bands. NRR has no application here. NRR and SNR are not synonymous and the numbers are not interchangeable.
There is a bewildering array of hearing protection on the market, can you recommend some specific types?
Yes, and they are listed on the hearing protection advice page for you.
More information on hearing protection in the workplace
