Doing your own noise assessment
Key points for doing your own noise assessment
You can do it yourself but the Control of Noise at Work Regulations 2005 (the ‘Noise Regs’) and HSE’s L108 Controlling Noise at Work (Third Edition) give several considerations which must be addressed.
It must be done by someone ‘competent’, which means both suitably qualified and experienced. It doesn’t specify precisely what that is but I would look for specific training in noise assessment, not a generalist qualification such as a NEBOSH Diploma.
The noise meters must be Class 1 or Class 2, and ‘integrating’. These are specific standards and cheap noise meters on places like Amazon do not meet this and must not be used.
Noise meters used must be within their calibration period, which is at least every two years.
On on-site calibration must be done before and after every set of measurements.
Understand the requirements for health surveillance and hearing protection as these need to be specified as part of it.
You can do a noise assessment yourself and there is a lot of information on this website which gives you pointers on it, but beware that it is not as straight forward as it may appear. I am not telling anyone not to do it themselves and the information below may help, from the common errors seen in an in-house noise assessment so you know what to avoid to tips on what you need to do regarding noise meters, competence training etc.
Common errors on in-house noise assessments
I have seen noise assessments where someone has had a valiant go at it themselves and given it a good try but the wheels do seem to come off fairly early on. It can be helpful to know where things go awry and common issues I’ve seen are:
They didn’t know there are two decibel scales used, so no understanding of dB(A) or dB(C).
They miss the averaging aspect of dB(A). I see this a lot where people attempt a noise assessment themselves where they record the dB(A) as the highest dB(A) level they saw, whereas what the Noise Regs want is the average dB(A) over a cycle.
As an example: I saw an edge bander recently recorded as a noise level of ‘118 dB(A)’ on an internal noise assessment, whereas the average noise level for the complete cycle was 89 dB(A) - they’d recorded the highest level they’d seen for a few seconds rather than the average for the entire routine.
Measuring too far away. I read of a CNC’s airline being measured from five metres away. You need to measure noise right where the operator is standing, not far away as air gun noise in this instance attenuates quickly with distance.
They used a cheap noise meter off Amazon. Again, not a criticism as to non-specialists they probably all look the same but a cheap noise meter is not compliant with the standards the HSE say a noise meter must meet, not even close. They are not ‘integrating’, and they do not have their calibration checked on the day.
In-house assessments commonly missing the average dB(C) which is needed as a means of assessing hearing protection - this is what is used for SNR calculations. A cheap Amazon noise meter doesn’t measure average dB(C).
I’ve seen a lot of noise assessments which don’t come close to being completed by someone ‘competent’, as required by L108.
So, if you are thinking of doing a noise assessment yourself then you certainly can, just make sure you have covered off the key elements below. All the references here are to ‘L108’, which is the HSE’s rules governing undertaking noise assessments at work.
Things to make sure you have in place for an in-house noise assessment
This is what you need to make sure is in place if your are considering doing a noise assessment. I don’t want to just highlight problems but also give solutions so most of the information below has recommended solutions for each element.
Noise assessments must be done by someone ‘competent’
Noise assessments need to be done by someone ‘competent’, which means someone suitably trained, qualified and experienced in noise assessment at work.
HSE’s L108: Noise assessments must be done by someone competent to do it
A NEBOSH Certificate is just about enough training in noise safety to allow someone to get into trouble, and a NEBOSH Diploma gives enough training and knowledge to really get it wrong rather than just a little bit wrong. Both those are generalist, and very good, Health and Safety qualifications - I myself have both of them - but they teach you a little bit of everything rather than focusing in on a lot of detail. They are like having tapas for a meal, a little taste of everything but specialist in no one thing.
When you drill down into a subject area you quickly realise how shallow they really are and they barely scratch the surface of noise assessment. A NEBOSH Diploma is not really a deep enough level of competence to do a noise assessment without further specialist training on top.
Recommended training for competence in noise assessment
I would recommend the Institute of Acoustics Certificate of Competence in Noise Assessment as the one to go for. The IOA courses typically cost something around £1,300 + VAT.
IOSH also do them but if you want to be competent in noise then always better to go to the people who are specialist in noise. It is normally around a one week course.
✅ Make sure the training is good enough to be ‘competent’ to do it.
Standards for noise meters used in a noise assessment
There are a few bits and bobs here and if you are looking to get a noise meter for a noise assessment at work, make sure it meets these.
Noise meters used in a noise assessment must be ‘integrating’.
HSE’s L108: Noise meters must be integrating
Cheap noise meter
That means they don’t only show the immediate dB(A) level but can average it over the period of the entire measurement - i.e, if a machine’s cycle is 20 minutes then the noise meter needs to be able to measure for the entire period and give you the average and peak levels for that. A cheap noise meter doesn’t do that.
Meters for anything from £30 to around £500 are not going to be Integrating and therefore cannot be used for a noise assessment in the workplace.
In their listings they often say ‘fast’ or ‘slow’ but that is not a synonym for ‘integrating’. The meter shown here also claims in its listing to be ‘suitable for use in factories’ but it carefully doesn’t say it can be used for noise assessments.
✅ Make sure the noise meter you choose is ‘integrating’.
✅ ‘Suitable for use in factories’ doesn’t mean suitable for a noise assessment itself.
Noise meters must be Class 1 or Class 2
The ‘class’ of a noise meter means how accurate it is. Class 0 is lab standard, and then Class 1 or Class 2 are what we use in workplace noise assessments.
Noise meters used in a noise assessment at work must be at least Class 2 (Class 1 is higher). The cheap noise meters do not meet this standard, or any kind of standard really.
HSE’s L108: Noise meters must be Class 1 or Class 2
✅ Make sure the noise meter is certified as at least Class 2
Phone apps
A noise assessment done via a phone app is a simple ‘no’.
Getting hold of a proper noise meter - buy or rent
Be prepare to spend a few quid. The most basic of basic compliant noise meters will cost you something like £730 + VAT. That’s for a Class 2 integrating noise meter, and they go up in price from there. The ones I use cost something around £2,500 each.
You then need a calibrator as well and for a very basic Class 2 integrating meter and a calibrator as a kit together you will pay something like £950 + VAT.
You may also need wearable meters, and they need a reader/calibrator unit with them as well. They are pricey at around £500 each.
Renting noise meters is a possibility
Rather than buying, you could a rent a noise meter and that can be much more cost-effective for someone who will rarely use a noise meter.
Noisemeters.co.uk’s current price a the time of writing for a one week rental of their most basic but suitable noise meter is about £164 + VAT.
Alternatively, noisemeters.co.uk also rent a kit including a better noise meter, five wearable dosemeters and the on-site calibrator and those are around £430 + VAT for one week.
Daily calibration check is needed as well as the main calibration
A calibration check must be done every day before and after any measurements. This is not the same as the annual or bi-annual calibration certificate.
For a hand-held meter you will need an external calibration unit which is slotted onto the end of the noise meter before and after each set of noise measurements.
HSE’s L108: Calibration check must be made every day
If you are getting a noise meter for a noise assessment at work, you will need to also get hold of one of the external calibration units as well.
The ‘main’ annual or bi-annual calibration is also needed, the HSE say a noise meter shall be independently calibrated at least every two years.
✅ Make sure the noise meter has its main calibration and it is in-date.
✅ Make sure you have a calibration unit for the daily on-site calibration check.
✅ The calibration unit must also be within its own main calibration and certified as such.
Doing a noise assessment yourself - summary checklist
Despite how it may sound, I am not trying to make out only the Special Ones should do a noise assessment, but I am trying to stress that it is not as simple as buying a cheap noise meter, Amazon, pointing it at your tools and seeing what it says.
As a checklist for making sure a noise assessment ‘is suitable and sufficient’, make sure it covers all these as a minimum:
✅ Measures average dB(A), peak dB(C) and average dB(C).
✅ The outcome is the noise people receive, not always the same as a machine’s noise.
✅ Calculate daily average exposures for each person at risk.
✅ If longer shifts are worked, calculate using that, and also routine overtime.
✅ Assess current PPE - is it suitable for the noise, not too low and not too strong.
✅ Is specific PPE needed for specific use-cases, e.g. forklift drivers.
✅ Identify who needs to be included in noise training programmes.
✅ Identify who needs to be included in health surveillance (not the same criteria as training).
✅ Identify potential noise reduction measures.
✅ Identify what signage is needed in the workplace.
✅ Are any personnel at risk due to poor hearing? (Also links to health surveillance).
✅ Make sure you detail competence for undertaking the noise assessment.
✅ Use a Class 2 or Class 1 noise meter, plus dosimeters if needed, and calibrate on-site.
✅ Be clear that a noise assessment is not the final noise risk assessment.
Have a search through the ‘Articles’ section of this website as there are loads of nuggets of useful information on the various parts of this such as:
Noise assessments vs noise risk assessments
dB(A) and dB(C) in noise assessments
Noise assessment for non-routine jobs
How to choose the right hearing protection based on your noise assessment
The health surveillance element of a noise risk assessment
Make sure you know your dB(A) from your dB(C), your 3 dB changes, your NRR from your SNR, what health surveillance is, how long to measure noise for, your peak dB(C) from your average dB(C), how a shift length of more than eight hours impacts on the daily limits, and so on. Make sure you have the right type of noise meter and that you’ve done some kind of specific training in noise assessment. If you can cover all that, then crack on with it, you are good to go.
Getting the correct noise meter is vital, buying or renting, and please don’t fall for the cheapo ones on places like Amazon as they are not compliant.
FAQ: Doing your own noise assessment
Can I do my own noise assessment in-house or do I have to get someone in for it?
As much as my bank manager would thank you for it, there is nothing saying you have to get a specialist in to do a noise assessment. L108 Controlling Noise at Work (Third Edition) specifies what must be covered off in terms of competence, equipment and content so if you can meet that then there is nothing stopping it. The article above tells you what training to get and where you can get equipment from.
Why do I need to pay a lot of money for a noise meter when there are ones on Amazon for £150 or so?
Those meters are little more than glorified phone apps frankly and are not sufficient for a noise assessment. They do not meet the required standards for a noise meter used in a noise assessment, usually have no on-site calibrator, are not Class 1 or 2, and are not integrating.
Can I use a phone app to measure the noise in my workplace?
You can, but it is useless as a noise assessment. Phone apps are not only inaccurate, they are also inconsistently inaccurate meaning they are out by various degrees over time. They are also uncalibrated, have no on-site calibration, and often don’t average out the noise over the exposure time (what we call ‘integrating’), and often don’t measure average dB(C), if they do dB(C) at all.
More information on noise assessments at work
