Doing your own noise assessment
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. Noise assessments quickly get very murky so you really do need to know your onions before diving into it.
I had an interesting conversation with a company owner in the Tottenham area of London about this earlier this week. He has had the HSE in and the Inspector told him he needed a noise assessment, which is common enough, but then told him he would be fine with a cheap noise meter off Amazon and then a quick glance at the Ready Reckoner in L108.
In 30 years of noise assessments, including 20 years doing it on a consultancy basis, this is the first time I’ve heard of an HSE inspector coming out with this and the exact opposite is normally true. I did a noise assessment only a few weeks ago for a client elsewhere in the UK where a noise assessment had been done using the same kind of cheap noise meter, then the HSE turned up and jumped on them for it being insufficient. They were charged a Fee for Intervention and follow-up enforcement action threatened.
The issue in Tottenham is that what the Inspector is saying is, to put it bluntly, utter and absolute cobblers. In this instance she may be happy with that approach but Inspectors move on and the next one who rocks up at the door will more than likely have a far more accurate idea of what is ‘suitable’ for a noise assessment. They will then declare an in-house thing with a cheap meter ‘insufficient’ and get their best irate look on their face. I suspect the Inspector herself in this case hasn’t got much of a clue about noise assessment to be even suggesting this to a business owner.
Telling him he can use a cheap noise meter from Amazon and then look at the HSE’s Ready Reckoner is wrong on so many levels:
He had no idea of the difference in decibel scales, so no understanding of dB(A) or dB(C), and nor should he, he’s got his own job to do.
He didn’t appreciate the averaging impact of dB(A). I see this a LOT where people attempt a noise assessment themselves and 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.
The Ready Reckoner he’d been pointed at is all about dB(A) but ignores dB(C) - he had no idea about dB(C) or the separate limits for that. The Ready Reckoner is a bit of fudge tool the HSE came up with to help with one single element of noise assessments, not a solution for all of it.
A cheap noise meter on Amazon is not compliant with L108, not even close. It is not integrating, it is uncalibrated. ‘Calibrated’ in this instance means you check the calibration each and every day on the site before doing a measurement, not a separate annual or bi-annual calibration certificate supplied with the noise meter itself. You do that with a separate calibration unit.
He had no idea about average dB(C) as a means of assessing hearing protection - this is what is used for SNR calculations. A cheap Amazon noise meter doesn’t even give you average dB(C).
If an assessment was done in this way it doesn’t come remotely close to being done by someone ‘competent’, as required by L108.
So, if you are thinking of doing a noise assessment yourself, these are the things to watch out for and make sure you have covered off. All the references below are to ‘L108’, which is the HSE’s laws and rules governing noise assessment at work.
Noise assessments must be done by someone ‘competent’
Noise assessments also need to be done by someone ‘competent’, which means someone suitably trained, qualified and experienced in noise assessment at work.
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 screw it up rather than just a little bit of a screw up. Both those are generalist, and very good, Health and Safety qualifications - I myself have both - 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.
I would recommend the Institute of Acoustics Certificate of Competence in Noise Assessment as the one to go for. The courses typically cost something around £1,300 + VAT.
The standards for a noise meter 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 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. 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 to be suitable for use in factories but it carefully doesn’t say it can be use for noise assessments.
Noise meters must be integrating
Noise meters must be Class 1 or Class 2
The ‘class’ of a noise meter is basically how accurate it is. Class 0 is lab standard, and then Class 1 or 2 are what we use in workplace noise assessments.
Noise meters used in a noise assessment at work must be Class 1 or Class 2. The cheap ones do not meet this standard, or any kind of standard really.
Noise meters must be Class 1 or Class 2
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 noise meter before and after each set of noise measurements.
Calibration check must be made every day
If you are getting a noise meter for a noise assessment at work, you normally need to also get hold of one of the external calibration units as well.
The ‘main’ calibration is also needed, and the HSE say a noise meter shall be independently calibrated at least every two years.
If you do want to do a noise assessment in-house
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 off Amazon, pointing it at your tools and seeing what it says.
Firstly, make sure you are trained as noise can become very murky and complex very quickly.
Get hold of a proper noise meter - buy or rent
Be prepare to spend a few quid. The most basic of basic compliant sound meter will cost you something like £730 + VAT. That’s for a Class 2 (the lower of the classes) integrating 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 you will pay something like £950 + VAT.
You may also need wearable meters, and they need a reader/calibrator unit with them as well.
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 with a better noise meter and a few wearable dosemeters as well, and the on-site calibrator, and those are around £430 + VAT for one week, with a decent noise meter and five wearable ones.
By the way, a noise assessment done via a phone app is a simple ‘no’.
Some other advice on actually doing a noise assessment
Have a search through the ‘Articles’ section of this website as there are loads of nuggets of useful information there, for example:
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
Summary on doing a noise assessment in-house
Don’t get me wrong, I am not saying people shouldn’t do a noise assessment in-house, but only where they know what they are doing. Noise is not as simple as it may appear.
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 8 hours impacts on the daily limits, and so on. If you know that, then crack on with it, you are probably good to go.
Getting the correct noise meter is vital, buying or renting, and do not fall for the cheapo ones on place like Amazon as they are not compliant.
