Choosing the right noise assessment equipment

Get a coffee before you go any further as in this subject lies a preponderance of choices.

Firstly, you have two categories, portable equipment and fixed equipment and for the purposes of a noise assessment we are talking about portable stuff here, so are not talking about fixed signs which illuminate when it get noisy, etc. 

As a wee diversion, should you be wanting things like fixed signs which continually monitor noise levels and illuminate when it is getting too high then head over to the fine people at noisemeters.co.uk as they have a range of these which can delight any purchaser in their Noise at Work section. But, they are not for use in noise assessments. 

So, back to hand held meters for measuring noisy stuff. Here are some tips and advice on what to invest your money in. Don't forget, if you don't want to buy them or the stingy accounts-types won't spend some pennies then again, those fine people at Noisemeters.co.uk rent them out for short-term use - see below for guidance on deciding between renting and purchasing. There is no connection between this site and Noisemeters, just that I've used them over many years myself and like them.

Class 1, Class 2, etc. noise meters

The first choice is how good a noise meter do you need? There are various levels of noise meter with them being categorised on how accurate they are.

  • Class 0 is the mutt's nuts. This is laboratory-reference standard and you definitely don't need this for a noise risk assessment. Nor do you want to spend the money these things cost.
  • Class 1 or Type 1 is good, very good. People who do a lot of noise assessments such as noise consultants should be using these. I'd also recommend large factories use these noise meters purely as there will be a lot of employees at risk.
  • Class 2 or Type 2 is plenty good enough and this is the standard specified in the L108 noise bible (page 88). This is good enough for a noise at work risk assessment.
  • Basic or Type 3 non-integrating meters do have their uses but they are not good enough for a noise risk assessment. Think of them as like holding a wet finger up to work out if it is windy while Class 1 are more like a nice posh whirly-fan anemometer thing that gives accurate windspeed readings. These cannot be used for noise assessments but there are still some uses for them.

Just remember - if you see 'non-integrating' anywhere in the description then they cannot be used for a noise assessment so avoid them and you'll not go far wrong.

There are also apps for your phone. Consider these as somewhere below the bottom category at best, so they can have some limited uses but don't rely on them for a proper noise assessment.

As a side-note, if you see something somewhere saying 'Type 1', 'Type 2' etc. then it's reasonable to interpret this is 'Class' - it's mildly different but not in any significant way and Type was the old system for categorising noise meters, replaced by Class. Here is a page on Class vs Type should you want to read up on it.

Class 1 and Class 2 are expensive but they are worth it. And check out, yes, you've guessed it, Noisemeters.co.uk again as they do sell some refurbished units so you can get the top quality at a slightly reduced price if you want.

Summary: Buy a Class 2 or Class 1 integrating noise meter.

Noise meter battery type

A rather specific subject but one arising from my own experience - for hand held meters I'd recommend you always buy a noise meter with swappable batteries and not built-in rechargeable batteries. The only reason for this is that no matter what type of battery you go for, your hand-held meter is guaranteed to die in the middle of an assessment at some point. Usually at the most inconvenient time. If you have one with swappable batteries then it is no problem to pop some new ones in and off you go again, whereas one with rechargeable batteries is a right pain in the bum as you are stuck until it can be recharged.

For wearable meters like dosebadges though, rechargeable is fine as they are pretty much limited to that by size.

Summary: Buy noise meters with replaceable batteries rather than built-in.

Key measurements

If you can, get a noise meter which measures all these at once:

  • Average dB(A) over the period of the measurement
  • Average dB(C) over the period of the measurement
  • Peak dB(C) during the measurement
  • Octave band

There are a lot of noise meters which will measure each of these separately and they are perfectly fine, indeed I used them for years, but that does mean measuring the same job twice. If you have say 50 measurements to make and 15 minutes per measurement, the last thing you want is to double up on each measurement if you can help it. If you get a meter which records everything at once then that is frankly bloody marvellous and you should keep it on a pillow on a small altar in your office for it is something to worship as it means one measurement only is needed. 

If costs restrict you to one which does the dB(A) and dB(C) things and then the Octave Band stuff separately then so be it and no problem. Also, if costs are really tight, get a hand held meter over wearable meters every time. Here is a page on why - it's worth having a read through this if you are thinking of buying meters or getting a consultant in.

Summary: Make sure the noise meter covers the minimum measures above.
Summary: If costs are tight, a hand-held meter is more important than wearable.
Summary: Hand-held is better than wearable in most situations.

Basic meters and phone apps

There is a use for these even though they are not always massively accurate and this is for a rough and ready indication of whether a noise assessment is needed at all.

Basic noise meter

A basic meter may be a hundred quid or so and an app only a few quid. If you have never done a noise assessment for the site then one of the first questions is 'do we actually need to do a full noise assessment'. You may decide you do need it based on manufacturer's data, or based on the fact it is simply bloody loud in there, but some times having a rough and ready indication of the levels can be handy. 

As a very rough rule of thumb, as apps and these basic meters (Type 3) may not be massively accurate, if they come in around 80dB(A) then I would recommend a proper noise assessment is done as 80dB(A) on a meter with a variation of say +/- 4 to 5dB(A) could mean the levels are reaching the magic 85dB(A) figure.

And before you ask, can I recommend a phone app? Aye, I can. The one I've used on general health and safety risk assessments to help determine if I think a proper full noise assessment is needed is one called SPL Pro. When comparing it to a noise meter costing several thousand quid it remained fairly close and gives you dB(A) and dB(C) levels. Given the price difference between them I would even say that SPL remained disappointingly close to the posh meter! A fiver well spent. 

Summary: Cheap meters are for rough indication only, not noise assessments 

Some noise meter suppliers

This really comes down to personal choice. I always go through Noisemeters.co.uk (you'll be unsurprised to know by now) but within that do tend to choose Pulsar or Cirrus equipment. I've used a Pulsar 30 Type 1 hand held meter all over the place in some fairly extreme environments, from supermarket sub-zero cold stores at about -20C, to ships out at sea, hot and steamy food factories to bouncing fire engines and the meter has kept on working. The only time it had a real problem was when I dropped it and it landed pointy-end down and damaged the microphone. That was an expensive repair so I don't recommend doing that

Dosebadge

For wearable measurements I prefer cableless designs such as these dosebadges. There are no buttons for anyone to fiddle with and no cables to get caught anywhere meaning the result is more likely to have better accuracy and less subject to interference. 

Rent or buy noise meters?

This really comes down to how often you are thinking you will be using your noise meters. Here's a rough suggestion for how to work it out. 

  1. Have a ponder on how many days you think you will need to do decent noise measurements for your workplace.
  2. Look at what the rental cost would be for that number of days. 
  3. Look at the purchase price of a decent hand held meter, calibrator and maybe three or four personal wearable meters (dosemeters). 
  4. Get a quote for how much it will be to have them all calibrated (every two years remember, it doesn't have to be every year). 
  5. Add up your purchase and calibration prices.

You will probably be looking at something like every three years to do a full noise assessment for your site so you have that rental cost every three years. If you have say a ten year lifespan of the meters you are looking at three times the rental costs compared to the purchase and calibration costs. That will give you a rough indication of which is financially more cost effective and will make the accountants very happy, and these are not people who are naturally predisposed towards happiness, filled with gloom as they are over their life choices which caused them to end up becoming accountants.

Other rent vs buy considerations

There is one big advantage to having purchased your own noise meters, and this is the ability to respond quickly to changes in the workplace with no additional costs. For example, if the production department introduce new machinery or maybe relocate existing machinery, build a new wall, knock a wall down, etc. you can quickly update your assessment with new measurements.

If the site changes hours of work and working patterns such as job rotation by the way, you do not automatically need to actually measure the noise again. You could simply take the existing measurements and recalculate exposures for maybe prolonged exposures in one area and reduced exposures in another. That is a job that doesn't necessarily mean actually remeasuring.

So, if your production chaps and chapesses are always buggering about with changes to the facility then that is another factor in favour of buying, whereas if it stays fairly static then the balance is more back towards a pure financial decision.