Type or Class of noise meters
This comes down to how good a noise meter you need. There are various levels of noise meter with them being categorised on how accurate they are. Although 'Class' is the newer terminology it is perfectly fine to use 'Type' or 'Class' as you feel like and you will see both in use fair interchangeably around the internets.
- Class 0 is frankly just showing off. This is laboratory-reference standard and you definitely don't need this for a noise risk assessment.
- Class 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 to use this purely as there will be a lot of employees at risk.
- Class 2 is good enough and this is the minimum standard specified in the L108 noise bible. This is good enough for a noise at work risk assessment.
- Class 3 has it's uses, but is not good enough for a noise risk assessment. Think of it as like holding a wet finger up to work out if it is windy, while Type 1 is a nice posh whirly-fan anemometer thing which gives accurate readings. There are some uses for this though.
Here is a page on Class vs Type should you want to read up on it further and it includes the accuracy limits of both categories. It is by Cirrus who make some very good noise meters indeed and know their onions.
Class 1 and Class 2 are expensive - expect to pay a couple of thousand quid or more for a good Class 2 noise meter, and more around £2500 for a Class 1 such as the Pulsar P45 shown here, (both plus VAT). Class 3 meters may only be around the hundred quid mark.
If you want to save some pennies then have a look at Noisemeters.co.uk as they do sell some refurbished units so you can get the top quality at a slightly reduced price if you want. And if you don't want to pay for them, Noisemeters.co.uk also rent them out by the week. And no, this site is not sponsored by Noisemeters, it's just that I have used them many times over the years, including for my most recent noise-toys, and they have always been excellent to work with.
What is the use of Class 3 noise meters?
They do have a use and the best way I can think of describing it is being used in general risk assessments to determine if you may have a noise problem and that a proper full noise assessment is needed.
That kind of rough and ready information can be useful to have so Class 3 meters does have some value for that, just don't use them for a noise assessment itself as they are not good enough and don't meet the minimum standards.
If the accountant or purchasing-suit wants to save money by buying a cheap Class 3 for use in noise assessments then you can explain to them that they are not being wise.
By the way, dosimeters don't have various Classes or Types so you won't see Class 1, Class 2 etc when looking at personal wearable meters, unless it is one of a small special section of them which can act as both a wearable and a hand-held meter in one.