Noise Assessments and the law

Noise surveys or noise assessments are used where noise is suspected to be a hazard and risk assessments for noise are required by the Control of Noise at Work Regulations 2005. One of the first questions employers have to decide is whether they need a noise survey in the first place, after all, there's no point in paying someone to do a noise assessment if there is no risk present. This initial decision is a bit of guesswork on the part of the employer but the following are useful signs to look out for:

  • People have to talk loudly to be understood by someone 2m away. I SAID, PEOPLE HAVE TO TALK LOUDLY...
  • Employees complain that their ears 'ring' when they go somewhere quiet.
  • Do your employees comment on people at home complaining that they have the TV or radio too loud - especially if to them it sounds normal.
  • Information from equipment manufacturers such as a plate fixed to the equipment itself or values given in the accompanying documentation. This will not tell you exactly what noise exposure the operator gets but is a useful guide.

If you think any of these may apply to your workplace or to people working in the areas in question then a noise survey is needed to measure the actual levels present.

Free noise guidance

Free guide - how to choose the right hearing protection Download our free guide: Choosing the right hearing protection (pdf)
Guide to noise regs Lower down the page, a guide to how often you need to re-do the noise assessment
Guide to noise regs Some info on competence to do noise assessments if you want to do them in-house
Guide to noise regs Below: Chart summarising the 2005 noise regs. Click for larger / clearer version

Chart of the 2005 noise regulations

Reviewing / renewing your noise assessment

A common question is 'how often do I need to re-do my noise assessments?'. Firstly, there is no 'thou shalt do it every 12 months' requirement.

Once you have done a proper noise assessment, the need for renewing or updating it is down to a decision as to whether you have reason to believe that it is no longer accurate or valid. For example:

  • Has some equipment been changed or moved around in the workplace
  • Has the construction material of a wall changed - a harder surface laid over it for example.
  • Have you increased the usage of the machines so more are running at once, or they are running for longer.

If you have a noise assessment in place, sit down and have a think about these issues, and anything else which you think may have caused the measurements in the noise assessment to become invalid. If you believe everything is the same and there is no problem then you are done. We would recommend that you document this review giving a paper trail should you ever need to prove to an inspector, insurer or other person that you have looked at it.

The one additional recommendation - and this is just a recommendation from us - is that every few years, say four or five, you get the complete assessment re-done from scratch as noise levels may have changed via natural wear and tear in the machinery. It is amazing just what a difference to noise levels one worn bearing or one newly replace motor can make.

Competence for noise assessment

One point to be clear on - noise assessments should be undertaken by someone who knows what they are doing. In-house personnel can be used but please please make sure they know the subject - and not from attending a simple one day course. If you want to send someone on a course to be qualified in-house then look at either IOSH's five day course, or the one offered by the Institute of Accoustics (IOA), which is also a five day course at centres around the country. If we had to pick one, we would recommend the IOA course.

Noise can be complicated and does not always follow what may seem to be common sense. If you use someone in-house they must understand concepts such as:

  • 3dB is effectively a doubling of noise energy.
  • We have two machines at an employee's workstation and their exposure is 88dB(A) and both machines are doing the same job and are generating the same level of noise. The plan is to remove one of them with the hope that it will reduce noise levels significantly however removing one of the machines will probably then give us a remaining noise level of 85dB(A).
  • Someone works in an area of 100dB(A) for eight hours and wears hearing protection which reduces their noise exposure to 75dB(A) however they remove the hearing protection for three periods of five minutes through the day to talk to someone. Despite wearing the protection for 7hr 45 mins out of 8 hrs, their noise exposure will increase from 75dB(A) to 85dB(A).

We are not stating this to try and confuse but as a tool to stress that people measuring noise must know the subject. We see a lot of well-intended in-house assessments which are way off accurate when looked at closely - in fact a lot tend to be more of a noise survey (not legally compliant) than a noise assessment (which is what's needed) . We have enough work coming in to keep us busy so aren't wanting to scare people off doing the tests in-house just to generate more work for ourselves, but please, for your own liabilities and value for money on your investment, make sure that the person doing the assessments knows their onions.

(If you are wanting to hire noise equipment for in-house tests, have a gander at

Some useful links for further info on noise law

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