How to apply for a noise impact assessment



Do you need a noise impact assessment for your plant? Paul Doyle, Technical advisor and acoustics lead of the Environment Agency, explains how to make the application process as quick and simple as possible.

When it comes to safeguarding our environment, good regulation is essential. But it can be hard to get every aspect of an application right – and we appreciate that.

So, let’s shed some light on the processes behind commissioning a noise impact assessment (NIA) and discover how to make the whole process as quick and easy as possible. After all, good communication between applicants and acoustic consultants is crucial in ensuring a robust NIA.

The first step is to establish if you actually need to prepare an NIA at all since some applications do not. You can check this using our risk assessment guidance here. In 2024, our team will be launching a public screening tool, which will identify whether an NIA is required. We will let industry know when this is available. In the meantime, you can also get in touch with us for some basic (free) or enhanced (paid-for) pre-application advice here.

Paul Doyle
Technical advisor and acoustics lead of the Environment Agency Paul Doyle.

Our team has developed some documents to assist at the basic pre-application stage, which you can request by emailing: We recommend using our enhanced service if your site operates 24/7, is of high public interest or has other complexities, such as a history of noise complaints.

If you choose to hire an acoustic consultant, they must have experience using the British Standard BS 41421 – methods for rating and assessing industrial and commercial sound. A suitable consultant will have a postgraduate qualification in acoustics or a related subject and be a member of the Institute of Acoustics.

By clearly defining the scope of the permit application and providing the consultant with all the information you have, you will receive a better NIA as a result. Always advise them that the NIA will support an environmental permit application, as our requirements are different from those for planning, which is what consultants deal with most often.

Always discuss the site with the consultant before they do any work. As well as existing receptors, any planned residential developments need to be considered, as they may affect your ability to comply with your permit. It’s also good to ask the consultant to provide their survey methodology. Remember: it’s being done on your behalf, so you should be happy it meets your needs.

Be cautious of data that covers the “bare minimum” requirements from BS 4142.

Be cautious of data that covers the “bare minimum” requirements from BS 4142, as this is not enough on which to base an assessment. Remember, the survey should cover the site’s operating periods; a survey on a Monday morning will not represent the weekend sound climate, for example – this is a common issue.

For active sites with variation applications, background survey data should not include the operational site – another common issue. You can help the consultant by arranging a site shutdown where feasible. They can propose alternatives if this is impractical. You can also help by identifying noise-generating processes and sound sources and, if you have the manufacturer’s acoustic data, send it to them.

If you already operate a site, the consultant can make measurements of sound levels from the existing plant. Our team often requests missing raw survey data and noise-modelling files. Ask the consultant for these so you can submit them with your application.

An assessment outcome hinges on two things: context and uncertainty.

An assessment outcome hinges on two things: context and uncertainty; read the NIA and check both are present before submission. You should understand the scale of the BS 4142 impacts being shown. We will not grant a permit where there is a risk of a significant adverse impact. Where an NIA shows them, your site must be working to appropriate measures.

Where the consultant has recommended mitigation to meet our requirements, you should agree on any proposals. If you receive any Schedule 5 requests from us, discuss them with the consultant to agree on a way forward. They should only reply on your behalf with your agreement. We recommend you are present at any meeting so you understand the issues and the implications this may have on the permit determination.

More noise and vibration guidance for NIAs is available here and technical requirements guidance for NIAs is available here.

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