ProPG: the two stage approach to noise near new homes
ProPG runs an initial site noise risk assessment then a four element full assessment. The element reports most often skip is the one officers look for first.
ProPG planning and noise sets out a two stage approach for new residential development affected by transport noise: an initial site noise risk assessment that places the site in one of four risk categories, followed, where the risk is more than low, by a full assessment built on four elements. The guidance was published jointly by the Association of Noise Consultants, the Institute of Acoustics and the Chartered Institute of Environmental Health, and most environmental health officers in England now expect residential noise evidence to follow it.
It is guidance rather than a standard, and that distinction matters. ProPG describes a process for reaching a recommendation, and a report that produces numbers without showing the process has missed the point of it.
Stage 1: the initial site noise risk assessment
Stage 1 asks a simple question early: how noisy is this site, and does that change what should be built here.
It uses free-field daytime and night-time noise levels across the site, from measurement or from calculation where a road or rail source can be modelled reliably, and plots them against the risk categories in the guidance. The output is a category and a recommendation about whether the scheme should proceed and, if so, what work follows.
Do it before the layout is fixed. That is the whole purpose of a stage that sits before the design work, and running it after the drawings are complete reduces it to a label attached to decisions already taken.
Where a site is affected by industrial or commercial sound rather than transport, ProPG is not the right framework and BS 4142 applies instead. Sites affected by both need both, reported separately and drawn together in the conclusion.
The four risk categories and what each triggers
| Category | What it indicates | What follows |
|---|---|---|
| Negligible | Noise is unlikely to be a determining issue | Confirm the position and record the reasoning |
| Low | Development is likely to be acceptable | Good acoustic design still expected and evidenced |
| Medium | Noise needs to shape the scheme | Full Stage 2 assessment with design iteration |
| High | Development should normally be avoided | Full assessment plus clear justification for proceeding at all |
The categories are defined against noise level ranges set out in the guidance, so read the current document for the figures rather than working from a summary table in an old report.
A high risk finding is not an automatic refusal. It is a signal that the scheme has to work considerably harder, and that the local planning authority will weigh residual effects against the benefits of the development.
Element 1: good acoustic design as a process
This is the element reports skip, and the one officers look for first.
Good acoustic design means using layout, orientation, building form and internal planning to reduce exposure before reaching for glazing and ventilation specifications. In practice that means putting the least sensitive uses towards the source, using perimeter blocks or buildings to screen quieter courtyards, orientating bedrooms away from the road, and arranging flats so that habitable rooms have at least one facade with a lower exposure.
The evidence is a narrative of what was considered and what changed. Show the layout options tested, the effect of each on exposure, and the reason for the one chosen. A single layout presented with mitigation bolted on does not demonstrate the process, however good the final numbers are.
Where the site cannot be designed around the noise, say so and explain what remains.
Element 2: internal noise level guidelines
Element 2 sets internal targets, drawing on BS 8233:2014 and related guidance: broadly 35 dB LAeq,16h in living rooms during the day, 30 dB LAeq,8h in bedrooms at night, and attention to individual noise events measured as LAFmax at night where the source produces them.
Two things trip reports up here.
The first is the ventilation assumption. Internal levels achieved with windows closed are only meaningful if the dwelling has an alternative ventilation route that does not reintroduce the noise. Set out the ventilation strategy alongside the acoustic performance, with the attenuation of any acoustic vent or mechanical system stated.
The second is overheating. A design that relies on closed windows for acoustics and openable windows for cooling contradicts itself. Part O of the Building Regulations and the CIBSE TM59 methodology approach the same building from the other direction, so run the Overheating Risk Assessment and the acoustic work together rather than sequentially. Environmental health officers and building control now check the two against each other.
Element 3: external amenity areas
Gardens, balconies, terraces and communal amenity space are assessed against the external guideline range in BS 8233, with the guidance acknowledging that higher levels can be unavoidable in urban locations where other benefits apply.
Be specific about which spaces are being assessed and why. A balcony on a noisy facade serving a flat that also has access to a screened courtyard is a different case from a single private garden facing a dual carriageway.
Where the guideline cannot be met, say so plainly, describe the mitigation attempted, and set out what the residents will actually experience. Officers respond better to an honest residual effect than to an assessment that quietly assesses the quietest corner of the site.
Element 4: other relevant issues
The fourth element gathers everything the first three leave out: compliance with the development plan's own noise policies, the magnitude of change the development creates, the acoustic design's effect on the wider area, and any wider planning benefits weighed against residual adverse effects.
This is also where the framework in the Noise Policy Statement for England fits, with its distinction between the lowest observed adverse effect level and the significant observed adverse effect level, and the requirement to avoid the latter and mitigate the former.
Agent of change belongs here too. Where the site sits next to an existing venue, workshop or transport operation, the responsibility for mitigation sits with the incoming residential development.
Writing an acoustic design statement
The acoustic design statement is the output of the whole process and the document the council reads.
- Describe the site, the sources and the survey or modelling, with the data appended.
- State the Stage 1 risk category and the reasoning.
- Narrate the design process, showing the options tested and the effect of each.
- Give the predicted internal levels by room type, with the ventilation strategy and its acoustic performance.
- Give the external amenity assessment for each type of space.
- Address the fourth element, including local policy, the change in the acoustic environment and any residual effects.
- Recommend conditions in draft, covering the acoustic specification and post-completion verification.
A statement structured that way is far easier to accept than a Noise Impact Assessment that reports levels and stops. For the section by section detail of how ProPG and BS 8233 sit together in a report, the companion piece on ProPG and BS 8233 report sections goes further.
This is general guidance, not legal advice. Acoustic assessment for planning should be carried out by a suitably qualified acoustician, and for specialist technical reports qualified professional input may be required.
To see what else a residential site near a busy road is likely to need, browse the PlanScope report types.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.
Frequently asked questions
When should the initial site noise risk assessment be done?
Before the layout is fixed. The whole point of a stage that sits ahead of design is to let the risk category shape the scheme. Running it after the drawings are complete turns it into a label attached to decisions already taken, and officers can usually tell which happened.
Does a high risk category mean refusal?
No. It signals that the scheme has to work considerably harder and that the authority will weigh residual effects against the benefits of the development. A high risk site needs a full assessment, a demonstrable design process and a clear justification for developing there at all.
Does ProPG apply to industrial noise?
No. ProPG addresses new residential development affected by transport noise. Sound of an industrial or commercial nature is assessed under BS 4142 instead. Where a site is affected by both, report each under its own framework and draw the conclusions together at the end rather than blending the methods.
How do noise and overheating requirements interact?
They pull against each other. Internal noise levels achieved with windows closed only work if there is an alternative ventilation route, and Part O overheating compliance often assumes openable windows. Run the acoustic work and the overheating assessment together, because building control and environmental health now check one against the other.
What goes into an acoustic design statement?
The site and sources, the survey data, the Stage 1 risk category, a narrative of the design options tested and their effect, predicted internal levels by room type with the ventilation strategy, the external amenity assessment, the wider policy and residual effects, and draft conditions covering specification and verification.
Sources and further reading
This article is general guidance about the planning system in England and, where stated, the rest of the UK. It is not legal or professional advice. Check your local planning authority’s validation requirements and take professional advice for your specific site.