Answering a noise refusal with BS 4142 evidence

A noise refusal is usually answerable, because it is almost always a refusal about evidence rather than about principle. The reason will say the proposal would cause unacceptable harm to residential amenity through noise from plant or activity, and it will have been written by a planning officer repeating an environmental health objection. Winning a noise refusal planning appeal means doing properly what was not done first time: measuring the background sound level at the right place at the right hour, predicting the specific sound level of the actual equipment, applying BS 4142 character corrections honestly, and offering an attenuation scheme that can be conditioned and verified.

What a noise refusal reason alleges

Strip the planning language away and the allegation is one of three things. The sound from the proposed plant or activity would be audible and intrusive at a neighbouring dwelling. The assessment submitted was inadequate, so harm cannot be ruled out. Or the mitigation relied on is unproven, undrawn or unenforceable.

The second and third are the common ones, and they are good news. A refusal for inadequate evidence is cured by better evidence. A refusal on principle, where the authority says no acoustic design could make the use acceptable in that location, is much harder and sometimes points towards a different site.

Read the officer's report alongside the environmental health consultation response rather than relying on the decision notice wording, which compresses several objections into one sentence. The method for taking a refusal apart is set out in the guide to reading a refusal notice and turning it into a plan.

Background sound measurement and its timing

This is where most weak assessments fail. BS 4142:2014+A1:2019 compares a rating level against the background sound level, expressed as LA90,T, so the background measurement is half the answer and it has to be defensible.

Four things get challenged:

• Position. The microphone belongs at the most affected facade or in the garden of the nearest sensitive property, not at the site boundary or in a car park where traffic props the background up.
• Time. The reference time intervals are one hour during the day, between 07:00 and 23:00, and 15 minutes at night, between 23:00 and 07:00. The relevant period is the quietest one in which the plant will run, which for a restaurant extract fan means 22:00 to 23:00 on a weekday rather than lunchtime.
• Duration. A single 15-minute sample is not enough to show the typical background. Unattended monitoring across several days, with the measured data presented as a time history, settles the argument before it starts.
• Contamination. Road traffic, aircraft, birdsong and an adjacent building's existing plant all inflate the background. Say what was excluded and why.

A deliberately low background measured during a quiet spell helps nobody, because it narrows the headroom available. An honest, well-documented background is the foundation of everything else.

Rating level, corrections and context

The rating level is the specific sound level of the source plus corrections for the character of the sound. Those corrections are where the acoustician's judgement shows, and where an environmental health officer will push back hardest.

BS 4142 then gives an indication rather than a pass mark. A rating level around 10 dB above background indicates a significant adverse impact; around 5 dB above indicates an adverse impact; at or below background, a low impact is indicated. Context has to be taken into account alongside the arithmetic, including absolute sound levels, the character of the area and the sensitivity of the receptor.

Pair that with the Planning Practice Guidance on noise and the Noise Policy Statement for England framework of effect levels, where LOAEL is the lowest observed adverse effect level and SOAEL the level above which adverse effects become serious. Those two documents are what the planning balance is struck against, while BS 4142 supplies the numbers. An appeal statement that gives only the decibel difference, without placing it in that policy framework, leaves the inspector to do the translation.

Internal levels matter too. Predicted levels in neighbouring bedrooms and living rooms, assessed against the BS 8233:2014 guideline values, are often more persuasive to a lay reader than an external rating level, and they are the test a future statutory nuisance complaint would be judged against.

Attenuation design and its evidence

An appeal is won on a drawn, specified and costed mitigation scheme, not on a promise that attenuation will be provided.

Specify the plant by make and model with manufacturer sound power data. Show the acoustic enclosure or louvre with its insertion loss. Where a barrier is relied on, draw it in section with the source and receiver heights so the screening can be checked. Where the solution is operational, for example limiting deliveries to daytime hours or locking out the night-time setting on a condenser, say how that is secured.

Then show the resulting rating level at each assessment position with the mitigation in place, and show it without, so the inspector can see the mitigation doing work.

One practical point: attenuation that compromises airflow does not get installed. Specify the enclosure with the fan performance checked, or the contractor will quietly remove the silencer on commissioning and the condition will be breached from day one.

Conditions offered instead of refusal

Offer the condition wording. A noise condition that works has three parts: a numerical limit, a requirement to install the approved scheme before the use starts, and post-installation verification by measurement.

A workable form is a limit expressed as a rating level not exceeding the measured background level at the nearest noise-sensitive facade, determined in accordance with BS 4142:2014+A1:2019, coupled with a requirement to submit a verification report within a stated period of the plant being commissioned. Avoid conditions phrased as no noise being audible at the boundary, which are not enforceable and which inspectors dislike.

Where the concern is activity rather than plant, a management plan condition covering delivery hours, external seating hours, waste handling times and staff training is usually the proportionate answer, and it travels with the land to future occupiers.

Environmental health officer positions

Environmental health officers are not opponents, and the single most useful step after a refusal is a meeting with the one who objected. Ask what measurement would satisfy them, at what position, over what period, and what limit they would accept in a condition.

Two tactical points. First, if the application was heading for a noise refusal and the acoustic work was not ready, withdrawing was often the better move, as set out in the guide to withdrawing an application before refusal. Second, the Framework's agent of change approach puts the burden on a new noise-sensitive development arriving next to an existing business, so an occupier facing a refusal caused by recently built flats should say so explicitly.

Presenting acoustic evidence on appeal

A section 78 appeal against refusal of a commercial application must normally be lodged within six months of the decision, and written representations suit a single-issue noise case well.

Structure the statement of case around the refusal reason. State the allegation, set out the new evidence, show the rating level with and without mitigation, address the environmental health response point by point, and offer the conditions. Put the full acoustic report in as an appendix and keep the statement readable without it.

Attach the drawings. An enclosure detail and a section through the barrier do more work than three pages of prose. Where a neighbour has objected, expect their representations to be before the inspector too, which is the position described in what objectors can do once a planning appeal starts.

A Noise Impact Assessment for an appeal needs a qualified acoustician for the measurement and prediction work, and councils expect a suitably qualified author. A structured draft helps assemble the planning case around that technical work rather than replacing it, and you can start one by entering your postcode on PlanScope.

This is general guidance, not legal advice. Check the position with your local planning authority or a qualified professional before relying on it. PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval.