Answering an odour refusal: the extraction case

An odour refusal planning appeal is won on a drawn extraction system, not on an argument about reasonableness. The refusal reason will say the proposal would harm the living conditions of nearby occupiers by reason of cooking or process odour. Behind it sits an environmental health objection, and behind that is almost always one of three gaps: no odour risk assessment, a discharge point too low or too close to a window, or an abatement specification that was described in words rather than drawn and scheduled.

All three are curable. The fourth situation, where the authority says no system could make the premises acceptable because the only available flue route terminates beside bedroom windows two metres away, is not, and recognising it early saves an appeal fee.

What an odour refusal reason alleges

Read the environmental health consultation response rather than the decision notice. The notice compresses the objection into one sentence, and the sentence rarely tells you which of the following is being alleged.

That the proposed cooking type generates odour at a level requiring abatement which has not been specified. That the discharge point is too low, too close to openings, or discharges towards a neighbouring facade. That the airflow rate is inadequate for the kitchen size, so odour escapes through the front door instead of the duct. Or that no maintenance regime has been offered, so even an adequate system would degrade.

Each of those has a specific answer and a specific drawing. Taking the refusal apart into its component allegations is the first task, and the method is set out in the guide to reading a refusal notice and turning it into a plan.

Risk assessment and the sensitivity of receptors

The recognised approach in England is risk-based. Defra's guidance on the control of odour and noise from commercial kitchen exhaust systems works through an odour risk rating derived from the type of food cooked, the scale of the kitchen and the proximity and sensitivity of receptors, and then matches a level of abatement to that rating.

Three inputs drive the rating, and all three belong in the assessment:

• Cooking type. Char-grilling, frying and tandoor cooking sit at the high end. Reheating, steaming and baking sit lower. State the menu and the equipment schedule, because an officer who has to guess will assume the worst case.
• Scale. Kitchen floor area and the extract airflow rate in cubic metres per second, with the calculation shown.
• Receptors. Distance and relative height to the nearest habitable room windows, balconies and ventilation intakes, measured on a drawing rather than described.

Relative height is the input most often missed. A flat above the unit, or a bedroom window on the rear elevation of the building next door at the same level as the discharge, changes the risk rating more than horizontal distance does.

For process odour rather than cooking, the Institute of Air Quality Management's guidance on assessing odour for planning is the usual framework, and in either case councils expect a suitably qualified author. An Odour Assessment is a report type where professional review is strongly advised.

Filtration stages and discharge point design

Abatement is specified as a train of stages, and the number of stages follows the risk rating.

The discharge point does more work than the filters. Vertical discharge at height, at a velocity that carries the plume clear of the building envelope, prevents the downwash that produces complaints. A cowl or a bend at the top of the flue defeats the design and should not appear on the drawing.

Specify the equipment by make and model with performance data. Carbon filtration quoted as a carbon filter will be rejected. Carbon filtration quoted with the media type, contact time, bed depth and the airflow it is rated for will not.

One practical warning: abatement adds resistance to the system, so the fan has to be selected for the pressure drop across a dirty filter rather than a clean one. Systems specified on clean-filter performance get the silencers and filters removed within a year, and the condition is then breached.

Duct routing through a building in other ownership

This is where takeaway and restaurant schemes stall. A ground-floor unit in a building with flats above has no internal route to the roof that does not pass through somebody else's property.

Planning permission can be granted for a flue the applicant has no right to install. It simply cannot be implemented. So deal with the legal position in parallel:

1. Establish ownership of every part of the building the duct will pass through, and of the roof.
2. Serve the correct ownership notice with the application, using certificate B or C where the applicant is not the sole owner, since a wrong certificate can invalidate the application.
3. Negotiate a wayleave, licence or lease variation for the duct route before relying on it in the appeal.
4. Where the building is listed, obtain listed building consent for the flue separately, and expect an internal route to be preferred over an external one.
5. Where no route exists, consider a recirculating system with a high specification abatement train, accepting that authorities treat these cautiously and that the risk rating has to be low.

A Ventilation and Extraction Statement is the document that sets all of this out in conditionable form: route, stages, fan, discharge location, and the maintenance schedule.

Maintenance regimes and conditions

Offer the maintenance regime and offer the condition wording. Environmental health officers refuse schemes because they expect the system to be neglected, and an odour management plan addresses that directly.

A workable plan states the filter replacement interval for each stage, who carries out the work, the log book kept on the premises, the arrangement for recording complaints, and the person responsible. Conditions then tie the use to it: no cooking until the approved system has been installed and commissioned, the system to be maintained in accordance with the approved odour management plan, and the log to be available for inspection.

Avoid conditions phrased as no odour being detectable at the boundary. They are unenforceable, inspectors dislike them, and they help nobody when a complaint arrives.

Where the proposal also attracts a highway or parking objection, which is common for hot food premises, that strand needs its own evidence, and the approach is described in the guide to highway safety refusals and the evidence that answers them.

Evidence from comparable installations

Inspectors respond well to evidence that the same specification works somewhere else. Two routes are available.

Measurement at a comparable premises, using dynamic olfactometry to BS EN 13725 on the discharge, gives an odour concentration that can be fed into a dispersion calculation. It is the stronger evidence and it costs more.

Structured observation by trained assessors at a comparable site, recording odour intensity at set positions over several sessions including peak trading, costs less and is often sufficient where the risk rating is medium. Record the method, the dates, the positions and the weather, because an unexplained sniff test carries no weight.

Either way, say openly why the comparison site is comparable: same cooking type, similar airflow, similar receptor distances and heights. A comparison with a premises cooking a different menu into an open car park will be dismissed.

Answering an environmental health objection

Meet the officer who objected. Ask what abatement train they would accept for this risk rating, what discharge arrangement, and what condition wording. Most will answer, and some will say in terms what would have been approved.

Then build the appeal statement around the refusal reason rather than around the policy. State the allegation, give the risk assessment, show the abatement train with performance data, show the discharge point on a section with receptor heights marked, provide the comparable site evidence, offer the odour management plan and the conditions, and confirm the legal route for the duct.

A section 78 appeal against refusal of a commercial application must normally be lodged within six months of the decision. Written representations suit a single-issue odour case, and the drawings do more than the prose.

For specialist technical reports, qualified professional input may be required. You can see where the odour and extraction documents sit alongside the rest of a change-of-use pack in the full report index.

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.