Airport public safety zones and new dwellings
A public safety zone is drawn from an individual risk contour, not a noise line. Inside one, the policy objective is no increase in the number of people living, working or congregating, which rules out new dwellings.
A public safety zone for airport housing purposes is the area at each end of a runway at a designated airport where national policy sets out that there should be no increase in the number of people living, working or congregating, and that the number should fall over time. New dwellings are not acceptable inside one. Neither, in most cases, is a replacement dwelling, because the policy is concerned with occupancy rather than with built form.
That catches developers out because a public safety zone looks like a designation you can mitigate. It is not. It is a third-party risk control, and the arithmetic behind it does not respond to design quality.
This is general guidance, not legal advice; check the position with your local planning authority or a qualified professional before relying on it.
What a public safety zone is
A public safety zone is an area of land at the end of a runway within which development is restricted to control the risk to people on the ground from an aircraft accident on take-off or landing. The zones exist at designated airports, and the current policy on controlling development within them is set out in Department for Transport Circular 01/2010.
The shape is not arbitrary. Each zone is drawn to follow the contour at which the individual risk of death from an aircraft accident reaches one in one hundred thousand per year, extending outwards from the runway end along the approach and departure path. Inside that outer boundary there is a smaller area where the risk reaches one in ten thousand per year, and policy there is stricter still: the objective is clearance of residential property and of commercial or industrial buildings used as workplaces.
The zones are reviewed as traffic forecasts change, so a boundary checked five years ago may not be the current one. Ask the airport operator and the local planning authority for the current plan, and record the version you relied on.
The restriction on new and replacement dwellings
The policy objective counts people rather than buildings. Any development that would increase the number of people living, working or congregating in the zone runs against it.
For housing that means a new dwelling is refused on public safety grounds regardless of its design, its sustainability credentials or the housing land supply position. A replacement dwelling is normally caught too, because replacing an old house with a larger one usually increases the number of people living there, and because the policy intent is to reduce occupancy over time rather than to renew it.
The practical consequence for a site appraisal is blunt. If part of your site sits inside a public safety zone, that part is not developable for housing, and the density assumptions for the rest of the site have to carry the whole scheme. Finding this out after the land is under option is expensive.
Be careful with partial overlaps. A red line that clips the zone by a few metres still needs the housing to be laid out outside it, and an officer will ask for a drawing showing the boundary against the proposed plots.
Development that can go inside a zone
The Circular lists categories of development normally regarded as acceptable, and the common thread is low occupancy with no residential or assembly element.
Uses that generally work include long-stay and employee car parking, open storage, warehousing with very low staffing levels, golf courses and outdoor recreation without spectator facilities, and some agricultural and horticultural uses. Uses that do not work include dwellings, hotels, hostels, schools, nurseries, hospitals, places of worship, stadia, retail with any customer footfall and offices with normal occupancy densities.
The assessment turns on occupancy per hectare rather than on the label in the Use Classes Order. A small warehouse with an intensive picking operation and 200 staff on shift is not the same proposition as a cold store with six. Where you propose a use in the acceptable category, the supporting evidence should state the expected number of people present, the shift pattern and the floorspace per employee assumed, because that is the number the officer is testing.
How the risk contours are produced
The contours come from a risk model that combines accident frequency data for the relevant aircraft categories with the distribution of crash locations around runway ends and the airport's forecast movements, usually looking some years ahead so the zone does not need redrawing every season.
Two things follow from that. The zone reflects forecast traffic, so an airport with an expansion consent may have larger zones than its current movements suggest. And the contour is a calculated line rather than a surveyed one, so its position on a local plan proposals map is a reproduction at map scale. For a site close to the edge, get the boundary confirmed against coordinates rather than reading it off a plan at 1:10,000.
The model deals with individual risk to a person at a fixed location. It does not assess societal risk from a large gathering, which is part of why assembly uses are treated separately and more restrictively.
Where public safety zones and aerodrome safeguarding differ
These two controls are often confused, and they do entirely different work.
| Public safety zone | Aerodrome safeguarding | |
|---|---|---|
| Protects | People on the ground | Aircraft operations |
| Concerned with | Occupancy and risk contours | Height, obstacles, birds, lighting, radar |
| Geometry | Contour at each runway end | Safeguarding maps and obstacle limitation surfaces |
| Policy source | DfT Circular 01/2010 | Safeguarding circular and the procedure order consultation duties |
| Typical outcome | Use is unacceptable | Condition, design change or height limit |
Safeguarding consultation operates through the development management procedure, with the aerodrome operator consulted on applications affecting safeguarded areas, and the technical framework in the Civil Aviation Authority's aerodrome safeguarding guidance, CAP 738. A tall building outside any public safety zone can still be refused on obstacle grounds. A bungalow inside a zone can be refused on public safety grounds while raising no safeguarding issue at all.
A site can of course be caught by both, along with noise contours and, for some airports, air quality management areas. Constraints of this kind also change over time, and our note on planning constraints that lapse, expire or are revoked covers how to check whether the version on the proposals map is still current.
Existing buildings, extensions and intensification
Existing lawful uses continue. The policy operates on new development, so a house already inside a zone can be lived in, sold and maintained.
Extensions are assessed on whether they increase occupancy. An extension that adds a bedroom is treated differently from one that enlarges a kitchen, and some authorities apply that distinction quite literally. Loft conversions creating additional bedrooms sit on the wrong side of it.
Intensification of a non-residential use is the area where applicants most often assume there is no issue. Changing a low-occupancy store into a distribution unit with a large workforce is an increase in the number of people working in the zone even if no building work is proposed at all, and where planning permission is needed for that change, the policy applies.
Where a property inside the inner contour is affected, the Circular's clearance objective may bring the airport operator's acquisition arrangements into play. That is a matter to raise with the operator directly rather than through the planning application.
Checking a site and evidencing the position
Run these checks before you commit to a site.
- Identify every licensed aerodrome within a few kilometres of the site, including smaller airfields, and establish whether it is a designated airport with public safety zones.
- Ask the local planning authority for the current public safety zone plan and the date it was adopted onto the proposals map.
- Ask the airport operator for the current zone plan and the safeguarding map, and note any difference between the two sources.
- Check the national planning data service and the local plan policies map for the mapped constraint layers.
- Plot the boundary on your own site plan, with coordinates where the site is close to the edge.
- Set out the occupancy figures for any use you propose within the zone.
Then deal with it explicitly in the Planning Statement. A statement that omits a public safety zone the officer can see on the constraints layer loses credibility on everything else. A statement that shows the boundary, states which parts of the scheme fall inside it, and gives the occupancy evidence for those parts, is arguing from the same facts as the officer.
Browse all 66 PlanScope report types to see which supporting documents a constrained site near an airport is likely to need, and enter your postcode on PlanScope to check the automatic constraint layers against your site.
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Frequently asked questions
Can I build a house in an airport public safety zone?
No. The policy objective in Department for Transport Circular 01/2010 is that there should be no increase in the number of people living, working or congregating in a public safety zone, and that numbers should reduce over time. A new dwelling increases residential occupancy, so it is refused on public safety grounds whatever its design.
Is a replacement dwelling treated differently?
Usually not. Replacing an existing house normally renews or increases residential occupancy in the zone, which runs against the objective of reducing it over time. Some authorities take a narrow view where the replacement is demonstrably smaller with fewer bedrooms, but you should establish the position in pre-application discussion rather than assuming it.
How do I find out whether my site is in a public safety zone?
Ask both the local planning authority and the airport operator for the current zone plan, because the version on a proposals map may predate a review. Check the mapped constraint layers on the national planning data service as well. If the site is near the boundary, get the line confirmed against coordinates rather than reading it off a small-scale plan.
What is the difference between a public safety zone and a noise contour?
A public safety zone is drawn from the risk to people on the ground from an aircraft accident, expressed as an individual risk contour at the runway end. A noise contour maps sound exposure. They overlap geographically but are assessed under different policies, and a site can be acceptable on noise grounds while being unacceptable on public safety grounds.
Does the restriction affect commercial development?
It affects occupancy rather than the use class label. Low-occupancy uses such as open storage, long-stay parking, warehousing with few staff and outdoor recreation without spectator facilities are generally acceptable. Offices, retail, schools, hotels and assembly uses are not, and intensifying an existing low-occupancy building can itself be a problem.
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.