Evacuation strategy at planning stage: what to fix early
Stay put or simultaneous evacuation is a massing decision, not a Building Regulations detail. What the fire statement asks, and what the answer does to your core.
The evacuation strategy is the part of a fire safety strategy that decides how people leave the building, and on a tall residential scheme it has to be settled at planning stage because it changes the plan. Stair count, lobby depth, lift shaft positions and the location of refuges all follow from it. For a relevant high-rise building the fire statement submitted with the application already asks the question, so an architect who leaves evacuation thinking until Building Regulations will be redrawing cores at the worst possible moment.
Two approaches dominate English residential design. Stay put, where the fire is contained in the flat of origin and everyone else remains where they are, and simultaneous evacuation, where an alarm sounds through the building and everybody leaves at once. The choice sets stair widths, alarm infrastructure and how much of the floor plate the core eats.
Why the evacuation strategy reaches the planning application
Article 9A of the Town and Country Planning (Development Management Procedure) (England) Order 2015 requires a fire statement with applications for relevant buildings, on the form published by the Secretary of State. This is Planning Gateway One, and the Health and Safety Executive is the statutory consultee. Relevant buildings are those of 18 metres or more, or seven or more storeys, containing two or more dwellings or educational accommodation.
The form asks how occupants will evacuate, how the fire service will reach and fight a fire, and where water supplies come from. None of that can be answered without a position on evacuation. A Fire Statement is one of the report types where the law expects fire-engineering competence rather than a general planning author, and the same is true of the fuller Fire Safety Strategy prepared to BS 9991.
Planning does not approve the detail. It does approve the massing, the core positions, the site access and the distance from a hardstanding to the building, and those are evacuation decisions wearing planning clothes.
Single stair and second stair arrangements
England allowed single-stair residential buildings well above 18 metres for years, on the back of compartmentation and a firefighting shaft. That changed. An amendment to Approved Document B introduced a second staircase for new residential buildings above 18 metres, with transitional arrangements for schemes already in train, and the current text on gov.uk is the only version worth designing to.
The planning consequence is floor area. A second stair with its own lobby takes space on every storey, and it usually pushes the core off centre or forces a wider plan. On a tight urban site that can remove a flat per floor, which in turn moves the viability case and sometimes the whole massing.
So the stair decision is a massing decision. Make it before the planning drawings are fixed, not after an officer has already consulted the HSE on a single-stair plan.
Stay put against simultaneous evacuation
| Issue | Stay put | Simultaneous evacuation |
|---|---|---|
| What moves people | Only the flat of origin, plus any floor directly affected | A common alarm sounding throughout |
| Stair capacity | Sized for escape from one flat and firefighting | Sized for the whole occupied population leaving together |
| Alarm | Detection within each flat, no building-wide system | Building-wide detection and alarm, with maintenance obligations |
| What it relies on | Compartmentation between flats and corridors holding for the design period | Alarm reliability and occupant response |
| Planning consequence | Smaller core, fewer ground-floor exits | Wider stairs, more discharge points, larger entrance lobby |
Stay put is not a lesser strategy, and it is still the default for most new blocks of flats in England. It depends on the compartmentation being built as designed, which is why the strategy document has to say what it assumes about construction and what the management arrangements are.
Simultaneous evacuation appears on refurbishment schemes where compartmentation cannot be demonstrated, and on buildings with a mixed occupancy where one use evacuates and another does not. Where you expect a phased or simultaneous approach, the stair has to be sized for it from the first plan.
Evacuation lifts and refuges
An evacuation lift is a lift kept available during a fire for people who cannot use stairs. BS 9991 sets out the provisions: a protected lobby at every level served, a secondary power supply, protection of the shaft and controls that let a marshal hold or direct the car.
That is a real demand on the core. The lobby cannot be a token recess, the shaft needs its own protection, and the switchgear and secondary supply need a room somewhere. On a plan drawn for a firefighting lift alone, adding an evacuation lift late tends to eat a riser or a store.
Refuges sit alongside. A refuge is a relatively safe space within a protected stair enclosure or its lobby where someone can wait and communicate with whoever is managing the evacuation. Two-way communication matters as much as the floor area. A refuge with no means of telling anyone you are in it is a cupboard.
Residents who cannot use stairs
In workplaces the Regulatory Reform (Fire Safety) Order 2005 has long produced personal emergency evacuation plans for named individuals. Residential buildings are different, because nobody controls who moves in, and the government has consulted on arrangements for residents who cannot self-evacuate. Check the current position on gov.uk before writing anything definitive about residential duties.
What a designer can do is build in the options. Accessible flats placed where an evacuation lift serves them. Lobbies deep enough to hold a wheelchair without blocking the stair. Clear, sheltered external refuge at ground level where people gather. And a sprinkler or suppression position taken early rather than offered as a concession at Gateway Two.
Local planning authorities have the public sector equality duty under the Equality Act 2010 in the background. An application that silently assumes every occupant can walk down twelve storeys invites the question.
What the strategy does to the floor plan
The evacuation strategy constrains four things an architect cares about. Travel distance from a flat entrance door to the stair, which limits how many flats one core can serve. Dead-end corridor length, which decides whether a single-stair plan works at all. Lobby arrangement, which determines whether smoke can reach the stair. And ventilation of the common corridor, usually a smoke shaft, which needs a continuous vertical route and a terminal at roof level that the elevation has to accommodate.
Those four between them set the flats-per-core figure that drives the whole scheme. Get the number wrong early and the unit mix changes later, which means revised drawings, a new Planning Statement narrative and sometimes a fresh consultation.
A practical sequence for the design team:
- Fix the evacuation strategy in principle before the core is drawn.
- Test the flats-per-core figure against travel distance and dead-end limits.
- Size the smoke shaft and the stair, then check the terminal against the roof design.
- Decide on an evacuation lift and locate its lobby and plant.
- Write the fire statement from the drawings, not the other way round.
Who may prepare the strategy
A fire safety strategy to BS 9991 or BS 9999 is a fire-engineering document. It needs someone with fire-engineering competence, which in practice means a chartered or incorporated engineer with Institution of Fire Engineers membership, or an equivalent record of designing and signing comparable buildings. A fire risk assessor qualification is a different thing and does not cover design.
PlanScope can produce an AI-assisted draft of a Fire Statement or a Fire Safety Strategy that sets out the structure, the policy and standards framework and the questions the form asks, with a clear flag wherever a site fact is missing. That draft is a starting point for the fire engineer, never a substitute for one. The sign-off has to come from the competent professional, and PlanScope's professional directory exists for that step.
One honest uncertainty: the transitional arrangements around the second staircase requirement have caused more argument than the requirement itself, and the answer for a particular scheme depends on when drawings were deposited. Ask the HSE through pre-application engagement rather than assuming.
If you are at the stage of writing the fire statement, browse the report types and start from the section structure rather than a blank page.
PlanScope provides AI-assisted draft reports for planning applications. Reports should be reviewed before submission. We do not guarantee planning approval. For specialist technical reports, qualified professional input may be required.
Frequently asked questions
Does a planning application need an evacuation strategy?
Not as a separate document, but a relevant building needs a fire statement under Article 9A of the Development Management Procedure Order 2015, and the form asks how occupants will evacuate. You cannot complete it without a position on evacuation. Larger or more unusual schemes usually submit a fuller fire safety strategy alongside it.
What counts as a relevant building for Planning Gateway One?
A building of 18 metres or more in height, or with seven or more storeys, that contains two or more dwellings or educational accommodation. The Health and Safety Executive is a statutory consultee on those applications. Height and storey counts are measured as the legislation and guidance define them, so check both before deciding the gateway applies.
Is stay put still acceptable for new blocks of flats?
Yes. Stay put remains the normal strategy for new residential blocks in England, and it rests on each flat being a fire-resisting compartment. The strategy document has to state what it assumes about compartmentation and management. Where those assumptions cannot be shown, a simultaneous or phased approach is used instead, with a larger stair.
Who is competent to write a fire safety strategy?
Someone with fire-engineering competence, typically a chartered or incorporated engineer with Institution of Fire Engineers membership or a comparable record. A fire risk assessment qualification covers occupied-building assessment, not design. Councils and the Health and Safety Executive both look at the author's credentials when they read the statement.
Does an evacuation lift replace the firefighting lift?
No. A firefighting lift carries fire crews and equipment up the building, while an evacuation lift carries occupants who cannot use stairs down it. Some designs combine functions in one shaft under specific provisions, but the planning drawing still has to show protected lobbies, shaft protection and space for a secondary power supply.
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.