Stay put vs simultaneous evacuation: which applies to your block?
Two very different strategies rely on completely different building conditions being true. Here is how to tell which one your building can actually support.
Stay put relies on a building's compartmentation containing a fire to its flat of origin, so only the affected flat evacuates while others remain in place until told otherwise by the fire service. Simultaneous evacuation, used where compartmentation cannot be relied on, evacuates the whole building on any alarm. The correct strategy depends on the building's construction and condition, not on preference, and must be stated and justified in the fire risk assessment.
stay put, simultaneous, and temporary/defend-in-place variants
Who decides the strategy
The responsible person
on the FRA's recommendation
Type 3/4 assessment needed when
compartmentation unverifiable
visually, without intrusive checks
The principle behind stay put
Stay put is not a policy of complacency; it is an engineering strategy that depends on a specific, verifiable physical condition being true: that the building's compartmentation — fire-resisting walls, floors and doors — will contain a fire within the flat of origin for a defined period, typically 60 minutes, without fire or smoke spreading into the common corridor or stairway. If that condition holds, it is genuinely safer for residents in unaffected flats to remain where they are, behind a protected front door, than to move into a smoke-logged corridor. The fire and rescue service fights the fire in the flat of origin, and evacuates other flats selectively only if and when necessary, rather than every resident self-evacuating simultaneously through a single stairway that could become congested or smoke-filled.
The conditions stay put actually requires
For stay put to be a defensible strategy rather than a hopeful assumption, several things need to be true at the same time, and an assessor should be able to point to evidence for each.
Compartmentation between flats, and between flats and the common parts, is intact — fire-resisting walls and floors with no unfilled service penetrations
Every flat entrance door is a certified fire door, fitted correctly, self-closing and undamaged
The external wall system does not provide a route for fire to spread past the compartment of origin — a critical point post-Grenfell for buildings with combustible cladding
There is an automatic fire detection and alarm system appropriate to the risk, so a fire in one flat can be identified and the fire service can be alerted quickly even if the alarm does not sound throughout the building
The common escape route (stairs, lobbies, corridors) is protected and kept clear, so it remains usable if evacuation of specific flats does become necessary
When stay put fails or must be suspended
Stay put breaks down the moment any of its underlying assumptions stop being true, and the assessor's job is to identify exactly where that break is likely to occur in a specific building. Known common causes of stay-put failure include known defective compartmentation identified during a fire door inspection or intrusive survey, combustible external wall materials that risk vertical or horizontal fire spread bypassing compartment lines, fire doors that have been removed, damaged or wedged open, and a fire that has already spread beyond a single flat by the time it is detected. Where any of these risks are present and cannot be remedied quickly, stay put should not be relied upon and an interim strategy — most commonly simultaneous evacuation supported by a waking watch — must be put in place until remedial works restore the compartmentation.
The buildings behind this advice
Simultaneous evacuation
Simultaneous evacuation means everyone in the building leaves as soon as the fire alarm activates anywhere in the building, regardless of where the fire actually is. It is the default and correct strategy for buildings where compartmentation cannot be relied on — including many buildings awaiting cladding remediation, buildings with known widespread fire door defects, and most low-rise or converted properties without engineered fire separation between units. It requires a building-wide detection and alarm system capable of alerting every resident (not just the flat of origin), and escape routes and stairways sized and protected to cope with everyone using them at once, which is a materially different design assumption than stay put's single-flat evacuation.
Building-wide alarm coverage, not just detection within the flat of origin
Stairways and escape routes designed or verified to cope with simultaneous use by every occupant
A clearly communicated instruction so residents know to leave immediately, not to wait for further information
Regular testing of the common alarm so a false sense of stay-put security does not creep back in
Waking watch as an interim measure
Where stay put has been suspended because of an identified defect — most commonly unsafe external wall materials — but the physical remediation works will take time, a waking watch can be used as an interim control while permanent works or a suitable alarm upgrade are completed. A waking watch is a team of trained personnel patrolling the building continuously, ready to raise the alarm and support evacuation immediately if a fire starts, compensating for the compartmentation defect until it is fixed. It is expensive, disruptive to residents living with round-the-clock patrols, and was widely criticised during the post-Grenfell remediation period for being used as a long-term substitute for actual remedial works rather than a genuinely short-term bridge.
Why a common alarm usually beats a waking watch
Current good practice, reflected in guidance from the National Fire Chiefs Council, is to install or upgrade a common fire alarm system (a 'simultaneous evacuation alarm') as soon as practicable, since it is both more effective and, over any meaningful timeframe, cheaper than an indefinite waking watch. A common alarm system detects and alerts consistently, at any hour, without depending on a patrolling individual's attentiveness during a long night shift, and once installed it carries none of the recurring staffing cost that makes waking watch bills climb into tens of thousands of pounds a month on larger blocks. Leaseholders and managing agents pushing for a faster switch from waking watch to an alarm system are, in nearly every case we see, making the financially and practically sound argument.
Waking watch vs common alarm system as an interim measure
Common alarm system
Waking watch
Ongoing cost
One-off install, low running cost
Recurring, often very high monthly cost
Reliability
Consistent, not fatigue-dependent
Depends on patrol attentiveness
Speed to alert all residents
Immediate, building-wide
Depends on patrol coverage and speed
Typical duration used for
Can remain as permanent solution
Meant to be short-term only
Government and NFCC guidance both favour common alarm systems as the faster route away from stay-put suspension.
What the fire risk assessment must say
A fire risk assessment for any residential building must explicitly state the evacuation strategy in place, the evidence supporting why it is appropriate for that specific building's construction and condition, and — where stay put is in place — confirmation that the compartmentation on which it depends has actually been checked rather than assumed. Where the assessor cannot verify compartmentation without intrusive investigation, the assessment should say so plainly and recommend either a Type 3 or Type 4 intrusive assessment or a precautionary move to simultaneous evacuation pending that further investigation, rather than defaulting to stay put on the basis that it 'has always been stay put'.
Changing the strategy for an existing building
Changing from stay put to simultaneous evacuation, or back again, is not a paperwork exercise — it has to be actively communicated to residents, since assuming the old advice will simply be replaced in people's memory is unsafe. Landlords and managing agents changing strategy should update the resident fire safety information required under the Fire Safety (England) Regulations 2022, put clear notices at flat entrance doors and in common parts, and, where practical, hold a resident meeting or send a direct communication explaining the change and the reason for it. The fire and rescue service should also be informed, since operational crews plan their attendance around the stated strategy for the building.
Update the written resident fire safety information and reissue it, not just amend an internal file
Post clear notices at every flat entrance and in lift lobbies stating the current strategy
Hold a resident meeting or send a direct written communication explaining the change and why
Inform the local fire and rescue service, since attending crews plan around the stated strategy
Record the change, its date and its justification in the fire risk assessment itself
What we see going wrong on London blocks
In practice, the strategy on a building's front-door notice and the strategy that is actually safe for the building are more often out of step in 1960s and 1970s purpose-built blocks than anywhere else, because many were designed to a stay-put assumption decades before intumescent seals, self-closers and certified fire doors were routine, and the original compartmentation was never as robust as later buildings. Deck-access estates present a different problem: long, semi-external corridors can behave differently from the enclosed lobbies stay put was designed around, and smoke logging along a deck can affect flats well beyond the flat of origin. We also regularly find flat entrance doors replaced by leaseholders with standard domestic doors bought online, with no FD30(S) rating and no self-closer, quietly turning a stay-put building into one that cannot actually support the strategy on its own notice board.
Cost of establishing the correct strategy
Confirming which strategy a building should use is rarely a large additional cost on top of a routine fire risk assessment, but it becomes more significant where intrusive investigation is genuinely required. A standard Type 1 assessment for a small block, which includes a visual check of the factors relevant to strategy, typically sits in the £150–£250 range; a larger block runs from around £250 up to £600 depending on scale. Where visual inspection cannot resolve doubt about compartmentation, a Type 3 or Type 4 intrusive assessment is a separate, specialist piece of work costed on the building's size and complexity, and is worth commissioning promptly rather than leaving the strategy unresolved.
