In the years following the Grenfell tragedy, ‘stay put’ policy has received criticism, but often based on misconceptions which need to be addressed.
First, let’s consider the alternative.
Simultaneous evacuation is an alternative often put forward, but it presents some difficulties. This strategy is sometimes applied to buildings converted into blocks of flats, but usually only where it has not been possible to achieve the level of compartmentation required for a ‘stay put’ policy. In purpose-built blocks of flats, experience has shown that most residents do not need to leave their flats when there is a fire elsewhere. In some circumstances, they might place themselves at greater risk when they do so. This strategy is less equitable than stay put, when we consider that within the general needs population and that there will be people with mobility, cognitive, and sensory impairments who may require assistance. When thinking about high rise residential buildings, descending via stairs can cause exertion, and this may trigger life threatening situations. Anyone with an underlying health condition, such as lung disease or cardiac problems may find walking down numerous flights of stairs perilous. Vulnerable people within a general needs population such as pregnant women or the elderly may also be put at risk.
Simultaneous evacuation can be achieved by interconnected heat detection so that only a confirmed fire, triggers the alarm. A false alarm from smoke detection, should an occupant burn the toast, is undesirable. Inevitably, this would breed complacency among residents and raise the risk of the alarm being ignored. Heat detection can overcome this, as it is less susceptible to false alarm. However in the event of a fully involved fire in a flat, this increases the criticality of passive fire precautions doing their job because the strategy would automatically encourage occupants to venture out from the relative safety of their flat, into what could be a smoke filled environment and prior to FRS attendance. Passive fire precautions are critical in both simultaneous and stay put strategies. Malicious activation to trigger total evacuation may be a concern for residents and the FRS. Many Housing Associations and Councils are aware of the challenges related to gang crime within inner city areas. Terrorists have used fire alarm systems to evacuate occupants onto the street and then detonate an improvised explosive device (IED). In active shooter situations fire alarms have been used to entice sheltering victims out of safe locations. It’s worth us remembering that some of these locations have security grilles in front of doors to protect vulnerable people in society from gang crime or domestic violence. Fire professionals can look at the fire problem in isolation and fail to see other social issues which pose a greater risk in communities than the threat of fire and affect many people every day.
Simultaneous evacuation triggered by the sounding of an alarm throughout the entire building may also cause unnecessary anxiety or harm to those with mobility, sensory or cognitive impairments that may require assistance and may well be safer, remaining within their flat (like everybody else), rather than attempting to evacuate.
Evacuation lifts can be a solution for mobility impaired occupants and can be incorporated in new builds, but they generally still require someone to operate them at the ground floor or fire service access level, and the number of occupants wanting to use them may lead to congestion and take too long to evacuate – particularly for those closest to the flat of origin. The next revision of BS 9991: 2021 will likely include commentary on driver-assisted and occupant operated evacuation lifts. Fire-fighting / Evacuation lifts are of course incorporated into new build fairly easily. Incorporation of evacuation lifts retrospectively across the UK’s housing stock will be a challenging requirement if it were to be mandated, and existing smoke control designs may also need consideration if the evacuation strategy is altered.
A long stated challenge with evacuation in residential premises, stemming from the work on human behavior, from the late Jonathan D Sime , is the broad range of human behavior that can be anticipated within the general needs population within their own homes, and how this may effect pre-movement times. Sime highlighted that individuals with close psychological ties will attempt to escape with other group members. “A mans home is his castle”, was the old adage that expresses the fact people enjoy the position of rulers in their own homes and right of entry, or exit is a matter of choice. Some occupants will not evacuate without their pets, or possessions and therefore criticality of compartmentation is fundamental regardless. The most direct reference to human behavior was contained in BS 5588-1  was in Section 31 on fire detection and alarm systems. It noted that common fire alarm systems should only be provided where some control could be achieved over the occupants so that a predetermined response could be initiated.
The ability to manage a fire alarm system is rarely possible in a block of flats unless staffed at all times, eg by a concierge or caretaker. Allowing residents to silence and reset a system is inappropriate in these circumstances. Access to use of these facilities also enables major disablement of a fire alarm system. This could expose landlords and others with responsibility for managing fire safety to liability if, through the actions of a resident, the system is left inoperative and fails to perform correctly in the event of a fire.
It is preferable that evacuations are managed, and in a residential building, there would be potentially no-one to determine if it is safe to re-occupy the building, unless the FRS are called. In high rise residential buildings a simultaneous evacuation strategy poses risks during the evacuation and is less inclusive or equitable than the adoption of a stay put policy for all, and freedom evacuate if able.
Another challenge posed by simultaneous is that the fire service on arrival will be presented with a far more complex situation than they need have to deal with. Occupants evacuating down the stairs, without an assembly point is a consideration. The demands on the handful of firefighters who make up the first attendance will be greater in terms of physical work and command and control complexity. This can only lead to less favorable outcomes. Early intervention to extinguish the fire is critical to achieve the best outcomes in terms of life safety.
Stay put policy
The concept of stay put policy can be traced back at least as far as the beginning of the construction of high-rise residential buildings in the post-war years. The 1962 British Standard Code of Practice 3, Chapter IV, Precautions Against Fire, Part 1 (precautions in flats and maisonettes over 80 feet),  provided that:
“The assumption should no longer be made that buildings must be evacuated if a fire occurs, and high rise residential buildings should, therefore, be designed so that the occupants of a floor above a dwelling which is on fire may, if they choose, remain safely on their own floor. It may be necessary to evacuate the floor on which the fire occurs, and in some circumstances those floors which are in the immediate vicinity of the fire, but the occupants of these floors should be free to reach safety in any other part of the building via the staircase.”
In the UK, stay put is ‘Plan A’
One of the basic design principles is that buildings should be designed in such a way so that all people can escape to a place of safety without external assistance from the fire and rescue service. It states this in the current version of Approved Document B: Volume 1 – Buildings other than dwellings 2019 Edition . This is one reason we should keep our focus on making sure ‘Plan A’ works and adopt a defense in-depth (DiD) or layered approach involving both active and passive measures to ensure plan A works and that the outbreak of fire is confined to the flat of fire origin.
The criticality of compartmentation to ‘Plan A’.
Regardless of whether Plan A is a stay put policy, or simultaneous. The integrity of compartmentation is imperative because we a talking about sleeping risk within high rise, and cannot anticipate the range of human behavior which may be expected with people in their own homes. Even if simultaneous is adopted it would be unwise to lose focus on the importance of compartmentation in this use-class of building. Many of those that contest the benefits of stay put and highlight issues with build quality, fail to recognise that in this use-class of building it will still be critical for simultaneous, and we will never be building purpose built blocks of flats without compartmentation due to occupant characteristics.
However let’s focus on the criticality of compartmentation in stay put scenarios which are likely to be the norm.
The prevailing construction material at the time ‘stay put’ was introduced was concrete. In fire, concrete performs well – both as an engineered structure, and as a material in its own right. However, cement production generates around 2.5 billion tonnes of carbon dioxide (CO2) per year—about 8% of the global total. Widespread use of concrete is exhausting supplies of useable sand. Moreover, concrete consumes almost 10% of the world’s industrial water supplies. It is essential that we innovate with other more sustainable materials. It is of course possible to inhibit the spread of fire within a building with other more environmentally friendly forms of construction, but care must be taken during construction to ensure the specification and installation is correct, so that compartmentation is maintained.
In his report on the Grenfell Inquiry , Sir Martin Moore-Bick rightly pointed out that compartmentation is a critical factor. Sub-division of the building with fire-resisting construction and the installation of a suitable automatic fire suppression system are typical measures considered by those responsible for designing, constructing and maintaining high rise residential buildings with ‘stay put’ policies. Construction quality is important for all buildings but critical for stay put policy, phased, or progressive horizontal strategies which exit in other use classes.
During construction, quality control is essential. There is a need to ensure the design is realised through the construction process, that the right products are installed correctly and that they perform as intended in the event of a fire.
Hindsight is of course notably clearer, than foresight when considering how well a building has performed. Fortunately, there will be many buildings that are never tested and will not experience fire. What we do know is that the property and construction sector has been complacent regarding the criticality of compartmentation where stay put policy exists, but since the introduction of the Regulatory Reform (Fire Safety) Order 2005 , and for almost two decades, there has been an increasing focus on this aspect. There have been a number of developments built and handed over, only to be found with compartmentation issues and then subsequently decanted with residents put up in hotels at considerable cost to the developer, not to mention the cost and disruption caused to residents themselves. Since 2016 there has been a steady increase in demand for fire assurance services throughout the construction process which is testimony to the fact that many residential developers are now taking this aspect and indeed external wall safety, far more seriously than ever before.
A layered approach to plan A.
Amendments to the Building Regulations in 2018 concerning Regulation 7(2)  which states that “building work shall be carried out so that materials which become part of an external wall, or specified attachment, of a relevant building are of European Classification A2-s1,d0 or A1” are probably the most impactful change to UK fire safety so far and in fairness to the UK Government they acted quickly and decisively on this. Now all buildings over 11m in height are to be provided with sprinklers which compliment the compartmentation requirement because they control or extinguish a fire. A NFSN/CFOA report  in 2019 indicates the performance effectiveness of sprinkler systems was 99% across all building types. The latest BS 9251:2021 , adds more resilience to the design with backup power supplies and many Fire Engineers are now specifying enhanced smoke ventilation. So plan A has become even more robust and there are not many more tools in a Fire Engineers arsenal that can be used within high rise residential. Changes proposed to ensure greater competency and control, plus penalties for contraventions will all help ensure a layered approach to Plan A, continues to work as national fire statistics have proved so far.
Proof of concept – ‘Plan A’
In the words of Sir Martin Moore-Bick “Compartmentation has thus been an essential feature of the design of high-rise residential buildings for over 50 years and the “stay put” strategy, which is integral to that, has in general proved to be sound (although there have been important exceptions, such as the Lakanal House fire)”.
This accords with the guidance contained within the LGA Guide – Fire Safety in Purpose Built Blocks of Flats  which states “This principle is undoubtedly successful in an overwhelming number of fires in blocks of flats. In 2009-2010, of over 8,000 fires in these blocks, only 22 fires necessitated evacuation of more than five people with the assistance of the fire and rescue service”.
BS 8629 2019 – Evacuation alert systems for buildings containing flats  also states “The success of this strategy is well established. Every day in England, around 20 – 30 fires occur in blocks of flats, but the need for occupants of flats, other than that in which the fire occurs, to evacuate is very uncommon”.
Our National Fire Statistics  paint a compelling picture that accidental fires are becoming a rarer occurrence and the long-term picture shows that the total number of fires attended by FRSs year ending March 2021 was the lowest figure recorded since comparable statistics became available in year ending March 1996. It is reported in these statistics that 518,263 incidents were attended and fires accounted for 29% of this.
The development of a high rise residential building with a ‘stay put’ policy should be considered the ‘norm’. However, we should remain vigilant and not place total reliability on historical data. It is possible for an outlying ‘black swan’ event to occur. The different Risk Assessment types 1-4 which have been undertaken since the publication 2011 Local Government Guide will, if carried out correctly, provide some level of assurance and legal requirements contained within Articles 9,11, 17, 21 and 22 of the Regulatory Reform (fire safety) Order 2005 all support this risk mitigation effort. An interpretation of this legislation can be found in the Enforcers Guide (2015) 
Common misconceptions about ‘Plan A’
There is often a misconception that should plan A (stay put) become untenable or even undesirable that this must be an indefinite strategy, maintained during a fire even when its apparent that the situation has, or may become, untenable in some parts. Of course not. It has always been the case that residents can choose to evacuate if they are able, and buildings should be suitably designed to facilitate this option.
“It has always been the case that residents can choose to evacuate if they are able”.
The LGA Guide – Fire Safety in Purpose Built Blocks of Flats  states “It is not implied that those not directly involved who wish to leave the building should be prevented from doing so. Nor does this preclude those evacuating a flat that is on fire from alerting their neighbours so that they can also escape if they feel threatened”.
Should a resident see or smell the products of combustion, should they hear fire or sense an impending emergency they can evacuate if they choose to. Just as a man’s home is his castle, a resident is free to exit at will.
If remote from the fire, are not in danger, and not aware of any danger then it also states: “All other residents not directly affected by the fire would be expected to ‘stay put’ and remain in their flat unless directed to leave by the fire and rescue service”. This has always been plan B and the idea of plan B is not new news. The fire service can and should intervene as necessary.
Fire Service intervention – Plan B
Fire service intervention was always the plan B. If, on rare occasions, the fire and rescue service consider that occupants of other flats do need to evacuate, they will alert these occupants simply by knocking on the doors of their flats. This is only likely to apply to a small number of flats, and so is, normally, readily manageable. On even rarer occasions there may be a need to encourage a full simultaneous evacuation of a building and an evacuation alert system can be included. So there should always have been a plan B and an evacuation alert system for fire service use. as per BS 8629: 2019, may in some circumstances be useful addition to the strategy in order to instigate plan B.
BS 8629: 2019  alert systems provide the fire service with the ability to evacuate a building floor by floor. This selective evacuation strategy means that only those who may be in danger can be evacuated, which minimises the problems the fire service face with occupants in the stairs, and minimises the hazard caused to occupants taking part in an evacuation. It would be rare indeed for it to be necessary to evacuate occupants on the floors below the floor of origin.
Could stay put be made safer?
As highlighted in an article entitled Fire Safety’s Misinformation problem, if Grenfell Tower was a building with cladding of limited combustibility and sound compartmentation then, as has been our experience since Post-War Building Studies, the stay put evacuation strategy could have worked and the fire may not spread further than a few apartments. It is clear stay put (plan A) should not have been an indefinite strategy and there was a lost opportunity to change tactics and execute a plan B earlier. Changes are being made by Fire and Rescue Services.
Plan B is the area of focus. Sir Martin Moore-Bick concluded that “the knowledge that high-rise buildings are constructed on the basis of effective compartmentation itself created a barrier to thinking about evacuation”. He went on to make a number of recommendations. The Government, Fire and Rescue Services and Fire Industry are now considering the the practicality of these recommendations.
At the time of writing, we are informed that fire and rescue services have already begun implementing these recommendations and evacuations managed by the fire and rescue service have been performed using smoke hoods.
This article has highlighted a number reasons why a ‘stay put’ policy is still be preferable over a simultaneous evacuation within new build and existing high rise residential buildings throughout the United Kingdom, where a layered approach to passive and active fire precautions is in place, to protect people in their own homes. A layered approach to plan A is critical and there is robust, enforceable legislation and supporting guidance in-place to support this. Compartmentation is critical regardless of stay put or simultaneous within this use-class of building. Stay put is preferable when thinking about safe evacuation or rescue of mobility impaired persons. Plan B (Rescue) should be effected by the fire and rescue service as enshrined in the Fire and Rescue Services Act 2004 . The ban on the use of combustible material, requirements for sprinklers above 11m, and now that the Building Safety Bill received Royal Assent and became an Act of Parliament on 28 April 2022 , it will usher in the biggest swathe of regulatory changes to the UK built environment in almost 40 years.
Physical fire precautions have constantly evolved and improved over many years, in response to lessons learnt from past fires and as a result of advances in technology. Thus, serious, multiple fatality fires are less likely now than at any time since the industrial resolution. Public perception of risk and risk tolerance where fire is concerned is probably at an all time low. There are a number of explanations for why the perception of risk is not based on these rational judgements. These reasons include: systematic biasing of risk information, the use of mental shortcuts, and the way that risk information can be presented.
Whilst the term ‘stay put’ policy can be misunderstood. In a well designed, constructed, managed and maintained building, stay put as a concept is safe. There are things we can do to make it safer, but one out, all out simultaneous evacuation (the alternative) is not as safe when considering high rise residential buildings and occupant characteristics one might reasonably expect.
Chief Executive for and on behalf of BB7 Group Limited
This article is not intended to tackle assisted evacuation of mobility impaired persons by family, friends, neighbours or the fire and rescue service. Nor does this article tackle, why single stair buildings can be designed, engineered and occupied safely, but how public opinion may shape national design guidance. The next two articles will tackle these important and topical conversations. This newsletter is all about the betterment, upward trajectory and evolution of building safety. We hope it stimulates professional debate.
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