Changing evacuation strategy during an incident involving flats will be difficult, time consuming and resource intensive, the available time may be limited, and the building will generally not be designed to facilitate simultaneous evacuation. Although not common, some buildings may have an evacuation alert system or voice alarm, that personnel can use to reassure, advise and alert occupants when and if it becomes necessary to evacuate areas or the entire building.
Although it will not be possible to develop plans for all eventualities, planning for this transition will ensure appropriate resources are available, methods of communicating the change in status have been considered and personnel have an awareness of what may be required during this period. Depending upon the number of properties within a fire and rescue services area, it may be possible to develop tactical plans for specific risks, produce plans for high risk buildings, or develop generic plans for building types, for example buildings over a given height, or buildings with a single stairwell. Generic plans may be less relevant at older buildings that were built prior to current building regulations, or more modern buildings with complex fire engineering.
Appropriate intervention
Upon attendance at fires in tall buildings, initial operational activity should be based on the key objectives identified by the incident commander, considering the condition of the building, integrity of escape routes, fire development and spread.
It may be necessary to prioritise the evacuation and rescue of occupants rather than intervention, if:
- Operational activity is likely to compromise escape routes and make them unsafe for occupants without RPE
- Allocating resources to firefighting is likely to prevent successful evacuation
It is generally most likely that an appropriate speed and weight of attack will contain or control the fire sufficiently to allow evacuation, or remove the need for a change in evacuation strategy. However, this should be based on a careful risk-assessment of the incident and a firefighting intervention may not always be adopted as a default option where evacuation could be seen as a priority or if egress routes are in use on arrival and must be protected for a period. An awareness of fire safety measures such as sprinklers should be considered when determining the tactical priorities and objectives.
Firefighting facilities
Buildings at a height over 18m may be provided with additional provisions to assist firefighting such as firefighting shafts, firefighting lifts, 100mm or 150mm diameter rising fire mains and protected staircases, although this may not be the case in older buildings. Wet rising mains should also be installed in modern buildings over 50m in height, or 60m in older buildings.
The use of these facilities may assist personnel to deliver an appropriate speed and weight of intervention. Up-to-date information on the condition of firefighting facilities should be accessed where available. Where fixed installations are not functioning correctly, alternative methods should be considered. Refer to Implement firefighting contingency arrangements for more information.
Other agencies and the responsible person may be able to provide information about the condition of firefighting facilities, such as dry risers, access arrangements and water supplies.
Resources
The time taken to reach a staging area or bridgehead and the physiological stress of personnel should be considered when requesting resources. Additional time and resources may be required to implement safe systems of work for operations at elevated levels. For more information refer to Task rotation.
Integrity of escape routes
The effects on ventilation and smoke travel if breaching compartmentation, as well as the obstructions caused by hose and other equipment, may need to be considered particularly in tall buildings with a single staircase.
The integrity of escape routes should be considered, from initial attendance and throughout the incident so they can be used if it is necessary to evacuate the building. This may mean that personnel need to be assigned to protect specific routes; if this is a priority other operational activity may need to be delayed. Incident commanders should understand the effects of the fire on the rest of the building. For example, a flashover or wind-driven fire could create a pressurised wave of floor to ceiling smoke and heat that moves into common areas and that can pass through gaps in fire doors that are held open or are breached.
Hose-lines should be laid and charged in an area unaffected by fire or smoke and behind a fire resisting structure or door(s). Wherever possible, fire doors protecting stairwells or firefighting shafts should remain closed and intact. Such doors should not be cut or altered by firefighters in any way to enable hose to pass through or under. Breaching compartmentation designed to protect stairwells and other protected areas removes the protection offered and may prevent doors from fully opening or closing. Cutting or altering fire doors in any way to enable hose to pass through or under removes their integrity, and prevents them from serving the purpose they were designed for and should be avoided. Any attempts to breach compartmentation should always consider the impact on the stairwell, the bridgehead and how it could affect evacuation or firefighting personnel. Where available, the use of firefighting lobbies to mount an attack may also help protect the stairwells.
The use of equipment, such as smoke-blocking portable fire curtains, in corridors lobbies and at stair doors can prevent smoke and heat entering egress routes during firefighting. Before using methods to alter flow paths, personnel should consider the operation of mechanical smoke ventilation system (MSVS) and air flows associated with natural ventilation systems and ensure that they are not affected. The use of positive pressure ventilation (PPV) fans can be used in some buildings to prevent smoke entering, or to clear smoke from, access and egress routes. When using mechanically driven equipment personnel should consider the effects of fumes on personnel, particularly in stairwell(s) and corridors.
Stairwell protection teams
Stairwell protection teams are deployed to ensure the safety of occupants who may be leaving the building and to maintain conditions in the stairwell, in case evacuation is needed.
Personnel may be deployed to stairwells to:
- Search for occupants that may have been overcome by smoke and heat
- Prepare and maintain stairwells, to ensure they remain clear of smoke, obstructions and other hazards
- To assist with evacuation and rescue
- To assist with other operational activity
- Provide advice to occupants, including information about the evacuation strategy and the current state of the incident and operational activity
- Monitor and report on conditions in corridors or lobbies off the stair
- Monitor people evacuating and communicate information to the relevant sector
Sectorisation of high rise incidents needs to be dynamic to meet the needs of the incident. As the incident progresses it may be prudent that incident commanders are able switch from geographical sectors, to sectors determined by specific tasks and objectives. It may be necessary to organise the sectorisation of command structures, taking into account under which sector stairwell teams are deployed The stairwell sector may originally be assigned to the Fire Sector but then may be handed to the Search Sector, if and when the command role is assigned.
Because occupants may be in the stairwell when firefighting operations begin it is important to consider protecting stairwells at the earliest opportunity. Entering the fire compartment may cause a large amount of smoke to enter stairs or other egress routes. Containing or isolating a compartment fire may be considered if environmental factors, such as exterior wind or stack effect, dictate that entry to the fire compartment needs to be delayed while local areas are evacuated.
Stairwell protection teams can be deployed to defined stairwell zones, to an assigned number of floors, in preparation to respond to information that people are in danger or require assistance, for example from fire survival guidance calls or vulnerable persons requiring assistance
To ensure they are effective, and any information or assistance offered is appropriate, they should be briefed and immediately updated regarding any changes of evacuation strategy or significant changes to the incident.
Equipment such as portable gas monitoring; smoke blocker door curtains; smoke escape hoods and positive pressure ventilation (PPV) can be used to maintain conditions within stairwells.
When considering if, how and when to deploy teams to manage conditions in stairwells and assist with evacuation, the following things should be considered:
- Potential changes in conditions when the fire compartment is entered
- Delay in operational activity due to intensity of the fire, required resources or flow rates
- Prioritisation of those requiring immediate evacuation
- Risk of fire breaching compartmentation or spreading externally
- Likelihood that a change in evacuation will be or could be required
- Potential for people to be self-evacuating
- Likelihood that people require assistance to evacuate
- Fire and smoke behaviour, such as stack effect or wind driven fire
Extended travel distances to uppermost floors may mean that it is not practical for personnel to be deployed wearing breathing apparatus under air above the fire floor. In circumstances where teams need to work in an area above the bridgehead, that is not affected by fire or smoke and it has been confirmed that the building’s construction and any fire engineered solutions have not been compromised, teams should follow local service procedure. If this allows personnel to be committed with breathing apparatus (BA) but not under air, then all appropriate control measures should be followed including appropriate Breathing Apparatus Entry Control procedures, using a different BA entry control board. Regular communication should be maintained, and a safety officer deployed in the stairwell to observe changes in conditions, maintain contact with other safety officers, external observers, the bridgehead and the incident commander.
The decision to deploy stairwell protection teams should be risk assessed, particularly if distances above the fire floor may be extensive. When deploying stairwell teams, factors to consider include:
- The height of the building
- Distance from the bridgehead
- Confirmation that the building’s construction has not been affected
- Resources needed to deploy stairwell protection teams
- Likely development of the incident
- Current and potential condition of stairwells
- Quality of communications
- Indications of external fire spread or other building failures
- Appropriate control measures to monitor and maintain conditions
- Levels of fire resistance, and available protected areas or refuges
- Active fire protection, such as pressurised stairwells, and sprinklers
- Command structures and sectorisation
Teams not wearing respiratory protective equipment under air should be withdrawn as soon as it is believed there is a risk that fire or heavy smoke is likely to spread to the unaffected area. Stairwell teams should not continue to operate if communications are lost and they should return to the Bridgehead. A dedicated emergency team should be provided specifically for stairwell teams, when required by BA procedure.
Conditions in stairwells may become unsafe for both occupants and firefighters as the incident progresses. Conditions should be constantly monitored throughout, and control measures implemented to maintain conditions and provide early indication of deterioration.
Portable gas detectors can be used if available to indicate the concentrations of fire gases and smoke. Thermal imaging may also be used, if available, to monitor temperatures. If unsafe levels are reached, firefighters should withdraw or go under air but should not exceed Short-term exposure limits. The most appropriate Acute exposure guidance levels (AEGLs) or Fractional effective dose guidance (BS PD 7974-6:2019) may be considered, when determining acceptable tenability levels for occupants or vulnerable persons evacuating without RPE in egress routes compromised by smoke.
Further information can be accessed at the GOV.UK Chemical hazards compendium and the United States Environmental Protection Agency Acute Exposure Guideline Levels for Airborne Chemicals.
Access, egress and evacuation
Due to limited access and egress, and constraints of resources, particularly in tall buildings with a single staircase, it may be necessary to prioritise intervention or evacuation of a building in line with the evacuation strategy. Depending on the development of the incident it may be necessary to implement an alternative evacuation plan if the building evacuation strategy is no longer appropriate.
Where multiple staircases are available, it may be appropriate to designate operational and evacuation stairwells, identifying stairwells and floor numbers by fixed wayfinding signage if provided, and control the flow of people who are evacuating to reduce congestion. This information should be shared with all personnel at the incident and any fire control room involved in call handling, to inform the fire survival guidance being given to callers. For more information, refer to Evacuation.
If conditions become unsafe for occupants to evacuate via stairwells, and alternative routes are not available, it may be necessary to move them to a position of safety until conditions can be improved or assistance offered. Refuges may be identified in pre-planning, on site specific risk information or following review by personnel. Designated refuge areas should be used before considering other areas. If non designated refuges are to be considered, then personnel should assess how their integrity can be maintained and what further evacuation may be required.
Consider the use of RPE for occupants, such as smoke escape hoods. However, some RPE is designed to protect against contaminants or dangerous gases and not protect people from oxygen deficient atmospheres. Where occupants are evacuating a stairwell in what is considered a safe atmosphere, some vulnerable, elderly persons or young children may still require the protection of RPE or be refuged into a safe area until this becomes available. Anyone provided with RPE or left in refuge should be assisted and supported.
Although a building may have a “stay put” strategy in place, and fire service personnel believe that this should be adhered to, if occupants wish to leave the building they should be allowed to. This should be considered when deploying resources, and shelter for people who have left or are unable to enter the building should be considered.
Evacuation strategies should be reviewed regularly considering:
- Information received from fire control rooms, considering the number of calls and the location and spread of the fire
- Fire development
- Effectiveness of current operational tactics
- Evidence of external fire spread
- Evidence of a wind driven fire
- Failure of building features
- Changes to internal conditions such as smoke in the stairwell
Fire control rooms, other responders and all personnel on the incident ground, should be informed of any change in evacuation strategy. Fire control rooms and personnel deployed in the building should be regularly updated on evacuation strategies, even if no change has occurred to ensure that information passed to callers and people encountered remains appropriate.
Managing people that have evacuated the building is primarily not a fire and rescue service responsibility but if no other agency is available it may be necessary to make provision for shelter. Refer to Evacuation and shelter for more information.
Information should be gathered from people leaving the building and co-ordinated with:
- Fire survival guidance calls
- Other information from fire control personnel
- Information from the bridgehead
- Other credible sources of information
To ensure anyone who has not or is not able to evacuate are considered and to ensure previous callers who self-evacuate are identified, to prevent unnecessary deployments.
It may not be possible to confirm everyone has left the building and continued search and rescue may be required, after an evacuation strategy has changed.
Evacuation alert systems
Buildings may have evacuation alert systems or voice systems to assist fire services if a change to evacuation strategy is required. Systems will be secure and can be accessed via a key, gaining access by forcing the box will be difficult and time consuming, and is likely to cause damage. Personnel should gain access and control of the evacuation alert at the earliest stage if it is believed that it may be necessary to change evacuation strategy at any stage.
Evacuation alerts that meet the British standard will not allow the whole building to be cleared in one action and should not be linked to existing alarm systems, although there may be alarm systems that do not meet the standard installed. Alerts can be activated on a floor by floor basis, and in larger or more complex buildings, sections or zones of the building can be evacuated.
The decision of which areas to evacuate should be decided based upon current conditions and likely development, but personnel should consider the flow of people and the size of available egress routes when determining when and how to change evacuation strategies. For example, it may be suitable to evacuate the fire floor first, or if possible, to evacuate the face of the building where external fire spread is occurring.
If evacuation alerts are used, all personnel should be informed, and the following factors should be considered:
- Is it necessary to delay or change operational activity to support or clear routes for evacuation?
- What is the impact on conditions in the staircase and fire compartment caused by a change in evacuation strategy
- Is it necessary to deploy personnel to provide RPE or support to people evacuating certain floors?
- How will the evacuation effect operations outside the building and is the route to safety clear?
- Have arrangements for shelter been made?
- Are all routes clear and any secure doors opened?
- Are conditions in stairwells suitable for evacuation?
External observers, stairwell protection teams and safety officers should be briefed regarding the changes to evacuation strategy and should monitor and provide updates about any changes in conditions.
Evacuation of a tall building will still take significant amounts of time and occupants may not be able to evacuate without assistance. It is necessary to consider both these factors when determining when to change strategy.
To prevent tampering or accidental activation and monitor for faults, once the evacuation alert system has been accessed, personnel should be deployed to maintain control. Faults will be indicated on the panel and the incident commander should be informed of any failure to operate. The use of the system should be recorded.
Where evacuation alert systems are not available, other means of changing an evacuation alert system include:
- The use of media and social media messaging
- Changing advice to callers to fire control
- Loud hailers
- Drones (unmanned aircraft) with announcement systems
- Deploying personnel to floors to inform occupants
- The use of aerial platforms with announcement systems
- The Use of building features, such as door entry communication systems
Ventilation
Doors and vents may open or close automatically as part of fire engineered solutions; the building management systems and fire engineered solutions should be considered prior to opening or closing doors or vents. Fire and rescue services may have access to specialists that can interpret and assess the effects of fire engineered solutions and the likely effects of firefighting actions and environmental impacts that may cause systems to fail during a fire.
Firefighting media
When firefighting internally, it is important that water supplies are maintained; any action that reduces pressure or supply may affect the safety of personnel inside the building. The effect of drawing water from a supply that is being used to supply internal firefighting media to fight the fire externally should be considered. Where possible, alternative sources of water should be identified and accessed. For further information, refer to Water and extinguishing media management and planning.
Search co-ordination
When multiple compartments or floors in a tall building require searching, it is important that the search is effectively co-ordinated. This should be ongoing and consider the information obtained from:
- Fire control rooms, including the fire survival guidance being given to callers
- Personnel debriefs
- External observations
- Credible witnesses
It may be appropriate to share information about ongoing search activity with fire control rooms, so that fire survival guidance can be amended if necessary.
Effective search patterns and a clearly defined search area are necessary to ensure the search activity is co-ordinated. Assistance may need to be prioritised for vulnerable people who require assistance to evacuate.
For further information refer to Procedures for search and rescue when using breathing apparatus.
To effectively co-ordinate searches, sectorisation of tall buildings will need to consider external and internal sectors. For more information, refer to Sectorisation.