‘Evacuation’ is the immediate and urgent movement of people away from a threatened or existing hazard. The response of people to emergencies can vary from inaction to panic; a key factor in maintaining control and order when conducting evacuation is communication.
The need to evacuate or shelter people could be due to:
- An act of terrorism
- The actual or threatened release of hazardous substances
- An unstable or collapsed structure
- The risk of explosion
- Severe weather, including widespread flooding
- Environmental contamination
- Transport incidents
When producing Site-Specific Risk Information (SSRI) and developing incident plans, the evacuation or shelter of large numbers of people should be considered. Planning should be carried out with statutory resilience forums who may be able to mobilise resources to assist during the emergency phase of an incident.
Personnel at the incident and in the fire control room should develop a joint understanding of risk when determining if there is a need for evacuation, shelter in place or ‘stay put’. To achieve this effectively, robust communications should be established and maintained throughout the incident. For further information see: Have a communications strategy.
The decision to evacuate, and the size of the area to be evacuated, should be based on a joint understanding of risk which is agreed by the Strategic Co-ordinating Group (SGC). As a decision to evacuate is likely to affect multiple agencies, they should all be consulted if possible. If this is not possible, all agencies involved should be informed as quickly as possible.
The police are normally the lead agency for evacuation, and are likely to make a decision to evacuate in consultation with the local authorities. However, the police can only recommend evacuation and have no power to force responsible adults to leave their homes, with the exception of evacuation of the inner cordon for a terrorist incident.
In any decision about whether or not to evacuate, the overriding priority should be the safety of the public and emergency responders. It is possible that evacuating people to the open may put them at greater risk; buildings may provide protection against some types of risks and the public may be safer seeking shelter in a suitable building.
Unless they are provided with specific instructions, people are likely to follow the most obvious or familiar egress route; this could result in a stampede, evacuating towards the hazard, or result in people being trampled.
Evacuation time comprises the time taken for individuals to move towards an exit, plus the time taken before movement is initiated – the time taken to recognise there is a danger and to decide on the most appropriate course of action. Communication and sharing of information should aim to enhance the effectiveness of evacuation. For further information see Warn, inform and advise people.
For further information, see the Cabinet Office publication, Understanding Crowd Behaviours: Supporting Evidence
Once implemented the evacuation plan should be regularly reviewed, to take into account:
- The development of the incident
- Changes in weather conditions
- Information gathered from emergency responders and the public
- The effectiveness or impact of the evacuation
Fires in buildings
Taller or larger buildings are likely to have scalable evacuation plans, with some occupants remaining in relatively safe areas of the building during firefighting operations.
To prevent access, egress and escape routes becoming compromised, compartmentation and suitable routes for firefighting teams should be identified and secured at the earliest opportunity. Building signage should not be relied on for suitable access and egress routes.
Access and egress routes should be suitably and sufficiently protected by:
- Using personnel with appropriate firefighting media
- Making use of the building’s fixed installations
- Maintaining the structure and integrity of fire-protected areas
The primary objective of an evacuation strategy is to ensure that in the event of a fire, the occupants of a building can reach a place of ultimate safety outside the building. The evacuation procedures are an essential part of the overall fire strategy. There are two basic categories of evacuation procedure:
Total evacuation of the occupants to a place of ultimate safety, by either simultaneous or phased procedures:
- The default approach, where it is unreasonable to expect the occupants to remain in the building for a prolonged time when there is a fire
- A common approach adopted in high-rise premises where the storeys are separated by fire resisting construction, or in certain atrium buildings
- The first people to be evacuated are all those on the storey most immediately affected by the fire, and those on other storeys with impaired ability to evacuate, unless their personal emergency evacuation plan (PEEP) has determined otherwise
- The remaining storeys are then evacuated, usually two storeys at a time, at phased intervals
Progressive evacuation of the occupants, initially to a place of relative safety within the building where they can remain or, if necessary, complete the evacuation to ultimate safety as part of a managed system. There are two categories of progressive evacuation:
- Progressive horizontal evacuation
- The process of evacuating people into an adjoining fire compartment on the same level, from which they can later evacuate to a place of ultimate safety
- Zoned evacuation
- A common approach adopted in large retail developments, where an operational loss could be created by evacuating a large building for a relatively small fire
- A zoned evacuation is achieved by moving the occupants away from the affected zone to an adjacent zone; for example, in a shopping centre where the occupants would be moved to the adjacent smoke control zone while the fire-affected zone was brought under control
Occupant evacuation or escape strategies
Occupant evacuation or escape strategies will vary; the responsible person should be able to provide information about them. Some buildings have a policy to simultaneously evacuate when hearing an alarm, others maintain a ‘stay put’ or ‘defend in place’ policy and some adopt a vertical phased approach.
The ‘stay put’ policy, as detailed in the Local Government Association’s Fire safety in purpose-built blocks of flats may be considered appropriate, based on the levels of fire resistance for compartment walls and floors. The use of occupant evacuation or escape strategies that are based on ‘stay put’ or ‘defend in place’ policies should be kept under review throughout the incident.
When determining the evacuation strategy the following factors should be considered and reviewed to maintain the safety of occupants:
- That there is a clear passageway to all evacuation routes
- The risks to the occupants exiting along firefighting access routes
- Exposure to potential hazards
- Whether any occupants require assistance to evacuate
- If the evacuation routes are clearly marked, and are as short and direct as possible
- Whether there are enough exits and routes available for all people to evacuate
- If emergency doors open easily in the direction of evacuation
- Whether there is emergency lighting provided where needed
- If training has taken place about using the evacuation routes
- Whether a safe assembly point has been designated and communicated
Evacuation of medical facilities
Medical facilities are likely to contain patients, visitors and staff. These people will have varying levels of familiarity with their surroundings and the evacuation procedures. It is also likely that some people will be impaired by physical or mental disabilities.
Fire and rescue service personnel may be able to provide assistance to evacuate non-ambulant patients.
Medical facilities may have more than one evacuation strategy. This may include simultaneous evacuation, where people immediately go to a designated assembly point, ‘horizontal phased’ or ‘vertical phased’ evacuation.
Methods of horizontal phased evacuation are particularly useful when dealing with seriously ill or infirm people, who may require life support equipment, medical gases or strict environmental conditions for their wellbeing.
The aim should be to reduce the impact of a hazardous material on members of the public not originally involved in the incident, but who could potentially become involved as the material moves from the incident. This may be achieved by implementing an evacuation or shelter in place plan.
An assessment about which course of action is correct for protecting the public should be made by a hazardous materials adviser (HMA), and provided to the incident commander. For further information about the information that will influence this assessment see:
Hazardous materials – Safe and controlled approach: Hazardous materials
For information regarding contaminated casualties, see Hazardous materials - Controlled evacuation of contaminated casualties.