Control measure Evacuation
Control measure knowledge
It may be necessary to advise the public on whether they should evacuate a given area or remain and shelter indoors. This can include risks to life or health from:
- acts of terrorism
- release or threatened release of radioactive materials or other hazardous substances
- spread of fire
- risk of explosion
- damage caused by severe weather
- risk from serious flooding
- risk of environmental contamination
- transport failures
It is normally the police who recommend whether to evacuate and define the area to be evacuated. Their recommendation will take account of advice from other agencies. The police can only recommend evacuation and have no power (except within the inner cordon in response to a terrorist incident) to require responsible adults to leave their homes.
In any decision to evacuate or not, the over-riding priority must be the safety of the public and emergency responders, and it is necessary to assess whether bringing people outdoors may put them at greater risk. Buildings can provide significant protection against most risks and the public may be safer seeking shelter in the nearest suitable building.
Emergency evacuation is the immediate and urgent movement of people away from the threat or actual occurrence of a hazard. Since emergencies are relatively rare individual responses can vary from inaction to panic; a key factor in maintaining control and order when conducting evacuation is communication.
Without specific instruction people may rush to escape a developing situation, which could result in an uncontrolled stampede towards a destination that may cause further danger, for example; bottlenecks in areas of danger and trampling of people.
Evacuation time concerns not only the time taken for individuals to move towards an exit, but also the time taken before movement is initiated i.e. the time taken to recognise there is a danger and to then decide which is the most appropriate course of action. To enhance the efficiency of evacuation and, in particular, to start people moving, communication and information are vital.
For further information, see - Cabinet Office publication - Understanding Crowd Behaviours: Supporting Evidence
When producing Site-Specific Risk Information (SSRI) and developing incident plans the evacuation of large numbers of people from incident locations must be considered. This should be carried out in conjunction with local resilience partners who may be able to mobilise resources to assist during the emergency phase of an incident and beyond.
Fires in buildings
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
- Simultaneous evacuation should be 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.
- Phased evacuation is a common approach adopted in high-rise premises where the floors are separated by fire resisting construction, or in certain atrium buildings. In a phased evacuation, the first people to be evacuated are all those on the storey most immediately affected by the fire, and those on other floors with impaired ability to evacuate, unless their Personal Emergency Evacuation Plan (PEEP) has determined otherwise. The remaining floors are then evacuated, usually two floors 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. Progressive horizontal evacuation is 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. Zoned evacuation is 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. The zoned evacuation is achieved by moving the occupants away from the affected zone to an adjacent zone. An example of this would be a shopping centre where the occupants would be moved to the adjacent smoke control zone while the fire-affected zone was brought under control.
To determine an occupier evacuation policy, liaise with the responsible person. Consider the impact of phased evacuation, risks to the occupants exiting along firefighting access routes, and exposure to potential hazards – occupier evacuation strategies may need to be revised to maintain the safety of occupants.
Occupier evacuation or escape strategies will vary. 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.
When deciding upon the evacuation strategy the following factors must be considered:
- Do occupants have a clear passageway to all evacuation routes?
- Will any occupants require assistance to evacuate?
- Are evacuation routes clearly marked, short and as direct as possible?
- Are enough exits and routes available for all people to evacuate?
- Do emergency doors open easily in the direction of evacuation?
- Is there emergency lighting provided where needed?
- Has training taken place for all staff/occupants to know and use the evacuation routes?
- Has a safe meeting/assembly point for staff/occupants been designated and communicated?
In the event of fire, the ‘stay put’ or ‘defend in place’ strategy may be considered in blocks of flats where each flat has a minimum 60 minutes fire resisting compartment.
It is accepted, following the work carried out for the Initial Operational Response that the majority of a contaminant can be managed and then removed by:
- Evacuating – getting people away from the scene of contamination;
- Disrobing - removal of the outer layers of clothing; and
- Decontaminating – using an improvised method of dry decontamination (when a non-caustic agent is suspected), this may need to be changed to a wet decontamination process when a caustic agent is suspected.
The first principle is that evacuation, followed by disrobing, should be considered as the primary action and started as soon as possible.
The removal of the person from the scene of contamination and point of release will significantly reduce the likelihood of any further contamination occurring. Likewise, 'exposure' through the casualty's unprotected respiratory system will reduce by an initial evacuation.
An area away from the scene of contamination should be identified. Where practicable, it should be upwind and ideally uphill. Any casualties who are able to walk should be directed to this area with the minimum of direct physical contact from emergency responders. It is essential that responders communicate effectively with casualties.
There are two recognised methods of reducing 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. These are either ‘shelter-in-place’ or evacuation.
There are a number of considerations to be made by a hazardous materials adviser (HMA) when advising the incident commander on which course of action is correct for protecting the public. These are:
- The physical state of the material – solid, liquid or gas, and the impact this will have on the ability for a hazardous material to move from the incident
- The size of the inner cordon and the numbers of people already exposed or potentially at risk
- The realistic potential for the hazardous materials to spread whilst the response plan is being implemented
- The quantity and nature of the release, for example, a single release of a large amount of material over a very short period of time, or the steady flow of a material over a prolonged period of time
- That most materials will generally lessen as they disperse from an incident. Either due to the effects of downwind, dilution, oscillation, obstacles and retention (DDOOR) for gases or the general spreading out as solids or liquids move (see downwind, dilution, oscillation, obstacles and retention DDOOR, Hazard – Unsafe approach to hazardous material incidents, Control measure – Approach the incident safely and estimate potential hazard zone)
- The effect that weather conditions such as wind speed and direction will have on a plume –consider using specialist services to assist in plotting a chemical plume
- The topography of the area. Liquids and solids will generally travel in the direction of any slope
- The toxicity/harm a hazardous material can cause to human health – seek advice from toxicologists in public health agencies
When advising the public to shelter-in-place consider:
- How long the public are likely to need to shelter from any release – how long will the atmosphere outside the property likely to be considered hazardous?
- The age, type and construction of the properties in the affected area and how likely the property will prevent the material from entering
- The location of the properties in relation to the incident and the likely reduction in the effect of the material the greater the distance from the release
- The demographics of the people involved and their resistance to the nature of the hazardous material, for example their age or health condition
- The location of any at risk groups, for example, at hospitals, homes for the elderly, schools etc.
- The air exchange for a building – what equipment is in place (air conditioning systems) and can they be switched off?
- The time of day and how this may affect the demographics of the community and the number of people in the affected area
- Vehicles are not generally accepted to be a suitable location in which to shelter
- How to communicate the message to shelter-in-place and to explain the process of shutting doors and windows and reducing any ventilation
- How to communicate the 'all clear' message and how often updates are likely to occur
- Liaising with the partner agencies to agree on how the shelter-in-place will be controlled and the public informed; this would be via the police or the public health agencies
- Weather conditions
When advising the public to evacuate consider:
- Liaising with the police services who will generally be responsible for carrying out the evacuation
- Recognising that fire and rescue service personnel may need to assist when police resources are limited and an evacuation is required immediately
- That when carrying out an evacuation, the area closest to the incident should be evacuated first and, as more resources arrive, the evacuation can be extended
- The risk to responders carrying out the evacuation
- Liaising with the local authorities to establish a suitable location for an assembly point for displaced members of the public – ensuring that such an assembly point is out of the risk area and will remain so if weather conditions change (in particular wind direction or speed)
- Evaluating the nature of the release and the environment through which the public will need to travel to be evacuated.
- The demographics of the people being evacuated and the way a hazardous material may vary in its effect (for example, the elderly and young tend to be more vulnerable to hazardous materials)
- The availability of safe accommodation
- Communicating the evacuation (for example, using a fixed alarm system, responders with megaphones, door knocking, avoiding panic, radio and TV announcements)
- Establishing a safe holding area for members of the public being evacuated or consider a dispersal plan
- Establishing a method of identifying empty properties
Aerodrome emergency orders identify the key groups of people that could be affected by an emergency and outline the structures and processes that are put in place to provide care and assistance to them.
Reception centres provide care and shelter for people affected by an emergency. Establishing a centre also gives the emergency services an opportunity to collate information from the affected people and help communicate with them away from the trauma or danger of the incident area. The earlier the centres are set up and passengers taken away from the incident ground, the easier operations become for responding fire and rescue services.
To assist responding fire and rescue service personnel and other blue light services in controlling passengers evacuating from an aircraft, some aerodromes have introduced passenger emergency management systems (PEMS) to give evacuating passengers and air crew direction and guidance on a safe point to rendezvous having left the aircraft.
Systems will differ from one aerodrome to another, but primarily they are illuminated signs on the back of vehicles or freestanding signs with a loudspeaker giving visual and audible directions. These are erected in a safe location outside the inner cordon and within the outer cordon of the incident, upwind and uphill.
The aerodrome ground operations team normally operate these systems and fire and rescue service personnel simply need to be aware of their existence and, if required, to direct evacuating passengers to them, where immediate medical treatment and triage will be available from responding ambulance teams.
Fire and rescue services may be involved in detraining passengers from stranded rolling stock due to power failures, damage to overhead line equipment (OLE) or the third/fourth rail. Loose or disconnected parts of OLE and third/forth rail present a serious electrocution hazard.
The location of any damaged overhead line equipment and the risk of accidental contact must be considered. While damaged OLE is unlikely to be charged to maximum voltage, a significant residual current may well remain. Assume the OLE is live at all times.
The location of any damaged overhead line equipment must be confirmed before evacuation and routes should always avoid passing them. It should be remembered that the nearest or most appropriate point of safety to which passengers should be evacuated may be either ahead of or to the rear of the train.
There should be a suitable place away from the operational railway to which evacuees can be directed. The presence of a Network Rail mobile operations manager (MOM) or an appointed rail incident officer (RIO) will assist in agreeing a safe refuge area or egress route from the operational railway.
Ensure confirmation from Network Rail that train movements in the area have been stopped. The presence of the mobile operations manager and/or rail incident officer will ensure a greater degree of safety from train movements and track conditions during evacuation.
A site assessment should also consider the underfoot conditions, proximity of embankments, lighting, tunnels, and other infrastructure hazards, along with the presence of a suitable safe route from the train to the most practicable egress point.
Egress from the train should be conducted using on-train emergency ladders. The evacuation should always be carried out from a vehicle unaffected by damaged overhead line equipment to avoid accidental contact.
Where large numbers of people are evacuated from a station or rolling stock, it is important to provide appropriate, timely information as this will help to prevent potential further incidents occurring.
When dealing with incidents involving large numbers of people, either directly or as observers, their welfare should be considered to protect their dignity. Inclement weather can have an impact on displaced people.
The evacuation of large numbers of people from an incident involving a roadway should be carried out in conjunction with the police, highways agency and other relevant agencies following a sharing of situational awareness.
Evacuation should always be carried out in such a way as to minimise the risk to the passengers. It should be remembered that the nearest or most appropriate point of safety for passenger evacuation may be across a busy terminal.
There should be a suitable place away from operations to which evacuees can be directed. The ambulance service, police service and port authorities will assist in agreeing safe refuge and egress from the vessel. It is important to gain confirmation from the port or harbour master or control tower that vehicle movements in the area have been stopped.
A site assessment should consider the underfoot conditions and proximity of infrastructure hazards, along with a suitable safe route from the vessel to the most practicable egress point or safe haven.
Egress from the vessel may be conducted using on board emergency escape chutes, gangways, accommodation ladders or vehicle loading ramps.
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.
Wildfires may require different tactics for evacuation from the rural environment. In particular, consideration should be given to:
- The wide geographic area that may be involved
- The potential for relocation to other towns or villages
- The transport and other logistics required for relocating evacuees
- The time it will take to evacuate those at risk
Liaise and consult with developers, owners, occupiers and responsible persons of buildings, to provide expert safety advice and to develop tactical guidance and support arrangements for the associated hazards and actions to take to confirm the occupier’s evacuation policy or strategy
- Make arrangements with partner agencies to develop appropriate means to evacuate people from emergency incidents
- Ensure that incident commanders have access to pre-determined evacuation plans for venues that have developed these
- Develop guidance and support arrangements for the safe evacuation of people
- Develop emergency plans and support arrangements in conjunction with local resilience forum partners for evacuating large numbers of affected people at a major transport incident
- Test and exercise plans to ensure assumptions are realistic and achievable
- Participate in pre-planning and exercises for evacuating medical facilities
- Provide access to meteorological information (for example, the Met Office's FireMet in 'hazard manager') for predicting weather conditions
- Provide on-scene mapping facilities to enable risk areas to be identified and actions to be planned and documented
- Consider how messages can be communicated to large numbers of the public in a relatively short period of time (for example, radio and television reports or generic leaflet drop)
- Consider liaising with partner agencies who have air monitoring capabilities, public communication responsibilities and specialist knowledge on issues relating to human health
- Recognise the impact and resource requirements needed for an evacuation of a large number of the public
- Identify whether evacuation or stay put is the best action and record rationale for decision
Consider the impact of the incident on the local community and consider a shelter in place strategy
- When evacuation is necessary, identify the number of people and develop a strategy
- Ascertain the availability of pre-arranged evacuation plans
- Establish a safe evacuation point and consider safe egress routes and refuge points
Consider evacuating people affected by the incident to a relative place of safety
Ascertain the likely numbers of people affected and the impact on responders accessing the scene
Make contact with the relevant authorities for advice on evacuation arrangements and progress