Civil Engineering Reference
In-Depth Information
to the escape routes. Examples of pre-movement
behaviours are:
➤
Gathering together others, e.g. children
➤
Fire fi ghting
➤
Collecting personal belongings.
➤
Completing the activity being undertaken
➤
Trying to verify reality or importance of the warning
Well understood and rehearsed emergency evacu-
ation procedures help individuals maximise their recogni-
tion of the fi re danger and reduce any of the above,
possibly unnecessary and irrelevant, pre-movement
behaviours.
➤
Investigation, e.g. to determine source
➤
Safety activities, e.g. stopping machinery
➤
Security activities, locking tills
➤
Alerting others
Travel behaviours
If people perceive the building as unsafe then the nor-
mal response is to leave a building as soon as possible.
Whether the decision to evacuate is delayed or taken
as soon as possible, once it has been made, individual
occupants will begin to travel through the escape routes.
Their behaviour in this phase of evacuation is then infl u-
enced by such factors as:
➤
Their role
➤
The number of people in the building
➤
Their distribution within the building at different times
➤
Their familiarity with the building
➤
Their familiarity with the route
➤
The characteristics of the occupants and the building.
Table 10.1 provides some examples of how these
factors or 'travel time determinants' can infl uence the
travel times of people with various roles.
Figure 10.4
Pre-movement behaviours affected by the
job in hand
Table 10.1
The characteristics of the occupants and the building interact and together determine the time required to escape
Travel time determinant
Example
Role of the individual
Those with responsibility for others during a fi re, such as parents, elder siblings, nurses, teachers, etc.,
will delay their evacuation to ensure those they are responsible for are ready and able to escape.
Others will have follower relationships and affi liations with such leaders.
Number and distribution
If there are a large number of people in the building, the travel time will be dependent on the maximum
of occupants
fl ow capacity of the escape routes.
This is particularly relevant at times where the distribution of people in the building is concentrated in
certain areas, such as a canteen where there may be normal circulation problems.
Crowd fl ow can cause danger and prohibit safe escape but the fl ow can be modifi ed by emergency
evacuation messages.
Familiarity with the
People nearest to a familiar entrance route typically leave by that entrance. Familiarity means that even
escape route
when this route is not close, there is a tendency to return to it and use it as the escape route.
Regular use of a fi re exit route has a strong infl uence on people's inclination to leave by that fi re exit in
an emergency.
'Emergency Exit Only' signs, far from encouraging use of an exit in an emergency, may have a
detrimental rather than positive effect on travel times. It reduces people's familiarity with the route and
reduces their inclination to move towards it in an emergency.
The characteristics of the
People who are wide awake, fi t and mentally alert have the potential to escape quickly whereas others
occupants and the building
who may be less fi t or alert will take longer to escape.
In some cases individuals may be unconscious or non-ambulant in which case they will need extra
consideration when planning emergency evacuation procedures.
In the case of secure accommodation, e.g. detention centres and prisons, the occupants of a building
may wish to leave faster than the emergency procedure allows.
