User Manual

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4.4.6 Escape route design considerations
Travel distance
The travel distance (or exit distance) is measured from the
farthest point in a room to the door leading to a protected
stairway or to the final exit of the building. The minimum
recommended travel distances for applications with a
single escape route and for those with multiple escape
routes are defined in country-specific guidelines.
Exit width
The acceptable width of emergency exit doors (and exit
routes in general) is not only determined by the number
of people in the building, but the characteristics of those
people and the estimated fire growth rate in the building.
This approach is specified (for example) in the UK “Code
of practice for fire safety in the design, management and
use of buildings” (BS 9999: 2008)
[2]
, where a risk profile
(A1) is proposed for students in a classroom. The number
of available exits and the width of those exits can then be
used to determine the maximum number of people
permitted in the building at any one time.
Escape route doors
All doors should open in the direction of the fire exit
route; however, the re-hanging of doors that were
originally designed to open in the other direction may not
always be practicable.
Escape route identification
Although the majority of students will generally be
familiar with the layout of the building, it is still essential
that all emergency escape routes are adequately
signposted to help guide everybody to a place of safety.
As there may be a number of students who do not speak
the national language very well, the international
pictogram signs (as described in ISO 7010) should be
used. The general guideline is that an escape route
directional sign should be readily visible from any location
within the building.
The escape route should be regularly confirmed by
repetition signs, especially at “decision” points, e.g. where
corridors meet or open onto landings. All evacuation or
escape plans should conform to the format as described
in ISO 23601. The ambient lighting levels should also be
taken into account when determining which type of sign
should be used (e.g. back-lit, reflective, etc.). The problem
with this type of sign is that they may not be easily visible
in smoky conditions. For this reason the concept of way
guidance is becoming more widespread in new buildings.
Way guidance
To complement emergency escape signage, way guidance
equipment can be very useful in helping people to follow
exit routes. Way guidance systems usually consist of
photo luminescent material, lines of LEDs, or strips of
miniature incandescent lamps, forming a continuous
marked escape route at a lower level (e.g. handrail or
floor). These systems have proven particularly effective
when visibility is already affected by smoke. Such
technology can easily be integrated into modern schools
and universities.
Emergency lighting
The primary purpose of emergency lighting is to
illuminate the escape routes, but it can also be helpful in
illuminating other safety equipment. Following a power
failure the emergency lighting should automatically
switch on within a few seconds. The size and type of the
premises and the risk to the occupants will determine the
complexity of the emergency lighting required.