User Manual

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Siemens Switzerland Ltd
Building Technologies Division
4.4.4. Evacuation instruction
The single most important factor in a successful evacuation is providing people with clear instructions telling them
what they have to do. In such environments it is generally considered inadequate to rely on the visitors being able
to correctly interpret the meaning of the acoustic ‘alert’ and ’evacuate’ signals from simple sounders.
As described earlier, the Staff Alarm strategy relies on members of staff providing directions to visitors in such a
way that an efficient, panic-free evacuation will be carried out as soon as it is considered necessary. In larger
buildings this will require some form of public address system (or voice alarm system) to ensure that everyone
hears and understands the instructions being given.
In a large modern museum a voice alarm system would be recommended, which provides a microphone input
that allows the responsible fire officer to ‘speak’ directly to people in specific parts of the building as required.
4.4.5. Escape routes
Once the visitors have understood that they need to evacuate the building, following the appropriate escape
route must be made as straightforward as possible. Clear signage is essential as the best escape route may not
necessarily be the route that people would take under normal circumstances. In an emergency situation the travel
distance to a place of safety must be as short as possible. The purpose of the fire exit signs is to help people reach
the nearest exit by the most direct route.
Travel distance The travel distance (or exit distance) should be measured from the farthest point
in a room to the door leading to a protected stairway or to the final exit of the
building. If there is only a single fire exit, then some guidelines recommend that
the travel distance should not exceed 18 m. If there is more than one escape
route, the acceptable travel distance is considered to be 45 m. However, in
historical buildings it will frequently be difficult to fulfill such stringent
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 particular 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), where a risk
profile is proposed for visitors in a museum. 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 re-hanging
any doors that were designed to open in the other direction may not always be
practicable.
Escape route identification Visitors are not generally familiar with the layout of the building, making it
imperative that the emergency escape routes are adequately signposted to help
guide all occupants to a place of safety. As there may be numerous visitors who
do not speak the national language, 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 positioning of such signs in historical buildings can be the subject of heated
discussions as indiscriminate use may certainly affect the aesthetics of the rooms
and corridors of a building. A compromise solution may involve the use of signs,
which are not permanently fixed to the doorways, or are more aesthetically
compatible with their surroundings.
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.).