User Manual

Siemens Switzerland Ltd 21
Building Technologies Division
3.3. Smoke control
3.3.1. Objectives
Smoke presents the greatest danger to life in the case of a fire. This is not only due to smoke inhalation injuries
and asphyxiation, but also due to smoke-filled corridors and staircases, which make evacuation considerably more
difficult and raise panic levels. For this reason it is imperative that smoke is restricted to the immediate locality of
the fire for as long as possible and is actively extracted from the building by appropriate means. Many buildings
are subdivided into fire compartments by fire doors and fire-resisting walls and floors. Customized smoke control
systems are designed to restrict the spread of fire and smoke, conducting the heat and smoke through the
installed ducting into the external atmosphere (generally through the roof of the building).
3.3.2. Elements
Fire doors Fire doors are used to compartmentalize a building, effectively restricting smoke
to the immediate locality of the fire. Many fire doors are held open magnetically
and these will normally swing closed as the retaining power is removed when the
fire control panel detects a fire.
Smoke dampers and
extraction fans
Effective smoke control prevents it from spreading in an uncontrolled manner
throughout the building, for example, via the heating, ventilation and air
conditioning system. This is achieved by smoke dampers which are installed in
the air ducts and are controlled automatically by the fire protection system. The
smoke is conducted through the air ducts to the outside world and the efficiency
of this process can be increased by the use of extraction fans.
3.4. Evacuation
3.4.1. Objectives
The basic objective is to move those people in an endangered area to a place of safety. The evacuation of a
building, however, is a drastic measure and should only be initiated when absolutely necessary.
The measures required to ensure safe evacuation will vary from building to building and priority must be given to
the requirements specified by the local authorities. Unfortunately these regulations differ widely from country to
country and the local fire services often specify very distinct and individual evacuation concepts for buildings
within their jurisdiction.
Key objectives:
• People working in the building should remain undisturbed for as long as possible.
• An evacuation should be initiated as soon as it becomes unavoidable.
• The evacuation should be carried out as quickly and efficiently as possible.