User Manual

Siemens Switzerland Ltd

Building Technologies Division

4.3. Smoke control

4.3.1. 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.

Smoke may also cause considerable damage to room furnishings, paintings or other artifacts on exhibition.

Consequently, any measures which could restrict smoke to the immediate locality of the fire for a period of time

should be taken into consideration during the risk assessment process. Implementing smoke control measures in

existing buildings is feasible, but this would almost certainly require structural modifications that could have a

considerable impact on the authenticity of the building structure.

However, in modern, purpose-built museums, libraries and art galleries etc. smoke control should form an integral

part of the design process. In particular care must be taken to ensure that such buildings are subdivided into fire

compartments by fire doors and fire-resisting walls and floors. Customized smoke control systems will be

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).

4.3.2. Addressing general weaknesses

Compartmentalization Historical buildings were built when the mechanisms determining the spread of

fire were not well understood. Continuous roof spaces over entire buildings,

hidden voids behind plasterwork and feedthroughs left by the various installation

activities over the years all contribute to increase the risk of fire spreading rapidly

throughout the building.

The challenge is to find ways to restrict the spread of fire to the immediate

vicinity where the fire was initially detected. Compartmentalization is the process

of creating so-called fire compartments and finding the most effective ways of

preventing smoke and fire from spreading to any of the neighboring

compartments. In historical buildings this process is particularly challenging and

requires ingenuity, flexibility and experience to achieve the best results from

both the point of view of the fire protection specialist and the conservationist.

Fire doors Fire doors are used to compartmentalize a building, effectively restricting smoke

to the immediate locality of the fire. Fire doors are generally held open

magnetically and will swing closed as the retaining power is removed when the

fire control panel detects a fire.

The doors usually found in historical buildings present a number of challenges:

· They often do not fit as well as they should

· They are often relatively thin, with fire ratings insufficient to prevent

the spread of fire for more than a few minutes

· It is often difficult to install any auto-closing mechanism

Modifying the fire resistance of the doors is frequently impracticable; however, if

possible the doors should be fitted with an automatic closing mechanism (as

described above). The ill-fitting aspect may also be addressed by fitting

intumescent strips on the edges of the doors. These strips expand when exposed

to heat and can be effective in helping to restrict the spread of fire and smoke.