User Manual
32
Siemens Switzerland Ltd
Building Technologies Division
4.3. Extinguishing systems
4.3.1. Sprinkler systems
These automatic systems use water as the extinguishing agent and provide a very effective protection both for
property and human life. The advantages of sprinkler systems are their high reliability and wide application
spectrum in the protection of people and material assets. Not only do they stand out due to their relatively simple
and robust technology, there is generally a plentiful supply of the extinguishing agent – water.
Further advantages:
• Sprinklers only extinguish areas which need to be extinguished.
• Sprinklers outside the fire source remain closed.
• Extinguishing water released reduces smoke and dangerous gases.
• The cooling effect of extinguishing water increases the safety of rescue forces.
Figure 4.3.1-1 Schematic of an automatic sprinkler system
Sprinkler systems consist of a network of water pipes with sprinkler heads distributed evenly on the ceilings and
positioned such that (in case of fire) all areas to be protected would be reached by the extinguishing water spray.
The sprinkler heads react individually to heat, opening to discharge a pressurized water spray when the
temperature is sufficiently high. In this way an incipient stage fire can be suppressed at its source as only those
sprinklers in the immediate vicinity of the fire will be activated, minimizing any unnecessary water damage.
The pipework which feeds the sprinklers is generally subdivided into sections. This enables parts of the system to
be taken temporarily out of service to allow maintenance and repair work to be carried out on individual sections.
Each of these sections is connected to the main water supply via an alarm valve, which serves several purposes.
Activation of one (or more) sprinkler heads causes a drop in pressure in the corresponding section causing the
alarm valve to open and allowing water from the main riser to pass through. At the same time an alarm
(generated by a pressure switch) will be automatically transmitted to a continuously manned location – usually
the fire service.