User Manual

Siemens Switzerland Ltd

Building Technologies Division

Technological investigations have shown that malfunctions can occur in hard

disk drives when automated dry extinguishing systems are activated. These

malfunctions range from automatic shutdowns to more severe disturbances,

with a corresponding loss of data. Studies by independent organizations

concluded that it was primarily the high noise level generated by conventional

extinguishing systems during the discharge process, which caused the hard disk

drive malfunctions. Different factors can help to reduce the noise level generated

during a discharge, such as improving the room acoustics or extending the

discharge time. Research conducted by Siemens identified the nozzle design as

one of the main contributors to reducing the noise.

Kitchens The fire risk in kitchens is relatively high. This is due to a combination of the

cooking materials used (cooking oils, fats, etc.) and the heat from the hot

cooking equipment (hot-plates, ovens, vats, etc.). Kitchen fires are

predominantly fat fires, which often start spontaneously and rapidly generate an

intense heat. The flames are also fed by the highly combustible fat vapors and

can only be checked by interrupting the oxygen supply and reducing the

temperature of the cooking oil.

An additional problem related to kitchen fires is their inherent ability to spread

through the kitchen’s own air extraction system to the rest of the building. The

critical areas (e.g. cooking range, deep fat fryers, ovens and air extraction

system) should be protected by specially designed extinguishing systems. Wet

chemical fire extinguishers (Class F) should also be provided.

When extinguishing systems are used in commercial kitchens, then these are wet

chemical systems, which are installed immediately above the protection area or

within the air extraction hoods. They are stand-alone systems, which both detect

the fire and extinguish it automatically. The effectiveness of this extinguishing

agent relies on the cooling of the hot surfaces together with a highly efficient fire

suppression mechanism. On contact with the hot fat, the extinguishing agent

foams up to produce a soapy layer. This creates a dense barrier between the hot

fat and the surrounding air, effectively preventing the highly volatile fat vapors

from escaping and reigniting the fire.

If the building is equipped with a sprinkler system, then this should be extended

to protect the other parts of the kitchen. However, it must be ensured that the

water spray from the sprinklers cannot reach the critical areas of the cooking

range, deep fat fryers, ovens and air extraction system.