User Manual

Siemens Switzerland Ltd 19
Building Technologies Division
3.2.3. Alerting people in the building
In case of an alarm in data center, a step-by-step procedure should be accomplished to investigate first. After
verification of the situation if the situation cannot be contained or creates risks beyond the capabilities of the
personnel in attendance then a general alarm (evacuation) can then be activated
Acoustic alarms Acoustic alarm equipment is used to alert people in the danger zone as well as
internal intervention forces. Alarm devices are connected to the control unit
either directly with separated stub line or via a monitored output.
Visual alarms Visual alarms are used in very noisy environments such as generator rooms. For
these requirements visual alarm devices are required, checks should be made so
that they do not conflict with colors of other visual alarm devices creating
confusion as to their meaning.
Voice alarms Conventional alarm elements, such as flashing lights or horns, have limited
information content and are increasingly ignored also by trained staff. Using a
voice alarm system will provide clear voice information with the procedure to be
taken to reduce the danger in data centers. In addition the voice evacuation
system assures a programmed intervention information and evacuation
sequence in accordance with the evacuation plan. These systems enable step-by-
step alarm and evacuation depending on the situation.
In addition in data centers where extinguishing is used, a clear message is broad-
casted before starting the release of the extinguishing agent.
3.2.4. Alerting the public fire department
Alarm transmission to the intervention forces for the internal ‒ and external alarm or organization like the local or
remote fire brigade is accomplished by means of monitored dedicated lines, telephone lines, dialup connection,
radio connection, network connection or a combination of these transmission methods.
3.2.5. Alarm strategies
General alarms A general alarm is a defined audible signal which is sounded throughout the
building. The alarm is automatically activated by the fire detection system, or
manually from the control room. In the majority of buildings this should trigger
the immediate and total evacuation of the building.
Staged alarms Staged alarms are based on systems capable of generating an “alert signal” and a
different “evacuate signal”. Such systems may be applicable in large or complex
buildings. Generally those people potentially most at risk are those closest to the
point where the fire was detected or where the manual call point was activated.
These people should leave the building immediately and therefore an “evacuate
signal” will be sounded in this area. In other areas of the building an “alert signal”
will be sounded, indicating that people in those areas will only have to leave the
building if it becomes necessary, see evacuation.