User Manual

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Siemens Switzerland Ltd
Building Technologies Division
3.2.6. Alarm Verification Concept AVC
Figure 3.2.6-1 Alarm Verification Concept
The Alarm Verification Concept (AVC) allows in-house personnel to carry out a local investigation before the
municipal fire service is alerted or the building evacuated. This reduces the number of unnecessary calls and is
based on a dual timing principle. It is only applicable to the “day/manned” mode of the fire detection system. In
the “night/unmanned” mode (when a local investigation cannot be ensured) the fire service will be alerted
without delay. Manual call points and sprinkler flow switches also alert the fire service without delay (at all times).
In the “day/manned” mode any alarm initiated from an automatic smoke detector will start timer T1. If T1 times
out without any response from an operator, the fire service is called immediately. If the alarm is acknowledged on
the fire alarm panel while T1 is running, the system recognizes this as a sign that an operator is present. In this
case, timer T2 is started for a predetermined investigation period. The duration of this investigation period should
be determined in consultation with the fire service.
If the local investigation verifies the existence of a major fire, the fire service can be summoned immediately by
simply activating any manual call point. The fire service will also be called if T2 times out. On the other hand, if
local investigation establishes that only a minor, easily dealt with fire exists, the fire alarm can be reset while T2 is
still running.