Why you should activate the Alarm Verification Facility in your Fire Panel

AVF, or Alarm Verification Facility, in the context of fire detection and alarm systems, refers to a process or feature that verifies the legitimacy of an alarm signal before action is taken. It aims to reduce false alarms by confirming whether the detected signal actually represents a real fire emergency. 

Australian Standards AS 4428.1:1998 and AS 7240.2:2018 provide a framework for manufactures of Fire Detection Control and Indicating Equipment("FDCIE") to implement Alarm Verification or Type A, Alarm Dependency.

AVF is defined in both standards as follows;

AS4428.1:1998
1.4.3 Alarm verification facility (AVF) —
that function of the control and indicating equipment that verifies an alarm signal so that a spurious signal does not initiate an alarm signal to the monitoring service, ACF functions and alarm warning systems.

or

AS 7240.2:2018
4.4.12.1 Type A dependency
Following the receipt of an initial alarm signal from a fire detector, the entry to the fire alarm condition may be inhibited until the receipt of a subsequent alarm signal from the same fire detector, or from a fire detector in the same fire detection zone. In this case, the following shall apply.

1. The mode of operation shall be configurable at access level 3 for individual fire detection zones or individual detectors.
2. The initial alarm state need not be indicated.
3. It shall be possible to receive a subsequent alarm signal within 60 of the receipt of the initial alarm signal.
4. The initial alarm state shall be automatically cancelled within 30 min of the receipt of the initial alarm signal.
5. Information on the values of the configured delay times shall be accessible at access level 2 or 3.

When the initial alarm signal is received, the AVF will suppress the alarm signal from the designated zone, prompting the triggering device to reassess the environment following a delay ranging between 10 and 20 seconds.

If any alarm signal is received within 120 seconds after the resampling of the alarm zone's environment, it shall be treated by the Control and Indicating Equipment (CIE) as a legitimate alarm.

Should an alarm signal be received later than 300 seconds after the resampling of the alarm zone, the signal shall be subjected to alarm verification.

For Type A, Alarm Dependency, from AS 7240.2:2018 the requirements are different, given this Standard is an modification of ISO 7240-2:2017 to suit Australia.

In general terms, AS 7240.2:2018 states "Following the receipt of an initial alarm signal from a fire detector, the entry to the fire alarm condition may be inhibited until the receipt of a subsequent alarm signal from the same fire detector, or from a fire detector in the same fire detection zone."

According to Clause 3.3 of Australian Standard AS 4428.1:1998;

Where dependency on more than one alarm signal is used, it shall comply with the alarm verification facility requirement for CIE complying with AS 4428.1 or the type A requirements for CIE complying with AS 7240.2.

The following shall not be subject to dependency on more than one alarm signal:

1. Manual call points.
2. Subindicator panels.
3. Detectors used to activate fire suppression systems.
4. Detectors installed in hazardous areas.
5. Fire suppression systems.
6. Optical beam-type smoke detectors where a beam-interrupt fault overrides the alarm state.
7. Alarm zones containing fixed temperature (static) response heat detectors only.
8. Devices or equipment subject to other alarm confirmation methods, such as type B or type C dependency complying with AS 7240.2, dual zone operation or alarm acknowledgement facility.
9. Detection verification algorithms that will cause a delay in the detector alarm response of more than 60s.
10. Detectors that may take more than 60 s to become functional after a reset.

NOTE: Since the provision of alarm verification delays the initiation of an alarm signal, it is desirable that it only be provided where other efforts to eliminate unwanted alarm signals have been unsuccessful.