Specifications

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APPENDIX-E: ALARM VERIFICATION
Alarm verification provides FS-250 with a way to verify an alarm from area type addressable
smoke detectors connected to intelligent loops (FS-DLC). This feature reduces the incidence
of false alarms. Only detectors that do not contain an integral alarm verification feature can be
used.
Addressable detectors connected to FS-DLCs indicate that an alarm condition has been
detected. If the device is subject to alarm verification, the FS-DLC alerts the control panel that
the device has entered verification but is not yet considered to be in alarm. The FS-DLC starts
a timer using the FS-250 system Retard-Reset Period. When the timer expires, the FS-DLC
begins the fixed 60-second confirmation period. If the device is no longer in alarm during the
confirmation period, the verification cycle is considered complete and detection of a
subsequent alarm from that device results in the verification cycle restarting. If the device still
reports in the alarm state during this confirmation period, the alarm condition is reported to the
control panel and the system annunciates the alarm condition.
See the figure below for a graphic illustration of Alarm Verification.
NOTE: For devices connected to the FS-DLC, the Detector Restart period is 0
seconds.
ALARM VERIFICATION TIMING DIAGRAM
ALARM VERIFICATION PERIOD
RETARD-RESET-RESTART PERIOD -- MAXIMUM 60 SECONDS
NO ALARM AT CONTROL UNIT
CONFIRMATION PERIOD -- 60 SECONDS
ALARM REQUIRED AT CONTROL UNIT
OPTIONAL
REGION
A
A - Smoke detector goes into alarm.
AB - RETARD-RESET PERIOD (Control Unit) - Control unit senses detector in alarm and retards (delays) alarm signal, usually by de-energizing
power to the detector. Length of time vaires with design. (11 to 55 seconds)
BC - RESTART PERIOD (Detector Power-up Time) - Power to the detector is reapplied and time is allowed for detector to become operational for
alarm. Time varies with detector design.
AC - RETARD-RESET-RESTART PERIOD - No alarm obtained from control unit. Maximum permissible time is 60 seconds.
CD - CONFIRMATION PERIOD - Detector is operational for alarm at point C. If detector is still in alarm at point C, control unit will alarm. If detector
is not in alarm, system returns to standby. If the detector re-alarms at any time during the confirmation period the control unit will alarm.
DE - OPTIONAL REGION - Either an alarm can occur at control unit or restart of the alarm verification cycle can occur.
AD - ALARM VERIFICATION PERIOD - Consists of the retard-reset-restart and confirmation periods.
t=0 Seconds t=n Seconds
B
C
D
E
CONTROL UNIT
RETARD-RESET PERIOD
DETECTOR RESTART
(POWER-UP) PERIOD