106 AFP-3030 Programming Manual — P/N DOC-01-032:A 26/06/2015
Intelligent Sensing Applications Pre-Alarm
C.2.5 Cooperative Multi-Detector Sensing
Cooperative Multi-Detector Sensing is the ability of a smoke detector to consider readings from
nearby detectors in making alarm or pre-alarm decisions. Each detector can include up to two other
detectors in its decision. Without statistical sacrifice in the ability to resist false alarms, Cooperative
Multi-Detector Sensing allows a detector to increase its sensitivity to actual smoke by a factor of
almost 2 to 1. Ion, photo and laser detector types can participate. Cooperative Multi-Detector
Sensing also allows the combination of ionization with photoelectric technology in reaching an
alarm decision. The figure below shows a graph representing Cooperative Multi-Detector Sensing:
Figure C.5 Cooperative Multi-Detector Sensing
C.3 Pre-Alarm
C.3.1 Definition
The Pre-Alarm function is a programmable option which determines the system’s response to real-
time detector sensing values above the programmed setting. Use the Pre-Alarm function to get an
early warning of incipient or potential fire conditions. There are two levels of Pre-Alarm:
• Alert (Refer to “Alert Level” below)
• Action (Refer to Appendix C.3.3, “Action Level”, on page 107)
Alert and Action Pre-Alarm settings are set with point programming. Unique Pre-Alarm sensitivity
levels (PA) for individual detectors are listed in
Appendix C.4, “Detector Sensitivity Settings”, on
page 107.
The LEDs on detectors polled in FlashScan mode will light steady green when in prealarm.
C.3.2 Alert Level
Alert Functions
The control panel software, in addition to checking for alarm levels, checks for Prealarm thresholds
for each addressable, intelligent smoke detector programmed for Pre-Alarm. If a detector’s real-
time sensing level exceeds the programmed Alert threshold, the control panel indicates a Prealarm
condition for the detector. The control panel does the following functions when a detector reaches
prealarm level:
• The Prealarm message is sent to the History buffer and to installed printers. The message is
sent (and time stamped) at the time that it first occurred. This historical data could provide
valuable information about the progress of a fire.
• The PRE-ALARM LED flashes and the panel sounder pulses until acknowledged.
• Zone Z000 (general alarm) or any other zone and the System Fault and System Alarm relays
do not activate.
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