Pre-Alarm; Definition; Alert Level; Alert Functions - Notifier NFS-640 Programming Manual

Appendix C: AWACS™ Applications

Pre-Alarm

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 if you want to get an
early warning of incipient or potential fire conditions. There are two levels of Pre-Alarm:
Alert and Action Pre-Alarm settings are global. For instance, if you program Pre-Alarm for Alert, all
intelligent detectors programmed for Pre-Alarm are set to Alert (refer to "How to Select a Pre-Alarm
Level" on page 89). You can, however, set unique Pre-Alarm sensitivity levels (PA) for individual
detectors (refer to "Detector Sensitivity Settings" on page 90).

Alert Level

Alert Functions

The control panel software, in addition to checking for alarm levels, checks for Pre-Alarm 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 an Pre-Alarm
condition for the detector. The control panel does the following functions when a detector reaches pre-
alarm level:

Example of an Alert Level

When an ion detector is programmed for AL:7 and PA:5 (covered in "How to Use the Detector
Sensitivity Screen" on page 48), an Alert Pre-Alarm occurs at measured smoke detector levels that
exceed 1.00% per foot obscuration. When this happens the panel sounder and the
pulse, and displayed on the LCD, similar to the sample screen shown below appears:

Action Level

Action Functions

If you program a detector for Action Pre-Alarm and the detector reaches a level that exceeds the
programmed Pre-Alarm level, the control panel indicates an Action condition. Indication at the panel is
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• Alert (Refer to "Alert Level" below)
• Action (Refer to "Action Level" on page 88)
• The Pre-Alarm message is sent to the History buffer and to any installed terminal mode LCD-
80s and 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 - LED flashes and the panel sounder pulses until acknowledged.
PRE ALARM
• Zone F9 activates—but Zone 00 (general alarm) or any other zone, System Trouble relay and
System Alarm relay do not activate.
• The Pre-Alarm indication for this detector will restore automatically to normal if its sensitivity,
programmable to one of nine settings, drops below pre-alarm level. Zone F09 clears
automatically when no Pre-Alarm conditions exist.
• A subsequent alarm for this detector also clears the Pre-Alarm indication.
PREALM SMOKE (ION)
Figure 29 Sample Display of a Pre-Alarm Alert Condition
Pre-Alarm status banner
DETECTOR ADDR 1D102
084%/7 02:55P 071401 1D102
84%/7 indicates that 84% of
Pre-Alarm level 7 is reached.
NFS-640 Programming Manual P/N 51333:B 10/03/2003
Pre-Alarm
- LED
PRE ALARM