Pre-Alarm (AWACS™) Applications Overview
162 AFP-200 PN 15511:H2 10/14/2002
Appendix G Pre-Alarm (AWACS™) Applications
G.1 Overview
The control panel includes a facility to give early warning of incipient or potential fire
conditions (U.S. Patent Pending). This is a two-level (Alert and Action) Pre-Alarm
function called AWACS™ (Advance Warning Addressable Combustion Sensing).
G.2 Pre-Alarm Applications
G.2.1 Pre-Alarm Alert Level
The control panel software, in addition to checking for alarm levels, checks for
Pre-Alarm thresholds for each ionization or photo smoke detector (not analog thermal
detectors). If a Pre-Alarm level is reached that exceeds the programmed Alert or Action
threshold, the appropriate condition appears on the panel display.
Alert Level Functions
The system performs the following functions when a detector reaches an Alert level:
• The Pre-Alarm LED flashes and the panel sounder pulses until acknowledged.
• An Alert message is sent to the history file and to installed peripheral devices, such
as the LCD-80 and printer. The Alert message is also time-stamped (with the time
that the Alert occurred) to provide historical data about the progress of a fire.
• Zone 99 activates. No other zones or relays activate.
• The Pre-Alarm indication automatically restores to normal if its sensitivity drops
below Alert level. Zone 99 clears automatically when no Pre-Alarm conditions
exist.
• A subsequent alarm, or an Action level condition for this detector will clear the
Alert indication.
Example of a Pre-Alarm Alert Condition
Figure 151 shows a sample panel display of a photoelectric detector that reaches the
Pre-Alarm Alert condition. In this example, zone 99 is programmed to Alert= 40% of
Alarm. An Alert will occur at measured smoke levels that exceed 0.40 x 2.0% per foot
(30.48 cm) obscuration (low) = 0.80% per foot (30.48 cm) obscuration.
Figure 151 Sample Screen in Alert Condition
0.80 is a real-time display, updated every few seconds, to show the current reading of
this detector. In this example, the reading equals 40% of alarm, which puts the control
panel into Alert condition.
PREALM@SMOKE(PHOTO)
WEST@HALLWAY@FLR@5
ALERT: 0.80/2.00%@
12:00P@12/25/97@D13
PREALM is the Pre-Alarm
status banner.
2.0% is the programmed
alarm threshold (2.0% per
foot (30.48 cm) obscuration
is the low sensitivity setting).
Alert indicates that the Alert
level is reached.
Smoke (Photo)
is the type code
of the detector.
0.80 is the reading of smoke relative
to the sensitivity setting
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