3-8
The application described in this section operates in the following way.
Figure 3-5 shows a timeline for this application.
• Activation of the suppression release system occurs when either two
automatic initiating devices (detectors) or a single manual release point
(pull station) are activated. Release of the suppression agent is delayed for
30 seconds after the second automatic initiating device activates and for five
seconds after a pull station activates.
• At any time prior to the actual release of the suppression agent, an operator
can prevent the release by pressing an abort switch. Agent release is
prevented for the duration of time this switch is held. If the condition that
triggered the alarm is cleared (i.e., the detectors or pull station are reset)
and a System Reset is performed, release of the suppression agent does not
occur. If however, the abort switch is released and the condition that
triggered the alarm is still present, a 10-second Abort Switch timer starts.
After the timer expires, release of the agent occurs.
• NAC appliances operate in a slightly different manner depending on
whether the activated device is an automatic or a pull station.
- Automatic Initiating Devices. When the first automatic initiating
device activates, the NACs in the suppression release area sound a
pre-signal (Slow March Time). When a second automatic initiating
device activates, this tone converts to Fast March Time. At the time of
agent discharge, the tones convert to Steady, indicating that the agent
has been released.
- Manual Release Point (pull station). When a manual release point
activates, the NACs in the suppression area sound a Fast March Tone.
At the time of agent discharge, the tone converts to a Steady tone,
indicating that the agent has been released.
1St STAGE ALARM
CONDITION
1ST STAGE ALARM SIGNALS
2ND STAGE ALARM CONDITION
2ND STAGE PRE-DISCHARGE SIGNALS
2ND STAGE
DISCHARGE
SIGNALS
SOLENOID
ACTIVATION
RELEASE TIMER
ABORT STATION ACTIVE
Automatic
Initiating
Device
Activated
System
Reset
TIMER
Pull Station or
2nd Auto.
Initiating Device
Activates
Figure 3-5. Dual Detector, Pre-Signal, and Abort Switch with Delay
Continued on next page
Dual Detector, Pre-Signal, and Abort Switch with Delay
Introduction
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