Subsequent Automatic Activation; Automatic Activation By A Manual Pull Box; Manual Operation; Automatic Override Of Manual Activation - Simplex 4100U Application Manual

System Design Parameters,
Subsequent
Automatic
Activation
Automatic
Activation By a
Manual Pull Box

Manual Operation

Automatic Override
of Manual Activation
Continued
Once an automatic activation has occurred, subsequent alarm signals that would normally result in
the automatic actuation of a smoke control strategy shall be annunciated only. No fans or dampers
should be actuated in response to any subsequent automatic fire alarm signal in order to avoid the
possibility of defeating any smoke control strategies that are in process.
Activation of the smoke control system should be by smoke detectors and any other automatic
devices located within the zone covered by the specific air conditioning and ventilating system.
Manual fire alarm pull boxes should not be used to initiate specific zoned smoke control
strategies because such a pull box in an adjacent smoke zone may be pulled, thereby placing the
system in an incorrect mode.
It is desirable that the smoke control system be independently controlled from a smoke control
center which should have controls capable of overriding all other HVAC systems. A manual
command is capable of overriding either fully or partially any automatic activation that may be in
process. This is based on the assumption that any manual activation is performed by authorized
personnel in response to a known emergency condition.
Since smoke control operation must override any programmed HVAC function, it is considered
acceptable for the "Initial Automatic Activation" to override any manual control, initiated by any
other operator terminal other than the FSCS, which is currently in place.
NFPA Standard 92A requires that manual control initiated by the FSCS take precedence over
automatic control. Therefore, the smoke control system automatic programmed functions do not
override a manual FSCS control when a smoke control operation is initiated.
Example: When a switch at the FSCS is operated, the control point is activated or deactivated
at a priority higher than the automatic smoke control program or any other operator
terminal priority. This prevents the automatic smoke control program or manual
commands from other operator terminals from overriding commands initiated at the
FSCS.
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