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Chapter 1: Fire geometry and smoke movement in buildings
Electrical power requirements
All electrical installations must meet the requirements of
NFPA 70, National Electrical Code, in addition to
building code requirements. Normal electrical power
serving air conditioning systems will generally have
sufficient reliability for nondedicated zoned smoke
control systems.
Standby power for dedicated smoke control systems and
their control systems should be adequate for the
expected duration of a fire event.
Programming functions
Regardless of the type of smoke control system
installed, the control and programming device functions
will fall into three general categories:
•
The operation of fans: turning ON or OFF
•
The operation of compartmenting components
(dampers, doors, louvers, walls, or windows): to
OPEN or CLOSE
•
The toggling of HVAC system components from their
normal, nonfire condition: AUTO or AUTO OFF
From the two control categories the monitoring or status
of smoke control equipment will also be needed or
required.
Verification of devices results in a confirmation of:
•
An ON (fan) or OPEN (dampers, etc.) condition
•
An OFF (fan) or CLOSED (dampers, etc.) condition
Control and monitoring functions will fall into one of the
categories shown in Table 1 for fans or compartmenting
devices. Monitoring will take the form of a control panel
LCD or annunciator LED. Table 1 provides a list of
control actions and the devices they monitor.
Table 1: Control and monitoring functions
Control action
AUTO OFF
Turn Fan OFF
Turn Fan OFF
Turn Fan OFF
Turn Fan ON
Turn Fan ON
Turn Fan ON
26
Resulting control or LED status
Overrides normal HVAC Controls
Only when Fan is OFF
Only when Fan is ON
Fan is ON & OFF
Only when Fan is OFF
Only when Fan is ON
When Fan is ON & OFF
Control action
Turn Fan ON & OFF
Turn Fan ON & OFF
Turn Fan ON & OFF
CLOSE Damper*
CLOSE Damper*
CLOSE Damper*
OPEN Damper*
OPEN Damper*
OPEN Damper*
OPEN & CLOSE Damper*
OPEN & CLOSE Damper*
OPEN & CLOSE Damper*
AUTO ON
* For this table, damper is used to denote any compartmenting device.
For each of the control actions in Table 1 the verification
of the result is displayed at a monitoring point. For
example, a controlling action to "Turn Fan ON or OFF"
with a monitoring requirement to verify "Only when Fan
is ON" results in the capability to turn the fan ON or OFF
when a fire is detected. In addition, verification when the
fan is turned on in response to a fire will occur, usually in
the form of an LED at the VM-1 smoke control panel.
Note:
Typically for a nondedicated HVAC fan, when the
fan is in its normal or auto operating state, there will be
suppression of the LED monitor point.
Control and monitoring examples
For Figure 21 on page 27 both fans and dampers are
used for smoke control. There are two zones for the
multiple zone arrangement. In the example, there is a
supply and return vent for each area with dampers
located at each vent and the system is equipped with
mechanical exhaust.
The smoke control system designer has determined that
in the event of a fire, the smoke zone must be placed
under a negative pressure and adjacent zones must
have positive pressures to prevent smoke intrusion.
VM-1 Smoke Management Application Guide
Resulting control or LED status
Only when Fan is OFF
Only when Fan is ON
Only when Fan is ON & OFF
When Damper is CLOSED
When Damper is OPEN
When Damper is OPEN & CLOSED
When Damper is CLOSED
When Damper is OPEN
When Damper is OPEN & CLOSED
Damper is CLOSED
When Damper is OPEN
When Damper is OPEN & CLOSED
Returns HVAC to normal operation
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