Basic Smoke Control System Operation - Honeywell NOTIFIER SCS Series Operation And Installation Manual

Basic Smoke Control System Operation

Zoned smoke control can also be accomplished in situations where an HVAC system serves only one smoke control zone. An example would
be a three floor building where each floor is a separate smoke control zone that has a separate HVAC system serving each floor. Zoned
smoke control can be achieved by putting the HVAC system in the modes listed below:
• Smoke Zone: Turn off supply fan, close supply damper, open exhaust damper, turn on return fan
• Nonsmoke Zone: Turn off return fan, close return damper, open supply damper, turn on supply fan
2.6 Basic Smoke Control System Operation
Now that the fundamentals of how smoke moves, the basic types of smoke control systems, and the equipment necessary to perform smoke
control have been described, we need to know how to utilize these systems to prevent the movement of smoke. This section is used to pro-
vide a basic understanding of how the equipment is used to configure and operate a smoke control system for a particular building applica-
tion.
No matter what type of smoke control system is used, all smoke control systems utilize the operation of fans (turning on or off) and dampers
(opening or closing) for the control of smoke. In general, there are only two situations to consider when controlling a fan:
• The capability to turn a fan on, regardless of its current state
• The capability to turn a fan off, regardless of its current state
By combining the above two situations, a third situation can be obtained, the capability of turning a fan on and off. For each of the above sit-
uations, you may wish to verify the following:
• When the fan is on
• When the fan is off
Once again by combining the two situations a third results, verifying when a fan is on and when it is off. For a fan or damper to be used in a
smoke control system, the system must not only be able to control the device, but it must be able to verify what state it is in (ON/OFF or
OPEN/CLOSED). By combining the four basic capabilities shown above, smoke control systems can have nine different scenarios for con-
trol of a particular fan. The above argument also applies to the opening and closing of dampers. The full scenarios are explained below:
Scenario 1 The capability to turn a fan off. Verify only when the fan is off.
(The capability to close a damper. Verify when the damper is closed.)
Scenario 2 The capability to turn a fan off. Verify only when the fan is on.
(The capability to close a damper. Verify when the damper is open.)
Scenario 3 The capability to turn a fan off. Verify when the fan is on and when it is off.
(The capability to close a damper. Verify when the damper is open and when it is closed.)
Scenario 4 The capability to turn a fan on. Verify only when the fan is off.
(The capability to open a damper. Verify when the damper is closed.)
Scenario 5 The capability to turn a fan on. Verify only when the fan is on.
(The capability to open a damper. Verify when the damper is open.)
Scenario 6 The capability to turn a fan on. Verify when the fan is on and when it is off.
(The capability to open a damper. Verify when the damper is open and when it is closed.)
Scenario 7 The capability to turn a fan on and off. Verify only when the fan is off.
(The capability to open and close a damper. Verify when the damper is closed.)
Scenario 8 The capability to turn a fan on and off. Verify only when the fan is on.
(The capability to open and close a damper. Verify when the damper is open.)
Scenario 9 The capability to turn a fan on and off. Verify when the fan is on and when it is off.
(The capability to open and close a damper. Verify when the damper is open and when it is closed.)
For example, Scenario 8 is capable of turning a fan on and off, as well as, verifying when the fan is on. Regardless of its current state, this fan
can be turned on or off when a fire is detected. Also, verification when the fan is turned on in the response to a fire will occur, usually in the
form of an illuminated indicator. When the fan is in its normal state or when it is turned off, no verification in the form of an illuminated indi-
cator takes place.
The following example illustrates how a system of fans and dampers is utilized for smoke control. Figure 2.23 shows two zones of a multiple
smoke control zone layout. All the smoke control zones are served by two fans; one fan is used to supply air and the other is used as a return.
There are two vents per zone (one supply, one return) and dampers are located on each vent. If a fire should occur, the smoke zone must be
depressurized and all other zones must be pressurized. Depressurization of the smoke zone is accomplished by closing the supply damper
SCS Series Manual — P/N 15712:L 7/18/16
Concepts of Smoke Control
29