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SCS Series Manual —
P/N 15712:L 7/18/16
The SCS⁄SCE
Building-Specific Operation and Programming Examples
.
3.10.1 Dedicated System Design
Preliminary Design Considerations
Once the type of system has been determined, the designer must determine the number of fans and dampers that are to be controlled/moni-
tored. In this example we have four fans; one for the stairtower, one for the elevator hoistway, one for the supply of air to pressurize all non-
smoke zones, and one for the exhaust of smoke from the smoke zone. There are also 32 dampers; two dampers on the supply duct per floor,
and two dampers on the exhaust duct per floor.
The next step is to determine the capabilities of each fan/damper and the corresponding switch group type. All four fans need to have the
capability to turn on in response to a fire. Since the fans are normally off, the fans do not need to have the capability of being turned off in
response to a fire. We do want to ensure that the fans turn on when a fire is detected, so the fans also require the capability of being moni-
tored for the on state.
The dampers in this example can be broken into two groups - supply dampers and exhaust dampers. The dampers on the supply duct need to
be open on all nonsmoke zones and closed for the smoke zone. Since the supply dampers are normally closed, they only need the capability
to be opened. The dampers on the exhaust duct need to be open for the fire floor and closed for all nonsmoke zones. Since the exhaust damp-
ers are normally closed, they only need to have the capability to be opened. It is extremely important to make sure that the dampers which
need to be open are open and that the dampers which need to be closed are closed, so for this example all dampers will require verification of
when they are open and when they are closed. The results of the capabilities required for each device are as follows:
Stairtower
Supply
Fan
Return
Fan
Elevator
Shaft
Two Supply and
Two Return Dampers at
each Floor
Stairtower
Fan
Elevator
Hoistway Fan
Roof
Floor 8
Floor 7
Floor 6
Floor 5
Floor 4
Floor 3
Floor 2
Floor 1
Figure 3.35 Eight Story Building
Stairtower Fan (1): capability to turn on and verify on state
Elevator Fan (1): capability to turn on and verify on state
Supply Fan (1): capability to turn on and verify on state
Exhaust Fan (1): capability to turn on and verify on state
Supply Dampers (16): capability to open damper and verify open and closed state
Exhaust Dampers (16): capability to open damper and verify open and closed state