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SCS Series Manual —
P/N 15712:L 7/18/16
The SCS⁄SCE
Building-Specific Operation and Programming Examples
Equations such as these must be created to allow for all elements of the smoke control system to operate as they would in a fire condition.
Once created they must be
OR
ed together with the existing equations for a particular device. For instance, the stairtower fan, elevator fan,
and dampers could use Z199 to activate the control modules, which in turn will open or turn on the devices. The supply and exhaust fans
could use Z200 to activate the control modules, which would turn on the fans five minutes after the dampers open. For example, the new
equation for the elevator fan would be:
OR(Z199 Z201 Z202 Z203 Z204 Z205 Z206 Z207 Z208 Z209)
Once all programming on the FACP has been completed, the system can be tested for proper operation. If the testing is successful, the smoke
control system would be fully operational.
3.10.2 Non-dedicated System Design
Figure 3.35 will also be used to depict a Non-dedicated System example. Once again, the building is eight stories, where each floor is desig-
nated as a smoke control zone. There is also a stairtower and elevator shaft to consider. The system depicted here will utilize pressurization
where all nonsmoke zones will be pressurized. The stairtower will use a multiple injection system and the elevator hoistway will only be
pressurized to prevent the migration of smoke (it will not be used for evacuation). We will also assume that the FACP and associated devices
for fire protection are already installed. There are six smoke detectors and one pull station on each floor. There is also one waterflow switch
per floor on the sprinkler system to detect the flow of water on each floor.
In the dedicated system, all fans were defined as normally off, all supply dampers and all exhaust dampers were defined as normally closed
because the system was not used for any purpose other than smoke control. In the Non-dedicated System, the stairtower and elevator hoist-
way portion of the system will function the same as the dedicated system, but the HVAC equipment serves the dual purpose of HVAC control
during normal conditions, and smoke control during a fire condition. Because of this, the dampers and fans for the zoned smoke control por-
tion of the system can not be assumed to be in any one state. In order to ensure that smoke control takes precedence over HVAC functions,
the control modules, which normally control the devices (fans or dampers), will be configured as Form-C relays or be wired to control con-
tactors. The contactors will in turn control the devices and, if necessary, cut power from the HVAC controls, as shown in Section 5 “Ratings
and Wiring Diagrams”. The HVAC system for this example is a Central System with recirculation capability.
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 stairtower fan, one elevator hoistway fan, one HVAC supply fan, and one HVAC return fan.
There are also 33 dampers; two dampers on the supply duct per floor, two dampers on the return duct per floor, and one damper in the recir-
culation duct.
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. 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 monitored for the on state.
The dampers on each floor can be broken into two groups - supply dampers and return dampers. The dampers on the supply duct need to be
open for all nonsmoke zones and closed for the smoke zone, while overriding the HVAC controls. Since we do not know the current state of
the supply dampers, they need to have the capability to be opened and closed. The dampers on the exhaust duct need to be open for the fire
floor and closed for all nonsmoke zones, while overriding the HVAC controls. Since we do not know the current state of the exhaust damp-
ers, they need to have the capability to be opened and closed as well. 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 floor dampers will require verification of
when they are open and when they are closed.
NOTE:
The AM2020/AFP1010 must be programmed for receiving unit operation. Without this feature, troubles encountered during the
weekly testing may be restored at the conclusion of the test, and remain undetected.