SCS Series Manual —
P/N 15712:L 7/18/16
27
Smoke Control System Types
Concepts of Smoke Control
2.5.3 Zoned Smoke Control Systems
Buildings can usually be divided into a number of smoke control zones where each zone can be separated from the smoke zone to prevent the
movement of smoke. The smoke control zone boundaries are usually partitions, floors, and doors that can be closed. Often each floor of a
building is chosen as a smoke control zone boundary. However, a smoke control zone can consist of more than one floor, or a floor can con-
tain more than one zone. Also, all nonsmoke zones can be pressurized, or just those surrounding the smoke zone. See Figure 2.20 for some
examples of smoke control zone configurations.
Figure 2.20 Smoke Control Zone Configurations
1
Zoned smoke control is implemented by venting, or depressurizing, the smoke zone and by either pressurizing all other zones or those zones
surrounding the smoke zone. Venting of the smoke zone is important because it prevents significant buildup of pressures as a result of a fire
caused by the thermal expansion of gases. Venting can be accomplished through exterior wall vents, smoke shafts, and mechanical exhaust
(depressurization).
Exterior Wall Vents
Zoned smoke control using wall vents consists of a vented smoke zone without any fans to aid the exhaust of smoke and adjacent zones that
are pressurized. The wall vents in the smoke zone would automatically open when the smoke control system is activated. This method of
smoke control should be used for open area floor plans where each floor of the building is defined as a smoke control zone. The vents should
be evenly distributed on the walls to counteract the adverse effects of wind.
Smoke Shafts
Zoned smoke control using smoke shafts consists of one or more vertical shafts and adjacent zones that are pressurized. The vertical shafts
are designed to be a path for smoke movement from the smoke zone to the exterior of the building. The shafts can serve one floor, many
floors, or one shaft can serve all floors of a building. Each shaft has an opening above the roof level and an opening on each floor that it
serves. Each shaft opening is equipped with a normally closed damper that will open in response to a fire on that particular floor. This
method of smoke control should be used for open area floor plans where each floor of the building is defined as a smoke control zone. It is
recommended that smoke shafts be located as far away from exit passageways as possible to prevent additional problems for evacuation and
fire fighting. Additionally smoke shaft inlets should be located in or near the ceiling because hot smoke usually stratifies near the ceiling.
1. The figure on this page is reprinted with permission from NFPA 92A, Smoke Control Systems, Copyright © 1993, National Fire
Protection Association, Quincy, MA 02269. This reprinted material is not the complete and official position of the National Fire
Protection Association on the referenced subject which is represented only by the standard in its entirety.
Smoke Control Zone Every Three Floors
Smoke Control Zone Every Floor
Three Smoke Control Zones Per Floor
+
+
+
Fire Floor
+
+
+
+
Fire Floor
+
Smoke
Zone
+
+
+
+
+
+
+
+
+
+
+
+
Smoke Zone
+
+
}
Fire Floor
}
{
+
+
+
+
+
+
Fire Floor
+
+
+
+
+
+
+
+
+
Fire Floor
+
+
+
A plus sign (+) indicates pressurized spaces
NOTE:
This method should not be used when the floor plan involves many partitions or walls.