The Fundementals of Smoke Control
1-12 Infinity Smoke Control Guide
TOC
Separating Zones
You must separate smoke zones from one another by smoke barriers,
which prevent smoke from passing through them. Smoke barriers can be
a wall, a floor, or a ceiling. Any openings in the smoke barrier must be
closed with a smoke-proof fitting. For example, all duct work going
through a smoke barrier must have a smoke damper in it. A smoke
damper is a damper that prevents smoke from passing through it when
fully closed. (Refer to the dampers section below for more information.)
During a smoke emergency all of the fittings should seal themselves, so
that smoke cannot penetrate the barrier.
Since the smoke control zones should be the same as the fire control
zones, you usually separate your zones with a fire rated partition. A fire
rated partition is a wall that is built of fire resistant materials and that
reaches from floor to ceiling. Different floors should be separated by a
fire rated ceiling, a ceiling made of fire resistant materials. Both fire
rated partitions and fire rated ceilings are rated for the amount of time
they can withstand a fire. Any openings in a fire rated partition or ceiling
must be sealable with a fire rated closure, such as fire rated doors or fire
damper.
Selecting Dampers
The dampers used to isolate the smoke zone must be smoke dampers.
Smoke dampers are dampers that meet the requirements given in UL
555S, Standard for Leakage Rated Dampers for Use in Smoke Control
Systems. Following this standard ensures that the dampers are able to
block the smoke when they are fully closed. These dampers may be
different from those you might use in an HVAC system that does not
perform smoke control.
In a smoke control system, the dampers must be able to travel to their
desired setting in 75 seconds. All dampers must be fitted with end
position microswitches to provide feedback to the smoke control
system. These switches let the control system know the position of the
dampers, since smoke dampers are usually either fully closed or fully
open.
Dampers sometimes function as both smoke dampers and fire dampers.
Fire dampers are dampers that block a fire from penetrating a fire rated
partition via a duct. These dampers are normally open, held in place by
a fusible link. The fusible link is a heat-sensitive device that releases the
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