ASHRAE Journal - October 2014 - 77

TECHNICAL FEATURE

annually. Section 909.20.3 of the IFC
does state specifically that dampers
are included in the smoke control
system testing.
Section 909.12 of the IBC and
the IFC are identical. They require
that detection and control systems
comply with UL 8645 and are listed
as smoke control systems. UL 864
Section 49.7 states that dedicated
systems must perform a weekly selftest. The test includes provisions
for verification of actuation and
override control capability. The test
here will confirm that the damper
indication switches function. Nondedicated systems are not required
to perform the self-test.
There is frequent confusion
between the two types of damper
applications. For clarity they are
referred to here as "containment"
dampers where required by Chapter
7 of the codes, and "smoke control
system" dampers when required as
part of a smoke control system in
Chapter 9 of the codes. The term
"compartmentation" damper is also
used by some code officials when
referring to dampers required by
Chapter 7.
Table 1 contains a summary of the
periodic testing requirements. The
balance of this article explains the
damper types and applications
for purposes of identifying those
requirements.

Dampers Required by IBC Chapter 7
Chapter 7 of the IBC requires
that fire dampers be installed in
fire walls, barriers, partitions, and
horizontal assemblies. Chapter 7
requires that smoke dampers be
installed in smoke barriers, and
smoke partitions. Combination fire
and smoke dampers can be installed

in any of the applications that
require both fire-rated construction
and smoke containment. They are
meant to resist the passage of both
flames and smoke particulates.
In the U.S. most fire dampers have
fusible links that melt at (typically)
165°F (74°C), allowing gravity or a
shaft spring to close the damper.
Fire dampers are rarely actuated in
the Americas (although they are frequently actuated in Europe so that
they can be automatically tested).
See Figure 1 for a typical curtain fire
damper. Spring-loaded ceiling fire
dampers have fusible links also.
Fire dampers have a relatively high
smoke leakage rate and cannot be
used to restrict smoke. They are factory tested and constructed under
UL 5556 or UL 555C,7 which are the
listing standards for fire dampers
and ceiling dampers, respectively.
A containment application smoke
damper is connected to a duct
smoke detector or to a relay from the
fire alarm or smoke control panel.
In event of a fire and concomitant
smoke, an actuator springs the
damper closed to prevent smoke
movement from one area to another.
All smoke dampers are actuated
since there is no method to mechanically sense smoke and electrical
sensing and control is required.
Smoke dampers are tested and listed
to UL 555S8 which is the standard for
smoke dampers and actuators. Most
of these dampers are rectangular,
multiblade type; however, there are
round and single blade variations.
A combination fire and smoke
damper looks very similar to a
smoke damper, but has a high temperature sensor to close the damper.
It meets the UL 555 testing standards for fire dampers but also has

TABLE 1 Periodic testing requirements for dampers.

Chapter 7 IBC and IFC "Containment" Dampers
Commissioning
End of First Year
Every Four Years Except in Hospitals Every Six Years
Chapter 9 IFC "Smoke Control System" Dampers
Dedicated

Commissioning
Semi-Annually

Non-Dedicated
Commissioning
Annually

Chapter 9 IBC & IFCFire Detection and
Smoke Control Systems
Dedicated

Weekly Self-Test

Non-Dedicated
Not Required

FIGURE 1 Curtain fire damper. (Photo courtesy of
Greenheck Fan Corporation.)

seals that resist smoke passage to
meet the requirements of UL 555S. It
is actuated so that a smoke detector
or relay can cut power to spring the
damper closed (Figure 2).
Combination fire and smoke
dampers can be controlled several
ways. Most commonly, on modern
dampers is the use of an electrical temperature-activated bimetal
switch. When the contacts are
closed, the actuator is powered and
drives the damper open. When heat
is detected, the contacts open and
the actuator springs the damper
closed. In addition, a smoke detector
or relay contact from the area smoke
detection system panel is wired in
series with the temperature switch.
If smoke is detected, the contact
opens and the actuator springs the
damper closed. A duct smoke detector is installed within 5 ft (4.5 m) of

O CT O B E R 2 0 1 4

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