ASHRAE Journal Supplement - AMCA InMotion - October 2020 - 20

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manufacturers have UL-approved instructions outlining

side of a damper is too close to a ceiling, wall, or ﬂoor,

the materials to be used and any applicable fasteners

the manufacturer may provide options for removing the

needed for the modiﬁcation.

mounting angles from that side of the damper. Where

Shortening or trimming a sleeve to accommodate

mounting angles have been removed, a ﬁ restop mate-

UL-approved duct connections. This type of modiﬁca-

rial or an intumescent caulk can be used to protect the

tion commonly is outlined in manufacturer installa-

through opening in a ﬁ re-rated barrier. Approved ﬁ re-

tion instructions allowing sleeves to be shortened or

stop materials and correct installation will be outlined

trimmed as long as electrical or mechanical components

in UL-approved installation instructions.

are not damaged.
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Cutting a hole in a sleeve to route an electrical or pneu-

Sealants

matic power connection to an internally mounted actu-

Questions concerning gaps between mounting angles and

ator, position-indication switch, or other device. Such

rated barriers and how to seal them sometimes arise. The

a penetration should be as small as possible and made

sealants approved for these applications will be listed in

per local electrical or mechanical code.

UL-approved installation instructions.

Each of these modifications has the potential to

It is common for sealants approved for sleeve modi-

introduce a point of duct leakage, so additional sealing

ﬁcations also to be approved for sealing gaps between

may be needed. All permitted sealants will be listed in

mounting angles and barriers. Note: These sealants typi-

UL-approved installation instructions.

cally are not allowed in the annular space between damper

As with any installation, it is advised to cycle a damper
after a modiﬁcation is completed to make sure the damper

sleeves and openings; they are allowed where mounting
angles touch a barrier.

will operate properly.

Actuators
Mounting/Retaining Angles

UL requires all actuators supplied on life-safety dampers

The annular space between a damper and a barrier opening

to be factory-installed and cycle-tested prior to shipment.

(Photo B) allows the damper to expand and work properly

"Dampers Marking and Application Guide" (Page 12)

during high heat exposure. Typically, damper installation

states the following with regard to ﬁeld modiﬁcations

instructions require mounting angles on all four sides of

of actuators:

a sleeve to cover the annular space and do not allow any
materials to be installed in the annular space. When one

Smoke dampers and combination ﬁre-smoke dampers
are equipped with factory installed electric or pneumatic
actuators which remotely control the dampers. The airﬂow
and pressure ratings marked on the dampers are dependent upon the particular combination of damper type,
actuator type and linkages between the damper blades
and actuator. As such, ﬁeld mounting or substitution of
actuators is not covered within the scope of the UL certiﬁcation of the product. However, this does not necessarily
preclude replacement of actuators in the ﬁeld. Like any
appliance, ﬁeld servicing of these products is not covered
under the scope of the UL certiﬁcation program. As with
any part of the damper, it is expected that replacement

PHOTO B. Annular space between a damper and
a barrier opening.

2020 A M CA i n m o t i o n

of actuators in the ﬁeld be done in accordance with the
damper manufacturer's normal ﬁeld servicing program.

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ASHRAE Journal Supplement - AMCA InMotion - October 2020

Table of Contents for the Digital Edition of ASHRAE Journal Supplement - AMCA InMotion - October 2020