Greenheck FD Installation, Operation And Maintenance Instructions page 3

Example: A 12 in. x 12 in. (305mm x 305mm) damper would re-
quire a minimum clearance of 1/4 in. (6mm) on width
and 1/4 in. (6mm) on height
A 48 in. x 12 in. (1219mm x 305mm) damper would
require a minimum clearance of 1/2 in. (13mm) on
width and 1/4 in. (6mm) on height.
2. gAUgES AnD LEngtHS OF FIRE DAMPER
SLEEvES
All fire dampers must be installed in a steel sleeve of
the required gauge and length. See table 1 for required
minimum sleeve gauges. Maximum sleeve thickness is
10 gauge (3.5mm). Sleeve inside dimensions must equal
damper outside dimensions.
Sleeves shall extend a maximum of 6 in. (152mm)
beyond the wall or floor opening on each side (see
Figure 1). When an access door is incorporated as a
part of sleeve, the sleeve may extend a maximum of
16 in. (406mm) beyond the wall or floor opening on the
access door side.
Sleeve Gauge Duct Dimension
14 ga. (0.075 in.)
- 10 ga. (0.138
All duct sizes
in.)
[2mm - 3.5mm]
36 in. (914mm) max. width
16 ga. (0.060 in.)
24 in. (610mm) max. width
[1.5mm]
24 in. (610mm) diameter
16 ga. (0.060 in.)
All duct sizes
[1.5mm]
18 ga. (0.048 in.) 85 in. (2159mm) wide and
[1.2mm]
20 ga. (0.036 in.) 55 in. - 84 in. wide
[0.9mm] (1397mm - 2134mm)
22 ga. (.030 in.) 31 in. - 54 in. wide
[0.76mm] (787mm - 1372mm)
24 ga. (0.024) 13 in. - 30 in. wide
[0.6mm] (330mm - 762mm)
26 ga. (0.018 in.) 12 in. wide and under
[0.46mm]
Sleeve thickness must not be less than the gauge of the connecting duct.
UL Standard 555 requires all ducts to terminate at fire damper sleeves.
table 1: Minimum sleeve thickness for fire dampers.
Type of Duct
to Sleeve
Connection
Permitted
Rigid or
Breakaway
Rigid or
Breakaway
over
Breakaway only
(305mm)
Vertical mount without
factory mounted sleeve
1/4 in. minimum
total clearance
(See Section 1)
See
Section 2
Duct
Retaining Angles
(See Section 4)
Type A
Retaining angle leg
shall not exceed 7 in.
(178mm)
Type B
On types R & CR factory
furnished duct collar
qualifies as breakaway
conneciton (See Section 5)
Duct
Type C, CO, CR & R
When dampers installed vertically, the
blade stack must be on the top..
Figure 1
Wall or floor
See
Section 2
Damper
Sleeve
(See Sections 2 & 3)
Wall or floor
Sleeve
Damper
Duct
Wall or floor
Damper
Sleeve
3
Mounting
(See Para
1
t
(S