Duct to Sleeve Connection
Sleeve Gauge and Connection Type Requirements
Sleeve Gauge
Duct Dimension
Type of Duct to Sleeve
Connection Permitted
14 ga. (0.075 in.) -
10 ga. (0.138 in.)
[2 mm - 3.5 mm]
All duct sizes
Rigid or
Breakaway
16 ga. (0.060 in.)
[1.5 mm]
36 in. (914 mm) max. width
24 in. (610 mm) max. height
24 in. (610 mm) diameter
Rigid or Breakaway
16 ga. (0.060 in.)
[1.5 mm]
All duct sizes
Breakaway only
18 ga. (0.048 in.)
[1.2 mm]
85 in. (2159 mm) wide and
over
20 ga. (0.036 in.)
[0.9 mm]
55 in. - 84 in. wide
(1397 mm - 2134 mm)
22 ga. (.030 in.)
[0.76 mm]
31 in. - 54 in. wide
(787 mm - 1372 mm)
24 ga. (0.024)
[0.6 mm]
13 in. - 30 in. wide
(330 mm - 762 mm)
26 ga. (0.018 in.)
[0.46 mm]
12 in. wide and under
(305 mm)
See Breakaway Connection section for additional information.
UL Standard 555 requires all ducts to terminate at fire damper sleeves.
The size of the damper/duct determines the required sleeve gauge and the required duct to sleeve connection (see
table to the right). The sleeve thickness must also not be less than the gauge of the connecting duct. Any duct
connection other than the breakaway connections described below are considered rigid.
Out of Wall Fire and Combination Fire Smoke Dampers
7
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