Preparation of Openings
• Corridor dampers are rated in ceiling constructions with a fire resistance rating of one hour.
• Frame corridor openings as shown below. Maximum size of opening is 24 in. x 24 in. (610 mm x 610 mm).
(
see Figure 1 & 2
).
• Corridor ceiling must be covered with a minimum of one sheet of
5
⁄
8
in. UL rated gypsum board on both sides.
• All construction and fasteners must meet the requirements of the appropriate corridor ceiling design. Gypsum
panels should be attached, 12 in. (305 mm) O.C. maximum, to all stud and runner flanges surrounding opening
with fasteners as designated by the appropriate corridor ceiling design. (See UL Fire Resistance Directory) and/
or local codes.
Figure 1
Steel
studs
2 in. x 4 in.
(nominal)
wood studs
Steel Stud Assembly
Wood Stud Assembly
24 in.
max.
24 in. o.c. max.
24 in.
max.
24 in. o.c. max.
Opening lined
with UL rated
5/8 in. gypsum
board
Figure 2
Steel
studs
2 in. x 4 in.
(nominal)
wood studs
Steel Stud Assembly
Wood Stud Assembly
24 in.
max.
24 in. o.c. max.
24 in.
max.
24 in. o.c. max.
Opening lined
with UL rated
5/8 in. gypsum
board
Clearances Required Between Corridor Damper Sleeves and Ceiling
Openings
The interior dimension of the prepared ceiling opening should be
1
⁄
4
in. (6 mm) larger than the overall size of the
damper and sleeve assembly.
These are total clearances (ignoring fastener heads) and do not need to be spaced equally around the damper.
Maximum Assembly Table
Damper Model
Maximum Single
Section Size
(inches)
CFSD-211, -212
24 x 24
Horizontal Mount
CFSD Series
3
®
