Document number 462105
FABRICATION AND FIELD
INSTALLATION INSTRUCTIONS
®
Support Mullions for use in Oversize Openings
These installation instructions apply to the fabrication and construction of generic support mullions. Support mullions
are necessary whenever static fire dampers are installed into a vertical opening that is larger than the largest UL rated
size for that damper. The mullions allow construction of a fire barrier that is larger than the maximum available size.
The opening must not exceed 120 in. (3048mm) high, but can be any width provided a vertical support mullion is used a
maximum of every 120 inches (3048mm).
To properly use support mullions they must be fabricated and installed according to the following instructions.
Application
Wall Opening
Generic steel mullions can be used to separate vertically
mounted galvanized steel fire dampers in wall openings
larger than the UL permitted multiple damper assembly
size. Mullions can either be used vertically, horizontally or
both to split up a vertical wall opening requiring use of a
damper having a 11/2 hour fire resistance rating. Maximum
mullion span is 120 in. (3048mm) plus expansion allowance
when used either horizontally or vertically.
Steel mullions are intended for use in a concrete block or
solid concrete wall.
Hollow concrete blocks are to be filled with concrete
(minimum 3500 psi) to permit proper mullion anchoring.
Wall thickness is to be 7 in. (178mm) minimum, 12 in.
(305mm) maximum.
Sleeves are to be around each damper assembly. Mullions
are not intended to be in the airstream, (i.e. exposed to
flow) or to be a part of the ductwork.
Wall Mullion Cap
B-B (Typical)
Mullion Assembly
A-A (Typical)
Retaining Angles (Typical)
G
Sleeve (Typical)
G
Horz. to Vert.
Mullion Cap
C-C (Typical)
G
E
E
G
F
F
D
D
SPECIAL NOTE: Support
mullions may only be used
with static-rated fire damper
assemblies; they cannot be used
to install combination fire-smoke
dampers in wall openings that
exceed the maximum UL-approved
size for the fire-smoke damper
model being installed.
Support mullion assemblies consist of three basic parts:
the wall mullion cap, the horizontal to vertical mullion cap
and the mullion sections. Determine the quantity of each
piece required to complete the installation.
Formed Section View (2 req’d)
33/8
7/8
3/4
Table 1
2
Dimensional Information shown in inches (mm).
Opening Width/Height
D
H
12 (305)
111/2 (292)
31/4 (83)
24 (610)
231/2 (597)
3 3/8 (86)
36 (914)
33 3/8 (847)
31/2 (89)
48 (1219)
471/4 (1200)
3 5/8 (92)
60 (1524)
59 1/8 (1501)
33/4 (95)
72 (1829)
71 (1803)
3 7/8 (98)
84 (2134)
82 7/8 (2105)
4 (102)
96 (2438)
943/4 (2406)
4 1/8 (105)
108 (2743)
1063/4 (2711)
4 1/4 (108)
1183/4 (3016)
4 3/8 (111)
120 (3048)
C-4
2
C= Wall Thickness
Assembled View
31/2
D
3/16 in. blind rivet (stl) or 3/4 in.
long intermittent welds 12 in. on
center, 6 in. maximum from both
ends, both sides of assembly.
E = Wall Thickness in. (13mm)
F = Wall Thickness + 1/4 in. (6mm)
3/16 in. typical
rivet location
1/2
Detail A-A
Mullion Assembly
All dimensions shown are in inches.
Fabrication of Wall Mullion Caps
2
Wall mullion caps must be constructed from 12 ga. steel
with a minimum yield strength of 42,000 psi.
1. Fabricate the formed section as shown to right.
113/16
2
H
H
2. Shear the cap end plate to required dimensions.
Formed Section
End View
3. Weld the cap end plates to the formed section with
1/8 in. (3mm) fillet welds completely around the top
edges of the formed section.
4. Drill and countersink 8 holes ( 4 on each side) for
1/4-20 flat head machine screws.
Mullions must be constructed from 16 ga. (1.5mm) steel
with a minimum yield strength of 42,000 psi.
2. Connect the two mullion sections together. Use 3/16
in (4.7mm) steel blind rivets of 3/4 in. (19mm) long
intermittent welds 12 in. (305mm) on center and a 6
in. (152mm) maximum from both ends.
Important: Both sides of the mullion piece should be
fastened using the method described above.
H
E/8
Important: The “D” dimension shown has been calculated
to include the necessary clearances required for thermal
expansion in the mullions. The values can be found using
the wall opening dimensions and tables on this page.
1.Form two identical pieces of mullion section as
shown.
Wall Mullion Cap
Assembled View
Weld
­Fabrication of Mullion Sections
31/4
Cap End Plate
(2 req’d)
E/4
E
E/4
E/4
31/4
Detail B-B
Wall Mullion Cap
E/8
All dimensions shown are in inches.
Fabrication of Horizontal to Vertical
Mullion Caps
Horizontal to vertical mullion caps must be constructed
from 12 ga. (2.7mm) steel with a minimum yield strength of
42,000 psi.
Important: The H, E and F dimensions shown have been
calculated to provide the correct performance. The values
can be found by using the wall opening dimensions and
Table 1.
1. Form the horizontal mullion channel as shown.
2. D
rill 12, 3/ 16 in. (4.7mm) dia. holes into the horizontal
mullion channel using the dimensions shown.
3. Form the center channel as shown.
NOTE: If the center channel is to be made from two pieces,
weld them together with an 1/8 in. (3mm) fillet weld.
4. Shear the end plates to the dimensions required.
5. Weld the end plates to the center channel with 1/8 in.
(3mm) fillet welds completely around the top edges of
the center section.
3/4
dia.
(12 holes)
11/2
6
Side View
11/2
3/4
F
ntal Mullion Channel
3/4
3/16 in.
dia.
(12 holes)
H
End View
Weld
Center Channel
31/4
3/4
1
1" min.
Assembled View
11/2
3/4
Top View
11/2
Side View
One or two piece
End Plate
1/2
Total expansion
clearance between sleeve and wall/
Weld
mullion of 1/8 in. (3mm) per foot of wall opening or mullion
span should be allowed. Maximum clearance is 11/4
inches (31mm).
Center Channel
H
6
11/2
One or two piece
End View
1
1
11/2
Side View
F
1/2
End Plate
Top View
Static Fire Damper Installation
Galvanized steel static fire dampers must be UL classified
for 11/2 hour fire resistance. They must be installed in
One or two piece
galvanized steel sleeves and
be retained by minimum
Weld retaining
in. (38mm
Channel x 38mm), 16 ga. (1.5mm)
End Plate 1 1/2 in. x 1 1/2Center
angles on each side of the wall. Retaining angles must
overlap mullions or wall by 1in. (25mm) minimum. Fasten
Side View
H
to sleeve using 1/4 in. (6mm) dia. bolts, 3/16 in. (4.7mm)
steel rivets, welding, or #10 sheet metal screws. All
must be attached 6 in. (152mm) on 13centers, 2 in. (51mm)
1 /16
E
31/4
maximum from corners. Do not fasten
retaining angles to
End View
the wall or mullions. Mullions must be free to float.
Horizontal Mullion Channel
3/16 in.
Note: Mullion caps must be inserted into the ends of the
mullions before they are anchored to the vertical mullions
or wall.
113/16
End View
E
Weld
Side View
1
M
Use 3/16 dia. steel blind
rivets at installation
31/4
1 1/2 in. x 1 1/2 in.
min. 16 ga.
galvanized
retaining angle
113/16
End View
E
3/4
Assembled View
End View
Wall
Sleeve
Retaining
Angles
Detail D-D
Weld
Detail E-E
1" min.
Use 3/16 dia. steel blind
rivets at installation
Assembled View
Mullion
Wall
13/8
3/16
d
Mullion
1 1/2 in. x 1 1/2 in.
min. 16 ga.
galvanized
retaining angle
Use 3/16 dia. steel blind
rivets at installation
Sleeve
Sleeve
Retaining
Angles
1" min. D-D
Detail
Detail E-E
Mullion
Mullion Cap
Wall
Mullion
Installation
Before the static fire dampers are installed into the wall
the mullions must first be anchored into the wall. The fire Mullion
dampers may then be installed
into the mullion assembly.
3
1/4"
Min.
Wall Thickness
7"min. & 12" max.
1 /8
3/16
attach
theSleeve
mullions to the wall follow these
Retaining
Angles
1/4-20
Sleeve
x
in.
1. Anchor wall mullion caps to wall using
3/8 in. (9.5mm) diameter by 1
long flat Detail
head steel
bolts andMullion
D-D
Mullion Cap
in. (25mm) long concrete expansion anchorsDetail
(Hilti). IfE-E
steel
lintels are present, use two 1 in. (25mm) long welds on
each side of mullion caps.
Mullion
G
Det
Detail F-F
5/16
Note: End caps must be inserted into the ends of the
mullions before they are anchored to the wall.
Retaining
Angles
Detail F-F
13/8
3/16
1 1/2 in. x 1 1/2 in.
Toga.correctly
min. 16
galvanized
steps:1" min.
retaining angle
W
7
G
G
1/4"
G
End Cap
Min.
Wall Thickness
7"min. & 12" max.
Mullion
2. Anchor horizontal
mullion caps to vertical mullion
Sleeve
caps with 3/16 in. (4.7mm) diameter steel blind rivets in 12
Detail F-F
places.
G
Detail G-G
E
Detail E-E
Copyright © 2013 Greenheck Fan Corporation
D
E
462105
G Support Mullion Rev. 5 Jan 2013
F
G
F
D