Greenheck DFD Series Installation, Operation And Maintenance Manual page 35

Installation continued....
2) All installations require the entire exterior perimeter of the damper assembly to be secured to structural supports
(example: concrete block wall, structural steel, etc.) which is supplied by others. The fastening method used to
secure the damper to the structural support and the design of the structural support is the responsibility of field
engineers.
3) Due to shipping constraints, some large damper assemblies may ship in multiple
sections and require field assembly. The damper sections must be attached together
with #10 sheet metal screws,
welds, or ⁄ in. (4mm) diameter steel pop rivets. Attachments must be spaced a
3
16
maximum of 12 in. (305mm) on center and a maximum of 2 in. (51mm) from corners.
Attachments must be made on front face and back face (air entering and air exiting
side) of damper sections. Figure 2
4) Multiple section VCD damper assemblies may require additional structural support
between the sections based on the following criteria:
a) Single section wide x unlimited sections high assembly:
• No additional structural support is required between sections
b) Unlimited sections wide x single section high assemblies:
• No additional structural support is required between sections
c) Two section wide x two section high assemblies:
• Pressures up to and including 4 in. wg (1 kPa): a 14 gauge (2mm) 5 in. (127mm) wide horizontal steel
mullion plate spanning the entire width of the damper assembly is required between the top and bottom
sections.
• Pressures above 4 in. wg (1 kPa) (see submittals for model specific pressure limitations): a 14 gauge (2mm)
7 ⁄ in. (191mm) wide horizontal steel mullion plate required between top and bottom sections.
1
2
Note: For vertical blade models, in lieu of the horizontal mullion plates, a vertical mullion plate is required
between left and right sections.
d) Three or four section wide x two section high assemblies:
• Pressures up to and including 6 in. wg (1.5 kPa)- Full length 8 in. wide mullion assembly. Figure 3.
• Pressures above 6 in. wg (1.5 kPa) (see submittals for model specific pressure limitations): Structural
supports shall be provided such that there are no unsupported banks of dampers more than two sections
wide by two sections high. Two section wide x two section high banks shall have mullion plates as required
by sections 4a - 4c.
Note: For vertical blade damper models, in lieu of the horizontal mullion plates, a vertical mullion plate is
required between left and right sections.
e) Assemblies larger than four sections wide x two sections high:
• Structural supports shall be provided such that there are no unsupported banks of dampers more than four
sections wide by two sections high. Individual banks shall have mullion plates as required by sections
4a - 4d.
⁄ in. (6mm) diameter nuts and bolts, tack or spot
1
4
12.000
O.C.
MAX.
Figure 2
VCD, FBH, and FBV Series 3