6
Laboratory Exhaust Systems
®
Refer to VKCURB Curb Assembly Instructions #475588
for additional details. Instructions are shipped with the
roof curb or can be found online at greenheck.com
under the library section.
The figures below illustrate three common methods
used to install Vektor systems. Methods used to attach
a Vektor unit are dependent on local codes, roof
construction design and roof construction materials.
Consult an architect or structural engineer for proper
means of attachment.
NOTE
Steel, concrete or wood roof support is per structural
engineer and in accordance with load requirements
and applicable building codes.
Wood
WOODEN STRUCTURAL SUPPORT
(BY OTHERS, SEE NOTE ABOVE)
Greenheck Roof Curb
Install 3/8 inch
(9.525 mm)
SS lag or thru-bolt with
1 inch
(25.4 mm)
O.D. washer
2.5 inch
(63.5 mm)
maximum spacing from curb corners
4.5 inch
(114.3 mm)
maximum bolt spacing
3.5 inch
(88.9 mm)
minimum tread engagement,
not including tapered tip
2 inch
(50.8 mm)
minimum edge distance,
centered in flange
Pre-drill holes 40-60% of lag diameter
ALL HARDWARE BY OTHERS
Steel
Concrete
STEEL STRUCTURAL SUPPORT
(BY OTHERS, SEE NOTE ABOVE)
Continuous weld or stitch weld.
Minimum 6 inch
(152.4 mm)
stitch weld by
3.25 inch
(82.5 mm)
spacing minimum.
Minimum 6 inch
(152.4 mm)
weld on each corner.
OR
Install 5/16 inch
(7.9375 mm)
24 Dril-Flex® Self-Drilling
Tapping Screws. 3/16 inch
(4.7625 mm)
minimum thread
engagement into A36 steel, centered in flange.
4.5 inch
(114.3 mm)
spacing
5/8 inch
(15.875 mm)
minimum edge distance
ALL HARDWARE BY OTHERS
Greenheck Roof Curb
CONCRETE STRUCTURAL SUPPORT
(BY OTHERS, SEE NOTE ABOVE)
Install 3/8 inch
(9.525 mm)
SS power wedge bolts
2.5 inch
(63.5 mm)
maximum spacing from curb corners
4.5 inch
(114.3 mm)
maximum bolt spacing
3.5 inch
(88.9 mm)
minimum embedment
4.5 inch
(114.3 mm)
minimum edge
distance centered in flange
ALL HARDWARE BY OTHERS
Greenheck Roof Curb
When mounting the fan assembly to structures other
than the VKCURB or VKERS-CURB, it is critical that
a structural engineer be consulted to validate the
structure’s capability to bear the operating weight and
provide adequate structural stiffness to avoid structural
resonance. The supporting structural elements should
be designed such that the first natural frequency is a
minimum of 120% of the maximum operating speed of
the fan and accounts for the inertia from the rotating fan
rotor mass. Weak or undersized structural support may
impact fan performance or facility occupant comfort
and system longevity. The structure must support the
entire perimeter and any cross member of the bypass
air plenum or fan.
Roof Curb and Mounting Details
