FloAire FKB-INLINE - Manual (Page 5)

5
Recommended Discharge Ductwork Size
Blower
Size
Min.
Rectangular
Duct Size
Min.
Round
Duct
Diameter
Min. Straight
Duct Length
10 14 in. x 14 in. 19 in. 48 in.
14 20 in. x 20 in. 26 in. 72 in.
18 24 in. x 24 in. 33 in. 86 in.
20 26 in. x 26 in. 37 in. 108 in.
25 32 in. x 32 in. 46 in. 168 in.
Curb and Ductwork
This fan was specified for a specific CFM and static
pressure. The ductwork attached to this unit will
significantly
affect the airflow performance.
Flexible ductwork and square elbows should not be
used. Also, transitions and turns in ductwork near
the fan inlet will cause system effect and will
drastically increase the static pressure and reduce
airflow.
Follow SMACNA guides and
recommendations for the remaining duct run.
Fans designed for rooftop installation should be
installed on a prefabricated or factory built roof curb. Follow curb manufacturer’s instructions for proper
curb installation. Curbs should be connected to structural roof members with at least four (3) lug screws,
anchor bolts, or other suitable fasteners (not furnished) per curb flange. Curb flanges should be caulked
to roof.
The fan should be installed on a curb and/or rail elevated not less than 14” above any surface when
installed outdoors. Be sure duct connection and fan outlet are properly aligned and sealed. Secure fan
to curb through vertical portion of the ventilator base assembly flange using a minimum of eight (8) lug
screws, anchor bolts, or other suitable fasteners (not furnished). Shims may be required depending upon
curb installation and roofing material. Check all fasteners for tightness. The diagrams below show
different mechanical installation configurations.
Ensure duct connections are properly aligned and sealed. When this fan unit is used in commercial
grease ductwork, the ductwork connections must be FULLY WELDED to the fan. Clearance ratings of
ductwork connected to the unit apply to the fan as well. Ductwork must be listed or installed in
accordance with the IMC.