IBC AHU Series Installation And Operating Manual

2.3 Duct work
Ducting design and installation should adhere to
SMACNA and/or ASHRAE guidelines. Install the
ducting system to NFPA 90B (latest edition). Adhere
to the following:
Size the supply air plenum duct fitting to the
size of the unit's supply air opening, and
extend for 3' above the unit.
Size the supply and return air ducting
according to ASHRAE standards or
equivalent.
Seal all joints and connections to prevent air
leakage from the ducting system.
Choose accessories that will not
excessively restrict the air flow and create
excessive pressure drop on the system.
2.3.1 Sizing the ducts
If using flex / insulated flex ducting, ensure that you allow for the higher pressure drop.
Branch Duct - CFM at .25"wc external static pressure (galvanized duct)
Round CFM range
3" 20-30
4" 30-35
5" 55-65
6" 90-100
7" 135-160
Table 3 Sizing round galvanized duct for CFM range
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Section: Installation

IBC AHU Series Specifications

General

Brand	IBC
Model	AHU Series
Category	Air Handlers
Language	English