Thread: Metal duct near crawl space floor

The home was remodeled in 04. This duct was about 2 inches off the ground. Is the clearance requirement 6? I know they spared no exspense on the support.

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M1601.3.2 Support.

Metal ducts shall be supported by

1

/2-inch (13 mm) wide 18-gage metal straps or 12-gage galvanized
wire at intervals not exceeding 10 feet (3048 mm)

or other approved means.

M1601.3.4 Duct insulation.

Duct insulation shall be
installed in accordance with the following requirements:
1. A vapor retarder having a maximum permeance of
0.05 perm [(2.87 ng/(s m2 Pa)] in accordance with
ASTM E 96, or aluminum foil with a minimum thickness
of 2 mils (0.05 mm), shall be installed on the
exterior of insulation on cooling supply ducts that
pass through nonconditioned spaces conducive to
condensation.
2. Exterior duct systems shall be protected against the

elements.

M1601.3.6 Duct separation.

Ducts shall be installed with
at least 4 inches (102 mm) separation from earth except

where they meet the requirements of Section M1601.1.2.

M1601.1.2 Underground duct systems

I can't remember how many metal ducts I've seen rusted from being on or close to the crawl space floor. None of them were properly supported. They use duct tape and coat hangers. Same thing with the flexable ducts...except with severe bends.

Originally Posted by David Argabright

I can't remember how many metal ducts I've seen rusted from being on or close to the crawl space floor. None of them were properly supported. They use duct tape and coat hangers. Same thing with the flexable ducts...except with severe bends.

Well duct tape for support is not good but a wire hanger looks like it might meet code. Of course it depends on how it's installed . . . .

jus sayin.