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P/N 780100700 07/18 Rev F
ASHRAE recommends that the fresh air intake be located at least 10 feet from any source of pollutants
such as auto exhaust, dryer exhaust, exhaust from any fuel-burning appliance, etc. Avoid installation
near odor sources such as garbage bins or barbecue grills. A minimum of 3 foot above ground is
recommended to avoid ingress of leaf litter, grass clippings, etc. Do not use a crawl space, basement
or attic as a source of intake air. Always be sure to comply with local building code requirements
regarding fresh air inlets.
7Aiii. Intake Air Connection and Duct Installation
Ductwork Specifi cation
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All fl exible ducts must meet UL safety standards for Class I air ducts and connectors.
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All ducting must be installed according to HVAC codes and standards.
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All duct connections should be sealed with UL181 foil tape or mastic to prevent leakage.
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Insulated duct of at least R-4 insulating value with a continuous vapor barrier must be used for the
intake duct. The vapor barrier must be sealed at both ends.
•
Exterior intake should be installed above snow line or a minimum of 18” above ground level,
whichever is greater.
•
Exterior intake hood must be weather resistant and must have a screen (1/4” openings) to
prevent debris, animals and insects from entering ductwork.
