UnderDuct: The better choice for underground HVAC applications

FRP offers many advantages over buried metal duct


UnderDuct’s Fiberglass Reinforced Duct is specifically designed to withstand the harsh underground environment. Our FRP duct stands up to water, temperature changes and acidic soil conditions. In very wet or corrosive environments, UnderDuct is the clear choice over stainless steel, galvanized, PVC, or PVC coated galvanized.
Filament wound FRP Composites have a higher strength-to-weight ratio than steel. Being a structural material, large lightweight fiberglass duct sections can be shop fabricated and shipped to the jobsite for easy installation. Light weight components also save on transportation and installation costs. UnderDuct does not require concrete encasement. When buried in compacted sand or pea gravel UnderDuct does not require hold downs.
Sustainable, Green Building
UnderDuct is a sustainable alternative to metal duct and is an excellent choice for green building and design. UnderDuct is resistant to mold, corrosion, leakage and moisture damage. Smooth interior walls provide improved air flow for maximum efficiency and energy savings. UnderDuct buried duct systems allow for more open design concepts.
Underduct assemblies are built to approved shop drawings . Shop assembled sections can be in the range of 20’ long allowing as few field joints as possible. Not only does this lessen shipping costs, it also assures better quality control and cuts expensive field installation costs.
Unlike metal, UnderDuct is inherently non-conductive.
UnderDuct is built to last the life of the building. Even after a flood or a sprinkler system release UnderDuct can be pumped out with no ill effects.
All surfaces of UnderDuct and fittings, as a finished composite, meet the Flame and Smoke requirements of the Class 1 duct per UL 181 and UMC 10-1. Verifications of performance are done by an ASTM E-84 testing laboratory, recognized by the following building code organizations under the Council of American Building Officials: ICBO; BOCA; SBCCI.