Circular Factory-Built Grease Duct
High-efficiency circular grease duct, single-wall, double-wall air-insulated, and zero-clearance fiber-insulated to UL 1978 / UL 2221.
Overview
High-efficiency, prefabricated cylindrical grease duct systems engineered for commercial kitchen ventilation and certified to UL 1978 and UL 2221 (2-hour fire-resistance) standards. Available in single-wall, double-wall air-insulated, and double-wall high-density fiber-insulated profiles. Zero-clearance models feature an integrated 2-hour fire-rated enclosure tested to UL 2221, eliminating the spatial footprint and labor cost of a field-constructed fire shaft. Superior interior fluid dynamics and minimized static pressure drop optimize exhaust velocity and allow for reduced structural slope, making them the ideal solution for horizontal runs exceeding 75 feet.
Listings · UL 1978 · UL 2221 · NFPA 96
Specification Highlights
What this system delivers.
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Flow Advantage
Laminar circular cross-section eliminates the turbulent corner pockets of rectangular duct.
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Three Wall Configurations
Single-wall, double-wall air gap, and double-wall fiber-insulated (zero-clearance).
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Extended Horizontal Runs
Lower static pressure drop enables code-compliant runs beyond 75 ft with reduced slope.
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Integrated Fire Shaft
Zero-clearance UL 2221 enclosure removes the need for field-built drywall or masonry shafts.
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