Industry Articles From Kaempf and Harris

The Ultimate List Of Commercial Ductwork Parts


If you're building a commercial building from scratch, you're going to need commercial ductwork. (Check out this guide for more info.)

If you're not sure what's what when talking to contractors, the sheet metal experts at Kaempf & Harris have come up with this comprehensive list of common commercial ductwork parts:

Access Door: Used to allow access to an enclosed space behind a wall, floor, or ceiling

Elbow: Used to make necessary tight corners for maintaining the best airflow for maximum efficiency in HVAC ductwork

Ceiling Box: Used to attach a register in the ceiling to supply air in any room

China Cap: Used to mount on the top of a piece of sheet metal duct that extends through a commercial building’s roof to keep rain and snow out of the duct system

Damper Sleeve: Used to regulate the amount of air flowing through each branch of a commercial building’s heating and air conditioning ductwork

Duct Booster Fan: Also known as a booster fan, a device used to increase airflow to different rooms in the building that are farther away from heating and cooling systems

Duct Sealant: A way to seal ductwork in order to prevent leaks, holes, and poorly connected ducts

End Cap: Galvanized steel that’s used to terminate a commercial ductwork run

Flashing: A series of metal vent pipes that exhaust hot air from a natural gas heating unit or ventilation fan through the roof, usually sealed with mastic to prevent water leakage into a commercial building

Flex Duct: Also known as flex, a flexible plastic that can be molded over a wire coil to shape a tube for thermal insulation  

Floor Box: Also known as a register box, a galvanized steel grille with moving parts that’s capable of being opened and closed with the airflow directed

Hanger Strap: Used with or without holes to hang HVAC manifold gauges during ductwork installation

Manifold Gauge: A three-chamber assembly that has three ports and two valves that are used to check the pressure, supply, and drain of an air conditioning unit

Pancake Taper: Round connectors used to butt joins together while transitioning in size

Plenum: An air distribution box that heats or cools the air and is directly attached to the supply outlet of the HVAC equipment and connected to the ductwork

Reducer: A ducting fitting used when a change from one size duct to another size is needed

Return Air Diffuser: Used to introduce conditioned air into a space to achieve even distribution and mixing with minimum noise

Saddle Tap: Used to branch a round duct run off of another round sheet metal duct run at a 45-degree angle for improved airflow and efficiency

Stackhead Boot: Also known as a stack boot, used to transition a round pipe or flexible insulated duct to oval pipe or a sidewall grille or register

Start Collar: Used to transition from a flat surface that’s made from metal, ductboard, or insulated liner to a round pipe or insulated flexible duct

Straight Boot: Used to transition from a round branch off of a main supply duct to a floor, wall or ceiling register

Supply Air Diffuser: An air terminal device that distributes conditioned air in various directions through the use of its deflecting vanes and is designed to promote the mixing of conditioned air with existing air

Vent Cap: A fitting that provides protection for the open end of a ductwork vent stack

Wye: A short pipe with a branch joining it at an acute angle

For a labeled diagram of basic commercial ductwork, download Kaempf & Harris' Commercial Ductwork Anatomy infographic by clicking on the button below:

Click Here For Your Infographic 

Topics: Metals, Sheet Metal Fabrication

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