HVAC Duct Connectors: Gaskets, Flanges and Getting Tight Joints

An HVAC or industrial duct system is only as good as its joints. Every connection is a potential leak point, and leaks waste fan energy, reduce airflow at the far end of a system and can let dust or fumes escape. Choosing the right HVAC duct connectors is one of the simplest ways to keep a system performing as designed.

Types of Duct Connections

• Slip joints, common on smaller round duct, sealed with mastic or tape.
• Angle ring connections, where formed steel rings are bolted together on large or heavy-duty duct.
• Flanged connections such as KwikFlanges, screwed to the duct and fastened together.
• Flexible connectors that isolate fan vibration from the ductwork.

Why Gaskets Matter

A gasket fills the gap between two flanges or rings so air cannot leak through. Gaskets must suit the temperature, pressure and air stream of the system, and quality material holds its seal for years rather than compressing and cracking.

Matching Connectors to the Job

Smaller low-pressure runs may only need slip joints. Medium and large diameter duct, elevated installations and medium-pressure systems benefit from flanged or angle ring joints, which are stronger and quicker to align.

Controlling Airflow at Branches

Blast gates installed in branch lines let operators open and close individual drops, concentrating suction where it is needed and reducing operating costs. They come in full and half sizes, with manual or automatic operation.

Installation Tips

Keep flange faces clean, use the correct gasket width, tighten fasteners evenly in a cross pattern and support duct so joints are not under strain. Leak-test before insulating.

Supplier

Haltom Industries, a national leader in angle rings, KwikFlanges and heavy-duty duct components, stocks ductwork gaskets, HVAC duct connectors and blast gates for new systems and retrofits.

Takeaway

Spending a little more attention on connectors and gaskets pays off in lower energy costs, better airflow and a cleaner, safer workplace.