TinnerFlow
Stainless & Specialty Duct ยท Specialty Materials

Aluminum round duct

Lightweight/corrosion-resistant run

ConnectionSlip/gasketed/flanged aluminum joint
SupportBroad band/saddle with isolation

Before you start

  • Confirm the aluminum alloy, wall thickness, joint type, fire and temperature suitability, sealant compatibility, support design, and any required dissimilar-metal isolation.
  • Inspect for dents, cracks at formed edges, crushed ends, and shipping damage.
  • Use clean soft handling equipment because aluminum dents and scores easily.
  • Verify the system is appropriate for the specified service before installation.

Tools and materials

Aluminum round duct, compatible slip, gasketed, or flanged fittings, aluminum or approved compatible fasteners, compatible sealant, soft slings, broad bands or saddles, isolation pads, hand seamer, snips, level, and marker.

Lay it out

  1. Establish the centerline, elevation, support points, seam orientation, and fitting rotation.
  2. Check clearances where isolation is required between aluminum and steel or copper.
  3. Plan joints so the full perimeter can be seated and inspected.

Set and support it

  1. Use broad bands or saddles that preserve the round shape.
  2. Add approved isolation between aluminum and incompatible support materials.
  3. Support both sides of fittings and heavy accessories so the soft duct wall is not loaded.

Make the connection

  1. 1

    Inspect and reshape only minor end distortion using appropriate hand tools.

  2. 2

    Align the sections without squeezing them out of round.

  3. 3

    Seat the specified slip, gasketed, or flanged joint.

  4. 4

    Install compatible fasteners without overdriving or tearing the aluminum.

  5. 5

    Apply compatible sealant after the mechanical connection is complete.

  6. 6

    Set the section into its broad support and verify the duct stays round.

Check the install

  • The duct remains round with no crushed or flattened section.
  • Fasteners and sealant are compatible with aluminum.
  • No unapproved contact with copper or carbon steel is present.
  • Fastener holes are not enlarged or torn.
  • Joints are fully seated, sealed, and supported.

Common mistakes

  • Overdriving screws and stripping the thin aluminum.
  • Using a narrow hanger that flattens the duct.
  • Using an incompatible sealant or dissimilar fastener.
  • Trying to hammer out severe dents overhead.

Stop and ask

Stop if the service temperature, fire requirement, alloy, thickness, fastener, sealant, or isolation requirement is unknown or exceeds aluminum-system suitability.