TinnerFlow
Stainless & Specialty Duct ยท Specialty Materials

Aluminum rectangular duct

Pool/chemical or specialty air

ConnectionAluminum flange/angle joint
SupportIsolated trapeze

Before you start

  • Confirm alloy, thickness, reinforcement, pressure class, chemical or pool environment, flange system, compatible gasket and sealant, and support isolation.
  • Inspect panels, formed corners, flanges, and reinforcement for cracks or distortion.
  • Keep steel grinding dust and copper contact away from the aluminum.
  • Review exterior or chemical-service protection requirements before installation.

Tools and materials

Aluminum rectangular duct, specified aluminum flanges or angles, compatible gasket and sealant, aluminum or approved fasteners, wide isolated trapezes, clean clamps, padded dunnage, level, and dedicated cutting and forming tools.

Lay it out

  1. Establish duct centerline, bottom elevation, support locations, and reinforcement orientation.
  2. Keep joints accessible and supports off the flange connection.
  3. Plan isolation at steel structure or hardware contact points.

Set and support it

  1. Use wide trapezes that support the bottom panel without point loading.
  2. Install approved isolation between aluminum and incompatible steel supports.
  3. Support both sections level before connecting the flange.

Make the connection

  1. 1

    Clean the flange faces and inspect for cracks.

  2. 2

    Install the compatible gasket or sealant system.

  3. 3

    Bring the sections together square without forcing the soft flanges.

  4. 4

    Install compatible hardware loosely and tighten in a balanced pattern.

  5. 5

    Complete the specified joint seal.

  6. 6

    Install and verify required reinforcement.

  7. 7

    Load the supports and inspect the panels for distortion.

Check the install

  • Flanges remain flat and corners are not cracked.
  • Panels do not sag or oil-can beyond the approved condition.
  • Hardware and sealants are compatible.
  • No galvanic contact or steel contamination is present.
  • Reinforcement and supports match the approved design.

Common mistakes

  • Using steel angle or fasteners without isolation.
  • Overtightening bolts and deforming the aluminum flange.
  • Grinding aluminum aggressively and thinning a corner.
  • Skipping reinforcement because the material feels lightweight.

Stop and ask

Stop if alloy, thickness, reinforcement, chemical compatibility, or isolation details are not verified, or if cracks appear at bends or flanges.