Flat-oval reducer

Before you start

• Confirm the flat-oval size, major and minor axis orientation, material, pressure class, joint type, and support detail against the approved drawing.
• Inspect the duct for sidewall dents, flattened ends, twisted axes, damaged beads, split seams, and shipping damage before lifting it.
• Check that the mating pieces use the same oval profile. A round-looking end and a truly matched flat-oval end are not the same thing.
• Stage the correct fittings, joint hardware, approved fasteners, sealant or gasket system, supports, lifting equipment, and hand tools before starting.

Lay it out

1. Confirm the large and small oval profiles, reducer direction, length, and any eccentric or flat-side requirement.
2. Mark top, bottom, and major-axis orientation before lifting.
3. Check whether the reducer affects drainage, headroom, or adjacent equipment alignment.

Set and support it

1. Support both adjoining runs so the reducer is not used as a hanger.
2. Hold the reducer against rotation while the first connection is made.
3. Provide support close enough to both ends to keep the profile true.

Make the connection

1. 1

   Set the large end at the correct orientation and connect it.

2. 2

   Verify the reducer body is not rolled and the flat or offset side is where shown.

3. 3

   Align the small-end run to the reducer without twisting the fitting.

4. 4

   Complete the small-end connection.

5. 5

   Install approved fasteners and seal both joints.

6. 6

   Load the adjacent supports and inspect the reducer for distortion.