Butt Weld Reducing Tees — ASME B16.9

What is a Reducing Tee?

A reducing tee has two run ends of the same size and a smaller branch at 90°. The branch is formed integrally from the body, so the change of size happens inside the fitting without a separate reducer or a cut-and-welded stub. ASME B16.9 tabulates the run and outlet size combinations and centre-to-end dimensions. It is chosen when the branch is one or a few sizes smaller than the header; for much smaller branches, a branch outlet fitting (olet) is often more economical.

Key features

• Branch smaller than the run, combinations per ASME B16.9
• Run and branch can be ordered in different schedules
• Integral branch with no reinforcement pad
• Ends bevelled to ASME B16.25

Specification

Applications

• Branch connections from process headers
• Instrument and drain take-offs on larger lines
• Steam distribution headers
• Cooling water and utility networks
• Pump manifolds

Reducing tee vs branch outlet (olet)

A reducing tee replaces a section of the header and has three butt welds; it suits branches close to the run size. A branch outlet such as a weldolet is welded onto the header through a hole, needing only one or two welds, and suits branches much smaller than the run. Piping specifications usually include a branch table that states which one to use for each run and branch size.