An equal tee, otherwise called straight tee, is a buttweld fitting used to branch a pipeline, or any other pipework, at 90 degrees.
Equal tee asme b36.19
A pipe tee is defined “equal” when the bore size at the run and branch sides have the same diameter. An equal tee is, therefore, used to connect two pipes of the same nominal diameter.
Equal tees are available in sizes from half an inch to 48 inches (or larger) and in seamless and welded execution (seamless up to 24 inches, welded for tee sizes above 24 inches).
Buttweld tees are manufactured according to ASME B16.9 (carbon and alloy) and MSS SP 43 (stainless steel and nickel alloy).
A reducing tee features a smaller bore size at the branched pipe side (generally 2/3 sizes smaller).
In case a larger bore size reduction is necessary, then a reinforced branch connection (such as a Weldolet) shall be preferred to prevent turbulence and have a smoother flow reduction.
reducing tee asme b36.19
The standard dimensions and tolerances of equal and reducing pipe tees are covered by the ASME B16.19 specification (carbon and alloy steel) and by the MSS SP 43 spec (for stainless steel and nickel alloys tees).