How are pipe tees labeled?

Reading Reducing Fittings

A variety of types most commonly required for piping systems are illustrated on this page. In these illustrations, each opening of the fitting is identified with a letter which indicates the sequence to be followed in reading the size of the fitting.

In designating the outlets of reducing fittings, the openings should be read in the order indicated by the sequence of the letters "A", "B", "C", and "D". The following information is based on ASME B16.11 and MSS SP-106.

Tee

Reducing on outlet
(1 x 1 x 3/4) Tee

Reducing on one run
(1 x 3/4 x 1) Tee

Reducing on one run and outlet
(1 x 3/4 x 3/4) Tee

Reducing on both run (bullhead)
(3/4 x 3/4 x 1)

Cross

Reducing on one outlet
(1 x 1 x 1 x 3/4) Cross

Reducing on both outlets
(1 x 1 x 3/4 x 3/4) Cross

Reducing on one run and outlets
(1 x 3/4 x 1 x 3/4) Cross

Reducing on one run and both outlets
(1 x 3/4 x 3/4 x 3/4)

Lateral

Reducing on branch
(1 x 1 x 3/4) Lateral

Reducing on one run
(1 x 3/4 x 1) Lateral

Reducing on one run and branch
(1 x 3/4 x 3/4) Elbow

Reducing elbow
(1 x 3/4)

Reducing tees, regardless of their material composition, are always described in the same fashion. To describe a reducing tee, you must first locate the largest size on the run of the tee (1" in the example below). The next size indicated in the description of the reducing tee is the side opposite to that with the largest size on the run of the body (3/4" in the example below). The final size in any description of a reducing tee is the branch side (1/2" in the example below). All together, the tee in the following example would be described as a: 1" x 3/4" x 1/2" reducing tee.

Reducing tees are available in 150# Malleable Iron, 300# Malleable Iron, 125# Cast Iron, 250# Cast Iron, 125# Brass, Copper Pressure, Carbon & Stainless Butt Weld & PVC.

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