Flanged Base Bends and Tees
Bases are faced and drilled only when specified on the purchase order. When a base fitting is ordered with base faced and drilled, the base will be plain faced and drilled as shown in the table below.
Dimension “R” is the finished dimension; unfinished bases will be slightly longer. For supporting pipe sizes and base drilling, see below.
Base dimensions and weights are the same for full opening bends and tees, as well as for reducing bends and tees – see Bends and Tees. The proper base is determined by the largest opening. To compute the total weight of a reducing base bend or tee, add the weight of the base only (shown below) to the weight of a reducing bend or tee of the size and class as selected from the preceding tables.
When ordering reducing base bends always specify which flange is opposite the base. To order base tees reducing on the branch, specify sizes in proper order and give the figure number shown below.
Bases other than shown here – such as on the side of a fitting – are special and may be available on 14" and larger bends. See Standard Dimensions for some available base locations. Consult AMERICAN for special base locations.
To avoid an error, it is recommended that AMERICAN be consulted prior to ordering any base fittings.
Bases of these fittings are intended for support in compression and are not to be used for thrust anchors or supports in tension, bending or shear.
Flanged Base Bends

Size (in.) |
Pressure Rating (psi) |
Dimensions in Inches | Weight in Pounds | ||||||
---|---|---|---|---|---|---|---|---|---|
R | S Dia. |
T | U | Short Radius | Long Radius | ||||
Base Bend |
Base Only |
Base Bend |
Base Only |
||||||
4 | 250 | 5.5 | 6 | 0.62 | 0.5 | 55 | 10 | 65 | 15 |
6 | 250 | 7 | 7 | 0.69 | 0.62 | 85 | 20 | 110 | 30 |
8 | 250 | 8.38 | 9 | 0.94 | 0.88 | 145 | 40 | 195 | 55 |
10 | 250 | 9.75 | 9 | 0.94 | 0.88 | 210 | 45 | 280 | 65 |
12 | 250 | 11.25 | 11 | 1 | 1 | 300 | 65 | 420 | 95 |
14 | 250 | 12.5 | 11 | 1 | 1 | 360 | 70 | 490 | 105 |
16 | 250 | 13.75 | 11 | 1 | 1 | 445 | 75 | 615 | 110 |
18 | 250 | 15 | 13.5 | 1.12 | 1.12 | 565 | 115 | 800 | 170 |
20 | 250 | 16 | 13.5 | 1.12 | 1.12 | 700 | 120 | 985 | 175 |
24 | 250 | 18.5 | 13.5 | 1.12 | 1.12 | 1030 | 130 | 1430 | 190 |
30 | 150 | 23 | 16 | 1.19 | 1.15 | 1625 | 190 | 2400 | 295 |
30 | 250 | 23 | 16 | 1.19 | 1.15 | 1625 | 190 | 2400 | 295 |
36 | 250 | 26 | 19 | 1.25 | 1.15 | 2385 | 250 | 3680 | 395 |
42 | 250 | 30 | 23.5 | 1.44 | 1.28 | 3465 | 410 | 5515 | 650 |
48 | 250 | 34 | 25 | 1.56 | 1.42 | 4610 | 515 | 7635 | 845 |
541 | 250 | 38 | 27.5 | 1.69 | 1.55 | 4790 | 1050 | - | - |
601 | 250 | 42 | 32 | 1.88 | 1.75 | 6465 | 1500 | - | - |
641 | 250 | 44 | 38.75 | 2.12 | 1.75 | 8995 | 2250 | - | - |
Flanged Base Tees

Size (in.) |
Pressure Rating (psi) |
Dimensions in Inches | Weight in Pounds | ||||
---|---|---|---|---|---|---|---|
R | S Dia. |
T | U | Base Fitting |
Base Only |
||
4 | 250 | 5.5 | 6 | 0.62 | 0.5 | 75 | 10 |
6 | 250 | 7 | 7 | 0.69 | 0.62 | 110 | 15 |
8 | 250 | 8.38 | 9 | 0.94 | 0.88 | 185 | 30 |
10 | 250 | 9.75 | 9 | 0.94 | 0.88 | 300 | 30 |
12 | 250 | 11.25 | 11 | 1 | 1 | 430 | 45 |
14 | 250 | 12.5 | 11 | 1 | 1 | 485 | 50 |
16 | 250 | 13.75 | 11 | 1 | 1 | 600 | 50 |
18 | 250 | 15 | 13.5 | 1.12 | 1.12 | 740 | 75 |
20 | 250 | 16 | 13.5 | 1.12 | 1.12 | 930 | 75 |
24 | 250 | 18.5 | 13.5 | 1.12 | 1.12 | 1410 | 80 |
30 | 250 | 23 | 16 | 1.19 | 1.15 | 2270 | 120 |
36 | 250 | 26 | 19 | 1.25 | 1.15 | 3320 | 160 |
42 | 150 | 30 | 23.5 | 1.44 | 1.28 | 4740 | 270 |
42 | 250 | 30 | 23.5 | 1.44 | 1.28 | 5850 | 270 |
48 | 150 | 34 | 25 | 1.56 | 1.42 | 6235 | 335 |
48 | 250 | 34 | 25 | 1.56 | 1.42 | 7720 | 335 |
541 | 250 | 38 | 27.5 | 1.69 | 1.55 | 6590 | 565 |
601 | 250 | 42 | 32 | 1.88 | 1.75 | 8905 | 855 |
641 | 250 | 44 | 38.75 | 2.12 | 1.75 | 12275 | 1275 |
Base Flange Details

Fitting Size (in.) |
Dimensions in Inches | No. of Bolts |
|
---|---|---|---|
B.C. Bolt Circle |
Bolt Hole Diameter |
||
4 | 4.75 | 3/4 | 4 |
6 | 5.5 | 3/4 | 4 |
8 | 7.5 | 3/4 | 4 |
10 | 7.5 | 3/4 | 4 |
12 | 9.5 | 7/8 | 4 |
14 | 9.5 | 7/8 | 4 |
16 | 9.5 | 7/8 | 4 |
18 | 11.75 | 7/8 | 4 |
20 | 11.75 | 7/8 | 4 |
24 | 11.75 | 7/8 | 4 |
30 | 14.25 | 1 | 4 |
36 | 17 | 1 | 4 |
42 | 21.25 | 1 1/8 | 4 |
48 | 22.75 | 1 1/4 | 4 |
541 | 25 | 1 1/4 | 4 |
601 | 29.5 | 1 3/8 | 4 |
641 | 36 | 1 3/8 | 4 |
Size of Supporting Flanged Pipe for Base Fittings | ||||||||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Fitting Size (in.) |
4 | 5 | 6 | 8 | 10 | 12 | 14 | 16 | 18 | 20 | 24 | 30 | 36 | 42 | 48 | 54 | 60 | 64 |
Supporting Pipe Size (in.) |
2 | 2 1/2 | 2 1/2 | 4 | 4 | 6 | 6 | 6 | 8 | 8 | 8 | 10 | 12 | 16 | 18 | 20 | 24 | 30 |