Straight Tee Dimensions
A straight tee takes a branch off the run at 90°, with the branch the same size as the run. It is the standard way to split or combine flow in welded pipe, and after the elbow it is the most-used fitting on most jobs.
Run and branch.
The run is the through path; the branch is the outlet at right angles to it. On a straight tee all three ends share the same nominal size, so the R dimension (center to run end) and the B dimension (center to branch end) come straight from the table.
Full-size branching without a weldolet.
Where the branch is the same size as the header, a tee is the cleaner answer than a fabricated branch connection: a factory-made fitting to ASME B16.9 with a known rating, rather than a reinforcement calculation you have to defend.
How To Read These Dimensions
ASME B16.9 dimensions the straight tee and rates it as a fitting, which is the practical argument for using one instead of a fabricated branch: there is no reinforcement calculation to defend. The R and B center-to-end dimensions below are the standard figures.
- O.D.
- Outside diameterOutside diameter at the welding end, matching the pipe it welds to.
- I.D.
- Inside diameterBore through the fitting, set by the wall thickness.
- T
- Wall thicknessNominal wall at the welding end, matched to the pipe schedule.
- R
- Center to end, runFrom the intersection of the centerlines to the welding face on either end of the run.
- B
- Center to end, branchFrom the intersection of the centerlines to the welding face on the branch outlet.
121 sizes across 6 schedules · dimensions in inches, weights in pounds · ASME B16.9
Schedule STD
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to Center R | Center to End B | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|---|
| ½ | 0.84 | 0.622 | 0.109 | 1.00 | 1.00 | 40 | 0.35 |
| ¾ | 1.05 | 0.824 | 0.113 | 1.12 | 1.12 | 40 | 0.50 |
| 1 | 1.32 | 1.049 | 0.133 | 1.50 | 1.50 | 40 | 0.75 |
| 1¼ | 1.66 | 1.380 | 0.140 | 1.88 | 1.88 | 40 | 1.30 |
| 1½ | 1.90 | 1.610 | 0.145 | 2.25 | 2.25 | 40 | 1.90 |
| 2 | 2.38 | 2.067 | 0.154 | 2.50 | 2.50 | 40 | 3.20 |
| 2½ | 2.88 | 2.469 | 0.203 | 3.00 | 3.00 | 40 | 5.80 |
| 3 | 3.50 | 3.068 | 0.216 | 3.38 | 3.38 | 40 | 7.20 |
| 3½ | 4.00 | 3.548 | 0.226 | 3.75 | 3.75 | 40 | 9.50 |
| 4 | 4.50 | 4.026 | 0.237 | 4.12 | 4.12 | 40 | 12.70 |
| 5 | 5.56 | 5.047 | 0.258 | 4.88 | 4.88 | 40 | 20.80 |
| 6 | 6.62 | 6.065 | 0.280 | 5.62 | 5.62 | 40 | 33.10 |
| 8 | 8.62 | 7.981 | 0.322 | 7.00 | 7.00 | 40 | 56.50 |
| 10 | 10.75 | 10.020 | 0.365 | 8.50 | 8.50 | 40 | 90.90 |
| 12 | 12.75 | 12.000 | 0.375 | 10.00 | 10.00 | * | 136.00 |
| 14 | 14.00 | 13.250 | 0.375 | 11.00 | 11.00 | 30 | 162.00 |
| 16 | 16.00 | 15.250 | 0.375 | 12.00 | 12.00 | 30 | 206.00 |
| 18 | 18.00 | 17.250 | 0.375 | 13.50 | 13.50 | * | 272.00 |
| 20 | 20.00 | 19.250 | 0.375 | 15.00 | 15.00 | 20 | 350.00 |
| 24 | 24.00 | 23.250 | 0.375 | 17.00 | 17.00 | 20 | 508.00 |
| 30 | 30.00 | 29.250 | 0.375 | 22.00 | 22.00 | * | 835.00 |
| 36 | 36.00 | 35.250 | 0.375 | 26.50 | 26.50 | * | 1294.00 |
| 42 | 42.00 | 41.250 | 0.375 | 30.00 | 28.00 | * | 1495.00 |
| 48 | 48.00 | 47.250 | 0.375 | 35.00 | 33.00 | * | 2300.00 |
Schedule XS
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to Center R | Center to End B | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|---|
| ½ | 0.84 | 0.546 | 0.147 | 1.00 | 1.00 | 80 | 0.37 |
| ¾ | 1.05 | 0.742 | 0.154 | 1.12 | 1.12 | 80 | 0.58 |
| 1 | 1.32 | 0.957 | 0.179 | 1.50 | 1.50 | 80 | 0.87 |
| 1¼ | 1.66 | 1.278 | 0.191 | 1.88 | 1.88 | 80 | 1.60 |
| 1½ | 1.90 | 1.500 | 0.200 | 2.25 | 2.25 | 80 | 2.30 |
| 2 | 2.38 | 1.939 | 0.218 | 2.50 | 2.50 | 80 | 3.90 |
| 2½ | 2.88 | 2.323 | 0.276 | 3.00 | 3.00 | 80 | 6.50 |
| 3 | 3.50 | 2.900 | 0.300 | 3.38 | 3.38 | 80 | 9.00 |
| 3½ | 4.00 | 3.364 | 0.318 | 3.75 | 3.75 | 80 | 12.20 |
| 4 | 4.50 | 3.826 | 0.337 | 4.12 | 4.12 | 80 | 16.20 |
| 5 | 5.56 | 4.813 | 0.375 | 4.88 | 4.88 | 80 | 26.60 |
| 6 | 6.62 | 5.761 | 0.432 | 5.62 | 5.62 | 80 | 41.80 |
| 8 | 8.62 | 7.625 | 0.500 | 7.00 | 7.00 | 80 | 76.20 |
| 10 | 10.75 | 9.750 | 0.500 | 8.50 | 8.50 | 60 | 115.00 |
| 12 | 12.75 | 11.750 | 0.500 | 10.00 | 10.00 | * | 169.00 |
| 14 | 14.00 | 13.000 | 0.500 | 11.00 | 11.00 | * | 237.00 |
| 16 | 16.00 | 15.000 | 0.500 | 12.00 | 12.00 | 40 | 284.00 |
| 18 | 18.00 | 17.000 | 0.500 | 13.50 | 13.50 | * | 353.00 |
| 20 | 20.00 | 19.000 | 0.500 | 15.00 | 15.00 | 30 | 442.00 |
| 24 | 24.00 | 23.000 | 0.500 | 17.00 | 17.00 | * | 625.00 |
| 30 | 30.00 | 29.000 | 0.500 | 22.00 | 22.00 | 20 | 1065.00 |
| 36 | 36.00 | 35.000 | 0.500 | 26.50 | 26.50 | 20 | 1610.00 |
| 42 | 42.00 | 41.000 | 0.500 | 30.00 | 28.00 | * | 1788.00 |
| 48 | 48.00 | 47.000 | 0.500 | 35.00 | 33.00 | * | 2300.00 |
Schedule 40
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to Center R | Center to End B | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|---|
| ½ | 0.84 | 0.622 | 0.109 | 1.00 | 1.00 | 40 | 0.35 |
| ¾ | 1.05 | 0.824 | 0.113 | 1.12 | 1.12 | 40 | 0.50 |
| 1 | 1.32 | 1.054 | 0.133 | 1.50 | 1.50 | 40 | 0.75 |
| 1¼ | 1.66 | 1.380 | 0.140 | 1.88 | 1.88 | 40 | 1.30 |
| 1½ | 1.90 | 1.610 | 0.145 | 2.25 | 2.25 | 40 | 1.90 |
| 2 | 2.38 | 2.072 | 0.154 | 2.50 | 2.50 | 40 | 3.20 |
| 2½ | 2.88 | 2.474 | 0.203 | 3.00 | 3.00 | 40 | 5.80 |
| 3 | 3.50 | 3.068 | 0.216 | 3.38 | 3.38 | 40 | 7.20 |
| 3½ | 4.00 | 3.548 | 0.226 | 3.75 | 3.75 | 40 | 8.50 |
| 4 | 4.50 | 4.026 | 0.237 | 4.12 | 4.12 | 40 | 9.50 |
| 5 | 5.56 | 5.044 | 0.258 | 4.88 | 4.88 | 40 | 12.70 |
| 6 | 6.62 | 6.060 | 0.280 | 5.62 | 5.62 | 40 | 20.80 |
| 8 | 8.62 | 7.976 | 0.322 | 7.00 | 7.00 | 40 | 33.10 |
| 10 | 10.75 | 10.020 | 0.365 | 8.50 | 8.50 | 40 | 56.50 |
| 12 | 12.75 | 11.938 | 0.406 | 10.00 | 10.00 | 40 | 90.90 |
| 14 | 14.00 | 13.124 | 0.438 | 11.00 | 11.00 | 40 | 165.00 |
| 16 | 16.00 | 15.000 | 0.500 | 12.00 | 12.00 | 40 | 210.00 |
| 18 | 18.00 | 16.876 | 0.562 | 13.50 | 13.50 | 40 | 275.00 |
| 20 | 20.00 | 18.812 | 0.594 | 15.00 | 15.00 | 40 | 355.00 |
| 24 | 24.00 | 22.624 | 0.688 | 17.00 | 17.00 | 40 | 510.00 |
Schedule 80
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to Center R | Center to End B | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|---|
| ½ | 0.84 | 0.546 | 0.147 | 1.00 | 1.00 | 80 | 0.37 |
| ¾ | 1.05 | 0.742 | 0.154 | 1.12 | 1.12 | 80 | 0.58 |
| 1 | 1.32 | 0.962 | 0.179 | 1.50 | 1.50 | 80 | 0.87 |
| 1¼ | 1.66 | 1.278 | 0.191 | 1.88 | 1.88 | 80 | 1.60 |
| 1½ | 1.90 | 1.500 | 0.200 | 2.25 | 2.25 | 80 | 2.30 |
| 2 | 2.38 | 1.944 | 0.218 | 2.50 | 2.50 | 80 | 3.90 |
| 2½ | 2.88 | 2.328 | 0.276 | 3.00 | 3.00 | 80 | 6.50 |
| 3 | 3.50 | 2.900 | 0.300 | 3.38 | 3.38 | 80 | 9.00 |
| 3½ | 4.00 | 3.364 | 0.318 | 3.75 | 3.75 | 80 | 12.20 |
| 4 | 4.50 | 3.826 | 0.337 | 4.12 | 4.12 | 80 | 16.20 |
| 5 | 5.56 | 4.810 | 0.375 | 4.88 | 4.88 | 80 | 26.60 |
| 6 | 6.62 | 5.756 | 0.432 | 5.62 | 5.62 | 80 | 41.80 |
| 8 | 8.62 | 7.620 | 0.500 | 7.00 | 7.00 | 80 | 76.20 |
| 10 | 10.75 | 9.562 | 0.594 | 8.50 | 8.50 | 80 | 120.00 |
| 12 | 12.75 | 11.374 | 0.688 | 10.00 | 10.00 | 80 | 175.00 |
| 14 | 14.00 | 12.500 | 0.750 | 11.00 | 11.00 | 80 | 240.00 |
| 16 | 16.00 | 14.312 | 0.844 | 12.00 | 12.00 | 80 | 290.00 |
| 18 | 18.00 | 16.124 | 0.938 | 13.50 | 13.50 | 80 | 360.00 |
| 20 | 20.00 | 17.938 | 1.031 | 15.00 | 15.00 | 80 | 450.00 |
| 24 | 24.00 | 21.562 | 1.219 | 17.00 | 17.00 | 80 | 630.00 |
Schedule 160
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to Center R | Center to End B | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|---|
| ½ | 0.84 | 0.464 | 0.188 | 1.00 | 1.00 | 160 | 0.46 |
| ¾ | 1.05 | 0.612 | 0.219 | 1.12 | 1.12 | 160 | 0.73 |
| 1 | 1.32 | 0.820 | 0.250 | 1.50 | 1.50 | 160 | 1.09 |
| 1¼ | 1.66 | 1.160 | 0.250 | 1.88 | 1.88 | 160 | 2.00 |
| 1½ | 1.90 | 1.338 | 0.281 | 2.25 | 2.25 | 160 | 2.88 |
| 2 | 2.38 | 1.692 | 0.344 | 2.50 | 2.50 | 160 | 4.88 |
| 2½ | 2.88 | 2.130 | 0.375 | 3.00 | 3.00 | 160 | 8.13 |
| 3 | 3.50 | 2.624 | 0.438 | 3.38 | 3.38 | 160 | 11.25 |
| 4 | 4.50 | 3.438 | 0.531 | 4.12 | 4.12 | 160 | 20.25 |
| 5 | 5.56 | 4.310 | 0.625 | 4.88 | 4.88 | 160 | 33.25 |
| 6 | 6.62 | 5.182 | 0.719 | 5.62 | 5.62 | 160 | 52.25 |
| 8 | 8.62 | 6.808 | 0.906 | 7.00 | 7.00 | 160 | 95.25 |
| 10 | 10.75 | 8.500 | 1.125 | 8.50 | 8.50 | 160 | 143.75 |
| 12 | 12.75 | 10.126 | 1.312 | 10.00 | 10.00 | 160 | 211.25 |
| 14 | 14.00 | 11.188 | 1.406 | 11.00 | 11.00 | 160 | 296.25 |
| 16 | 16.00 | 12.812 | 1.594 | 12.00 | 12.00 | 160 | 355.00 |
| 18 | 18.00 | 14.438 | 1.781 | 13.50 | 13.50 | 160 | 441.25 |
| 20 | 20.00 | 16.062 | 1.969 | 15.00 | 15.00 | 160 | 552.50 |
| 24 | 24.00 | 19.312 | 2.344 | 17.00 | 17.00 | 160 | 781.25 |
Schedule XXS
| Nom. Pipe Size | Outside Diameter O.D. | Inside Diameter I.D. | Wall Thickness T | Center to Center R | Center to End B | Pipe Schedule Number | Approx. Weight in Pounds Lbs. |
|---|---|---|---|---|---|---|---|
| ½ | 0.84 | 0.252 | 0.294 | 1.00 | 1.00 | * | 0.51 |
| ¾ | 1.05 | 0.434 | 0.308 | 1.12 | 1.12 | * | 0.80 |
| 1 | 1.32 | 0.604 | 0.358 | 1.50 | 1.50 | * | 1.20 |
| 1¼ | 1.66 | 0.896 | 0.382 | 1.88 | 1.88 | * | 2.20 |
| 1½ | 1.90 | 1.100 | 0.400 | 2.25 | 2.25 | * | 3.16 |
| 2 | 2.38 | 1.508 | 0.436 | 2.50 | 2.50 | * | 5.36 |
| 2½ | 2.88 | 1.776 | 0.552 | 3.00 | 3.00 | * | 8.94 |
| 3 | 3.50 | 2.300 | 0.600 | 3.38 | 3.38 | * | 12.38 |
| 4 | 4.50 | 3.152 | 0.674 | 4.12 | 4.12 | * | 22.28 |
| 5 | 5.56 | 4.060 | 0.750 | 4.88 | 4.88 | * | 36.58 |
| 6 | 6.62 | 4.892 | 0.864 | 5.62 | 5.62 | * | 57.48 |
| 8 | 8.62 | 6.870 | 0.875 | 7.00 | 7.00 | * | 104.78 |
| 10 | 10.75 | 8.750 | 1.000 | 8.50 | 8.50 | 140 | 158.13 |
| 12 | 12.75 | 10.750 | 1.000 | 10.00 | 10.00 | 120 | 232.38 |
Materials We Supply
Straight Tee to ASME B16.9 in the grades below. Tell us the service and we will confirm the right one.
| Material | Specification | Typical Service |
|---|---|---|
| Carbon Steel | ASTM A234 WPB / WPC | General process, steam, oil and gas gathering and utility lines |
| Low-Temp Carbon Steel | ASTM A420 WPL6 | Cold service to −50°F; LNG and northern pipeline work |
| Chrome-Moly Alloy | ASTM A234 WP11 / WP22 / WP91 | Elevated temperature; refinery heaters, power plant steam |
| Stainless Steel | ASTM A403 WP304/304L, WP316/316L | Corrosive service, chemical, food and beverage, water treatment |
| Duplex & Super Duplex | ASTM A815 UNS S31803 / S32750 | Chloride and seawater service, offshore, desalination |
Common Questions
What is the difference between a straight tee and a reducing tee?
Branch size. On a straight tee all three ends are the same nominal size. On a reducing tee the branch is smaller than the run, which is the more common case when you are tapping a small line off a large header.
What do the R and B dimensions mean on a tee?
R is center-to-end along the run and B is center-to-end on the branch. Both are measured from the intersection of the centerlines to the welding face, both are marked on the drawing above, and both are listed by size and schedule in the tables.
Is a tee better than a weldolet for a full-size branch?
For a full-size branch, generally yes. A tee is a factory fitting made to ASME B16.9 with an established pressure rating, whereas a fabricated branch connection needs a reinforcement calculation. Branch fittings make more sense when the branch is much smaller than the header.
