The primary purpose of a tee is to make a 90° branch from the main run of pipe.Standard there are 2 possibilities,on behalf of the equal tee and reducing tee.The equal tee (or straight tee) is used as the branch has the same diameter as the run-pipe.The reducing tee is used as the branch has a smaller diameter as the run-pipe.
| NPS | Outside Diameter | RUn-C | Outlet-M |
| 16 | 16 | 12 | 12 |
| 18 | 18 | 13.5 | 13.5 |
| 20 | 20 | 15 | 15 |
| 22 | 22 | 16.5 | 16.5 |
| 24 | 24 | 17 | 17 |
| 26 | 26 | 19.5 | 19.5 |
| 28 | 28 | 20.5 | 20.5 |
| 30 | 30 | 22 | 22 |
| 32 | 32 | 23.5 | 23.5 |
| 34 | 34 | 25 | 25 |
| 36 | 36 | 26.5 | 26.5 |
| 38 | 38 | 28 | 28 |
| 40 | 40 | 29.5 | 29.5 |
| 42 | 42 | 30 | 28 |
| 44 | 44 | 32 | 30 |
| 46 | 46 | 33.5 | 31.5 |
| 48 | 48 | 35 | 33 |
| 50 | 50 | 36.75 | 34.5 |
| 52 | 52 | 38.5 | 35 |
| 54 | 54 | 40 | 37 |
| 56 | 56 | 41.5 | 38.5 |
| 58 | 58 | 43 | 40 |
| 60 | 60 | 44 | 41 |