NPS 3 Pipe
Outside diameter 3.500″
OD in mm 88.9 mm
NPT thread 3″ NPT (8 TPI)
Every NPS 3 pipe has this OD regardless of schedule — the schedule changes only the wall thickness and bore.
Schedules
| Schedule | Wall | Wall mm | Inside diameter | ID mm |
|---|---|---|---|---|
| 40 = STD | 0.216″ | 5.486 | 3.068″ | 77.927 |
| 80 = XS | 0.300″ | 7.62 | 2.900″ | 73.66 |
3″ NPT thread
| Designation | 3″ NPT |
|---|---|
| Threads per inch | 8 |
| Recommended tap drill | 3-1/4″ (3.2500″ / 82.55 mm) |
NPT is a tapered thread (3/4″ per foot on diameter) — it seals on the thread flanks with sealant. The size refers to the pipe's nominal size, not any measured thread diameter.