The NPT thread is a thread standard from America for a self-sealing pipe fitting. In practice, a sealant such as hemp or Teflon tape is placed between the threads of pipe fittings to ensure tightness. Only at low pressure is the thread self-sealing without sealant. The internal as well as the external thread have a conical thread form.
Thread Sizes |
Thread Pitch (mm) |
Outer Diameter (mm) |
Core Hole Diameter (mm) |
Gear number pro Inch |
NPT 1/16" | 0,941 | 7,90 | 6,00 | 27 |
NPT 1/8" | 0,941 | 10,24 | 8,25 | 27 |
NPT 1/4" | 1,411 | 13,62 | 11,00 | 18 |
NPT 3/8" | 1,411 | 17,06 | 14,50 | 18 |
NPT 1/2" | 1,814 | 21,22 | 17,75 | 14 |
NPT 3/4" | 1,814 | 26,57 | 23,00 | 14 |
NPT 1" | 2,209 | 33,23 | 29,00 | 11,5 |
NPT 1 1/4" | 2,209 | 41,99 | 37,50 | 11,5 |
NPT 1 1/2" | 2,209 | 48,05 | 44,00 | 11,5 |
NPT 2" | 2,209 | 60,09 | 56,00 | 11,5 |
NPT 2 1/2" | 3,175 | 72,70 | 66,50 | 8 |
NPT 3" | 3,175 | 88,61 | 82,50 | 8 |
NPT 3 1/2" | 3,175 | 101,32 | 94,50 | 8 |
NPT 4" | 3,175 | 113,97 | 107,00 | 8 |
NPT 5" | 3,175 | 141,30 | 134,50 | 8 |
NPT 6" | 3,175 | 168,28 | 161,00 | 8 |
NPT 8" | 3,175 | 219,08 | 221,50 | 8 |
NPT 10" | 3,175 | 273,05 | 265,50 | 8 |
NPT 12" | 3,175 | 323,85 | 315,79 | 8 |
* All information without guarantee.
Tip !
Pipe thread Sealing cord or sealing tape.