2-11.5 NPT vs 2-1/2-8NPSH: specs compared
Updated 05 September 2026.
72.16 mm
2-1/2-8NPSH wins on major diameter
On major diameter, 2-1/2-8NPSH leads: 72.16 mm versus 60.32 mm.
| Spec | 2-11.5 NPT | 2-1/2-8NPSH |
|---|---|---|
| Designation | 2-11.5 NPT | 2-1/2-8NPSH |
| Major diameter | 60.32 mm | 72.16 mm |
| Threads per inch / pitch | 11.5 | 8 |
| Thread form | tapered, 60 degree | straight (parallel), 60 degree |
| Seals on | on the thread flanks with PTFE tape | gasket in the coupling |
Questions and answers
Which has the higher major diameter, 2-11.5 NPT or 2-1/2-8NPSH?
On major diameter, 2-1/2-8NPSH leads: 72.16 mm versus 60.32 mm.
How do 2-11.5 NPT and 2-1/2-8NPSH compare?
On major diameter, 2-1/2-8NPSH leads: 72.16 mm versus 60.32 mm.