2-1/2-8NPSH vs 3-8NPSH: specs compared
Updated 05 September 2026.
88.14 mm
3-8NPSH wins on major diameter
On major diameter, 3-8NPSH leads: 88.14 mm versus 72.16 mm.
| Spec | 2-1/2-8NPSH | 3-8NPSH |
|---|---|---|
| Designation | 2-1/2-8NPSH | 3-8NPSH |
| Major diameter | 72.16 mm | 88.14 mm |
| Threads per inch / pitch | 8 | 8 |
| Thread form | straight (parallel), 60 degree | straight (parallel), 60 degree |
| Seals on | gasket in the coupling | gasket in the coupling |
Questions and answers
Which has the higher major diameter, 2-1/2-8NPSH or 3-8NPSH?
On major diameter, 3-8NPSH leads: 88.14 mm versus 72.16 mm.
How do 2-1/2-8NPSH and 3-8NPSH compare?
On major diameter, 3-8NPSH leads: 88.14 mm versus 72.16 mm.