NPT threaded fittings have American National Standard taper pipe threads to ASME B1.20.1. NPT is the standard thread for ASME B16.11 threaded fittings and the most widely used pipe thread in the oil, gas and process industries of the Americas and the Middle East.
Raaj Fittings machines NPT threads on forged elbows, tees, couplings, caps, plugs, bushings and nipples at our two plants in India, in Class 2000, 3000 and 6000, in carbon, alloy and stainless steel, duplex and nickel alloys, with every thread checked by gauge.
| Nominal size | Threads per inch |
|---|---|
| ⅛" | 27 |
| ¼" and ⅜" | 18 |
| ½" and ¾" | 14 |
| 1" to 2" | 11½ |
| 2½" and larger | 8 |
NPTF (dryseal, ASME B1.20.3) threads are made with controlled crest and root truncation so they seal by metal contact without sealant, and are used mainly in hydraulic and fuel systems. Standard pipe fittings use NPT with a sealant.
NPT and BSP threads look similar but have different thread angles (60° against 55°) and, in most sizes, different pitches. Screwing an NPT fitting onto a BSP thread damages both and leaks. See BSP threaded fittings.
Every NPT fitting is made from PMI-verified material, dimensionally inspected against the ordered standard and marked with material, size, rating and heat number. Orders are supplied with EN 10204 3.1 certificates; EN 10204 3.2 certification and inspection by the buyer's nominated third-party agency are available on request.
National Pipe Taper, the American taper pipe thread defined in ASME B1.20.1.
½" and ¾" NPT threads have 14 threads per inch; 1" to 2" have 11½, and ¼" and ⅜" have 18.
Yes, standard NPT threads need a thread sealant or PTFE tape to seal the small spiral clearance. NPTF dryseal threads are designed to seal without it.
No. NPT and BSP threads have different thread angles and pitches and will not seal together.