BSP threaded fittings have British Standard Pipe threads, the Whitworth-form pipe threads used across the UK, Europe, Asia, Africa and Australia. Pressure-tight BSP threads are defined in BS 21 and ISO 7-1; parallel fastening threads in ISO 228-1.
Raaj Fittings machines BSPT and BSPP threads on forged elbows, tees, couplings, caps, plugs, bushings and nipples at our two plants in India, in the same classes and materials as our NPT fittings, for buyers whose plants and equipment use British threads.
| Designation | Thread | Where |
|---|---|---|
| R | Taper external (BSPT) | ISO 7-1 / BS 21, pressure-tight |
| Rc | Taper internal (BSPT) | ISO 7-1 / BS 21, pressure-tight |
| Rp | Parallel internal, for use with R taper external | ISO 7-1 / BS 21, pressure-tight |
| G | Parallel (BSPP), sealed by a washer or O-ring, not on the thread | ISO 228-1 |
| Nominal size | Threads per inch |
|---|---|
| ⅛" | 28 |
| ¼" and ⅜" | 19 |
| ½" and ¾" | 14 |
| 1" and larger | 11 |
All BSP threads have a 55° thread angle with rounded crests and roots; taper threads have a taper of 1 in 16, the same as NPT.
Although ½" and ¾" BSP and NPT both have 14 threads per inch, the 55° and 60° thread angles differ and the joint will leak. Always order the thread used by the mating equipment. See NPT threaded fittings.
Every BSP 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.
BSPT threads are tapered and seal on the thread with sealant; BSPP (G) threads are parallel and seal with a washer, bonded seal or O-ring.
Pressure-tight BSP threads are defined in BS 21 and ISO 7-1; parallel G threads that do not seal on the thread are in ISO 228-1.
They should not be. The thread angles differ (55° and 60°) and most pitches differ, so the joint will leak or the threads will be damaged.
Yes, BSPT and BSPP threaded fittings are made in stainless steel, carbon steel and other grades, in the same classes as NPT fittings.