BSPT & BSPP Threads
British Standard Pipe Taper (BSPT) & British Standard Pipe Parallel (BSPP) Threads
|BSP||BRITISH STANDARD PIPE||Also known as whitworth 55° thread form|
|BSPT||BRITISH STANDARD PIPE TAPER||Thread form as 1722.1, BS 21, ISO 7-1, DIN 3852-2 FORM C (MALE), DIN 3852-2 FORM Z (FEMALE)|
|BSPP||BRITISH STANDARD PIPE PARALLEL||Thread form per as 1722.2, ISO 228 (THREAD TYPE), ISO 1179|
|BSPO||BRITISH STANDARD PIPE PARALLEL O-RING||Thread form per as 1722.2, ISO 228 (THREAD TYPE), ISO 8434-6, BS 5200|
- British Standard Pipe Taper (BSPT)
- British Standard Pipe Parallel (BSPP)
BSPT Pipe Threads can be combined into two types of joints:
1. Jointing Threads: These are pipe threads where pressure-tightness is made through the mating of two threads together. They always use a taper male thread but can have either parallel or taper female threads. (International standards require all female threads to be parallel.)
2. Long Screw threads: These are parallel pipe threads used where a pressure-tight joint is achieved by the compression of a soft material (such as an o-ring seal or a washer) between the end face of the male thread and a socket or nipple face, with the tightening of a back nut.
British Standard Pipe threads are similar in function to NPT threads, but are generally not interchangeable.
BSPT male threads seal against threads of fixed BSPT female.
Contact is made on the flanks of the threads.
Use of a thread sealant is recommended for BSPT male to BSPT female connections.
Measure the BSPT male thread OD and female thread ID at the first full thread near the end of the fitting.
BSPT male and BSPP male with conical 30° seat (60° included angle) seal against matching conical 30° seat of BSPP female swivel.
BSPP male, with chamfer to locate Bonded Seal also seals against flat external surface of BSPP female port.
Surface irregularities require a Spot Face to ensure effective sealing. Elbows and tees have Lock Nut to allow orientation of fitting to required direction.
|BSPT & BSPP SIZE & PITCH||DASH SIZE||BSPT MALE THREAD OD||BSPP MALE THREAD OD||BSPT FEMALE THREAD ID||BSPP FEMALE THREAD ID|
|1/8 – 28||-02||9,5||0.37||9,6||0.38||8,4||0.33||8,6||0.34|
|1/4 – 19||-04||12,8||0.50||13,0||0.51||11,2||0.44||11,9||0.47|
|3/8 – 19||-06||16,3||0.64||16,5||0.65||14,7||0.59||15,2||0.60|
|1/2 – 14||-08||20,4||0.80||20,8||0.82||18,3||0.72||19,1||0.75|
|5/8 – 14||-10||22,5||0.89||22,8||0.90||20,6||0.81||20,8||0.82|
|3/4 – 14||-12||25,9||1.02||26,3||1.04||23,9||0.94||24,6||0.97|
|1 – 11||-16||32,6||1.28||33,1||1.30||29,7||1.17||30,7||1.21|
|1.1/4 – 11||-20||41,1||1.62||41,8||1.64||38,6||1.52||39,4||1.55|
|1.1/2 – 11||-24||47,0||1.85||47,7||1.88||44,5||1.75||45,5||1.79|
|2.1/2 – 11||-40||74,1||2.92||75,1||2.95||71,9||2.83||72,6||2.86|
|3 – 11||-48||86,6||3.41||87,9||3.46||84,6||3.33||85,4||3.36|
Pitch is Threads Per Inch (TPI). “Gas”, “R” & “G” also refer to BSP. “Male Iron (Pipe)” may be BSP or NPT.