B.S.P.T.

British Standard Pipe Thread


British Standard Pipe Thread is a family of standard screw thread types that has been adopted internationally for interconnecting and sealing pipe ends by mating an external (male) with an internal (female) thread.


A list of 16 thread sizes are defined by the standards, ranging from 1⁄16 Inch to 6 Inch. The size was originally based on the inner diameter measured in inches of a steel tube for which the thread was intended. This often causes confusion, as people think the size refers to the outside diameter of the male thread.

Two types of threads are used:

Parallel (straight) threads, British Standard Pipe Parallel thread (BSPP)

Taper threads, British Standard Pipe Taper thread (BSPT)

Just to confuse things, often the T in BSPT refers to Thread and doesn't indicate either Taper or Parallel.

The threadform follows the British Standard Whitworth standard


The table below shows dimensions for male threads.


Thread

Threads per inch

Pitch mm

Outside Diameter mm

Outside Diameter inches

1/16 Inch

28

0.907

7.723

0.304

1/8 Inch

28

0.907

9.728

0.383

1/4 Inch

19

1.337

13.157

0.518

3/8 Inch

19

1.337

16.662

0.656

1/2 Inch

14

1.814

20.995

0.825

5/8 Inch

14

1.814

22.991

0.902

3/4 Inch

14

1.814

26.441

1.041

1 Inch

11

2.309

33.249

1.309

1¼ Inch

11

2.309

41.910

1.650

1½ Inch

11

2.309

47.803

1.882

2 Inch

11

2.309

59.614

2.347

2½ Inch

11

2.309

75.184

2.96

3 Inch

11

2.309

87.884

3.46

4 Inch

11

2.309

113.030

4.45

5 Inch

11

2.309

138.430

5.45

6 Inch

11

2.309

163.830

6.45


This is a 1/2 Inch thread, you can count 14 threads in one inch.


An end view of a 1/2 Inch male thread



As the name of the sizing does not match the actual diameter, there can be some confusion over sizing. We have shown some pictures of two of the more popular sizes along side popular UK coins.

First, a half inch thread which is similar in size to a 1 penny coin.



Second, a three quarter inch thread which is similar in size to a 2 pence coin :


Typical uses and sizes are :

1/4 Inch - Compressed air connections

3/8 Inch - Oil line connections

1/2 Inch - Basin and sink taps, radiator inlets, old outside tap outlets

5/8 Inch - Old outside tap outlets (very rare)

3/4 Inch - Bath taps, washing machine inlet hose connections, modern outside tap outlets

1 Inch Domestic heating boilers

1.25 Inch - Wash hand basin wastes (bathroom sink)

1.5 Inch - Kitchen sink wastes (kitchen sink), bath wastes, WC syphon outlets

2 Inch - Modern toilet flushvalve outlets


A selection of "Black Iron" BSPT fittings :

BSPT fittings


A selection of plumbing fittings with BSP threads : stevenson-plumbing-and-electrical


8mm x 1/4 Inch Male BSP Compression Elbow | Brass Fitting
1.38
End Date: 18-Mar 08:11
Buy It Now for only: US 1.38
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1/4 Inch Brass Male x Female Elbow | ? BSP M x F
2.50
End Date: 10-Mar 12:03
Buy It Now for only: US 2.50
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Brass Washing Machine Y Piece - Union Type - 3/4" BSP
5.99
End Date: 24-Mar 08:56
Buy It Now for only: US 5.99
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8mm x 1/4 Inch Male BSP Compression Coupler | Brass Fitting
1.57
End Date: 08-Mar 21:11
Buy It Now for only: US 1.57
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Radiator Valve Tails | 1/2 Inch BSP | 2 Pack
3.49
End Date: 09-Mar 16:21
Buy It Now for only: US 3.49
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3/4? Brass Blanking Cap and Washer | ? BSP | British Standard Pipe Thread
1.99
End Date: 10-Mar 14:41
Buy It Now for only: US 1.99
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8mm x 1/4 Inch Female BSP Compression Elbow | Brass Fitting
1.96
End Date: 23-Mar 21:11
Buy It Now for only: US 1.96
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1/2 Inch BSP Brass Male x Female Elbow (M x F) | British Standard Pipe Thread
3.94
End Date: 19-Mar 19:57
Buy It Now for only: US 3.94
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1/8 Inch BSP Brass Male x Female Elbow (M x F) | British Standard Pipe Thread
3.54
End Date: 10-Mar 15:00
Buy It Now for only: US 3.54
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1/4 Inch BSP Brass Socket | British Standard Pipe Thread Fitting
1.51
End Date: 09-Mar 21:18
Buy It Now for only: US 1.51
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3 Bar Pressure Relief Safety Valve - 1/2" BSP Male x Female (M x F)
5.49
End Date: 14-Mar 11:38
Buy It Now for only: US 5.49
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1/8 Inch BSP Brass Cap | British Standard Pipe Thread Fitting
1.27
End Date: 10-Mar 12:05
Buy It Now for only: US 1.27
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10mm x 1/2 Inch Female BSP Compression Elbow | Brass Fitting
2.49
End Date: 23-Mar 20:01
Buy It Now for only: US 2.49
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10mm x 3/8 Inch BSP Male Compression Coupler | Brass Fitting
1.76
End Date: 09-Mar 20:00
Buy It Now for only: US 1.76
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1 1/4 Inch BSP Plastic Back Nut | British Standard Pipe Thread Fitting
1.45
End Date: 10-Mar 15:00
Buy It Now for only: US 1.45
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1/4 Inch Brass Flanged Plugs | ? BSP | British Standard Pipe Thread | 2 Pack
2.52
End Date: 09-Mar 09:51
Buy It Now for only: US 2.52
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3/4 Inch BSP Brass Back Nut | British Standard Pipe Thread Fitting
1.25
End Date: 12-Mar 09:24
Buy It Now for only: US 1.25
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1/4 Inch BSP Brass Equal Tee | British Standard Pipe Thread Fitting
3.91
End Date: 03-Mar 10:15
Buy It Now for only: US 3.91
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3/8 Inch BSP Female x 15mm Compression Flexible Tap Connector Hose
2.80
End Date: 23-Mar 21:18
Buy It Now for only: US 2.80
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1 Inch BSP Brass Gate Valve
6.40
End Date: 08-Mar 20:13
Buy It Now for only: US 6.40
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15mm Compression Tee With 1/2 Inch Female BSP Branch. Useful For Drain Or Vent
2.76
End Date: 07-Mar 11:56
Buy It Now for only: US 2.76
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15mm x 1/2 Inch BSP Male Compression Elbow | Brass Fitting
1.58
End Date: 23-Mar 20:53
Buy It Now for only: US 1.58
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1/4 Inch Brass Female x Female Elbow | ? BSP (F x F)
2.99
End Date: 10-Mar 14:54
Buy It Now for only: US 2.99
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1 1/4 Inch BSP Brass Cap | British Standard Pipe Thread Fitting
3.96
End Date: 10-Mar 11:49
Buy It Now for only: US 3.96
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Braided Flexible Heating Oil Line 1/4 Inch Female x 1/4 Inch BSP Female Elbow
10.52
End Date: 09-Mar 09:36
Buy It Now for only: US 10.52
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1 1/2 Inch x 3/4 Inch Brass Hex Bush | BSP - British Standard Pipe Thread
3.99
End Date: 02-Mar 10:06
Buy It Now for only: US 3.99
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2 Inch BSP Brass Nipple | British Standard Pipe Thread Fitting
17.29
End Date: 10-Mar 11:49
Buy It Now for only: US 17.29
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1/2 Inch BSP Brass Equal Tee Fitting | British Standard Pipe Thread Fitting
5.23
End Date: 09-Mar 21:26
Buy It Now for only: US 5.23
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Brass Washing Machine Y Piece | 3/4 Inch BSP
4.99
End Date: 18-Mar 21:36
Buy It Now for only: US 4.99
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15mm x 1/2 Inch Female BSP Chrome Plated Compression Elbow
3.56
End Date: 23-Mar 17:09
Buy It Now for only: US 3.56
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Rubber Plumbing Heating 1/2" BSP Washers. 22mm Internal Diameter (10 Pack)
2.20
End Date: 15-Mar 13:14
Buy It Now for only: US 2.20
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3/8 Inch BSP Brass Blanking Plugs - British Standard Pipe Thread (2 Pack)
2.50
End Date: 09-Mar 20:41
Buy It Now for only: US 2.50
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1 1/2 Inch BSP Plastic Back Nut | British Standard Pipe Thread Fitting
1.45
End Date: 12-Mar 09:24
Buy It Now for only: US 1.45
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3/4 Inch x 1/4 Inch Brass Hex Bush | BSP - British Standard Pipe Thread Fitting
2.19
End Date: 18-Mar 08:11
Buy It Now for only: US 2.19
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1/2 Inch BSP Brass Blanking Cap | British Standard Pipe Thread Fitting
1.23
End Date: 09-Mar 20:00
Buy It Now for only: US 1.23
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1/2 Inch BSP Brass Socket | British Standard Pipe Thread Fitting
2.01
End Date: 10-Mar 12:24
Buy It Now for only: US 2.01
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22mm x 3/4 Inch Female BSP Compression Elbow | Brass Fitting
3.56
End Date: 20-Mar 21:18
Buy It Now for only: US 3.56
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3/8 Inch BSP Brass Back Nut | British Standard Pipe Thread Fitting
1.59
End Date: 12-Mar 09:26
Buy It Now for only: US 1.59
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8mm x 3/8 Inch Male BSP Compression Coupler | Brass Fitting
1.86
End Date: 09-Mar 20:00
Buy It Now for only: US 1.86
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1/2? Brass Flanged Back-Nuts | ? BSP | British Standard Pipe Thread | (2 Pack)
2.10
End Date: 08-Mar 21:00
Buy It Now for only: US 2.10
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15mm x 3/4 Inch Female BSP Compression Coupler | Brass Fitting
3.17
End Date: 08-Mar 09:04
Buy It Now for only: US 3.17
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1/4 Inch x 1/8 Inch Brass Hex Bush | BSP | British Standard Pipe Thread Fitting
1.00
End Date: 04-Mar 08:03
Buy It Now for only: US 1.00
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6 Bar 1/2 Inch BSP Safety Valve / Water Pressure Relief Valve
6.03
End Date: 09-Mar 16:24
Buy It Now for only: US 6.03
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1/2 Inch BSP Drain Cock Valve With Leakproof Gland (Type A)
2.72
End Date: 09-Mar 09:23
Buy It Now for only: US 2.72
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1/8 Inch Brass Socket / Coupler | BSP - British Standard Pipe Thread
1.00
End Date: 09-Mar 20:01
Buy It Now for only: US 1.00
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1 Inch BSP Brass Back Nut | British Standard Pipe Thread Fitting
2.10
End Date: 09-Mar 09:37
Buy It Now for only: US 2.10
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1/2 Inch BSP Male x 15mm Compression Coupler | Brass Fitting
2.99
End Date: 08-Mar 09:21
Buy It Now for only: US 2.99
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28mm x 1 Inch Male BSP Compression Coupler | Brass Fitting
3.90
End Date: 20-Mar 21:21
Buy It Now for only: US 3.90
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3/8 Inch Brass Male x Female Elbow | 3/8? BSP (M x F)
2.80
End Date: 08-Mar 07:48
Buy It Now for only: US 2.80
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22mm x 1 Inch BSP Male Compression Coupler | Brass Fitting
4.42
End Date: 08-Mar 09:21
Buy It Now for only: US 4.42
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