BSP fittings are a family of fittings used to connect up threaded pipe and equipment.
They are manufactured from pipe, bar, hollow bar, castings or forgings.
The pipe to be threaded must have a wall thickness of Schedule 40S minimum.
The fittings are used in non-critical, low pressure applications where welding is not possible or required. They therefore provide a relatively low cost method of connection.
BSP fittings are made only in type 316.
BSP fittings are usually fitted with a sealant (paste or tape such as PTFE) and are considered to be permanent pipe-work.
Low Pressure BSP Fittings are rated at 150lb and are made to wrought iron specification BS1740. BSP fittings are made only in type 316.
They are provided with a Certificate of Conformity only, and not a full Test Certificate.
Sizes ½ to 3 inch are the most commonly used and thus the most readily available.
External MALE threads are tapered and Internal FEMALE threads are parallel. The threads are cut to BS21: Part 1: 1985 and are called Whitworth Threads.
90o Elbow: Enables the pipe run to be turned through a right angle. Female thread both ends.
45o Elbow: Enables the pipe run to be turned through 45 degrees. Female thread both ends.
Equal Tee: This allows the connection of a branch at right angles from the main pipe run. Female thread at all three connections.
Socket: Used to connect two pipes or fittings that have male threads. Female thread both ends.
Half Socket: Used to connect two pipes or fittings that have male threads. Used when there is a confined space. Female thread both ends.
Reducing Socket: Used to connect two different sizes of pipe or fittings that have male threads. Female threads both ends.
Cap: Used to terminate a male threaded pipe run. Female threaded.
Union: Connects male threaded pipe or components. Used when easy or regular access is required e.g. for cleaning. Female thread both ends.
Hexagon Nut: Used to fix male threaded fittings. Female threaded.
Reducing Bush: Connects a larger female threaded component to a smaller male threaded component. Male thread at the large end and Female thread at the small end.
Hexagon Nipple: Used to connect two female threaded components. Male thread both ends.
Hexagon Reducing Nipple: Connects two female threaded components of different sizes. Male thread both ends.
Barrel Nipple: Used to connect two female threaded components of the same size. Male (taper) thread both ends.
Parallel or Equal Nipple: The only BSP fitting to have a male parallel thread. Used to connect female threaded components together.
Spigot or Welding Nipple: Weld prepared at one end and a male thread at the other. Used to weld onto equipment that is to be connected to a female threaded component.
Close Taper Nipple: Used to connect two female threaded components. No land between the threads so shorter than a barrel nipple and thus used where space is restricted. Male thread both ends.
Hexagon Head Plug: Used to blank off female threaded outlet. Cannot be used to blank off a pipe directly as pipes only have male threads. Male threaded.
Square Head Plug: Used to blank off female threaded outlet. Cannot be used to blank off a pipe directly as pipes only have male threads. Male threaded.
90o Bend: This has a larger radius than a 90-degree elbow and is again used to turn the pipe run through a right angle. Female thread both ends.
Hose Nipple: Used to connect a hose to the system. Male thread one end and hose serrations at the other.
Whitworth Threads/British Standard Pipe Thread
Nominal Size of Outlet (in)
Nominal Size of Outlet (mm)
Min O/D (mm)
Min O/D of Body Behind External Thread (mm)
Min I/D of Body Behind Internal Thread mm
No of Threads per Inch
1/8
6
15.0
9.8
8.6
28
1/4
8
18.5
13.3
11.4
19
3/8
10
22.0
16.8
15.0
19
1/2
15
27.0
21.1
18.6
14
3/4
20
32.5
26.6
24.1
14
1
25
39.5
33.4
30.3
11
1 1/4
32
49.0
42.1
39.0
11
1 1/2
40
56.0
48.0
44.8
11
2
50
68.0
59.8
56.7
11
2 1/2
65
84.0
75.4
72.2
11
3
80
98.0
88.1
84.9
11
4
100
124.0
113.3
110.1
11
5
125
151.0
138.7
135.5
11
6
150
178.0
164.1
160.9
11
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