In this article, I have listed pipe coupling dimensions for both socket weld and threaded coupling. These couplings are used in piping for taking small-size branch connections. Mainly to attached instruments.

Socket Weld Coupling Dimensions

NOMINAL PIPE SIZE OUTER DIAMETER SOCKET BORE DIAMETER BORE DIAMETER OF FITTINGS BORE DIAMETER OF FITTINGS BORE DIAMETER OF FITTINGS WALL THICKNESS
# 3000
WALL THICKNESS
# 3000
WALL THICKNESS
# 6000
WALL THICKNESS
# 6000
WALL THICKNESS
# 9000
WALL THICKNESS
# 9000
FULL COUPLING FULL COUPLING HALF COUPLING HALF COUPLING
Inch. A B C – 3000 C – 6000 C – 9000 D D D D D D L1 L2 L1 L2
Maximum
Minimum
Maximum
Minimum
Maximum
Minimum
Maximum
Minimum
Average Minimum Average Minimum Average Minimum
1/8 B+D 11.2
10.8
7.6
6.1
4.8
3.2
3.18 3.18 3.96 3.43 9.5 6.5 9.5 16.0
1/4 B+D 14.6
14.2
10.0
8.5
7.1
5.6
3.78 3.30 4.6 4.01 9.5 6.5 9.5 16.0
3/8 B+D 18.0
17.6
13.3
11.8
9.9
8.4
4.01 3.50 5.03 4.37 9.5 6.5 9.5 17.5
1/2 B+D 22.2
21.8
16.6
15.0
12.5
11.0
7.2
5.6
4.67 4.09 5.97 5.18 9.35 8.18 9.5 9.5 9.5 22.5
3/4 B+D 27.6
27.2
21.7
20.2
16.3
14.8
11.8
10.3
4.90 4.27 6.96 6.04 9.78 8.56 12.5 9.5 12.5 24.0
1 B+D 34.3
33.9
27.4
25.9
21.5
19.9
16.0
14.4
5.69 4.98 7.92 6.93 11.38 9.96 12.5 12.5 12.5 28.5
1 1/4 B+D 43.1
42.7
35.8
34.3
30.2
28.7
23.5
22.0
6.07 5.28 7.92 6.93 12.14 10.62 12.5 12.5 12.5 30.0
1 1/2 B+D 49.2
48.8
41.6
40.1
34.7
33.2
28.7
27.2
6.35 5.54 8.92 7.8 12.7 11.12 12.5 12.5 12.5 32.0
2 B+D 61.7
61.2
53.3
51.7
43.6
42.1
38.9
37.4
6.93 6.04 10.92 9.5 13.84 12.12 16.0 19.0 16.0 41.0
2 1/2 B+D 74.4
73.9
64.2
61.2
8.76 7.67 16.0 19.0 16.0 43.0
3 B+D 90.3
89.8
79.4
76.4
9.52 8.30 16.0 19.0 16.0 44.5
4 B+D 103.8
100.7
103.8
100.7
10.69 9.35 16.0 19.0 16.0 48.0
All Dimensions are in mm

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Threaded Coupling Dimensions

NOMINAL PIPE SIZE END TO END MINIMUM LENGTH OF THREAD OUTSIDE DIAMETER
Inch. Full Coupling Half Coupling # 3000 # 6000
A A/2 B C D D
1/8 32 A/2 6.7 6.4 16 22
1/4 35 A/2 10.2 8.1 19 25
3/8 38 A/2 10.4 9.1 22 32
1/2 48 A/2 13.6 10.9 28 38
3/4 51 A/2 13.9 12.7 35 44
1 60 A/2 17.3 14.7 44 57
1 1/4 67 A/2 18 17 57 64
1 1/2 79 A/2 18.4 17.8 64 76
2 86 A/2 19.2 19 76 92
2 1/2 92 A/2 28.9 23.6 92 108
3 108 A/2 30.5 25.9 108 127
4 121 A/2 33 27.7 140 159
All Dimensions are in mm

Pipe Fittings Dimensions Tolerance as per ASME B16.9

NOMINAL PIPE SIZE ALL FITTINGS ALL FITTINGS ALL FITTINGS ELBOWS AND TEES 180 DEG RETURN BENDS 180 DEG RETURN BENDS 180 DEG RETURN BENDS REDUCERS CAPS
NPS O.D. at Bevel (1), (2) I.D. at End
(1), (3), (4)
Wall Thickness (3) Centre-to-End Dimension A,B,C,M Centre-to-Centre O Back-to-Face K Alignment of Ends U Overall Length H Overall Length E
½ to 2½ 0.06
-0.03
0.03 Not less than 87.5% of nominal thickness 0.06 0.25 0.25 0.03 0.06 0.12
3 to 3 ½ 0.06 0.06 0.06 0.25 0.25 0.03 0.06 0.12
4 0.06 0.06 0.06 0.25 0.25 0.03 0.06 0.12
5 to 8 0.09
-0.06
0.06 0.06 0.25 0.25 0.03 0.06 0.25
10 to 18 0.16
-0.12
0.12 0.09 0.38 0.25 0.06 0.09 0.25
20 to 24 0.25
-0.19
0.19 0.09 0.38 0.25 0.06 0.09 0.25
26 to 30 0.25
-0.19
0.19 0.12 0.19 0.38
32 to 48 0.25
-0.19
0.19 0.19 0.19 0.38
NOMINAL PIPE SIZE NPS ANGULARITY TOLERANCES ANGULARITY TOLERANCES ALL DIMENSIONS ARE GIVEN IN INCHES. TOLERANCES ARE EQUAL PLUS AND MINUS EXCEPT AS NOTED.
Off Angle Q Off Plane P (1) Out-of-round is the sum of absolute values of plus and minus tolerance.
(2) This tolerance may not apply in localized areas of formed fittings where increased wall thickness is required to meet design requirements of ASME B16.9.
(3) The inside diameter and the nominal wall thicknesses at ends are to be specified by the purchaser.
(4) Unless otherwise specified by the purchaser, these tolerances apply to the nominal inside diameter, which equals the difference between the nominal outside diameter and twice the nominal wall thickness.
½ to 4 0.03 0.06
5 to 8 0.06 0.12
10 to 12 0.09 0.19
14 to 16 0.09 0.25
18 to 24 0.12 0.38
26 to 30 0.19 0.38
32 to 42 0.19 0.50
44 to 48 0.18 0.75

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About Author

Varun Patel, B.E – Mechanical, PMP®

19+ years of experience in the oil and gas sector, specializing in project management, contracts, project control, project coordination, QA/QC and inspection of large-scale Greenfield and Brownfield Projects such as Refinery, Petrochemical, Wellhead production, and Process platform. Proven track record of delivering large-scale projects while ensuring adherence to safety and quality standards. Skilled in leading and mentoring cross-functional teams and resolving technical issues to achieve successful project outcomes.