API 5L is an internationally recognized specification for carbon steel line pipes used in the transportation of oil, gas, water, and other fluids in onshore and offshore pipeline systems.
API 5L pipes are manufactured in both Seamless and Welded forms, allowing flexibility across different pressure levels, diameters, and project requirements. To ensure long-term performance, API 5L line pipes can be supplied with various external and internal coatings, selected according to environmental conditions, corrosion risk, and service media.
In terms of quality classification, API 5L pipes are divided into two Product Specification Levels:
PSL1: Standard quality level for general pipeline applications
PSL2: Enhanced quality level with stricter chemical composition limits, mechanical property requirements, and mandatory impact testing
API 5L pipe size and schedule charts define the nominal pipe size (NPS), outside diameter, wall thickness, and schedule, helping engineers and buyers select suitable pipes for pressure rating, flow capacity, and installation conditions.
API 5L Pipe Size and Schedule Chart
|
Outside Diameter
O.D. (in)
|
NPS
(in)
|
Pipe Schedule
|
|
SCH 10
|
SCH 20
|
SCH 30
|
SCH STD
|
SCH 40
|
SCH 60
|
SCH XS
|
SCH 80
|
SCH 100
|
SCH 120
|
SCH 140
|
SCH 160
|
SCH XXS
|
|
Wall Thickness (in)
|
|
0.405
|
1/8
|
|
|
|
0.068
|
0.068
|
|
0.095
|
0.095
|
|
|
|
|
|
|
0.540
|
1/4
|
|
|
|
0.088
|
0.088
|
|
0.119
|
0.119
|
|
|
|
|
|
|
0.675
|
3/8
|
|
|
|
0.091
|
0.091
|
|
0.126
|
0.126
|
|
|
|
|
|
|
0.840
|
1/2
|
|
|
|
0.109
|
0.109
|
|
0.147
|
0.147
|
|
|
|
0.187
|
0.294
|
|
1.050
|
3/4
|
|
|
|
0.113
|
0.113
|
|
0.154
|
0.154
|
|
|
|
0.219
|
0.308
|
|
1.315
|
1
|
|
|
|
0.133
|
0.133
|
|
0.179
|
0.179
|
|
|
|
0.250
|
0.358
|
|
1.660
|
1 1/4
|
|
|
|
0.140
|
0.140
|
|
0.191
|
0.191
|
|
|
|
0.250
|
0.382
|
|
1.900
|
1 1/2
|
|
|
|
0.145
|
0.145
|
|
0.200
|
0.200
|
|
|
|
0.281
|
0.400
|
|
2.375
|
2
|
|
|
|
0.154
|
0.154
|
|
0.218
|
0.218
|
|
|
|
0.344
|
0.436
|
|
2.875
|
2 1/2
|
|
|
|
0.203
|
0.203
|
|
0.276
|
0.276
|
|
|
|
0.375
|
0.552
|
|
3.500
|
3
|
|
|
|
0.216
|
0.216
|
|
0.300
|
0.300
|
|
|
|
0.438
|
0.600
|
|
4.000
|
3 1/2
|
|
|
|
0.226
|
0.226
|
|
0.318
|
0.318
|
|
|
|
|
|
|
4.500
|
4
|
|
|
|
0.237
|
0.237
|
|
0.337
|
0.337
|
|
0.438
|
|
0.531
|
0.674
|
|
5.563
|
5
|
|
|
|
0.258
|
0.258
|
|
0.375
|
0.375
|
|
0.500
|
|
0.625
|
0.750
|
|
6.625
|
6
|
|
|
|
0.280
|
0.280
|
|
0.432
|
0.432
|
|
0.562
|
|
0.719
|
0.864
|
|
8.625
|
8
|
|
0.250
|
0.277
|
0.322
|
0.322
|
0.406
|
0.500
|
0.500
|
0.594
|
0.719
|
0.812
|
0.906
|
0.875
|
|
10.750
|
10
|
|
0.250
|
0.307
|
0.365
|
0.365
|
0.500
|
0.500
|
0.594
|
0.719
|
0.844
|
1.000
|
1.125
|
1.000
|
|
12.750
|
12
|
|
0.250
|
0.330
|
0.375
|
0.406
|
0.562
|
0.500
|
0.688
|
0.844
|
1.000
|
1.125
|
1.312
|
1.000
|
|
14.000
|
14
|
0.250
|
0.312
|
0.375
|
0.375
|
0.438
|
0.594
|
0.500
|
0.750
|
0.938
|
1.094
|
1.250
|
1.406
|
|
|
16.000
|
16
|
0.250
|
0.312
|
0.375
|
0.375
|
0.500
|
0.656
|
0.500
|
0.844
|
1.031
|
1.219
|
1.438
|
1.594
|
|
|
18.000
|
18
|
0.250
|
0.312
|
0.438
|
0.375
|
0.562
|
0.750
|
0.500
|
0.938
|
1.156
|
1.375
|
1.562
|
1.781
|
|
|
20.000
|
20
|
0.250
|
0.375
|
0.500
|
0.375
|
0.594
|
0.812
|
0.500
|
1.031
|
1.281
|
1.500
|
1.750
|
1.969
|
|
|
22.000
|
22
|
0.250
|
0.375
|
0.500
|
0.375
|
|
0.875
|
0.500
|
1.125
|
1.375
|
1.625
|
1.875
|
2.125
|
|
|
24.000
|
24
|
0.250
|
0.375
|
0.562
|
0.375
|
0.688
|
0.969
|
0.500
|
1.219
|
1.531
|
1.812
|
2.062
|
2.344
|
|
|
30.000
|
30
|
0.312
|
0.500
|
0.625
|
0.375
|
|
|
0.500
|
|
|
|
|
|
|
|
32.000
|
32
|
0.312
|
0.500
|
0.625
|
0.375
|
0.688
|
|
|
|
|
|
|
|
|
|
34.000
|
34
|
0.312
|
0.500
|
0.625
|
0.375
|
0.688
|
|
|
|
|
|
|
|
|
|
36.000
|
36
|
0.312
|
0.500
|
0.625
|
0.375
|
0.750
|
|
|
|
|
|
|
|
|
|
42.000
|
42
|
|
0.500
|
0.625
|
0.375
|
0.750
|
|
|
|
|
|
|
|
|
|
Pipe NPS
|
Schedule No
|
Outside Diameter, Inches
|
Wall Thickness, inches
|
Plain End Weight, lb/ft
|
Outside Diameter, mm
|
Wall Thickness, mm
|
Plain End Mass, Kg/m
|
|
1/8
|
40/STD
|
0.405 Inches
|
0.068 Inches
|
0.24
|
10.3 mm
|
1.73 mm
|
0.37 Kg/m
|
|
1⁄4
|
40/STD
|
0.540 Inches
|
0.088 Inches
|
0.43
|
13.7 mm
|
2.24 mm
|
0.63 Kg/m
|
|
3⁄8
|
40/STD
|
0.675 Inches
|
0.091 Inches
|
0.57
|
17.1 mm
|
2.31 mm
|
0.84 Kg/m
|
|
1⁄2
|
40/STD
|
0.840 Inches
|
0.109 Inches
|
0.85
|
21.3 mm
|
2.77 mm
|
1.27 Kg/m
|
|
3⁄4
|
40/STD
|
1.050 Inches
|
0.113 Inches
|
1.13
|
26.7 mm
|
2.87 mm
|
1.69 Kg/m
|
|
1
|
40/STD
|
1.315 Inches
|
0.133 Inches
|
1.68
|
33.4 mm
|
3.38 mm
|
2.50 Kg/m
|
|
1-1⁄4
|
40/STD
|
1.660 Inches
|
0.140 Inches
|
2.27
|
42.2 mm
|
3.56 mm
|
3.39 Kg/m
|
|
1-1⁄2
|
40/STD
|
1.900 Inches
|
0.145 Inches
|
2.72
|
48.3 mm
|
3.68 mm
|
4.05 Kg/m
|
|
2
|
40/STD
|
2.375 Inches
|
0.154 Inches
|
3.66
|
60.3 mm
|
3.91 mm
|
5.44 Kg/m
|
|
2-1⁄2
|
40/STD
|
2.875 Inches
|
0.203 Inches
|
5.80
|
73.0 mm
|
5.16 mm
|
8.63 Kg/m
|
|
3
|
40/STD
|
3.500 Inches
|
0.216 Inches
|
7.58
|
88.9 mm
|
5.49 mm
|
11.29 Kg/m
|
|
4
|
40/STD
|
4.500 Inches
|
0.237 Inches
|
10.80
|
114.3 mm
|
6.02 mm
|
16.08 Kg/m
|
|
5
|
40/STD
|
5.563 Inches
|
0.258 Inches
|
14.63
|
141.3 mm
|
6.55 mm
|
21.77 Kg/m
|
|
6
|
40/STD
|
6.625 Inches
|
0.280 Inches
|
18.99
|
168.3 mm
|
7.11 mm
|
28.26 Kg/m
|
|
8
|
40/STD
|
8.625 Inches
|
0.322 Inches
|
28.58
|
219.1 mm
|
8.18 mm
|
42.55 Kg/m
|
|
10
|
40/STD
|
10.750 Inches
|
0.365 Inches
|
40.52
|
273.0 mm
|
9.27 mm
|
60.29 Kg/m
|
|
12
|
40
|
12.750 Inches
|
0.406 Inches
|
53.57
|
323.8 mm
|
10.31 mm
|
79.71 Kg/m
|
|
14
|
40
|
14.000 Inches
|
0.438 Inches
|
63.50
|
355.6 mm
|
11.13 mm
|
94.55 Kg/m
|
|
16
|
40
|
16.000 Inches
|
0.500 Inches
|
82.85
|
406.4 mm
|
12.70 mm
|
123.31 Kg/m
|
|
18
|
40
|
18.000 Inches
|
0.562 Inches
|
104.76
|
457 mm
|
14.27 mm
|
155.81 Kg/m
|
|
20
|
40
|
20.000 Inches
|
0.594 Inches
|
123.23
|
508 mm
|
15.09 mm
|
183.43 Kg/m
|
|
24
|
40
|
24.000 Inches
|
0.688 Inches
|
171.45
|
610 mm
|
17.48 mm
|
255.43 Kg/m
|
|
32
|
40
|
32.000 Inches
|
0.688 Inches
|
230.29
|
813 mm
|
17.48 mm
|
342.94 Kg/m
|
|
34
|
40
|
34.000 Inches
|
0.688 Inches
|
245.00
|
864 mm
|
17.48 mm
|
364.92 Kg/m
|
|
36
|
40
|
36.000 Inches
|
0.750 Inches
|
282.62
|
914 mm
|
19.05 mm
|
420.45 Kg/m
|
Conclusion
Choosing the correct API 5L pipe size and schedule is essential for ensuring pipeline safety, pressure integrity, and long-term operational reliability. By matching pipe grade, PSL level, wall thickness, and coating system to the actual service conditions, API 5L line pipes can meet the demands of modern energy and infrastructure projects worldwide.
FAQ
Q1: What is API 5L pipe used for?
A: Oil, gas, water, and fluid transmission pipelines.
Q2: What are the two API 5L product levels?
A: PSL1 and PSL2.
Q3: Which is stricter, PSL1 or PSL2?
A: PSL2 has stricter chemical and mechanical requirements.
Q4: Are API 5L pipes seamless or welded?
A: Both seamless and welded types are available.
Q5: What does pipe schedule indicate?
A: Wall thickness and pressure capacity.
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