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What is Pipe Schedule: Explanation and Pipe Schedule Charts

What is Pipe Schedule?

As the main function of the pipes is to carry fluid under pressure therefore their internal diameter is their critical dimension. This critical dimension is referred to as the nominal bore (NB). Obviously, for pipes containing pressurised fluids the wall thickness, and by implication the pipe’s strength, is important. Wall thickness is expressed in “schedules“, referred to as pipe schedules. The pipe schedule is abbreviated as SCH. For a given size and schedule the thickness of the pipe is fixed and defined in the applicable ASME standard. Other than the pipe schedule, pipe thickness can also be specified in mm or inches to the value corresponding to that specified in the ASME standard.



What Standards Govern Pipe Sizes?

In the oil and gas and related downstream industries the most common standards are
– ASME/ANSI B 36.10 Welded and Seamless Wrought Steel Pipe, and
– ASME/ANSI B36.19 Stainless Steel Pipe

Does Pipe Schedule Change with Pipe Size?

For all pipe sizes the outside diameter remains relatively constant. Therefore any variation schedule i.e. wall thickness, affects only the inside diameter. As the schedule number increases, the wall thickness increases, and the actual bore is reduced.

STD is identical to SCH 40 for NPS 1/8 to NPS 10, inclusive. XS is identical to SCH 80 for NPS 1/8 to NPS 8, inclusive. XXS wall is thicker than SCH 160 from NPS 1/8″ to NPS 6″ inclusive, and SCH 160 is thicker than XXS wall for NPS 8″ and larger.

Pipe Schedule Charts

The wall thickness associated with a particular schedule depends on the pipe size as can be seen from the charts below for some of the more common sized carbon steel pipes encountered.

Stainless steel pipe is most often available in standard weight sizes (noted by the “S” designation, for example “NPS SCH 10S”). However stainless steel pipe can also be available in other schedules.

Abbreviations used: NPS– Nominal Pipe Size, NB – Nominal bore, STD – Standard, XS – Extra Strong, XXS – Double Extra Strong.




NPS
inches

N.B.

O.D.
mm

10

20

30

STD

40

60

XS

80

100

120

140

160

XXS

1/8

6

10.3

1.24

1.45

1.73

1.73

2.41

2.41

1/4

8

13.7

1.65

1.85

2.24

2.24

3.02

3.02

3/8

10

17.1

1.65

1.85

2.31

2.31

3.2

3.2

1/2

15

21.34

2.11

2.41

2.77

2.77

3.73

3.73

4.77

7.47

3/4

20

26.67

2.11

2.41

2.87

2.87

3.91

3.91

5.56

7.82

1

25

33.4

2.77

2.90

3.38

3.38

4.55

4.55

6.35

9.09

1.1/4

32

42.16

2.77

2.97

3.56

3.56

4.85

4.85

6.35

9.7

1.1/2

40

48.26

2.77

3.18

3.68

3.68

5.08

5.08

7.14

10.16

2

50

60.32

2.77

3.18

3.91

3.91

5.54

5.54

8.74

11.07

2.1/2

65

73.02

3.05

4.78

5.16

5.16

7.01

7.01

9.52

14.02

3

80

88.9

3.05

4.78

5.49

5.49

7.62

7.62

11.12

15.24

3.1/2

90

101.6

3.05

4.78

5.74

5.74

8.08

8.08

16.15

4

100

114.3

3.05

4.78

6.02

6.02

8.56

8.56

11.12

13.49

17.12

5

125

141.3

3.40

6.55

6.55

9.52

9.52

12.7

15.87

19.05

6

150

168.3

3.40

7.11

7.11

10.97

10.97

14.27

18.26

21.95

8

200

219.1

3.76

6.35

7.04

8.18

8.18

10.31

12.7

12.7

15.08

18.26

20.63

23.01

22.22

10

250

273

4.19

6.35

7.80

9.27

9.27

12.7

12.7

15.08

18.26

21.44

25.4

28.57

25.4

12

300

323.9

4.57

6.35

8.38

9.52

10.31

14.27

12.7

17.47

21.44

25.4

28.57

33.32

25.4

14

350

355.6

6.35

7.92

9.53

9.52

11.12

15.09

12.7

19.05

23.82

27.79

31.75

35.71

16

400

406.4

6.35

7.92

9.53

9.52

12.7

16.66

12.7

21.44

26.19

30.96

36.52

40.49

18

450

457.2

6.35

7.92

11.13

9.52

14.27

19.05

12.7

23.82

29.36

34.92

39.67

45.24

20

500

508

6.35

9.53

12.70

9.52

15.08

20.62

12.7

26.19

32.54

38.1

44.45

50.01

22

550

558.8

6.35

9.53

12.70

9.52

15.87

22.22

12.7

28.57

34.92

41.27

47.62

53.97

24

600

609.6

6.35

9.53

12.70

9.52

17.47

24.61

12.7

30.96

38.89

46.02

52.37

59.54

26

650

660.4

7.92

12.70

9.52

12.7

28

700

711.2

7.92

12.70

15.88

9.52

12.7

30

750

762

7.92

12.70

15.88

9.52

12.7

32

800

812.8

7.92

12.70

15.88

9.52

17.47

12.7

34

850

863.6

7.92

12.70

15.88

9.52

17.47

12.7

36

900

914.4

7.92

12.70

15.88

9.52

19.05

12.7

40

1000

1016

9.53

12.7

 

5 comments

  1. Thank you for this valuable information and useful in the field of engineering work

  2. The information is very useful

  3. The detailed yet brief information is excellent to gain knowledge in piping.

  4. Niranjan Pradhan

    Very good basic definitions and fundamental descriptions about ” Piping Schedule ” I have read here,
    Which is very useful for site constructions, Thanking you all,,,,,,,,,,,

  5. Very useful for the subject of workshop in engineering

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