Size of pipe is defined by Nominal Pipe Size. They are defined in dimensional standards such as ASME B36.10 and ASME B36.19.
ASME B36.10 : Welded and Seamless Wrought Steel Pipes : Size Range 1/8″ to 80″
ASME B36.19 : Stainless Steel Pipe : Size Range : 1/8″ to 30″
Normally Stocked pipes are :
1/2, 3/4, 1, 1 1/2, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20 and 24.
Seldom used Pipe Sizes 11/4, 2 1/2 3 ½ and 5 inch. (unusual sizes are sometimes required for connecting to equipment, but piping is normally run in the next larger stock size after connection has been made).
1/8, 1/4, 3/8 and 1/2-inch pipe is usually restricted to instrument lines or to service and other lines which have to mate with equipment.
1/2-inch pipe is extensively used for steam tracing and for auxiliary piping at pumps, etc.
Small Bore Pipes less than 2″ are normally
either plain (PE). Big bore Pipes 2″ and above are Bevelled End
(BE). Small Bore threaded end pipes are supplied with one coupling per
length (threaded and coupled, or T&C). Rating of the coupling needs to
be specified.
Other types of ends, such as grooved for special couplings, can be obtained to
order.
NPS 14 and larger pipe has outside diameter equal to the nominal pipe size.
There are three different sources of Pipe Wall Thicknesses :-
1. The American National Standards Institute (ANSI) : Schedule Numbers.
2. The American Society of Mechanical Engineers (ASME) and the American Society for Testing and Materials (ASTM) : Wall Thicknesses STD (standard), XS (extra-strong), and XXS (double-extra-strong), They are as per dimensions established by manufacturers. Also termed manufacturers weights.
3. The American Petroleum Institute(API) : Standard 5L, for Line pipe. Dimensions in this standard have no references for individual sizes and wall thicknesses.
Manufacturers weight standards were supposed to be superceded by Schedule Numbers long time back. But demand for those wall thicknesses in process industry casued pipe manufacturers to continue their production. Certain fittings are available only in manufacturers weights. Pipe dimensions from the ASME/ASTM and API are included in American National Standard B36.10M.
Initially schedule numbers used to establish pipe wall thicknesses by formula, but as wall thicknesses in common use continued to depart from those proposed by the scheme. So schedule numbers now identify wall thicknesses of pipe in the different nominal sizes as ANSI B36.10M states as a convenient designation system for use in ordering.
LIST of Wall Thicknesses for Carbon Steel Pipes
1. Light Wall
2. Schedule 10 (Sch/10, S/10)
3. Schedule 20 (Sch/20, S/20)
4. Schedule 30 (Sch/30, S/30)
5. Schedule 40 (Sch/40, S/40)
6. Standard Weight (ST, Std, STD)
7. Schedule 60 (Sch/60, S/60)
8. Extra Strong (Extra Heavy, EH, XH, XS)
9. Schedule 80 (Sch/80, S/80)
10. Schedule 100 (Sch/100, S/100)
11. Schedule 120 (Sch/120, S/120)
12. Schedule 140 (Sch/140, S/140)
13. Schedule 160 (Sch/160, S/160)
14. Double Extra Strong (Double extra heavy, XXH, XXS)
LIST of Wall Thicknesses for Stainless Steel Pipes
American National Standard B3B.19 established a range of thin-walled sizes for stainless-steel pipe, indentified by schedules 5S and 10S
1. Schedule 5S (Sch/5S, S/5S)
2. Schedule 10S (Sch/10S, S/10S)
3. Schedule 40S (Sch/40S, S/40S)
4. Schedule 80S (Sch/80S, S/80S)
Pipe Wall Thickness Chart
|
NPS |
N.D. |
O.D. |
10 |
20 |
30 |
STD |
40 |
60 |
XS |
80 |
100 |
120 |
140 |
160 |
XXS |
|
1/8 |
|
10.3 |
1.24 |
|
1.45 |
1.73 |
1.73 |
|
2.41 |
2.41 |
|
|
|
|
|
|
1/4 |
6 |
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 |
|