Views: 14 Author: Monica Publish Time: 2025-09-17 Origin: Site
When we ask for price from stainless steel pipe suppliers, they will ask you about the pipe parameters. If you don't know these parameters and specifications, you may buy the wrong stainless steel pipe product that doesn't match your project. So, what are the parameters of steel pipe size?

Stainless steel pipe parameters include outside diameter, diameter, wall thickness, length (6 m for 20 ft, 12 m for 40 ft), end type, material grade, manufacturing standard, and SMLS/WELDED.
Once you know some pipe parameters, you can calculate the weight of the pipe, the price per foot or per meter, and the pressure the pipe can withstand.
In the steel pipe size specification chart, each parameter has a specific range to ensure the quality and safety of your program.
ASME B36.19:Dimension for Stainless Steel Pipes
DN | NPS | OD(mm) | Sch5S | Sch10S | Sch40S | Sch80S | Sch10 | Sch20 | Sch30 | Sch40 | STD | Sch60 | Sch80 | XS | Sch100 | Sch120 | Sch140 | Sch160 | XXS |
6 | 1/8 | 10.3 | 1.24 | 1.73 | 2.41 | 1.24 | 1.45 | 1.73 | 1.73 | 2.41 | 2.41 | ||||||||
8 | 1/4 | 13.7 | 1.65 | 2.24 | 3.02 | 1.65 | 1.85 | 2.24 | 2.24 | 3.02 | 3.02 | ||||||||
10 | 3/8 | 17.1 | 1.65 | 2.31 | 3.2 | 1.65 | 1.85 | 2.31 | 2.31 | 3.2 | 3.2 | ||||||||
15 | 1/2 | 21.3 | 1.65 | 2.11 | 2.77 | 3.73 | 2.11 | 2.41 | 2.77 | 2.77 | 3.73 | 3.73 | 4.78 | 7.47 | |||||
20 | 3/4 | 26.7 | 1.65 | 2.11 | 2.87 | 3.91 | 2.11 | 2.41 | 2.87 | 2.87 | 3.91 | 3.91 | 5.56 | 7.82 | |||||
25 | 1 | 33.4 | 1.65 | 2.77 | 3.38 | 4.55 | 2.77 | 2.90 | 3.38 | 3.38 | 4.55 | 4.55 | 6.35 | 9.09 | |||||
32 | 1 1/4 | 42.2 | 1.65 | 2.77 | 3.56 | 4.85 | 2.77 | 2.97 | 3.56 | 3.56 | 4.85 | 4.85 | 6.35 | 9.7 | |||||
40 | 1 1/2 | 48.3 | 1.65 | 2.77 | 3.68 | 5.08 | 2.77 | 3.18 | 3.68 | 3.68 | 5.08 | 5.08 | 7.14 | 10.15 | |||||
50 | 2 | 60.3 | 1.65 | 2.77 | 3.91 | 5.54 | 2.77 | 3.18 | 3.91 | 3.91 | 5.54 | 5.54 | 8.74 | 11.07 | |||||
65 | 2 1/2 | 73 | 2.11 | 3.05 | 5.16 | 7.01 | 3.05 | 4.78 | 5.16 | 5.16 | 7.01 | 7.01 | 9.53 | 14.02 | |||||
80 | 3 | 88.9 | 2.11 | 3.05 | 5.49 | 7.62 | 3.05 | 4.78 | 5.49 | 5.49 | 7.62 | 7.62 | 11.13 | 15.24 | |||||
90 | 3 1/2 | 101.6 | 2.11 | 3.05 | 5.74 | 8.08 | 3.05 | 4.78 | 5.74 | 5.74 | 8.08 | 8.08 | |||||||
100 | 4 | 114.3 | 2.11 | 3.05 | 6.02 | 8.56 | 3.05 | 4.78 | 6.02 | 6.02 | 8.56 | 8.56 | 11.13 | 13.49 | 17.12 | ||||
125 | 5 | 141.3 | 2.77 | 3.40 | 6.55 | 9.53 | 3.40 | 6.55 | 6.55 | 9.53 | 9.53 | 12.7 | 15.88 | 19.05 | |||||
150 | 6 | 168.3 | 2.77 | 3.40 | 7.11 | 10.97 | 3.40 | 7.11 | 7.11 | 10.97 | 10.97 | 14.27 | 18.26 | 21.95 | |||||
200 | 8 | 219.1 | 2.77 | 3.76 | 8.18 | 12.7 | 3.76 | 6.35 | 7.04 | 8.18 | 8.18 | 10.31 | 12.70 | 12.70 | 15.09 | 18.26 | 20.62 | 23.01 | 22.23 |
250 | 10 | 273.1 | 3.40 | 4.19 | 9.27 | 12.7 | 4.19 | 6.35 | 7.8 | 9.27 | 9.27 | 12.7 | 15.09 | 12.70 | 18.26 | 21.44 | 25.4 | 28.58 | 25.40 |
300 | 12 | 323.9 | 3.96 | 4.57 | 9.53 | 12.7 | 4.57 | 6.35 | 8.38 | 10.31 | 9.53 | 14.27 | 17.48 | 12.70 | 21.44 | 25.4 | 28.58 | 33.32 | 25.40 |
350 | 14 | 355.6 | 3.96 | 4.78 | 9.53 | 12.7 | 6.35 | 7.92 | 9.53 | 11.13 | 9.53 | 15.09 | 19.05 | 12.70 | 23.83 | 27.79 | 31.75 | 35.71 | |
400 | 16 | 406.4 | 4.19 | 4.78 | 9.53 | 12.7 | 6.35 | 7.92 | 9.53 | 12.70 | 9.53 | 16.66 | 21.44 | 12.70 | 26.19 | 30.96 | 36.53 | 40.49 | |
450 | 18 | 457 | 4.19 | 4.78 | 9.53 | 12.7 | 6.35 | 7.92 | 11.13 | 14.27 | 9.53 | 19.05 | 23.83 | 12.70 | 29.36 | 34.93 | 39.67 | 45.24 | |
500 | 20 | 508 | 4.78 | 5.54 | 9.53 | 12.7 | 6.35 | 9.53 | 12.70 | 15.09 | 9.53 | 20.62 | 26.19 | 12.70 | 32.54 | 38.1 | 44.45 | 50.01 | |
550 | 22 | 559 | 4.78 | 5.54 | 6.35 | 9.53 | 12.70 | 9.53 | 22.23 | 28.58 | 12.70 | 34.93 | 41.28 | 47.63 | 53.98 | ||||
600 | 24 | 610 | 5.54 | 6.35 | 9.53 | 12.7 | 6.35 | 9.53 | 14.27 | 17.48 | 9.53 | 24.61 | 30.96 | 12.70 | 38.89 | 46.02 | 52.37 | 59.54 | |
650 | 26 | 660 | 7.92 | 12.7 | 9.53 | 12.70 | |||||||||||||
700 | 28 | 711 | 7.92 | 12.7 | 15.88 | 9.53 | 12.70 | ||||||||||||
750 | 30 | 762 | 6.35 | 7.92 | 7.92 | 12.7 | 15.88 | 9.53 | 12.70 | ||||||||||
800 | 32 | 812.8 | 7.92 | 12.7 | 15.88 | 17.48 | 9.53 | 12.70 | |||||||||||
850 | 34 | 863.6 | 7.92 | 12.7 | 15.88 | 17.48 | 9.53 | 12.70 | |||||||||||
900 | 36 | 914.4 | 7.92 | 12.7 | 15.88 | 19.05 | 9.53 | 12.70 | |||||||||||
38 | 965.2 | 9.53 | 12.70 | ||||||||||||||||
1000 | 40 | 1016 | 9.53 | 12.70 | |||||||||||||||
1050 | 42 | 1066.8 | 9.53 | 12.70 | |||||||||||||||
1100 | 44 | 1117.6 | 9.53 | 12.70 | |||||||||||||||
46 | 1168.4 | 9.53 | 12.70 | ||||||||||||||||
1200 | 48 | 1219.2 | 9.53 | 12.70 |
The commonly used size standards for steel pipes are divided into ASME B36.10 and ASME B36.19.
ASME B36.10: This is the most fundamental and widely used dimensional standard for industrial piping. It standardizes the dimensions of welded and seamless carbon, alloy, and stainless steel pipes used for conveying fluids.
Its nominal pipe sizes range from NPS 1/8 to NPS 80. This standard defines a series of standard wall thicknesses, including the most common ones: Sch 5, 10, 20, 40, 80, 120, 160, and XXS.
ASME B36.19: This supplementary standard, B36.10, specifically addresses stainless steel and nickel alloy piping. This standard covers thin-walled corrosion-resistant stainless steel and nickel alloy pipes, both welded and seamless.
The size range covered is smaller than B36.10, typically ranging from NPS 1/8 to NPS 30. It also defines wall thickness series for these materials, including thin-wall schedules (e.g., Sch 5S, Sch 10S, Sch 20, Sch 40S, Sch 80S).

Nominal Pipe Size (NPS): NPS is a designation used to identify steel pipe sizes. It is not an exact measurement of the pipe's actual inside or outside diameter. NPS standardizes the connection dimensions between components in a piping system. All pipes, fittings, and valves with the same NPS have a uniform outside diameter at their connecting ends, ensuring they can mate and connect.
Nominal Diameter (DN): DN is the nominal size in the ISO/DIN system, equivalent to NPS. DN standardizes pipe connection sizes and is defined as NPS multiplied by 25 and rounded.
DN = NPS x 25
NPS = DN / 25
NPS and DN correspond to each other; each NPS has a corresponding DN.
Outside Diameter (OD): This refers to the actual measured diameter of the outer circumference of the pipe wall. It is a key physical dimension of the pipe.
Wall Thickness: Pipe wall thickness refers to the actual physical thickness of the pipe wall. To distinguish them from carbon steel pipes per B36.10, stainless steel pipe schedules under ASME B36.19 are identified with an "S" suffix.
Inside Diameter (ID): The inside diameter is the actual physical measurement of the inside circumference of the pipe wall. It is not a standardized designation but rather calculated:
ID = OD - (2 x Wall Thickness)

"SCH" is the schedule in steel pipe dimensions. It’s a standardized system used to define the wall thickness of pipes relative to their nominal size. Developed by the American Standards Association, schedules range from SCH 5 to SCH XXS at the extreme end.
SCH is not a direct measurement. Instead, it's a code representing a pipe's standardized wall thickness for a given Nominal Pipe Size (NPS). And SCH correlates loosely with a pipe's pressure-containing capacity. Higher SCH numbers generally indicate thicker walls and higher pressure.
The formula behind SCH is derived from historical standards:
SCH = \frac{1000 \times P}{S}
P: Maximum allowable working pressure (psi)
S: Allowable stress of the pipe material (psi)
Pipes with the same schedule number have different wall thicknesses across NPS sizes but similar pressure-bearing capabilities.
Same NPS + Same SCH = Same OD, but pipes with the same NPS share the exact same outer diameter (OD), regardless of SCH. Thicker walls (higher SCH) reduce the inner diameter (ID).

Example 1: Schedule 40 Steel Pipe Dimensions
Schedule 40 Steel Pipe is a carbon steel/alloy steel pipe wall thickness grade that complies with the ASME B36.10 standard. It belongs to the Standard Weight (STD) grade and is widely used in medium and low pressure industrial piping systems.
SCH 40 is a medium wall thickness, between SCH 10 and SCH 80. At the same NPS, SCH 40 has a thinner wall thickness than SCH 80 but thicker than SCH 10.
Example 2: Schedule 80 Steel Pipe Dimensions
Schedule 80 steel pipe is the thick-walled carbon steel pipe standardized under ASME B36.10, for high-pressure, high-stress applications.
For example: ASTM B163 Incoloy 825 Seamless Tubes, OD = 25.4mm, Wall Thickness = 2.11m, Length = 6000mm, Quantity = 100PCS.
Availability and delivery lead time.
Mill Test Certificate (MTC).
Country of origin / Mill name.
Price (FOB) and packing specification.
Reference photo if available.
Or: SMLS pipe ALLOY C276 size: 6", SCH 40S, QTY 6M.