Standard Schedule 20 steel pipe sizes are mainly listed from NPS 8 upward in ASME B36.10M. Smaller thin-wall pipes are sometimes sold under commercial or nonstandard descriptions, so buyers should verify the actual wall thickness instead of relying only on “SCH 20.”
Schedule 20 Pipe Dimensions and Wall Thickness Chart
Schedule 20 Pipe Thickness in MM
The following Schedule 20 pipe dimensions are based on ASME B36.10M for welded and seamless wrought steel pipe. Standard SCH 20 dimensions are listed from NPS 8 to NPS 36.
For smaller pipe sizes, buyers should not assume that a commercially described “Schedule 20” product corresponds to an ASME B36.10M wall thickness. Always confirm the actual wall thickness in millimeters or inches before ordering.
| NPS | DN | Outside Diameter (in.) | Outside Diameter (mm) | SCH 20 Wall Thickness (in.) | SCH 20 Wall Thickness (mm) | Inside Diameter (in.) | Inside Diameter (mm) | Weight (lb/ft) | Weight (kg/m) |
|---|---|---|---|---|---|---|---|---|---|
| 8 | 200 | 8.625 | 219.1 | 0.250 | 6.35 | 8.125 | 206.4 | 22.39 | 33.32 |
| 10 | 250 | 10.750 | 273.0 | 0.250 | 6.35 | 10.250 | 260.3 | 28.06 | 41.76 |
| 12 | 300 | 12.750 | 323.8 | 0.250 | 6.35 | 12.250 | 311.1 | 33.40 | 49.71 |
| 14 | 350 | 14.000 | 355.6 | 0.312 | 7.92 | 13.376 | 339.8 | 45.63 | 67.91 |
| 16 | 400 | 16.000 | 406.4 | 0.312 | 7.92 | 15.376 | 390.6 | 52.30 | 77.83 |
| 18 | 450 | 18.000 | 457.2 | 0.312 | 7.92 | 17.376 | 441.4 | 58.94 | 87.71 |
| 20 | 500 | 20.000 | 508.0 | 0.375 | 9.53 | 19.250 | 489.0 | 78.72 | 117.15 |
| 22 | 550 | 22.000 | 558.8 | 0.375 | 9.53 | 21.250 | 539.8 | 86.78 | 129.14 |
| 24 | 600 | 24.000 | 609.6 | 0.375 | 9.53 | 23.250 | 590.6 | 94.83 | 141.12 |
| 26 | 650 | 26.000 | 660.4 | 0.500 | 12.70 | 25.000 | 635.0 | 136.23 | 202.74 |
| 28 | 700 | 28.000 | 711.2 | 0.500 | 12.70 | 27.000 | 685.8 | 146.97 | 218.71 |
| 30 | 750 | 30.000 | 762.0 | 0.500 | 12.70 | 29.000 | 736.6 | 157.70 | 234.68 |
| 32 | 800 | 32.000 | 812.8 | 0.500 | 12.70 | 31.000 | 787.4 | 168.43 | 250.65 |
| 34 | 850 | 34.000 | 863.6 | 0.500 | 12.70 | 33.000 | 838.2 | 179.17 | 266.63 |
| 36 | 900 | 36.000 | 914.4 | 0.500 | 12.70 | 35.000 | 889.0 | 189.69 | 282.29 |
Note: Inside diameter is calculated as outside diameter minus twice the nominal wall thickness. Pipe weights are theoretical values and may vary slightly because of manufacturing tolerances. Always confirm the applicable standard, material grade and actual wall thickness before procurement.
Quick SCH 20 Wall Thickness Reference
For buyers who only need a quick Schedule 20 pipe thickness lookup:
| Nominal Pipe Size | Wall Thickness (in.) | Wall Thickness (mm) |
| NPS 8–12 | 0.250 | 6.35 |
| NPS 14–18 | 0.312 | 7.92 |
| NPS 20–24 | 0.375 | 9.53 |
| NPS 26–36 | 0.500 | 12.70 |
Schedule 20 pipe thickness therefore ranges from 6.35 mm to 12.70 mm, depending on the nominal pipe size. The schedule number does not indicate one fixed wall thickness, and it should not be treated as a pressure rating.
Schedule 20 Steel Pipe
What Is Schedule 20 Pipe？
- The definition of Schedule comes from the American standard ASME (American Society of Mechanical Engineers), which is used to regulate the thickness series of steel pipes. Schedule 20 pipe is one of the most common pipe wall thickness specifications.
- From a numerical point of view, the lower the Schedule value, the thinner the steel pipe wall thickness, the lighter the weight, the higher the fluid transportation efficiency, but also sacrifices the load-bearing capacity to a certain extent. Compared with sch40, sch80 and other specifications of pipes, this specification of pipe belongs to the thin wall series.
How Thick Is Schedule 20 Pipe
Schedule 20 pipe thickness ranges from 0.250 in. (6.35 mm) for NPS 8–12 to 0.500 in. (12.70 mm) for larger sizes such as NPS 26–36.
| Size range | SCH 20 thickness |
|---|---|
| NPS 8–12 | 0.250″ / 6.35 mm |
| NPS 14–18 | 0.312″ / 7.92 mm |
| NPS 20–24 | 0.375″ / 9.53 mm |
| NPS 26–36 | 0.500″ / 12.70 mm |
Schedule 20 Pipe Common Materials
Carbon steel
This is the most common material for all pipes，Commonly used in normal temperature and medium temperature environments with no or very weak corrosiveness
ASTM A106 Gr. B, ASTM A53 Gr. B, API 5L Gr. B / X42/X52
Stainless steel
Schedule 20 pipe made of stainless steel can be used in corrosive environments. Stainless steel Schedule 20 pipe is also best suited for applications requiring high cleanliness, such as medical and food processing.
AISI 304 / 304L, AISI 316 / 316L, AISI 321
Alloy material
Alloy material combines the advantages of many different materials and can be used in very extreme and harsh environments. However, although the alloy material of Schedule 20 Pipe is of good quality, the pipe is still relatively thin. In an environment with too high pressure, the alloy material of Schedule 20 Pipe is still not competent.
ASTM A335 P11, P22, P91
Schedule 20 pipe wall thickness varies according to pipe size.
Unlike Schedule 40 and Schedule 80, Schedule 20 is designed for lower-pressure applications where reduced weight and lower material cost are important considerations.
Schedule 20 Pipe Wall Thickness Quick Chart
Schedule 20 pipe does not have one fixed wall thickness. Under ASME B36.10M, the nominal wall thickness increases from 0.250 inches (6.35 mm) to 0.500 inches (12.70 mm) as the pipe size increases.
| Nominal Pipe Size | SCH 20 Wall Thickness (in.) | SCH 20 Wall Thickness (mm) |
|---|---|---|
| NPS 8–12 | 0.250 | 6.35 |
| NPS 14–18 | 0.312 | 7.92 |
| NPS 20–24 | 0.375 | 9.53 |
| NPS 26–36 | 0.500 | 12.70 |
Schedule 20 is a dimensional designation, not a pressure rating. Pipe pressure capacity must be determined according to its size, material grade, operating temperature, corrosion allowance and applicable design code.
Schedule 20 Pipe Pressure Rating
The pressure rating of Schedule 20 pipe depends on:
- Pipe size
- Material grade
- Operating temperature
In general, Schedule 20 pipe is intended for low-pressure systems and should not be selected solely based on schedule number.
For critical applications, pressure calculations should follow the applicable ASTM or ASME standards.
Note: Do not approve a pipe for pressure service solely because the quotation states “Schedule 20.”
| Maximum Allowable Pressure(psi)(kPa) | ||
| NPS (in) | Outside Diameter (in) (mm) | Schedule 20 |
| 8 | 8.625 | 1420 |
| 219 | 9791 | |
| 10 | 10.75 | 1140 |
| 273 | 7860 | |
| 12 | 12.75 | 961 |
| 324 | 6626 | |
| 14 | 14 | 1092 |
| 356 | 7529 | |
| 16 | 16 | 956 |
| 406 | 6592 | |
| 18 | 18 | 849 |
| 457 | 5854 | |
| 20 | 20 | 919 |
| 508 | 6337 | |
| 22 | 22 | 835 |
| 559 | 5757 | |
| 24 | 24 | 766 |
| 610 | 5282 | |
| 30 | 30 | 817 |
| 762 | 5633 | |
| 32 | 32 | 766 |
| 813 | 5282 | |
| 34 | 34 | 721 |
| 864 | 4971 | |
| 36 | 36 | 681 |
| 914 | 4695 | |
| 42 | 42 | 583 |
| 1067 | 4020 | |
Sch20 Pipe Size (NPS and DN)
NPS | 1/2 | 3/4 | 1 | 1¼ | 1½ | 2 | 2½ | 3 |
DN | 15 | 20 | 25 | 32 | 40 | 50 | 65 | 80 |
Schedule 20 Pipe vs Schedule 40 Pipe
| Item | SCH 20 | SCH 40 |
|---|---|---|
| Wall Thickness | Lower | Higher |
| Weight | Lighter | Heavier |
| Pressure Rating | Lower | Higher |
| Cost | Lower | Higher |
| Typical Use | Drainage | Water & Gas |
| Item | NPS 8 SCH 20 | NPS 8 SCH 40 |
|---|---|---|
| OD | 8.625″ | 8.625″ |
| Wall thickness | 0.250″ | 0.322″ |
| Approx. ID | 8.125″ | 7.981″ |
| Relative weight | Lower | Higher |
You can click the link below to view a comparison of Schedule 40 and Schedule 80 pipes.
Schedule 40 vs 80 Steel Pipe: A Comprehensive Comparison and Engineering Selection Guide
Schedule 20 Pipe Manufacturer
Are you looking for Schedule 20 pipe? Are you looking for carbon steel or stainless steel? If you have any inquiries or questions, please contact PANDAPIPE by clicking the button below. PANDAPIPE is a company that integrates manufacturing and sales, and our customer-centric approach is paramount. We are committed to timely delivery, impeccable product quality, and unparalleled customer service.
For smaller sizes, do not submit an RFQ using only “SCH 20.” Include the required wall thickness in mm or inches because the designation may not exist for that NPS in ASME B36.10M.
Sch 20 Pipe Application Areas
Schedule 20 Pipe is often used in low-pressure environments.
- Building water supply and drainage system: used for water supply and drainage pipe support of high-rise buildings, fire protection systems, and some industrial cooling water circulation systems.
- Chemical and power industries: used for the transportation of corrosive chemical media such as acids and alkalis, and used in cooling water pipe systems to prevent lightning induction or ground fault current conduction.
- Agricultural field: corrosion resistance is suitable for pipes used for agricultural water supply and irrigation.
- Food processing and pharmaceutical industries: Sch20 pipes can meet the corrosion resistance requirements after surface treatment such as galvanizing, and are responsible for the transportation of raw materials and semi-finished products.
FAQs
1. What is the material of Schedule 20 for fire protection system?
Usually, it uses No. 20 PVC or CPVC pipes.
2. Which one is thicker, Sch20 or Sch 80?
No. 80 pipe is thicker, and the wall thickness of SCH80 is almost 1.7 times that of SCH20.
3. Is Schedule 20 Pipe the Same as Schedule 20 PVC Pipe?
No. Schedule 20 refers to wall thickness classification and can be used for different materials, including carbon steel and PVC. Although both follow the same schedule designation system, pressure ratings and mechanical properties are different.
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