The major difference between schedule 40 and schedule 80 pipe is the wall thickness, inside diameter, and their weight. Schedule 80 will have a greater wall thickness, a smaller inside diameter and a higher weight than Schedule 40 pipe at a given nominal pipe size.
A 1″ NPS schedule 40 pipe has a thinner wall and a bigger inside diameter than a 1″ NPS schedule 80 pipe, and it is used for lower pressure and temperature applications. The main differentiator between SCH 40 and SCH 80 is the wall thickness, affecting the pressure-carrying capacity. SCH 80 pipes, with their thicker walls, can withstand higher pressures compared to SCH 40 pipes. This makes SCH 80 pipes suitable for applications where elevated pressure levels are a consideration.
Key Differences: SCH 40 vs. SCH 80 Steel Pipe
Wall Thickness: For any given Nominal Pipe Size (NPS), SCH 80 pipe features a thicker wall than SCH 40.
Internal Diameter (ID): Because the Outside Diameter (OD) remains fixed per NPS standards, the extra wall thickness of SCH 80 reduces its internal flow area.
Pressure Rating: The thicker wall of SCH 80 provides higher tensile strength and hoop resistance, allowing it to withstand significantly higher operating pressures.
Weight & Cost: SCH 80 pipe contains more raw material, making it heavier and higher in cost than SCH 40.
SCH 40 vs SCH 80 Steel Pipe Pressure Rating
| Nominal Pipe Size (NPS) | Outside Diameter (OD) | Schedule 40 Wall Thickness | Maximum Pressure (PSI) | Schedule 80 Wall Thickness | Maximum Pressure (PSI) |
| 1/8" | 0.405 | 0.068 | 810 | 0.095 | 1230 |
| 1/4 | 0.540 | 0.088 | 780 | 0.119 | 1130 |
| 3/8 | 0.675 | 0.091 | 620 | 0.126 | 920 |
| 1/2 | 0.840 | 0.109 | 600 | 0.147 | 850 |
| 3/4 | 1.050 | 0.113 | 480 | 0.154 | 690 |
| 1 | 1.315 | 0.133 | 450 | 0.179 | 630 |
| 1 1/4 | 1.660 | 0.140 | 370 | 0.191 | 520 |
| 1 1/2 | 1.900 | 0.145 | 330 | 0.200 | 470 |
| 2 | 2.375 | 0.154 | 280 | 0.218 | 400 |
| 2 1/2 | 2.875 | 0.203 | 300 | 0.276 | 420 |
| 3 | 3.500 | 0.216 | 260 | 0.300 | 370 |
| 3 1/2 | 4.000 | 0.226 | 240 | 0.318 | 350 |
| 4 | 4.500 | 0.237 | 220 | 0.337 | 320 |
| 5 | 5.563 | 0.258 | 190 | 0.375 | 290 |
| 6 | 6.625 | 0.280 | 180 | 0.432 | 280 |
| 8 | 8.625 | 0.322 | 160 | 0.500 | 250 |
| 10 | 10.750 | 0.365 | 140 | 0.593 | 230 |
| 12 | 12.750 | 0.406 | 130 | 0.687 | 230 |
| 14 | 14.000 | 0.437 | 130 | 0.750 | 220 |
| 16 | 16.000 | 0.500 | 130 | 0.843 | 220 |
| 18 | 18.000 | 0.562 | 130 | 0.937 | 220 |
| 20 | 20.000 | 0.593 | 120 | 1.031 | 220 |
| 24 | 24.000 | 0.687 | 120 | 1.218 | 210 |
How to Choose Between SCH 40 and SCH 80
Choose Schedule 40 when:
Operating pressures remain within standard utility or low-pressure processing limits.
Maximum flow rate is required (larger inside diameter reduces friction head loss).
System weight reduction and cost efficiency are primary project targets.
Choose Schedule 80 when:
System pressures exceed SCH 40 limits, or pressure spikes/water hammer are expected.
Pipes are installed in high-stress, hazardous, or highly corrosive environments.
Mechanical threading is required (threading removes wall material, reducing effective wall thickness).
Get Custom Steel Pipe Solutions & Technical Assistance
At Huitong Pipeline Equipment, we manufacture and supply full lines of carbon steel, stainless steel, and alloy steel pipes in SCH 40, SCH 80, and heavy-wall schedules, along with custom pre-fabricated pipe spools.
Need assistance selecting pipe schedules or calculating temperature-derated pressure ratings for your project?
Contact Our Engineering & Sales Team Today for technical support, instant pricing, and certified material test reports (MTRs).
