Views: 9 Author: Max Publish Time: 2025-12-15 Origin: Site
SCH 40 steel pipe is one of the most common "standard weight" pipe schedules. This schedule designation, defined by the American National Standards Institute (ANSI) and governed by standards such as ASTM A53 and ASTM A106, indicates the wall thickness relative to the pipe's nominal size.
This article is a reference for SCH 40 steel pipe dimensions and weights, based on ASME B36.10 (Welded and Seamless Wrought Steel Pipe) and ASME B36.19 (Stainless Steel Pipe) standards.
Pipe schedule (SCH) is a standardized system that defines the nominal wall thickness of a pipe relative to its diameter. It is meaning "SCH 40" does not directly correspond to 40 millimeters or 40 inches, but part of standards like ASME B36.10M.
The "Schedule" number (SCH) is a standardized index for pipe wall thickness, not an exact measurement. It is calculated from the formula involving internal pressure, allowable stress, and pipe diameter. Crucially, for a given Nominal Pipe Size (NPS), the outside diameter (OD) is fixed, but the wall thickness increases with the schedule number. Therefore, SCH 40 indicates a specific wall thickness for each NPS, resulting in a corresponding internal diameter (ID) and linear weight.
The table below details the specifications for SCH 40 pipes across a range of sizes. Note that weights are calculated based on a steel density of approximately 0.2836 lbs per cubic inch, and actual values may vary slightly depending on manufacturing tolerances and material grade.
Nominal Pipe Size (NPS) | Outside Diameter (OD, inches) | Wall Thickness (inches) | Inside Diameter (ID, inches) | Weight per Foot (lbs/ft) |
1/8" | 0.405 | 0.068 | 0.269 | 0.2447 |
1/4" | 0.540 | 0.088 | 0.364 | 0.4248 |
3/8" | 0.675 | 0.091 | 0.493 | 0.5676 |
1/2" | 0.840 | 0.109 | 0.622 | 0.8510 |
3/4" | 1.050 | 0.113 | 0.824 | 1.131 |
1" | 1.315 | 0.133 | 1.049 | 1.679 |
1 1/4" | 1.660 | 0.140 | 1.380 | 2.273 |
1 1/2" | 1.900 | 0.145 | 1.610 | 2.718 |
2" | 2.375 | 0.154 | 2.067 | 3.653 |
2 1/2" | 2.875 | 0.203 | 2.469 | 5.793 |
3" | 3.500 | 0.216 | 3.068 | 7.576 |
3 1/2" | 4.000 | 0.226 | 3.548 | 9.109 |
4" | 4.500 | 0.237 | 4.026 | 10.790 |
5" | 5.563 | 0.258 | 5.047 | 14.62 |
6" | 6.625 | 0.280 | 6.065 | 18.97 |
8" | 8.625 | 0.322 | 7.981 | 28.55 |
10" | 10.750 | 0.365 | 10.020 | 40.48 |
12" | 12.750 | 0.406 | 11.938 | 53.52 |
14" | 14.000 | 0.438 | 13.124 | 63.44 |
16" | 16.000 | 0.500 | 15.000 | 82.77 |
18" | 18.000 | 0.562 | 16.876 | 104.7 |
20" | 20.000 | 0.594 | 18.812 | 123.10 |
24" | 24.000 | 0.688 | 22.626 | 171.30 |
30" | 30.000 | 0.375 | 29.250 | 118.65 |
36" | 36.000 | 0.375 | 35.250 | 142.68 |
48" | 48.000 | 0.375 | 47.250 | 190.74 |
Understanding the Chart
Nominal Pipe Size (NPS): This is the approximate size designation, not the actual diameter. For pipes up to 12", NPS is close to the ID for SCH 40, but for larger sizes, it deviates.
Outside Diameter (OD): Fixed for each NPS, ensuring compatibility with fittings and flanges.
Wall Thickness: Increases with NPS to maintain pressure integrity, calculated per ASME B36.10M standards.
Inside Diameter (ID): Determined by OD minus twice the wall thickness, affecting flow capacity.
Weight per Foot: Critical for structural calculations, shipping, and support design. Weights are theoretical and assume plain-end pipes without threads or coatings.
The table below lists the pressure ratings of 304/304L and 316/316L stainless steel at ambient and higher temperatures.
Nominal Pipe Size (NPS) | Outside Diameter (inches) | Wall Thickness (inches) | ~100°F (psig) | 200°F (psig) | 400°F (psig) | 600°F (psig) | 800°F (psig) |
1/2" | 0.840 | 0.109 | 3,760 | 3,760 | 3,400 | 3,100 | 2,700 |
3/4" | 1.050 | 0.113 | 3,050 | 3,050 | 2,760 | 2,520 | 2,200 |
1" | 1.315 | 0.133 | 3,570 | 3,570 | 3,230 | 2,950 | 2,570 |
1 1/2" | 1.900 | 0.145 | 2,760 | 2,760 | 2,500 | 2,280 | 1,990 |
2" | 2.375 | 0.154 | 2,320 | 2,320 | 2,100 | 1,920 | 1,670 |
3" | 3.500 | 0.216 | 2,300 | 2,300 | 2,080 | 1,900 | 1,660 |
4" | 4.500 | 0.237 | 1,850 | 1,850 | 1,670 | 1,530 | 1,330 |
6" | 6.625 | 0.280 | 1,630 | 1,630 | 1,470 | 1,340 | 1,170 |
8" | 8.625 | 0.322 | 1,530 | 1,530 | 1,380 | 1,260 | 1,100 |
10" | 10.750 | 0.365 | 1,460 | 1,460 | 1,320 | 1,200 | 1,050 |
12" | 12.750 | 0.406 | 1,430 | 1,430 | 1,290 | 1,180 | 1,030 |
Values are for TP304/316 at typical allowable stresses.
The primary difference is wall thickness: SCH 80 has thicker walls than SCH 40, providing greater strength and pressure-handling capacity at the expense of higher weight, cost, and reduced internal flow area.
Parameter | SCH 40 | SCH 80 | Difference |
Wall Thickness | Thinner (standard weight) | Thicker (extra strong) | SCH 80 offers higher burst strength and resistance to mechanical damage |
Inside Diameter (ID) | Larger | Smaller (due to thicker walls) | SCH 40 allows higher flow rates; SCH 80 has more pressure drop |
Weight per Foot | Lighter | Heavier (typically 50-100% more) | SCH 80 increases shipping, handling, and structural support costs |
Pressure Rating | Lower (suitable for moderate pressures) | Higher (often 1.5-2x that of SCH 40) | SCH 80 for high-pressure systems |
Cost | Lower | Higher (more material required) | SCH 40 is more economical for non-demanding applications |
Strength/Durability | Adequate for general use | Superior for harsh conditions | SCH 80 better for corrosive or abrasive environments (extra wall allowance) |
Comparison Table for Common Sizes
NPS (inches) | OD (inches) | SCH 40 Wall (inches) | SCH 40 ID (inches) | SCH 40 Weight (lbs/ft) | SCH 80 Wall (inches) | SCH 80 ID (inches) | SCH 80 Weight (lbs/ft) |
1/2 | 0.840 | 0.109 | 0.622 | 0.85 | 0.147 | 0.546 | 1.09 |
1 | 1.315 | 0.133 | 1.049 | 1.68 | 0.179 | 0.957 | 2.17 |
2 | 2.375 | 0.154 | 2.067 | 3.65 | 0.218 | 1.939 | 5.02 |
4 | 4.500 | 0.237 | 4.026 | 10.79 | 0.337 | 3.826 | 14.98 |
6 | 6.625 | 0.280 | 6.065 | 18.97 | 0.432 | 5.761 | 28.57 |
8 | 8.625 | 0.322 | 7.981 | 28.55 | 0.500 | 7.625 | 43.39 |
10 | 10.750 | 0.365 | 10.020 | 40.48 | 0.594 | 9.562 | 64.43 |
12 | 12.750 | 0.406 | 11.938 | 53.52 | 0.688 | 11.374 | 88.63 |
Pressure Rating
Pressure ratings depend on material grade, temperature, and code. Generally, SCH 80 can handle significantly higher pressures due to thicker walls. For example, in ASTM A53 Grade B carbon steel at ambient temperature:
A 2" SCH 40 pipe might rate around 2,500-3,000 psi.
The same size SCH 80 can exceed 4,000-5,000 psi.
Prices are typically quoted per foot (US market) or per metric ton. Here's a summary for common black/plain carbon steel SCH 40 pipes:
Nominal Size (NPS) | Approximate Price per Foot (USD) | Notes |
1/2" | $1.50 – $2.50 | Smaller sizes often higher per foot due to processing |
1" | $2.00 – $3.50 | Common for plumbing |
2" | $3.50 – $5.50 | Popular structural size |
4" | $7.00 – $10.00 | Mid-range |
6" | $10.00 – $15.00 | Larger diameters |
8" | $15.00 – $22.00 | Industrial use |
10" – 12" | $20.00 – $35.00+ | Bulk pricing lower |
In summary, while the price range can be used as a reference, the pricing of SCH 40 steel pipe needs to be quoted in real time based on your requirements.
As a trusted steel pipe supplier, we supply A53/A106 SCH 40 steel pipe in various finishes and sizes at highly competitive prices. Please contact us and provide your requirements (size, quantity, material, delivery location) so that we can provide you with a quote and delivery.
