Pipe (structural) properties
Cross-sectional area, moment of inertia, and section modulus for standard-weight (Schedule 40) steel pipe used as a structural member. Round pipe is symmetric, so it bends and buckles equally in every direction.
Schedule 40 pipe section properties
| NPS | Area (in²) | I (in⁴) | S (in³) |
|---|---|---|---|
| 1/2 | 0.250 | 0.017 | 0.041 |
| 3/4 | 0.333 | 0.037 | 0.071 |
| 1 | 0.494 | 0.087 | 0.133 |
| 1-1/4 | 0.669 | 0.195 | 0.235 |
| 1-1/2 | 0.799 | 0.310 | 0.326 |
| 2 | 1.075 | 0.666 | 0.561 |
| 2-1/2 | 1.704 | 1.530 | 1.064 |
| 3 | 2.228 | 3.017 | 1.724 |
| 4 | 3.174 | 7.233 | 3.214 |
| 6 | 5.581 | 28.142 | 8.496 |
| 8 | 8.399 | 72.489 | 16.809 |
These are section properties, not flow dimensions. Area is the steel cross-section, I is the moment of inertia for stiffness and buckling, and S is the section modulus for bending strength. A round pipe has the same I and S about every axis through its center, which makes it an excellent column and a natural choice for handrails, posts, and light frames.
Need the wall and bore dimensions instead?
See the Schedule 40 Pipe Dimensions chart, or the Steel Beam Properties Chart for beams.
Pipe as a structural member
Because a round section is the same in all directions, pipe makes an efficient column with no weak axis to buckle about first, and a tidy member for railings, posts, and braces. The values here use Schedule 40 wall; a heavier schedule adds wall, raising area, stiffness, and strength for the same outside diameter.
Section properties from geometry
For a hollow round, the area is pi over four times the difference of the squared diameters, the moment of inertia is pi over 64 times the difference of the fourth powers, and the section modulus is that inertia divided by the outer radius. These are computed directly from the Schedule 40 outside and inside diameters, so they stay consistent with the dimension chart.
FAQ
What is the section modulus of 2 inch Schedule 40 pipe?
About 0.561 cubic inches, computed from its 2.375 inch outside and 2.067 inch inside diameters. It sets the bending strength.
Is pipe good as a column?
Yes. Its round section is equally stiff in every direction, so there is no weak axis, making pipe an efficient and stable column or post.
How are pipe section properties calculated?
From the outside and inside diameters: area from the squared diameters, moment of inertia from the fourth powers, and section modulus as the inertia divided by the outer radius.