Pressurized piping must be thick enough to resist rupture. Engineers typically rely on the thin-wall hoop stress formula where is the internal pressure, is the pipe diameter, and is the allowable material stress. This simple relationship helps with quick sizing during preliminary design.
Different materials support varying levels of stress. Carbon steel might allow around MPa, while stainless steel or alloys may permit higher values. For safety-critical systems, design codes often require additional factors or corrosion allowances. Always consult standards like ASME B31.3 or API 5L for specific guidelines.
| Material | Typical Stress (MPa) |
|---|---|
| Carbon Steel | 138 |
| Stainless Steel | 170 |
| Copper | 70 |
Assume a pipe with diameter mm, operating at MPa, and using material rated for MPa. The minimum wall thickness is
mm. Engineers generally round up and add corrosion allowance, so the practical design might specify a 3 mm wall.
Enter your expected internal pressure, the pipe's outside diameter, and the maximum allowable stress for the selected material. The output shows the theoretical minimum thickness. Many codes call for weld efficiency factors, mill tolerances, or other adjustments, so use this result as a starting point rather than the final specification.
By experimenting with various pressures or materials, you can gauge how design choices influence pipe weight and cost. Thicker walls are stronger but heavier and more expensive. Understanding these trade-offs early helps refine project budgets and construction timelines.
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