Estimate the structural wall thickness of a metal pipe from internal pressure, pipe diameter, allowable material stress, safety factor and corrosion allowance.
P = internal pressure, D = diameter, Sₐ = selected allowable material stress, SF = safety factor, E = joint efficiency and C = corrosion allowance.
Pressure conversions shown here are approximate display conversions; the calculator performs calculations using consistent SI units.
What is pipe wall thickness? It is the thickness of metal between the inside and outside surfaces of a pipe. For pressure service, the wall must resist the stresses produced by internal pressure as well as other applicable loads.
How is required wall thickness estimated? This tool uses a simplified thin-wall cylindrical relationship based on internal pressure, diameter, allowable stress, safety factor and joint efficiency, then adds corrosion allowance.
Does pipe diameter affect thickness? Yes. For the simplified relationship used here, required structural thickness increases approximately in proportion to pipe diameter when the other inputs remain constant.
What does the safety factor do? It increases the design margin by reducing the effective allowable stress used in the simplified calculation. The appropriate factor depends on the design method and applicable standards.
What is corrosion allowance? It is additional thickness intended to account for expected metal loss during service. The appropriate value depends on the fluid, environment, service life and corrosion mechanism.
What is weld efficiency? It is a simplified factor representing the effectiveness of a welded joint in this calculation. Actual weld requirements depend on the applicable design code, weld category and examination.
Can I calculate stainless-steel pipe thickness? Yes, but the built-in stainless value is only a reference allowable stress. Actual alloy, grade, temperature and code-specific allowable stress must be used for engineering design.
Can this calculator select a pipe schedule? No. It estimates thickness rather than selecting a commercial pipe schedule. Actual selection also requires manufacturing tolerances, code rules and available pipe dimensions.
Can this be used for compressed gas or high-pressure systems? It should not be used as the final design method for hazardous, high-pressure or safety-critical systems. Those applications require the applicable code and qualified engineering analysis.