Collapsing Pressure Data
Collapsing Pressure Calculator
This calculator estimates the external pressure at which a tube will collapse, based on its outside diameter and wall thickness.
Enter the tube's outside diameter and wall thickness, then choose a working safety factor. Depending on how thin the wall is relative to the diameter, the calculator applies one of two formulas — a thinner wall collapses primarily through elastic buckling, while a thicker wall collapses through plastic deformation, and each follows a different relationship to wall thickness. The calculator switches between them automatically; you don't need to know which one applies. It returns:
A conservative operating limit, calculated using your selected safety factor.
The theoretical failure point, with no safety margin applied (SF = 1).
For a 1/2" OD tube with a 0.065" wall and a working safety factor of 2, the calculator returns a working pressure of 4,940 psi and a collapsing pressure of 9,880 psi.
For a 2" OD tube with a 0.028" wall and a working safety factor of 2, the calculator returns a working pressure of 70 psi and a collapsing pressure of 140 psi — notably lower, since thinner-walled tubes are far more prone to buckling than thicker ones at the same diameter.