How to model the Vacuum Piping or external pressure load on piping in START-PROF

Read about START-PROF pipe stress analysis software

Vacuum piping analysis is possible following the code GOST 32388-2013.

To set the vacuum we must specify the negative operating pressure in pipes. The START-PROF operating pressure - is not absolute pressure. It's relative pressure, the difference between absolute internal and external pressures. If internal absolute pressure is zero (absolute vacuum), then operating pressure should be set to minus one atmosphere pressure i.e. -0.1 MPa.

Features of vacuum piping:

If the buckling analysis is failed the wall thickness should increased or stiffening rings must be added. The shape and distance between rings should be checked by analysis.

Buckling check of high-temperature piping is not possible because the method of analysis don't consider the creep effect. See 14.1.1 GOST 32388-2013: This code applies to piping operating under vacuum or external pressure, without metal creep. Wall temperature should not exceed 380 °С for carbon steel, 420 °С for low alloy steel, and 525 °С for austenitic steel.