Criticality of Pneumatic pressure test vs Hydrostatic on piping system
Hereto attached the criteria for evaluating the potential dangerous of
pneumatic test vs hydrostatic test from safety point of view.
In this concern, we should always remember that is necessary to evaluate
the design aspects of material selection for piping lines to be
submitted to pneumatic test due to Process requirements: in these cases
ASME B 31.3 require that the materials be guaranteed against their
brittleness at the ambient temperature during pneumatic test.
Typical cases are the plants where the ambient temperature could reach
even minus 50^C (in particular to places like Azerbaijan, Kazakhstan or
Chinese plants on Mongolian border).