This debate seems never to die, and I keep adding more examples to make my point crystal clear…
When pressure- and leak-testing piping, we are to use the Hydrostatic Method rather than the Pneumatic Method. ASME provides three (3) specific situations in which we can use Pneumatic Testing instead of Hydrostatic Testing. And these exceptions are very clear in their application, although many like to muddy the waters in their risk analysis.