you can't beat helium test if you n

[hacksaw]

you can't beat helium test if you need it,

if the hydro were strickly a leak test, then you would not need the pressure it requires, and even then it would only tell you if the blind flanges are made up correctly...

 

[metengr]

Hydrotesting has been around for many years as a way to verify no gross material defects, verifying pressure retaining capability design and one side benefit that most people do not understand is that hydrotesting of new material results in local strengthening at areas of stress concentration (geometric discontinuities and small inherent flaws).

So, comparing hydrotesting to helium leak tests is like comparing apples to grapefruit.