Leakage tests using air

[TheLucifer]

Hi all,
Has anyone performed leakage tests with air on hydraulic/fuel/water system after installation? Our contractor insists that a small amount of air leakage occurs in pumps/valves/closures, and a threshold is necessary to define the amount of leakage to say that test is failed. But we've always performed leakage tests with water and there was no threshold: any leakage was a failure. I assume that the leakage from equipment is an equipment design property, but can an air leakage happen from pipe connections, couplings etc?

 

[EdStainless]

I can't speak to hydrol systems in particular, but we use both air and hydro for testing tubing and fittings. Considering that the viscosity of air is a bit lower than water (100 times) then yes, you can expect to find systems with zero detectable leakage in water and measurable air leakage.

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[TheLucifer]

But how do you calculate the amount of reasonable leakage? is there a guideline for this?

 

[monkeydog]

There is an old report written by JPL;
Technical Report No. 32-926
"Basic Criteria and Definitions for Zero Fluid Leakage"
by Richard S Weiner dated December 15 1966
Prepared under contract NAS 7-100

Perhaps someone has redone this report in electronic media, or software.