I am testing for package leaks in non-porous packages. Quick details are: 1) Package is sealed at atmospheric pressure. There is some headspace inside the package which is just air. 2) A small hole is placed in the package (100-300 microns). 3) This package is then suspended in water in a small vacuum chamber. 4) Vacuum is drawn in the chamber (in.Hg) until air bubbles are seen coming from the hole. The height/depth of the water in the vacuum chamber is 9 inches. For ease of answering, lets assume that the pressure inside the package will remain constant, even though I believe the pressure would decrease as the package leaks air.
My question is: If the hole in the package is located so that it is submerged under 8 inches of the water, will the vacuum level required to make the package leak be greater than if the hole was only submerged under 1 inch of the water?
If the answer to this is yes, will the difference in vacuum level required to make the package leak be proportional to the height of the water? (1" of H2O = 0.0735" Hg) so (7" of H2O in this example means is would require 0.514" Hg more vacuum to make the package leak from the hole covered in 8 inches of water vs. only 1 inch)