In my experience, positive pressure leak testing is more sensitive and repeatable than vacuum decay. This is not always the case but I am only basing my answer off of my experience. How I have tested this in the past was with a leak standard that flowed 3 sccm @ 5 psi. I tested with the leak standard at positive pressure (5 psig) and negative pressure (5 psiv). The positive pressure was more accurate than the negative pressure. Please keep in mind this was an unscientific experiment and only my findings on the specific application. Both testing methods work well and are effective at identifying leaks. The decision to use one versus the other often has to do with the part sealing requirements. If the part has a large opening the vacuum helps to seal the part versus the positive pressure pushing against the sealing surface. Also, parts that are hermetically sealed are often tested in vacuum chambers looking for a pressure rise in the chamber indicating a leak from the part. Hope this is helpful!

@@russsorrells1007 Thank you for your reply. I have query. The leakage (pressure drop) from the components will remain the same or change if we maintain same temperature but varying atmospheric pressure means i am checking the components in different country with same temperature. Will the leakage will differ if we perform leak testing process like once by+50kpa and performing under same condition in vacuum -50Kpa? Your reply was in relative to flow i am talking about the pressure drop.Hope you got this.

JP TV, I don't have direct experience with the ATEQ testers. The most common technology utilized by ATEQ is differential test technology. Choosing the appropriate test technology is driven by a number of different factors. CTS offers differential pressure decay, pressure decay, and mass flow technologies. Have an awesome day and sorry for the delayed response!

Heard ATEQ are superior to CTS because of how the units are mastered.