Acceptable Leakage Rate For Nitrogen Helium Leak Test

Ask the Client. After all, it's the Client's gases that may leak.

Alternatively, recommend to the Client the leak rate that was acceptable on previous occasions using nitrogen.

Why is this so difficult <rhetorical question>? <sigh>

i did asked the client, but they've not answered till now. so still pending and progress delayed. and we are (contractor) being blamed for that. so we just suggest zero leak rate, but just not quite sure which reference to show, in case the client asked.

Then foreclose on it. "Unless (contractor) hears otherwise from (client) by (time/date), the leak test acceptability criterion shall be (criterion)." Get the Project Manager to send it, BTW.

There's no mileage in blaming a lack of progress on the failure to receive a criterion from anonymous posters to an international engineering forum, is there?

This sounds like a case of alligator mouth/hummingbird a$s syndrome. Why would you perform a test whose outcome you have no idea of?

You might get some idea by comparing the relative size of the Ni and He atoms.

The acceptable leak rates are decided based on plant and process requirements such as:

• hazards of fluid handles

• permissible leakages considering losses depending on plant process

Generally depending on plant fluids and processes following leak test methods are adopted

• Pneumatic test leak rate of 10^-3 cc/sec

• helium leak test sensitivity up to leak rate of 10^-12 cc/sec

Test methods are detailed in ASME Sec V however requirements depend on plant design

You can convert helium leak rate to nitrogen leak rate using formulae found in American Society for Nondestructive Testing Leak Testing Handbook Volume 1 (ISBN1-57117-071-5). Conversion factor for molecular flow is 0.374. For viscous flow, conversion factor is 1.12.

thank u for the comments... appreciate it.