When leak testing gas mains, how do you determine the test duration?

[brucebagnasco]

When leak testing natural gas facilities, besides the minimum test durations listed in subpart J of CFR49, part 192, what are the basis of recommended test durations?
Are there any standards, codes of formulas that are used to calculate or derive the test duration?

 

[unclesyd]

I haven't check this out to see if it will apply to higher pressure testing with a gas but I think it should be based on the same principles.

http://www.concrete-pipe.org/pdfs1/DD_39.pdf