I'm testing a gas piping system @30 psi and lost a pound or so after 24 hours. My debate with a coworker is expansion and contraction,can ambiant temperatures or compressed air temperatures when it was filled cause my pressure drop? I think so, what do you think? Thanks

Really depends on the volume that can expand or contract. In a small pipe, very short, 1# would be a lot. In a large pipe with a lot of air, 1 pound seems reasonable. However, what happened after another 24 hours?

Thanks for the feedback... about 50'of 2" and 50' of 1". I'll see tomorrow about anymore drop.

When the pipe was pressured up did you paint every joint with a detergent solution and check for bubbles. Just how did you check for leaks? Back to you, Tom

Tom,
Aren't gas lines normally tested at a much lower pressure, say around 5 to 10 pounds? Making a change more visible on the gauge and making temperature changes less of a factor.

I would think so Harold but I'm trying to find out how they tested for leaks. I just figured they upped the pressure for a more positive test. Regards, Tom