plumbing air pressure test

[scottpepsi]

I am adding a walk-in shower with rainshower head mounted from ceiling, 4 body sprays mounted in the wall, a handheld body wand, an exact temp control valve, and 3 volume control valves . I have 3/4" pex supply lines to temp valve, then 1/2" copper to control valves,then 1/2" pex to respective sprays. I have capped everything, and applied an air gauge. I placed 85 psi of air. In a period of appx. 40 hours, the pressure has dropped to 75 psi. Does this indicate a leak, or is this an acceptable loss attributed to tempature fluctuation or some other variable? What is generaly accepted as a succesful test?(time/pressure)

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[Ernie Willson]

When you consider all the variables involved, then, I think you have a valid test and that you can expect the system not to leak. Remember that air leaks a lot more easily than water.

EJ > I am adding a walk-in shower with rainshower head mounted from ceiling, 4

[Steve Barker]

turn on the water, that is the test.

s

[Roger Shoaf]

It does indicate a leak, but it does not necessarily indicate a water leak, nor does it rule it out either.

I would fill the system with water and try the pressure test again. I think that they only use pressure tests on gas lines and those are about 15 PSI for 24hrs.

[JC]

Yep, I was wondering abut that. I've never heard of an air pressure test on water lines although I suppose it could be a good indicator. I just did propane line. Code is 15 for 12 around here.

[JIMMIE]

They pressure test water lines here. I think the pressure has to hold for 48 hrs. I know because I was here when my neighbors house was built. It flunked the test 3 times, BAD GUAGE. What I dont understand id that it can leak some and still pass the test. I dont remember what the requirements were but it didnt make sense to me that it was OK for it to leak down any at all.

Jimmie

[Steve Barker]

actually the gas line test is 15 psi for 10 minutes.

s

[Charles Bishop]

Does it matter if it's natural gas or propane?

[snip]

[Steve Barker]

nope. except that if it's propane, the propane co. will usually test it for you before they hook up.

s

[Ed Pawlowski]

***************************************************** Molecules in air are smaller than water molecules, thus air can leak where water will not. Just as air can pass through a plastic storage bag. That is why you get freezer burn after a time.

[Tony Hwang]

Hi, Same in my area. They pressure test it for at least 48 hours in new build houses.

[Phisherman]

It would make it easy to install two ball valves in the supply lines.

[Bob F]

Get out a spray bottle of soap water (dish detergent in water or windex) and spray the joints and fittings, valves, etc. while the pipes are air pressurized. You will find the leak, fix it, then try the test again. If there are no air leaks, there should be no water leaks.

[Bob F]

Incidentially, I air tested my pipes when I replumbed, and was glad I did. It is a lot easier to re-solder joints before you put water in them.