All, I am curious about a recent inspection I had on my 1 ½ year old project – my retirement home in California.
The gas (propane) line pressure test – the inspector conducted a 15-minute test to see if the lines held 15 psi of pressure. We passed the inspection – however, after about three days there was a pressure loss down to 12 psi.
Should I worry about this and investigate further?? The lines are ¾ and ½ inch black iron pipe in the house and a run of 125 feet to the propane tank of 1 inch pvc coated black iron pipe.
Thanks
Replies
Did the pressure drop gradually, or was it sudden? Was there a corresponding change in temperatures over the 3 days? If it's a leak it's letting one molecule at a time through, that's gonna be hard to find. :) Joe H
The pressure drop was very gradual and the temprature range was 55 degrees a night to about 80 degrees during the day.
Thanks for your interest and comments.
Propane systems are typically 11" wc maximum pressure systems. What that means is the pressure exerted by a water column, the "wc" part, that is 11 inches high. 1 psi = 2.307 feet of water column, 15 psi would be the equivalent of 34.6 feet of water or 415.3 inches, over 37 times the normal pressure of you system.
"Should I worry about this and investigate further??"
No. 15 psi for 15 minute no noticeable pressure degradation means the system is tight for the intended service.
Regarding the propane leak question, on our new house, the propane pipe passed the "leak down" test, too. After one day the pressure is ten, after two days, it is six, at the end of the third day the pressure is ZERO. The contractor insists it passed the test, so there is nothing further they have to do. The county inspector says it passed the test, but it is obvious there is a major leak that must be repaired, but he cannot tag it because it passed the test.
This sounds like a dangerous situation for us, plus why should we pay for propane that is escaping into the atmosphere?
So, I guess I will have to pay someone else to rip up the walls to find the leak. Oh, well, aren't new houses fun?
The moral of this story is, take the gauge off as soon as the test is over.
Right on! Why do we sometimes over analyze?
Thanks for your through explanation. I understand the concept and can now hook-up the propane tank with confidence.
Regarding the propane leak question, on our new house, the propane pipe passed the "leak down" test, too. After one day the pressure is ten, after two days, it is six, at the end of the third day the pressure is ZERO. The contractor insists it passed the test, so there is nothing further they have to do. The county inspector says it passed the test, but it is obvious there is a major leak that must be repaired, but he cannot tag it because it passed the test.
This sounds like a dangerous situation for us, plus why should we pay for propane that is escaping into the atmosphere?
So, I guess I will have to pay someone else to rip up the walls to find the leak. Oh, well, aren't new houses fun?
Was the test done with propane or with compressed air? If it was done with propane, then yes, you have a problem. If it was done with air, you may or may not have a problem, and the only way to find out is to pressure it up with propane. It could very well be that the system will hold propane just fine, even if it won't hold air. I worked on an underground irrigation system for a golf course one time that would not pass a 24 hour leak test when filled with compressed air, but would hold water under the same pressure for days at a time.
Thanks for the tip, we were testing with air. Hope you are right, that could save me some drywall repair dollars! I will test it with propane.