Hydrostatic pressure test increased?
Hydrostatic pressure test increased?
(OP)
I have a hydrostatic pressure test for a HWS/R system, 1-1/4" pipe, approx 40 ft in length.
Initial test pressure was 225psi and after 4 hours the test pressure increase to 280psi. I'm used to test pressure decreasing due to a leak but never seen test pressure increase by 55psi.
I understand that test pressure may increase slightly if the temperature is exteremly hot and humid, but this test was conducted below grade not exposed to any extreme heat or direct sunlight. Air was vented and pressure was given enough time to stablize.
What could be the cause for such an high increase in pressure? Could the short distance of pipe being testing play a factor?
I appreicate the help. Thank you.
Initial test pressure was 225psi and after 4 hours the test pressure increase to 280psi. I'm used to test pressure decreasing due to a leak but never seen test pressure increase by 55psi.
I understand that test pressure may increase slightly if the temperature is exteremly hot and humid, but this test was conducted below grade not exposed to any extreme heat or direct sunlight. Air was vented and pressure was given enough time to stablize.
What could be the cause for such an high increase in pressure? Could the short distance of pipe being testing play a factor?
I appreicate the help. Thank you.





RE: Hydrostatic pressure test increased?
If even a small section is above ground it can have a big impact on the pressur if exposed to sun. Length is only relevant if the temperature changes all at the same rate. A longer line will generally just even out areas which increase temp with those that decrease, but volume doesn't come into it until you draw off some water.
See also this very comprehensive FAQ.
http://www.eng-tips.com/faqs.cfm?fid=1339
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way
RE: Hydrostatic pressure test increased?
RE: Hydrostatic pressure test increased?
RE: Hydrostatic pressure test increased?
RE: Hydrostatic pressure test increased?
less space, more pressure.
RE: Hydrostatic pressure test increased?
RE: Hydrostatic pressure test increased?
RE: Hydrostatic pressure test increased?
There's no interesting mystery here at all. Even two our three degrees C can easily make up the sort of pressure seen by the test. Staedler, please advise how long you left the pipe full of water before you did the test. Anything less than a couple of hours doesn't give the water time to stabilise with ground temp. Also what was burial depth? Anything less than 300mm or so will react to surface temp (sun etc) if you're somewhere where the sun shines a lot.
My motto: Learn something new every day
Also: There's usually a good reason why everyone does it that way