Pressure Testing HDPE Pipe
Pressure Testing HDPE Pipe
(OP)
Hi,
We're pressure testing some (approx 400m) HDPE piping with water and our client has given us a spec that we shall increase the pressure in the pipe to 125 PSIG and maintain this for the duration of the test. After one hour we are required to check for leaks.
Now our problem is that we are unable to find any leaks in the fittings etc, but our pressure drops 10 PSIG within 15 minutes of isolating our pump from the piping network. We think we have released all the air from piping. The water has been in the pipe for a few days so temperature gradients should be a problem and we aren't adding any water into the system each time we repressurize. I'm wondering if there is anything else that could be causing this decrease in pressure.
Any thoughts or ideas would lots of help
Thanks,
Gareht
We're pressure testing some (approx 400m) HDPE piping with water and our client has given us a spec that we shall increase the pressure in the pipe to 125 PSIG and maintain this for the duration of the test. After one hour we are required to check for leaks.
Now our problem is that we are unable to find any leaks in the fittings etc, but our pressure drops 10 PSIG within 15 minutes of isolating our pump from the piping network. We think we have released all the air from piping. The water has been in the pipe for a few days so temperature gradients should be a problem and we aren't adding any water into the system each time we repressurize. I'm wondering if there is anything else that could be causing this decrease in pressure.
Any thoughts or ideas would lots of help
Thanks,
Gareht





RE: Pressure Testing HDPE Pipe
David
RE: Pressure Testing HDPE Pipe
RE: Pressure Testing HDPE Pipe
If the problem is expansion of the piping due to pressure, then I suggest pressuization for a longer time prior to isolation. This should allow the piping to be fully expanded and eliminate that cause for any depressurization.
RE: Pressure Testing HDPE Pipe
What you are witnessing is the creep properties of PE. It doesnt behave like steel or ductile iron.