Underground Domestic Water Testing 3

[EmbassyConstruction]

We are using 4" glued Schedule 80 PVC pipe. We are allowed 1.89L/hr/100joints of leakage. We have 28 joints, in 560 feet of underground pipe. We are losing 4psi over a two hour period. How do we convert this PSI reading to Liters/hour?

 

[SteveWag]

The simple answer is that you cannot do this conversion. In order to do a volume/time test you would need equipment to maintain a more-or-less constant pressure while the water needed is measured over time. This means a pump, manual or automatic and a calibrated supply tank. A very cheap unit can be made using a power washer. (Be very careful not to blow the piping up, washers can make some high pressure.) Changes in pressure can be caused by temperature changes of the water, leaks, or many times air trapped in the line. When the air goes into solution, the pressure drops.

Steve Wagner

 

[cr1973]

Here's what you do:

Use a barrel of water to draw from using the pump. Get the main pressurized to the required testing psi (100 or 150 typically). Mark the level of the water inside the barrel using a crayon or marker.

Wait 2 hours. I assume it will lose 4 psi. Turn the pump on and draw water from the bucket. Pump the water line back up to the testing psi.

You should have pumped X number of gallons of water into the water line, so the water level in the barrel will now be below the marked level.

Take a measuring cup and count how many cups or gallons of water are needed to fill the water barrel back up to the marked level - that is how much water you lost over the 2 hr period.

 

[equimo]

You must follow the process of taking out the air into the pipe opening a relief valve at any upper point. If the loss of pressure persist and it is so difficult to found out the leaking, you have to account the water required to rise again the pressure. That is the convertion you are looking for. Besides in that way you could find the leaking for the humidity showed on ground surface.