WHAT GEAR FOR SIMPLE HYDEROSTATIC PRESSURE TEST?

[oldestguy]

I've a neighbor chemical engineer who apparently never heard of pressure testing of small water distributing system for shared domestic wells. Pipe is 2" pvc. He's in charge of a group of well sharers and they have a water leak somewhere.
Would not a reasonably large plumbing firm have the equipment?

What does it consist of for pump and measuring equipment?

Is this an unusual sort of test for these systems?

 

[bimr]

Residential water systems are tested according to the regulations in the building code. These tests are much simpler than the tests required for the municipal water system. Here is a typical procedure:

Water piping - Upon completion of a section or of the entire hot and cold water supply system, it shall be tested and proved tight under a water pressure not less than the working pressure in which it is to be used. The water used for tests shall be obtained from a potable source of supply. A fifty (50) pound per square inch (344.5 kPa) air pressure may be substituted for the water test. In either method of test, the piping shall withstand the test without leaking for a period of not less than fifteen (15) minutes.

The equipment that you will need is a small pump to pressurize the water system, a stop watch, and a pressure gauge good for 100 psig.

You probably are going to have to install additional valves so that you can block of and test segments of the system. It is easier to test segments than to do the entire system at once.

 

[bimr]

These tests are required when the house is constructed and sometimes when the house is remodeled.

Check with your local building code official for the procedure in your area.

 

[atook]

Stay away from doing a compressed air test, that's a safety hazard. For irrigation systems, I usually spec less than 2 psi drop (at operating pressure)over 2 hours for glued pipe. If it's gasketed pipe then I spec a volumetric test based on the number of joints.

 

[hydrae]

I assume you are looking for a leak,

have everyone stop using water during the test (I assume it is small system say less than 10 houses?)

Note the operation fequency of the well
or does the well have a water meter even better

Shut off the valves entering the houses one at a time and compare to the operation frequency of the well

(odds are someones toilet flapper valve is stuck open)

Hydrae

 

[oldestguy]

a good idea about the stuck valve.

Only about 4 houses on the well. Several unused lines also, but they are activated.

Coincidentally to the pump running maybe 5 times as often, (much bigger electric bill), a new, 1000 ft. line was connected in.

That line is not being used yet, but is active.

Of interest is the fact the pump runs more than usual, but not as often, when the newer line is closed off.

So finding the cause is perplexing.

You guessed it, they didn't run a pressure test on the new line. So far no unexpected springs are showing in the areas of the lines. The excuse for no test was "Small time plumber".

 

[BigInch]

Just a wild guess, but perhaps there is a leak somewhere in the old lines and the new line goes uphill.

The symptoms you describe could happen with the above configuration... if. With a new pipeline going mostly uphill or to any new point higher than what existed before, a higher static pressure might result after the pump stop. (And may have created a leak in the old pipe.) With a higher static pressure in the line, any leak in the old pipe at a low elevation would be a little faster and pressure would be lost faster, requiring more frequent pump starts during any given time.

The new line may also be holding more water volume under some elastic pressure due to pipe wall stretching, and backflow some of its water to the leaking area while the wall elasticity still maintains pressure above the pump's start pressure setting.

As I say, only a very wild guess.. or two.

http://virtualpipeline.spaces.msn.com

"What gets us into trouble is not what we don't know, its what we know for sure" - Mark Twain

 

[coloeng]

In our area some of the leak detection people are injecting helium at low pressure into the line and then using a gas sensor that detects where the helium surfaces. This has been pretty effective in detecting leaks and might be worth a try.