stoddard
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Registered: 23-8-06
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![[*]](./images/corporate/default_icon.gif) posted on 23-8-06 at 08:51 AM |
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length of time for pressure test
I've had a new gunite pool built. Before I have a concrete pool deck poured (which will cover pipes) and water put in the pool, the builder checked
the pressure by filling the pipes with water to 10 psi. The pressure held at 10 for several hours but declined to 0 psi within 24 hours. The builder
says this decline in pressure is normal, that it could be the result of a leak in one of the pipes that protrude thru the gunite wall into the pool
that are only temporarily capped (they will be cut to the finished length when the pool is plastered). Should I be concerned that the decline in
pressure over 24 hours indicates a leak?
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4Leakman
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Registered: 27-6-06
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| posted on 29-8-06 at 04:20 PM |
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My opinion
I always test with air. It has no viscosity so I can't get false readings. A pipe either leaks or it doesn't. If it does and it is very slow (while
pressured with air) I would check everything with a foaming solution (bubbles or similar) to see if indeed it is only losing at the pipe ends. If he
tested with water and it went into a dry pool ( as you stated )you should see the water in the bottom of the pool and be able to determine where it
came from. 
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ahhaha
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Registered: 23-11-06
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| posted on 23-11-06 at 05:06 PM |
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The builder doesn't have a clue.
When I do testing with water I allow the pressure to build on my Xmas tree gauge to 40psi which is usually availble from a hose bib. For underground
lines this pressure must be maintained for 3 days. The needle should not move at all. For above ground lines you can shorten this to 24 hours.
Why 40psi? Because system operating pressure is not likely to reach that level especially since most of the attached equipment is rated at something
around 30 - 35psi max..
Some tricks can occur. Air in the line can diffuse dissolve into the pipe filling water and this subtly changes the pressure state as the diffusion
proceeds. It is for this reason aside from the viscosity related sensitivity that air pressurizing is preferable to water.
As for the builder making some comment about leakjing caps, all lines must be throughly sealed in order to achieve any degree of viable test, and that
has nothing to do with finishing considerations.
Hope you didn't accept the builder's hand waving explanation because if you did, you're likely to have a pernicious leak.
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