Should the material immediately above the horizontal loop be soaked before backfilling?

Discussion in 'Vertical and Horizontal Loops' started by jerry99, May 10, 2013.

  1. jerry99

    jerry99 New Member

    My contractor is installing the first loop in the trench today. He's wasn't planning on soaking the material placed immediately above the loop before backfilling completely. Is soaking the material immediately above the loop a good idea? The material is screened material that was dug out of the trench. It has a lot of clay but small screened pieces.

    I could soak it easily with water from a garden hose.

    If geo line hisses when you cut the end off, is it leak-free and ready to backfill?
    My contractor is installing the geo line in the first trench today. We're doing one trench at a time and using material from the adjacent trench to backfill the last one. Before each trench is backfilled does the line in that trench have to be hydrostatically pressure tested? I ask because the manufacturer Charter Plastics indicates on its site that the line is pressurized with 8-10 lbs of air at the factory and that if you hear a hissing sound when you cut an end off you are "assured that your pipe is in perfect condition and ready to install"?

  2. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    We put the lines in, don't soak the soil (we ha mostly wet clay) and just backfill. We only pressure test at the end before we backfill the fused header. We only had a loop pipe leak once, and we simply abandoned that loop and installed another one. We take a calculated risk, but the chance of the loop pipe leaking is so small. That way we gain with a fast and efficient installation.
  3. Calladrilling

    Calladrilling Member Industry Professional Forum Leader

    I agree with the above statement.
    the loop is leak free is the hiss sounds when you cut the end off.
    We always backfill the loop field and leave the header trench open for psi check after all our fused joints are made.
    when the psi test passes, we then backfill the header trench.
  4. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    I'm not a closed loop guy, but soaking the first lift of dirt backfilled atop a horizontal loop trench seems like a great idea - cheap to implement and likely to reduce voids / air pockets proximate to tubes.
  5. Palace GeoThermal

    Palace GeoThermal Well-Known Member Industry Professional Forum Leader

    We always soak ours
  6. Calladrilling

    Calladrilling Member Industry Professional Forum Leader

    Adding water to a horizontal loopfield will help settle the back filled area, but it is not exactly a benefit over not adding water.
    Soaking the ground with a garden hose would add a lot of time to a simple backfill job. That's a job that should be factored in ahead of time so a more efficient way of soaking the ground can be arranged ( water tanker and transfer pump).
  7. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    RE soaking, the soil type certainly matters. For instance there would be little value in soaking damp sand/gravel. Clay on the other hand would benefit from soaking, but that is not a quick garden hose job. That would turn into a question of cost vs benefit.
    Bear in mind compaction will take place, it's simply a question of how soon.
  8. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    I think that the time it would take to water in the first lift would be negligible when compared to the potential benefit of 100% contact with the HX. We hydrostatically test every install prior to backfilling. In 12 plus years we have only had 2 bad vertical loops, after installation. We are convinced they were damaged by us, or in transit prior to install, not factory mulligans.
  9. ACES-Energy

    ACES-Energy Member Industry Professional Forum Leader

    In upstate, NY we do not soak ours. Our efficient process and large excavator, simply put we have it down to a science and soaking would slow us down and probably not gain anything. Homeowners can soak the trenches after and before they finish grade or wait 3-12 months and let the natural rain do it...Its all about saving energy...way run a well pump or pay for municipal water when the rain can do a better job!!

    We only buy hdpe that has shut fused ends with small air pressure for a piece of mind. We build the header and pressure test only to confirm the header has no leaks. We have only had a single header leak about 2 years ago and we caught it due to a poor fusion joint of 3/4". We have never had a loopfield leak but have caught several pipes that had been damaged by a fork truck before we got it at foot marks buried in the coil, so important to have your guys inspect all the piping while installing...

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