Lateral Piping Bury Depth with Shallow Bedrock

Discussion in 'Vertical and Horizontal Loops' started by Dave Hermantin, Mar 3, 2018.

  1. Dave Hermantin

    Dave Hermantin New Member

    Does anybody have design experience with how to deal with shallow bedrock preventing bury depth beneath the frost line?
    I have a friend (no really) that is designing a job with a 125' runout to boreholes and only 2' available bury depth. I was told that the project can't afford the rock removal and they are desperate to find a solution. They asked me if using a low K fill would act as an insulator (Gilsulate, K=0.80) . I'm at a loss if there is a solution for this. The building code bury depth for foundations is 48".

    Is there any merit to using insulation? Or, I know that some use geo for snow melt. I haven't yet, but, has anyone used it as heat trace to prevent shallow piping from being affected by frost?

  2. waterpirate

    waterpirate Well-Known Member Industry Professional Forum Leader

    High and welcome! You could adjust the amount of antifreeze in the loop to account for the shallow bury depth. Insulating the pipes in the trench is also a option. Keep in mind that the fluid will be travelling at a rate of 3gpm per ton when running. So in regard to your other post, at that flow rate how much gain or loss will the exchanger really see in your friends install?

    Hope this helps
  3. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Not sure I would be worried about this at 2' depth. The freezing should be protected down to 15F WITH ANTIFREEZE. How much lower do you expect the temp to be in CT. Plus you warm the ground with 25-30F "warm" water from the loop. Unlikely the water in the pipe drops below 25F at 2' depth.
  4. moey

    moey Member

    Most folks who have a system that was added after a house was built bring the pipes in the house above ground. Mine is at least they come into my garage and then make their way into the basement. I did insulate where they come in the garage outside didnt do anything to the pipes underground. Just bury it at 2 ft and dont worry about it.

    Make a small hill? :)

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