Replies

1. 
   MSA1 | Apr 13, 2005 04:44am | #1

   No real ideas, but I can tell you that what you suggest wont work. Insulation does not create heat it holds it. Think about your nice warm bed. Its cold when you get in, its your body that warms it up. The blanket just holds the heat. Same idea with insulation.

   Where are you located? How cold does it get? How deep is the pipe? 

1. 
   Piffin | Apr 13, 2005 05:04am | #4

   In North America, the average temperature year round at a depth of six feet or so is around 55-58°F That would be the heat that he wants to hold. As the earth radiates heat up and out, the insulation board will work top hold it in. The problem is that he would need a piece between four and eight feet wide, not just the width of a narrow trench. From apractical view, you are right, but not the reasoning why because the heat is there. 

    

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1. 
   MSA1 | Apr 13, 2005 05:14am | #5

   Thanks Piffin,

   I forgot about geo-therm, your right you would need a big piece of foam to catch enough of the heat. In that case his idea may work. Unless it was a typo HC was suggesting a "12' " wide piece of foam.

   Edited 4/12/2005 10:16 pm ET by MSA1

   Edited 4/12/2005 10:17 pm ET by MSA1

1. 
   Piffin | Apr 13, 2005 05:43am | #6

   I await his confirmation of details 

    

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1. 
   BillHartmann | Apr 13, 2005 06:40am | #7

   What concerns me is not the foam. This is basically the same as a frost protected shalllow foundation.But he does not want to backfill, but fill the trench with mulch.If I understnad correctly what he is talking about it will allow water to collect and become a conductor to freeze the water line quickly.

2. 
   PenobscotMan | Apr 13, 2005 08:48pm | #14

   On Vinalhaven, some people have a wire running down inside the pipe (well to house).  As long as the electricity doesn't fail, the warm wire is supposed to keep the water from freezing.  Last winter, the ground froze to 10', some claimed.

1. 
   Piffin | Apr 13, 2005 10:58pm | #16

   I'd hate to rely on that. In some cases, it would be a Looooonng heat tape, and they have been known to fail - matter of fact, the life expectancy is ten years more or less 

    

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2. 
   UncleDunc | Apr 13, 2005 04:48am | #2

   How shallow? What's the design frost depth where you live? Is this the water service to your house? What size is the pipe? What material? How much flow? Where does the water come from? What temperature is the water when it enters the pipe? How long is the pipe?

3. 
   Piffin | Apr 13, 2005 04:50am | #3

   How deep can you get it and how deep is your required foot/frost depth?

   In general. using foam doesn't gain you much in a narrow trench, 'cause you would need to get it out a couple feet to either side, due to the fact that heat loss occours in all directions, 360°

    

    

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   Taunton University of Knowledge FHB Campus at Breaktime.
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1. 
   GCNC | Apr 13, 2005 02:40pm | #8

   Most people in this area go for 24" minimum, I believe that is just below the frost depth. The forest will help some too. I am basically at the surface in one or 2 spots. I wanted to use mulch since it generates some heat as it decomposes., I can make the foam wider, maybe 24" wide. It would be nice to find a really thick pipe insulation. I also though about putting R-11 in really thick 55gallon trashbags and filling over them. Location Western NC, 3000 ft elevation. It is a seasonal house so draining the pipes is possible but I would rather find a way to insulate.
   HC

1. 
   BillHartmann | Apr 13, 2005 03:25pm | #9

   Heat from the compost will only last for short time.You want a 50 years solution, not a 50 day one.And you CAN'T leave the ditch open. It needs to be well covered with dirt. You need to keep the pipe dry. If you let water into the trench you let the cold right into the pipe.And PIPE INSULATION is the last thing that you want. You need to keep the pipe exposed to the (relatively) warm earth. Enclose it in insulation is a guarantee freeze.Now this is going to be seasonal usuage. And it will sit for months without any water flowing so it will cool down to ambinet.Insulation on exposed pipes do work where you have more or less continous flow. My city (375 homes) has an exposed, insulated water main running across the dam). But in that case water is being used 24*7.

2. 
   goldhiller | Apr 13, 2005 06:24pm | #10

   Is this the supply line from the well to the pressure tank?If so, is there down-pitch/fall on the underground supply line from the well-head to the pressure tank (whether that is in the house or in a pit)? Again, if so......jet pump or submersible............single compartment pressure tank or currently a bladder type tank?Knowledge is power, but only if applied in a timely fashion.

1. 
   GCNC | Apr 13, 2005 06:35pm | #11

   The well is below the tank and the house. submersable pump,
   HC

1. 
   goldhiller | Apr 13, 2005 07:28pm | #13

   Damn.If it were the other way around, you could simply install a Morrison wellhead delivering to the hole in the very top of a single compartment galvy tank. Supply line then becomes part of the air chamber and the Morrison head self-drains the supply line at the end of each pumping cycle. No water left in line to freeze. This is the set-up we have over at the farm, but there the wellhead is above the pressure tank. Knowledge is power, but only if applied in a timely fashion.

3. 
   Piffin | Apr 13, 2005 10:54pm | #15

   houston, we have a problem.The reason mulch generates heat is as a by-product of decomposition. in cold weather the bacteria that cause this go dormant and no decomposition takes place so no heat.Basiclty at surface? Is this because uyou don't want to dig deep or because there is soliod ledge there? The answer can make a diff, In suome places, the ledge conducts earth heat close to the surface.Forest? In my area, that means colder, longer, because of shade.If your typical frost depth is 2$", and you will be near surface, you will need to place the foam at least 24" to either side of the pipe, meaning 48" wide.
    

    

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1. 
   AndyEngel | Apr 13, 2005 11:04pm | #17

   Depends on the type of forest. If conifers, then yes, colder. If deciduous, then warmer. I've experienced some very cold winters where the frost penetrated several feet into bare ground, but where the most minimal vegetation kept the frost depth to six inches or so. That said, bury the line, or plan on draining it.

   AndyAndy Engel

   Senior editor, Fine Woodworking magazine

   Other people can talk about how to expand the destiny of mankind. I just want to talk about how to fix a motorcycle. I think that what I have to say has more lasting value. --Robert M. Pirsig

4. 
   DDay | Apr 13, 2005 06:45pm | #12

   Why can't you go down to the right depth?  All the idea's you have will not work, you need to put the pipe below the frost line.  All the insulation in the world, mulch, heat tape, etc will not work.  Like Hartman said, you want something that will last for a long time, not something that is a wing it idea.  And as piffin and others said, insulation keep the heat from being lost, you'll still need a heat source.  A very well insulated house will be the same temp outside in the winter if you don't heat the house.

   I wouldn't bother trying anything other than trenching to the right depth and covering the pipe with sand (it does not damage the pipe, also it does not hold water so the possibility of freezing is reduced significantly.  If there was an easier way that worked, people would be doing it already.  But you need something that will not be a worry, you need something that will last.