Outdoor Pipe Question


  #1  
Old 05-23-08, 09:12 PM
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Outdoor Pipe Question

Hi!

We have a really long length of pipe (about 30 to 35 feet) that runs from the house, under a deck, and to a spigot. At some point during every winter, the galvanized pipe that is currently in place freezes and cracks. The water supply to this line is shut off every autumn. So, the question is this: We want to replace the galvanized pipe with something else to prevent this cracking. What type of piping should be used? We want to run the new pipe in the same area as the old pipe. That is, the piping will be above the ground but beneath the decking. The piping will run about 12 to 18 inches above the ground. I've had someone tell me to use PVC and I thought I read once that flexible PE pipe should be used.

Thanks for any help or suggestions you can offer!
 
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Old 05-24-08, 12:50 AM
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Your problem is not the pipe material being used it is the fact of water remaining in the pipe after you shut off the supply.

ANY pipe will burst if it is full of water and exposed to freezing temperature. What you need to do is replace the burst pipe in a manner that will allow you to drain all the water from it before the freezing temperatures occur.

Install the new pipe with a downward slope from the point of supply to the end. Use a "stop and waste" valve at the supply or else add a tee and vent valve immediately after the supply shut-off valve. Before the cold weather close the supply and remove the little cap on the stop and wast (or open the vent) and then open the spigot on the outer end. Leave the spigot and vent open until the following spring when you put the pipe back in service.

The other alternative is to "heat trace" the pipe and then wrap it with insulation. Heat tracing means to install a special electrical cable to the pipe that will allow a small amount of heat, controlled by a thermostat, to keep the water in the pipe above the freezing point.
 
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Old 05-24-08, 10:09 AM
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Use Pex pipe and insulate the line, pex has memory in it, won't split when frozen.
 
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Old 05-26-08, 10:52 AM
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Thank you both for your help. These both seem like good solutions. A couple of questions: You can run PEX above ground outside? And with the insulation around it, there will be no degradation in the PEX material over time?

Thanks again!
 
 

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