Replies

1. 
   Guest_ | Jul 24, 2000 11:01pm | #1

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   Tom, I have probably installed miles and miles of type K copper underground for water lines. It is the material of choice especially where you are subject to the lines freezing in the winter. You can hook a welding cable on each end and defrost it.

1. 
   Guest_ | Jul 25, 2000 04:25am | #2

   *If the pipe you are going to use as a chase (or conduit) for your copper line is iron or steel make sure you use some kind of packing to seperate the dissimilar metals. If you don't, the copper may fail. Unless you have the copper on hand, you will save big bucks by transitioning to PVC for the outside line. I would also plumb a full flow ball valve inside the house so that you can close the line for maintenance without turning off water service.

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   Guest_ | Jul 25, 2000 05:39am | #3

   *When dissimilar metals contact, the metal that will corrode is the less noble metal, in this case the steel. Contact between copper and steel will not cause the copper to fail. Nevertheless it is a good idea to isolate the copper so that any movement is adsorbed.

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   Guest_ | Aug 21, 2000 08:23am | #4

   *The soils and water in my area tend to eat copper--houses plumbed with copper have sinks, tubs, toilets full of green stain. The pipe should be buried below the frost line to PREVENT freezing, with a frost-free hydrant installed. If the copper freezes, it may split. One particularly cold snap, my maintenance-guy neighbor had a pickup bed full of copper pipe while my PB was doing fine: even though it froze and thawed, it was elstic enough to survive w/o damage. I would rather put the money into new plastic pipe and hydrants than dig it up in winter and replace it. Of course, with the ball valve, you could wait until spring...

1. 
   Guest_ | Aug 21, 2000 09:41pm | #5

   *Tom, Freeze worries aside, if you go with copper, go with at LEAST grade L. As stated, K is good too, but grade M is not acceptable for underground use. It has a thinner wall which makes it more susceptable to failure due to corrosion. As always, check your local codes and your mileage may vary.

2. 
   Guest_ | Sep 08, 2000 02:40am | #6

   *Code here in Los Angeles, and most other places, requires type K copper (the thickest walls) for all underground installations. Type L is for general purpose use under pressure, and M, which is very much thinner than the others, is strictly for drain, waste, and vent. You find it mostly on Smitty pan drains and after relief valves. See http://www.plbg.com, which is an excellent place for all plumbing questions.-- J.S.

3. 
   Guest_ | Sep 09, 2000 04:34am | #7

   *Well, here in Philly, type M is commonly found in residential above grade water supply use. Type L is used more commonly in commercial use, and some residential. I haven't seen K used a whole lot, but then I'm not on as many sites anymore. For DWV, when they use copper they tend to use DWV type (yellow marks). As for the codes, the moral of the story is check with your local inspector. What's code in LA ain't necessarily so in Philly.