electrolysis

[atlast100]

I have an old stone building that has leaking water supply pipes imbedded in the cement with no room for an ajacent run. I do not want to run external lines. Depending on the diameter I use I can run a copper or black plastic smaller diameter line thru the existing line.It is 4 straight runs of 100’ each & I can break the line in places if necessary for soldering. Once I reach the end I plan to connect the new line to the old galvanized house line.

Questions:.
If I go with copper, will the use of copper ( internally & at the end connection to galvanized) cause electrolysis with the galvanized pipe?

What connection should I use- Brass Copper etc.

Will the smaller diameter cause much flow loss?

Thank You, Steve

[TheLocalPlumberParticipant]

Steve,
It seems as if you will have to re-core the holes to replace with new pipe. The new pipe if it is copper will need to be wrapped in at least a ten mil tape to prevent the concrete from repeating the damage to the new pipes.
I would not suggest to anyone that reducing the size of the pipe to get it into an existing hole is a good idea, the proper way would be to re-core the holes to the right size pipe with a tape over wrap.
When transitioning to copper from galvanized a brass pipe extender of at least 6″ between the two different metals will suffice.
Good Luck,
Bill
The Local Plumber
Tustin, California http://www.TheLocalPlumber.com

» This message has been edited by TheLocalPlumber on 10 December 2001

[SylvanLMPParticipant]

Hi Steve, According to normal practices in NYC it is common to use “ONE COMMERCIAL SIZED” smaller pipe when going from Galvanized to copper.

The reason being we know ferrous metals will have a reduction over the years and NYC water being slightly on the acid side leaves coper in pristine condition even after many years of service.

Now according to the code I remember it did state any pipe passing through a wall, floor shall be protected by an Iron pipe sleeve, etc., with lots of goodies thrown in.

This sleeve was use to prevent not only the piping from carrying any structural weight but to protect it from the effects of cement etc.

Personally If I were passing a copper line through a galvanized pipe I would coat the copper with either coal tar enamel or what is commonly called Mil wrap (PVC or other tape.

Check your local code book and you cant go wrong

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SylvanLMP

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