by jdmartin » Wed 09 Apr 2008, 15:53:41
$this->bbcode_second_pass_quote('frankthetank', 'J')D-For the record, i can't stand cast iron pipes! Talk about trying to get a leak free connection. I ripped out everything here at home and put in copper. Do they weld the big city pipes or something? I would love to see the roll of Teflon tape they are using

The plumbing at Machu Picchu is over 500 yrs old.
Frank,
Cast iron is pretty atypical for use in indoor home plumbing, unless it was really old turn-of-the-century stuff. Most indoor plumbing that "looks" like cast iron is really galvanized steel, which is junk - it corrodes from the inside out, eventually diminishing the interior diameter of the pipe until you can't get any volume out of the pipe.
Cast iron that's in the ground is restrained in 3 ways:
1. One end of the pipe is shaped like a bell. The other end of the pipe fits into a bell on another pipe, then lead is packed around it to keep it leak-free. This is the old-time way, and the joints often leak, but it's very long-lasting. Contrary to thought process, no lead gets in the water this way as the lead is packed around the outside of the pipe.
2. Again, one end of the pipe is shaped like a bell. Inside the bell is a small groove that a rubber gasket fits inside. You lube that gasket, then push the other end of another piece of pipe that's been slightly beveled into the gasket. When the line is filled with water and pressurized, the gasket seals tight. This is the new way of doing things, and also it's usually done with cast iron's replacement ductile iron. Ductile iron has a little magnesium in it to make it "ductile" or pliable, so it can give a little bit and not break. Cast iron is very rigid and brittle - if the ground shifts it will break. Anyway, the rubber gasket setup is brilliant and lasts a very long time; gaskets are already 50 years old in some places and still not leaking.
3. A mechanical coupling joins the 2 pipes together. You basically bolt them together with a gasket in between. This way is is the most solid and used where you can't take a chance of a bell socket coming apart. The coupling can slip on either end, or the pipe can have a flange built into it.
Anyways, ductile iron is the way to go. If your community is using any plastic material instead of ductile iron, eventually that plastic is going to fail because plastic gets brittle over time. Buried plastic is at least protected from UVs but I think 50 years from now there's going to be a lot of people panicking as their plastic starts coming apart everywhere.
Inside my house I'd use copper as a first choice. The price is through the roof right now but it's good stuff that doesn't heavily leach into the water if your water's not ridiculously aggressive (most municipal water shouldn't be).
PS: I meant cast iron for drinking water, not for sewer. It's very common for sewer even going back 50 years.
After fueling up their cars, Twyman says they bowed their heads and asked God for cheaper gas.There was no immediate answer, but he says other motorists joined in and the service station owner didn't run them off.