Repiping recommendations?

delcrossv

After more than a century of service, the galvanized potable water pipes at my MIL's 4 flat are getting pretty filled with scale with major drops in pressure. I have noticed when I opened the risers, that they're clear with just a little black coating, so I'm thinking the horizontal runs in the basement are probably most of the problem.
As the apartments are occupied, I'm not planning on replacing any of the risers.
So, what's the best way to handle this?

Re-do in galvanized? I'm set up to thread pipe, but if I'm going to have to put a union at every tee...😨

Copper with brass tees? That's code here and seems easiest. Sweat to thread and done.

Copper with dielectrics? Also code, but I've seen them leak after awhile so I'm a little dubious- just more unions.

Note, PEX is not codefor potable water here, so that's out.

mattmia2

Why is pex not code?

Copper with a brass nipple, fitting, or valve connecting to the galvanized is how I would do it.(actually how I would do it would be to replace the galvanized because I grew up in a house with galvanized and the associated anemic showers). I think you will find that the cold water risers are ok but the hot water risers are very scaled and clogged. Even the youngest galvanized hot water piping is beyond its service life. You will also find pinholes in various spots and you will get new ones in both the hot and cold.

Lance

A rule we decide on is if risers are good leave them alone. AS always the horizontals go bad first. takes about 80+ years for the verticals. of course all situations are unique. of course there is the valve choke points and don't forget aerators.

delcrossv

mattmia2 said:

Why is pex not code?

Powerful union?
Just another mystery of the Chicago Plumbing Code. IIRC it's been less than 20 years since they allowed rubber seals for CI rather than lead and oakum.

jhewings

Your building sounds similar to mine, also in Chicago (1927). I replaced all the galv water pipes about 20 years ago. I ran 1-1/4" copper for the cold water horizontals and service in the basement and 1" for the hot. 1" risers hot and cold for the bathroom and kitchen risers. Shower pressure has been fine on the top (3rd) floor (my living space). I might have to adjust the shower valve if someone in another unit bathroom uses water but has not been a problem.

ChrisJ

The fact they don't allow PEX makes your Romex comments null and void in my book.  


I was going to recommend Uponor right off the bat.

But since that's not an option id go type L copper into brass.  It really doesn't sound like you have much choice.  There's no way I'd do galvanized, just too many negatives about it.

We replaced my galv service a while back.  It was fun.   Some how a pipe primarily held together by dirt was holding 90 psig.  I replaced that with type K copper but probably should've just done polyethylene honestly.

hot_rod

Water lines have been grossly oversized for 60 or more years based on the Hunters Curve, which was developed in the 1940

Use this adjusted WDC calculator for sizing hot and cold water lines. Reducing or correct sizing can save big bucks with copper costs, and assure proper velocities and DHW delivery times

https://www.iapmo.org/water-demand-calculator/

Larry Weingarten

Hi, It would probably be a battle, but is there any chance you could get an engineer to sign off on using PEX? With that, the building department might just shrug and be happy it's no longer their responsibility. I'd go with Uponor also, because of the full port fittings.

Yours, Larry

delcrossv

Thanks Larry, but just not worth it for a small job like this. Copper and brass it is.

Larry Weingarten

Okay, one more suggestion. I'm concerned about the junction between brass/copper and galvanized. My imagination says it will get choked up with rust. A way around this is to put distance between the different metals, and this can be done by using plastic lined steel nipples. They are generally used at water heaters, but are available from 1/2' up, and in various lengths, so that might be a way to prevent this risk.

Yours, Larry