Copper Pipe Connected to Galvanized?

Glenn_4

I posted the following on finehomebuilding.com and someone referred me to this site (and I can see why) I recently bought an old house that has steam radiators (one way system). I noticed that in some places that copper piping (1 1/2" I think) was directly connected (screwed on)to the galvanized pipe (actually not sure if is galvanized since pipe appears to be very old) to finish a "run" to the steam radiator (no dielectric unions). My first question is this safe or allowed by code? If it is safe can you just sweat these connections like a regular copper water line or do you need special solder, etc. My second question is based on someone mentioning something about making sure there is no Glycol in the system, is this important and any idea how to test for this (I have well water that runs thru heavy duty carbon filtration system)? My third question is what type of pipe do you recommend using if I am going to move some pipes/radiators (ie. Galvanized, black pipe, or copper). My last question is how do you tell what type of material really old pipe is made of (Black pipe, galvanized, etc). Sorry for all the questions but your feedback is extremely appreciated!

ScottMP

Hi Glen

I have a feeling I wil only be the first of those to offer advice, since you Have come to the right place. Let me try and answer your questions allthought there are some real steam experts here.

1) I don't believe using copper on the steam piping violates any codes. It is not something that anyone with any steam experience would recommend. The high temperature of steam means the piping expands and contracts quite a bit. The difference in piping materials will create weakness in the joints due to the expansion. Also solder joints don't hold up well to the extreme heat. Go with black steel piping.

2) You have a steam system and this should not have any glycol in it. I think glycol will effect the way steam is produced. Besides since it is steam and steam dos'nt freeze you should have no reason to have anitfreeze in the system.

3) If you are to use new piping, use black steel piping. It expands well and withstands the heat. Use cast iron fitting. If a joint needs to be taken apart many times the steam has "welded" it together and the cast iron fittings can be broken so that a new connection can be made to the theaded piping.

Most importanly Glenn insulate your piping with fiberglass pipe insulation. A steam system needs to be insulated to operate properly. Many times over the years the insualtion has been removed for various reasons and can create a host of problems.

Good Luck and keep coming back for more help.

Scott Milne



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Glenn_4

Thanks!

Scott,
Very informative! Thanks! One question, any idea of how to tell if old steam pipe is galvanized or not (did they even have galvanized pipe way back when)?

Matt Undy

At this point it probably doesnt' matter. If it was galvanized the zinc is long gone form the inside. Also, Galvinizing doesn't provide corrosion porotection over about 100 degrees F. You cna rub it with steel wool, if its galvanized and the zinc is still on the outside it will become shiny silver, steel won't clean up this easily and galvanized is almost always gray when it corrodes. I don't think anyone really ever used galvanized for steam supply. If you add on you need to know what your doing or it won't work right. Others probably have better answers than mine but you can add on black steel[iron] to either glavanized or black.

Good luck

Matt

Jammer

Copper Steam and Safety

Copper is not a "preferrable" conduit for steam but it is approved.
Steps;
1) Use a heavy copper pipe, "K" is far better than "M"
2) Be very careful of chemical treatments, high alkilinity will burn through copper faster then a fat girl at the bon-bon dish.
3) Braze/Silver Solder, do not use regular solder. Plumbers seperate a bad solder joint by heating and hammering; steam can easily "pipe hammer".

Hope this helps

Jammer Don

hr

Copper and galv

is not a good mix, and yes some plumbing codes require a dielectric connection. Not sure what code covers steam piping. Regardless that is a potential problem with metals that far apart on the Galvanic Chart. The CDA has excellent data on this subject. www.copper.org

And you really do not want glycol in any galvanized materials. The inhibitors in hydronic system glycols will react with the zinc coating, particulary above 100°F. according to the Dow engineering guides.

Any idea how long the copper to galv connections have been in service?

hot rod

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Glenn_4

Current Copper Pipe is \"M\" - should I replace it?

Thanks,
I noticed that the current copper pipe is Type M, The date stamped on the pipe was from 1990, I see you suggested using type "K", do you think its necessary to replace it? It looks in good shape.