Plumbing expertise?

[Chris73]

To install a 3/4" tap and hose bibb to a 10" epoxy coated steel pipe (potable watermain) - would you just cut a female thread into the steel pipe and mount on a 3/4" copper pipe? Or are there fittings for that? And any concerns about the damage on the epoxy coat due to thread cutting and concerns about electrolytic reaktions between the steel and copper? Thanks for your help!

 

[snafuman]

You could do it as you said, of course the water in the main would have to be shut down. You could also install a service saddle and hot tap the main, then reduce to you 3/4". The service saddle would be bronze or steel. You should not directly connect copper to steel as there will be a galvanic reation.

 

[Chris73]

So what kind of adapter between steel and copper pipe would you recommend?

 

[dicksewerrat]

The "saddle" tap is held onto the main with 'u' bolts and is sealed by a neoprene or rubber gasket. I don't think the brass fittings ever touch the main. Go to a plumbing supply house and look throught he catalog. Maybe Goodin co. catalog is available online.

 

[HB2U]

As stated above you should use a tapping saddle/sleeve. Then you want a mueller Corporation Stop which you can get with a pressure coupling to attach your 3/4" copper line to.

Any good plumbing/pipe supply shop should be able to get you the parts you need. The tools that you might need are another story.

If I may ask, why are you tapping into a municipal water main? Most water companies will do that for you, thus eliminating your need to figure out what to use. Besides, I know that if joe public tried to tap into one of our water lines without our knowing it, we would consider it a terrorist act. Be careful of everybody's hightened anxiety due to the terrorist activities of late.

 

[Chris73]

HB2U,
We are not tapping an existing main - this is an extension of a water distribution system for which we had to design several meter and prv chambers. After completion of the design our client asked for some minor extras i.e. as the hose bibb. I am kind of reluctant to use a saddle in that case - on an existing main ok but on a new design I would like to connect it directly to the steel pipe by using a weld nozzle with FT as connection to the copper pipe. But I am not sure if a galvanic reaction between steel and copper is just a theoretical concern and what to do else. Using a pvc bushing in between may prevent direct contact between the two metals but wouldn't prevent a galvanic reaction. I have seen SS valves being in bad shape when installed in a copper line but maybe due to it's chromium content.

 

[dicksewerrat]

Well the time for the galvanic action to affect the main or the copper pipe is fairly long. I have seen copper/brass fittings screwed into cast iron water mains that have lasted over 100 years. The soil you are putting the pipe into will have a greater effect than the purely dissimilar metal reaction. Put in some corrosion protection.
That said, you could weld on a nipple and use iron pipe to the hose bib.

 

[KRSServices]

Yes, it is possible to hot tap into a pipe without shutdown (core hole, thread and insert mainstop), but you'd better know what you are doing! You will also need to rent or purchase a tapping machine. It is easier with a serivce saddle, but may be hard to retieve the coupon. The best bet would be to hire the local public works guys, thay will be quite experienced and have the tools. Failing that, you may want to hire a plumber. With reference to sorrosion, cadwelding a 15 lb. zinc anode painting an epoxy over the entire area should work fine. KRS Services

http://www.krs-services.com