Talk:Plumbing

I've had copper half buried in regularly wet cement for decades. I chipped a bit away to find no corrosion. Lots of houses have pipes in floor concrete, but resulting leaks are very rare.

(Reply to anonymous contributor) That's a bit like saying my Auntie Elsie smoked 60 a day all her life and didn't get lung cancer, heart disease etc and therefore it's a myth that smoking is harmful. FWIW I have several times seen copper pipes buried in concrete that are corroding. It's generally accepted that this may happen and that it is bad practice to install pipework this way (illegal in the case of gas), so I've changed the text to indicate this.

--John Stumbles 11:04, 24 December 2006 (GMT)

Millions of houses have copper in concrete, but corrosion leaks are rare, smoking deaths are common. Not comparable.

The prime reason for denso et al is thermal expansion rather than corrosion. Copper carrying hot water in concrete can pull soldered joints apart or break itself as it expands and the conrete doesn't. There was a thread debating this in ukdiy recentishly.

(Reply to anonymous contributor)

Do you have a reference to the thread (at google groups)?

With regards to gas pipework; movement - due to thermal or other causes - is referred to by BS6891:

8.8.3 Pipes buried in concrete ground floors shall be protected against failure caused by movement

But the Standard also talk about corrosion:

...
Reference should also be made to 9.2.1 for the application of adequate corrosion protection.

Where 9.2.1 is:

9.2 Buried pipework
9.2.1 Internal environment
9.2.1.1 Pipework that is buried in a solid floor or wall shall be factory sheathed, or protected on site by
wrapping or with suitable bituminous paint protection.
...
COMMENTARY AND RECOMMENDATIONS ON 9.2.1.1
Protective measures are applied as a precaution against electrolytic and/or chemical corrosion.

BS5444(1990) (on Central Heating) recommends:

Where it is necessary to run short lengths of circulation pipework in concrete floors or in walls they should:
... be adequately protected from damage and corrosion

I've certainly observed corrosion to buried pipework in practice. I'm sure thermal and other stresses on pipework buried directly in concrete, especially carrying hot water, may also cause problems. However the practical implications are surely the same: buried pipework requires adequate protection against these problems (as well as from heat loss in pipes carrying hot water, natch).

Risk factor magnitude

I guess its all a question of the magnitude of the risk factor. If millions of houses have copper direct in concrete, yet gas leaks from this are a rarity, then we could conclude that corrosion is a minor risk, one far below the level of the many other risks in houses.

This doesnt make a difference with new installs, but it does matter to whether people with existing copper in conrete would be well advised to dig it up or leave it alone and concentrate on the bigger risk factors in homes.

I googled but didnt find the thread I had in mind. NT 05:34, 2 January 2007 (GMT)

I think I see what you're getting at. From the POV of new installs it's a no-brainer: protect the pipe, for whatever reasons; but as you say, what if you find you have existing copper in concrete? If it's gas then although the probability of failure may be low the consequence of failure may be very high so it must be taken seriously. In the Gas Industry's classification of Unsafe Situations it would be Not to Current Standards if not showing any visible sign of corrosion (e.g where the pipe meets the concrete) or At Risk if it is. (Of course if it's leaking - which I have come across - it's Immediately Dangerous.)

For water pipes I'd say keep an eye on them and replace if possible e.g. if there's work going on in that area which makes it convenient, or before laying your £75/sq.m. hand-fired porcelain tiles over the top!

--John Stumbles 14:38, 2 January 2007 (GMT)

All in one?

Should all plumbing topics be imported into one huge plumbing article? I can see it being a very hard to digest article if its like that, and also harder to write for.

Re copper in concrete, I think there is significantly more to be said, and I think a fair sized piece on it within a general plumbing intro/basics article would be out of place, which is why I began it as a separate piece. Personally I think it needs to be a separate piece. Your thoughts would be appreciated. NT 19:08, 29 January 2007 (GMT)