outdoor taps and freezing

[Stephen]

Hello,

A relative has an outdoor tap. The walls and floors are concrete so difficult to drill (non-sds), so whoever fitted the tap took the easy option of drilling through the upstairs wall (there are no pipes downstairs on that side of the house) and dropping a 15mm copper pipe down the outside of the house. It was lagged but obviously not enough. There is a "tear" in the pipe where presumably the water froze in the winter. The repair has been one of those things no-one has got round to for several months!

I was hoping to help by using one of those repair compression fittings only I found I could not slide the nuts on. Do you think that the ice stretched the pipe and made it fractionally wider? If so, what use are these repair fittings?

The tap had a built in non return valve. I wondered whether these are perhaps a bad thing? I realise there should be a valve but would it be better fitted inside the house? If a tap was fitted without a valve and the pipe was isolated and the tap opened, wouldn't the pipe drain completely?

Now if a tap with built in valve was used, would the pipe drain under the same circumstances or does the non return valve require some pressure to open it? Would water remain in the pipe that could freeze and cause the damage that occurred?

I am thinking of taking my sds drill and see if it will drill through the concrete floor so that the pipe drop can be run inside the house and go outdoors at the last minute.

Thanks, Stephen.

[Tim Lamb]

In message , Stephen writes

Non return valves are designed to show how little our water authorities understand about supplying water.

I am not a plumber but... vertical stand pipes survive frosty weather due to the curious way water expands below 4deg. C This allows the coldest water and eventually ice to float on top.

Your relative has the unfortunate situation where the water freezes at the top preventing the trapped water from expanding without bursting the pipe.

IME non return valves do the same thing in miniature:-(

Good luck:-)

regards

[Roger Mills]

How old is the pipe? Could it be 1/2" rather than 15mm? If so, it would be

*slightly* bigger than 15mm and, with a bit of surface corrosion on top, it may be difficult to get a 15mm fitting over it. How have you cut out the damaged section? Have you left any burrs at the end of the pipe - because these, too, would stop an olive from going on easily.

[John MacLeod]

The message from Stephen contains these words:

Yes. I run a caravan site and have come across that problem frequently.

Very little :-(

John

[Harry Bloomfield]

Stephen explained :

You could always fit the valve inboard of the point where it goes out through the wall and inboard of an isolation valve. That way opening the tap and turning the isolation to off should drain it.

I would have thought so (see above)

I have a couple of taps outside and both only have the actual tap on the outside, all pipework is inside. We have never had any problems with freezing. There is a limit to how much lagging can help stop pipes freezing. If it stays cold enough for long enough, eventually the cold will get through and unless there is some heat source - the pipe will freeze.

[The Medway Handyman]

High pressure ring mains are quite common in food processing plants & usually have an outside take off for vehicle cleaning. Water freezing when already at 100 bar + static pressure is pretty unforgiving. Solution was a timer on that outlet that opened a drain valve at regular intervals to keep the water on the move so it couldn't freeze.

[Harry Bloomfield]

Another solution would to use electric trace heating - It is like a tape which is run down the length of the pipe, under the insulation. I think you can now get a tape which includes the facility to control itself, turning on and off as needed.

[nightjar]

I would replace the whole drop with black HDPE pipe. That won't care if the water inside freezes.

Colin Bignell

[chris French]

In message , nightjar writes

I used some Hep2O for the final feed for a greenhouse at the end of the garden. the pipe was never bothered, but one time when the water froze the pipe pushed out of the tap compression joint enough so that it leaked quite dramatically on thawing.

Might have been ok though if I had used specific fittings for the pipe I guess.

[PeterC]

Yes, having used Speedfit and Hep2o, the former is quick and the latter is more of a faf but less likely to be blown apart.

[Stephen]

No, it's definitely 15mm, or was!

I cut it with one of those pipe slices like this:

there were no burrs. It wasn't just the olive, I couldn't get the nut or the fitting on either.

By the way, how long should these pipe cutters last? I bought a Hilmor one from B&Q a few years ago but the metal rollers rusted and seized from getting wet in use.

I'm on my second now but I've noticed recently that sometimes the cutter slips and it engraves a "corkscrew" on the pipe rather than cutting it. I never had this with the first one. I changed the blade but even with a new one it sometimes does this. I notice there is an arrow on the body and I think this happens when you turn it against the arrow.

[Stephen]

Thanks, that explains it.

Someone mentioned HDPE but I could only find MDPE, will that do? How come that doesn't burst, are the walls very thick?

[PeterC]

MDPE was used by Anglia Water to repipe our village. The engineer in charge told me that it wasn't as good as HDPE but was adequate and cheaper.