This is a dull idea.
Pipes will sometimes burst when they freeze, because the water expands as it turns to ice.
So, as the pumbing is being assembled, simply slide in a strip of a closed-cell, non-toxic plastic foam. I'm imagining it would come on a roll, and would be about as thick as a pencil.
Then, if the pipes do freeze, the expanding water will simply compress the foam rather than bursting the pipe.
Issues: (1) problematic with soldered joints, as the plastic would melt/burn (but fine with compression joints) (2) How to hold the foam strip in place inside the pipe? This could be solved if the strips were bonded inside the pipes at the time of manufacture. You'd then need a little gadget to remove a piece of the strip near the cut end of a piece of pipe, if you are using solder joints.-- MaxwellBuchanan, Apr 29 2009 Same idea http://www.whynot.net/ideas/1005 [ldischler, May 04 2009] Re the link, you can certainly make unburstable pipes - in fact, plastic plumbing has enough 'give' to resist bursting in most cases. However, the idea here was to enable copper pipes (which are preferred in many applications) to be burstproof.
I'm not sure how the "self healing elastic" would work for plumbing. If it did burst, surely the water gushing out of the split would prevent the edges from rejoining?-- MaxwellBuchanan, Apr 29 2009 // You'd want pipes that are bigger in diameter // Yes and no. If you imagine a standard 15mm copper pipe (internal diameter ?14mm?), fitted with a foam strip 6mm in diameter. The area available for water then reduces from 154mm^2 to about 126mm^2, which I don't think would have much impact.
You wouldn't want this in drains (since you need a smooth bore to avoid clogging), but they are not usually a problem when it comes to freezing.-- MaxwellBuchanan, Apr 30 2009 Issues: 3) Getting plumbers to forego the ongoing source of income generated by burst pipes.-- 4whom, Apr 30 2009 Great idea. It's also interesting to note that this material would heat up very slightly as it's compressed.-- hippo, Apr 30 2009 Saw something similar in new scientist in the 70s .... t'was a plastic strip with a cross section a bit like a flying saucer which is pushed into the pipe. (Can't find no mention of it via that there google thing.) (ie, pretty much baked)-- pjd, Apr 30 2009 //something similar in new scientist in the 70s// Damn - can anyone else trace this prior art?-- MaxwellBuchanan, Apr 30 2009 Surely it would be better to have a foam tube that lines the inside of the pipe instead? Two reasons: the ice would exert all its pressure outwards and so all its pressure on the foam, and also, the foam would act as insulation against freezing in the first place. On the other hand it would be harder to install, and different for different sized pipes.-- mitxela, Apr 30 2009 If you're willing to have less capacity per amount of material in your pipe, why not just roll it down to an elliptical cross section? (Leave the ends round for joints, of course)-- lurch, Apr 30 2009 "This is a dull idea." thanks for pointing that out [+]-- simonj, May 04 2009 //why not just roll it down to an elliptical cross section? (Leave the ends round for joints, of course)// Several reasons. First, bending elliptical pipe is a pain. Second, you'd have to roll it down on-site (if the ends have to be left round). Third, pipe-clips etc are all designed for round pipe. Fourth, modifications (eg, breaking into a run of pipe to add a T-joint) would be difficult because of the need for leaving the jointed parts round.
The idea of the foam strips was that you could make, sell and install piping which would be compatible with existing systems and just as easy to use.-- MaxwellBuchanan, May 04 2009 Ah - well, that pretty much bakes it, I think. Case closed.-- MaxwellBuchanan, May 04 2009 With "foam lined pipes" i get 2 results, which is, by the way, the lowest non-zero results count i ever had.-- loonquawl, May 05 2009 random, halfbakery