*nerdy physics student
Specific heat capacity of water is 4.2J/g/K. Latent heat is 334J/g. So, to melt a gram of ice, it takes as much energy as it does to heat the water from 0C to 80C.

The pipe runs from the rising main, up behind the wall, across under the floorboards, back out of the ceiling and down to the basin in the downstairs toilet. The pipe branches from there to the tap outside so it's covered a good 20ft inside the house.
But after that outside tap, there's another 8ft or so before it enters the shed to the washing machine feed. That froze last week and burst the pump in the washer which was annoying.
( sandettie light vessel automatic New Twitter - @bollocksreally, Sun 19 Dec 2010, 17:25, 1 reply, 15 years ago)

thanks for the maths there mate! i was going off 30 year old memory...
yeah, bursts sure are a pain in the arse.
i seem to remember that the ice is at it's least dense at around -7c so if you can stop it getting quite that cold it helps.
also i've observed a real difference between old copper tube and new. the older stuff is harder (and less plastic) than new stock, the newer being more malliable and generally "softer" than the old. consequently there's quite a difference between the fractures with much more ballooning going on with new pipe and cleaner, straighter fractures in the old.
i've been pricing some pre-insulated 16mm uponor mlcp for a job, i think for exposed work it is the future.
( blaireau69 , the Cumbrian Travis Bickle., Sun 19 Dec 2010, 19:21, Reply)

Is there not
a type of compression fitting that can release pressure in the event of a freeze?

Will plastic pipe rupture if I replaced the outdoor copper? Mind you, it won't solve the problem of the washing machine breaking.
( sandettie light vessel automatic New Twitter - @bollocksreally, Mon 20 Dec 2010, 0:40, Reply)

cos of the difference in expansion co-efficients of brass and copper...
i've come across a number of compression fittings that have simply slipped off the end of the tube, leaving the circular marks where the olive was once firmly attached.
hep2o and suchlike seem more burst resistant, my personal choice is 16mm mlcp which is poly-ethylene and aluminium.
yeah, wouldn't have saved the washing machine.
anyway, duty calls...
( blaireau69 , the Cumbrian Travis Bickle., Mon 20 Dec 2010, 10:45, Reply)