crazy plumbing question????

[buffy27]

is it possible foe a 1" copper pipe run or any other pipe run for that matter to hold a 2 bar air test and then a few days later when heating operating a leak shows up in a concrete floor.is this possible ,have u ever seen something similar to happen ???it was found on further investigation that the 1" copper pipe was kinked in the floor !!
why would it happen that when the stove was put going and hot water circulatingf that this would show up ... all plumbers please reply regardless of experience!!!

thye air test was apparently left on for 20 mins!!!
thanks in advance for your opinion.... dara

 

[unguided1]

sounds like possibly when heat was introduced into the pipe it expanded, causing it to leak. was it a long run of pipe and did you put an expansion loop in

 

[secret squirrel]

I wouldn't have thought that was possible? surely a leak would have shown after a 20 minute test. If this is possible why test at all!

Definetley going to follow this one, I'm intrigued by the replies this is going to generate.

 

[buffy27]

wasnt my work ..a pal doing a job and the owner was giving him crap over it .. now he swore to me that he tested it and it held 2 bar air .it was a return pipe to a stove and yes was on a a straight run of around 10 meters .why would that matter. cheers buddy!!

 

[Plamber]

When i worked on sites i tested all my pipework, plumbing and heating to 4 BAR and when the hot water came on we had a few leaks. its the expansion witht the heat. if there is a bit not completely soldered the heat can break what pressure testing cant.

 

[unguided1]

what sort of heat was introduced into the pipe if its from a boiler it could range from 50 to 80 degrees and at those temps there is a hell of a lot of expansion on copper pipe, I cant remember how much but i am sure that some one a lot clevere than me could tell yer

 

[buffy27]

say if it was a 10 meter run of 1" copper then how much expansion would take place .. apparently the pip[e was cruched a bit when the opened the floor !!!

 

[unguided1]

apparantly, the rate of linear expansion per millimetre of copper pipe is 0.0000177 millimetres per degree C temperature rise.
that doesnt sound a lot but when you start adding it up its quite a bit i will grab me calculator and try and work it out with an averidge temp of 60 degrees C on 10 metres of 28mm pipe

 

[migoplumber]

went to a heating pipe leak years ago, the installation was 7 years old. the leak was coming from an unsoldered pipe. the flux had held it together for 7 years!

 

[dontknowitall]

Where can I buy some of that flux?!!!

Good grief!! SEVEN YEARS!!!

 

[unguided1]

I am now getting a headache but i think the answer is 10.62mm of linear expansion over 10m on 28mm pipe at a temperature of 60 degrees.
I am probably wrong so please can someone else find the right answer

 

[Deleted member 2053]

That's the right sort of ball park. I get 10.8mm using a coefficient of 16.8 x 10-6 /C .

In the good old days before I was a plumber I was renovating our house. When I went to chop the pipe that fed from the boiler to the airing cupboard it came apart at the elbow. The thing had held since installation without being soldered and had never let a drop of water onto the ceiling below. Perhaps being so close to the negative side of the pump encouraged it to hold together? Never seems to work for me nowadays!!

 

[stevetheplumber]

apparantly, the rate of linear expansion per millimetre of copper pipe is 0.0000177 millimetres per degree C temperature rise.
that doesnt sound a lot but when you start adding it up its quite a bit i will grab me calculator and try and work it out with an averidge temp of 60 degrees C on 10 metres of 28mm pipe

i dont do metric but 100 ft of copper raised 120 degrees f grows by 1.4 inches so 33 fts gonna grow by about half inch enough to mash the pipe and spring a leak id have thought if it was trapped in concrete
ive seen steel pipes rip the clips and rads of the wall by exspansion

 

[buffy27]

the pipe was apparently crushed and must have only popped on expansion!! so this si possible ?? thanks very much for the opinions ...its very much appreciated cheers dara!!

 

[flyboy]

I make it about 1.2mm expansion over 10m of pipe for 60 degrees. Seem reasonable.