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Dec 28, 2012
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How do most people carry out wet pressure testing on plastic pipework, what pressure do you usualy take it up to? Is it higher than the 1.5 times working pressure that copper pipework is tested to.
 
id never try 18, regs recomend 1.5 times max working pressure , (usually works out @ 4.5 bar)
 
How do most people carry out wet pressure testing on plastic pipework, what pressure do you usualy take it up to? Is it higher than the 1.5 times working pressure that copper pipework is tested to.
just ramp it up.... give it some..no leaks/... sound.
 
Am i missing a point by the way lads with air testing ? Sorry to hijack a thread but i read somwhere sombody saying i wouldnt wanna air test to 4 bar i use water much safer. But surely 4 bar is 4 bar weather it be air or water ? Fittings will blow off the same would they not ?
 
Thinking about it used to put co2 lines in pubs and clubs that was all jonh guest push fit ! That eases my thinking a little bit !
 
if you dont follow mfis when you get a leak its you to blame, if they say pressure to 18 so be it. I prefer leaving speedfit at 10 myself to get the rings to bed in
 
Am i missing a point by the way lads with air testing ? Sorry to hijack a thread but i read somwhere sombody saying i wouldnt wanna air test to 4 bar i use water much safer. But surely 4 bar is 4 bar weather it be air or water ? Fittings will blow off the same would they not ?

A lot more air in a pipe at 4bar than water. A very different result if it slips
 
I know someone who thought they were testing at 5 bar on copper and all the comp fittings kept blowing off as well as the smaller bore pipe was bending out of shape . He couldnt understand what was happening untill another fitter pointed out he was testing at 50 bar not 5 ,,,,oops
 
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Apparently air testing should only be done if the pipes must not have water in them. as too dangerous!!
 
When testing pipe work filling and venting of the air is most important. Water will not compress, so in the event of a stop end say pushing off. I does just that. If air is compressed the stop end will come off like a bullet.
Setting up a situation to branch in a 12" pipe into and existing 24" pipe the test on the 12" (approx one mile long)
Prior to shutting down the larger and cutting in the branch. The 12" had a flanged stop end approx 10'-00" from it destination was pressure tested. But no air was purged, just filled with a 1/2" supply at low end of pipe line and hand hydraulic pump to raise the pressure. When the stopend pushed off the bolt heads of the flange punch holes (bolt head shape like pastry cutter ) in to the 24" pipe. The windows where blown out of a mechanical digger that was in attendance at the time, there were no personal injuries but some very shocked facial expressions. (These were ductile steel pipes)
Try is out on say 3m of 15 mm with a stop end under controlled conditions. You will be amazed.
 
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When testing pipe work filling and venting of the air is most important. Water will not compress, so in the event of a stop end say pushing off. I does just that. If air is compressed the stop end will come off like a bullet.
Setting up a situation to branch in a 12" pipe into and existing 24" pipe the test on the 12" (approx one mile long)
Prior to shutting down the larger and cutting in the branch. The 12" had a flanged stop end approx 10'-00" from it destination was pressure tested. But no air was purged, just filled with a 1/2" supply at low end of pipe line and hand hydraulic pump to raise the pressure. When the stopend pushed off the bolt heads of the flange punch holes (bolt head shape like pastry cutter ) in to the 24" pipe. The windows where blown out of a mechanical digger that was in attendance at the time, there were no personal injuries but some very shocked facial expressions. (These were ductile steel pipes)
Try is out on say 3m of 15 mm with a stop end under controlled conditions. You will be amazed.
 
1. 5 x the maximum working pressure of the system, so for example a combi heating system with a max working pressure of 3 bar x 1.5 gives a test pressure of 4.5 bar look for visible signs of leakage
 
I might try a test of SF, Hep and PP with my hydraulic tester at the weekend. For the craic you understand.

I did this years ago when I had a couple of apprentices with me. We were doing a complete re plumb in Hep and one of them asked me what pressure it would take. I had a length of copper connected to a length of Hep with a speedfit coupling followed by a Hep tee and a loop of Hep. The copper was connected to the tested with a compression fitting (with no paste or ptfe on the olive). One of the ends of Hep deliberately had no insert.

I pressurised it to 120 bar and all of the fittings and pipe held. We then decided to see if we could make it leak. I tried twisting the hep and speedfit fittings at odd angles and it held. I then beat the Hep with a lump hammer until it was flat and it still held. It finally gave in when I smacked one of the fittings with a spade.

I wouldn't worry too much about pressurising to 18 bar.
 
are you saying every push fit that you fit is not going to hold properly unless a process of testing at 18 bar .

they more than likely hold fine however its UNDER MI advice to test to this .
However if you have an issue arise and you only tested to 5 bar then you have no come back only yourself to blame.Their are a whole host of rule sets to follow regarding testing and i bet 90 % on here just pump in 5 bar for 10 minutes and decide that will do .
 
On new build it was standard to test the first fix to 18 bar, had to be witnessed by the site agent then a certificate issued saying what pressure was applied and how long for.
When completing second fix and filling up it became obvious who hadn't tested properly with water leaks all over the property, ceilings/walls showing damp patches or worse.
 
I first fixed a 1 bedroom flat in copper last week. I air tested to 8bar but the pressure kept dropping slightly but I couldn't trace any leaks so I filled with mains water to 2 bar and a ball o fix valve popped off! With water going everywhere! Turns out it was only leaking very slightly originally on a speed fit cap end.
 
18 bar is pretty standard stuff on alot of plastic installs. Ive tested speedfit to 25bar with no failure just to see what would happen.

air testing is dangerous and should be done with caution and no other persons inside the building.


its alwasy good to get the new apprentice to cut a pipe at 18bar to take it off test, they always get wet and a good shock.
 
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the only reason I test isto make sure there wont be any water leaking everywhere, if done in copper there is very little chance that it will leak after a test and even less chance of it leaking 6 months down the line. and if air testing I would rather it flew off and then I know I hadnt done it right.
 
I dont get the whole water testing, if you have a leak then you will have water pooring everywhere.
 

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