Push-Fit Disaster

Discussion in 'Plumbing and Central Heating' started by DaydreamJay, 13 Feb 2008.

  1. DaydreamJay

    DaydreamJay

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    I walked into the bathroom this morning to be greeted by a fountain of water shooting out of a pipe that had come off one of the basin taps. It must have been running for hours, all the newly laid vinyl tiles had come off the floor and the plywood that we had stuck them to was all buckled up. The plasterboard ceiling in the kitchen underneath had fallen in, the new combi boiler doesn't work, the cooker is not working and so is the dishwasher and microwave. All the floorboards are soaked and there was 10" of water in the cellar.

    Typically it had to be the hot water tap so that meant that it was spilling hot water (until the boiler packed in) which created loads of steam so all the wallpaper has fallen off too.

    After switching the water off I took a look at the fitting that had caused the problem. It was a Hepworth fitting for flexi pipe, 15mm to 1/2 BSP with isolator valve. There was a plastic type olive with blades on the inner circumference that was supposed to hold the pipe in place, it all looked correct and the fitting looked like it had been tightened up to it's maximum. The metal insert that was inside the pipe was still inside the fittng and was pushed well past the o-ring as it was supposed to be. On the flexi pipe itself there were marks that commenced about an inch from the end that were left by the blades on the olive as it was dragged off. So all in all it was a bit puzzling.

    I am a bit concerned as the other 3 taps in the bathroom all have the same fittings on them but I cannot easily get to the ones on the bath as it would involve removing it and it was only fitted two weeks ago :(

    I wondered if anyone could give me a clue as to why the fitting could have failed and has anyone had one fail like this before? This one fitting has caused thousands of pounds of damage.

    Also, it's a stupid question but is there any device that is available that would protect against this sort of thing? I know it would be impossible to make such a thing as it would have to be able to differentiate between someone turning a tap on and a pipe coming off.

    Thanks in advance,

    Jay
     
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  3. ChrisR

    ChrisR

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    Jeepers. Sympathies. Pictures would be wonderful for us, wouldn't make you feel any better though.

    Sure it's Hepworth?? They have changed their design 2 or 3 times but mostly have used a metal-only grab ring. Some mfrs use a plastic ring with metal teeth protruding, perhaps they do too. I haven't looked for a while!

    Actually pictures might help - claim from Hepworth!

    There are devices about which are intended to shut water off if the flow pattern is wrong, like a continuous slow leak, or simply too much volume - which would have come in in your case, though a lot of damage could have been done already.
     
  4. heatingman

    heatingman

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    Hep 2o fittings are grey plastic, the latest ones I purchased have a green plastic ring with1/2 dozen teeth. Had one blow years ago, think it was old style, luckily no damage other than wet floor.
    Has anyone had a succesful claim against mans?
    A corgi inspector me told years ago that pressure fluctuations norm/very low can be a reason for fitting to creep off. Its the pressure that keeps them locked. That was one of his many reasons for them not being acceptable for gas use. Any comments to that more than welcome.
    Anyone remember the newspaper article about the millionaires mansion and plastic fittings?
     
  5. DaydreamJay

    DaydreamJay

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    Here's a picture of the fitting in question, it's not the same one of course as mine was a straight connector but the locking device is the same.

    Odd that the markings on the pipe were staggered by about 0.5mm a time so it either worked it's way off over a period of time or sort of juddered as it slid off, hard to tell.

    [​IMG]
     
  6. htgeng

    htgeng

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    Did you take a load of photos? I presume you will need to have done for the insurance company?
     
  7. DaydreamJay

    DaydreamJay

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    Yes we took a few photos, but the insurance company had a flood assesor there within an hour so the photos were more or less redundant.

    I'll upload the pics shortly.
     
  8. Softus

    Softus

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    That's a grey Hep2o 'Acorn' fitting - the latest incarnation has a green grab wedge, whereas earlier ones had a white one. The all-stainless grab rings are to be found on PolyPipe fittings. I have a feeling that the slimline Hep2o fittings also have a white wedge.

    I've seen a similar 'accident' to yours, where the pipe pulled out of the fitting - this was caused by a faulty grab wedge, the fault being that it was splayed open owing to a weak spot in the plastic.

    I come across faulty grab wedges occasionally - my gut feel of the frequency is about 0.5% of fittings, i.e. about 0.25% of grab wedges (ignoring tee fittings for the sake of simplicity).

    I returned the faulty grab wedge to the landlord for him to claim if he wanted to. However...

    For this reason the fitting of a faulty wedge is an installation error, not a manufacturing fault.

    Every installer should check every socket before pipe insertion, in the same way that every installer should check olive quality before trusting a compression fitting.
     
  9. doitall

    doitall

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    We had a stopcock come off on a 32mm mains in Christchurch, the water cut a grove in the blocks on the way up the wall before taking the ceiling out 8m up the stairwell. :rolleyes: :rolleyes:

    Water company said it can't happen as the pressure is only 3bar maximum.

    What they didn't know is I had fitted an special pressure gauge on the service to record the pressure for future equipment, A tad over 10bar it stopped at :rolleyes: , Mr water company went back and found a faulty non return valve in the pumping station.
     
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  11. ChrisR

    ChrisR

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    Some Hep fittings had the solid steel ring. I know cos I've found several of them broken!
    Now I'm reminded what they look like, I remember I've also seen the type you describe come off.
    I don't accept that a tug on the pipe would have necessarily made any difference. Pipes move all the time; if they move into the fitting they can unstick. Is there a spec on how hard you have to tug - I doubt it.

    Not fit for purpose!
     
  12. Softus

    Softus

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    Chris, if the pipe can move into the fitting after installation then it hasn't been fully inserted.

    Hepworth advocate pencil marking the pipe to verify full insertion, although after doing a few you can tell by feel when they've been fully inserted (although 28mm ones are something of a challenge).
     
  13. DaydreamJay

    DaydreamJay

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    Even if the pipe isn't fully inserted (which I think it was anyway,) it still shouldn't blow off should it? I mean it would leak but not blow off the coupling as it would only have to be past the olive section of the fitting for it to become trapped.
     
  14. Softus

    Softus

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    I don't follow your reasoning - it would have made some sense if you'd written "even if not fully inserted", so I can't answer your question on that one.

    And I don't understand why you think it could leak without pulling out - if the pipe moves enough to some out of the O ring then it's as likely to pull out entirely.

    And I don't understand what you mean by "become trapped".

    Sorry if I'm being thick, but could you restate those points?
     
  15. DaydreamJay

    DaydreamJay

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    OK, my take on these fittings is that they comprise two parts, the securing device which is the plastic and steel olive and the sealing part which is further into the device and is an O-ring. Normally an olive would also form part of the sealing mechanism but in this case it cannot as it is segmented and not water tight. Therefore the o-ring performs this task. I therefore presume that in this particular fitting (and not necessarily all push type fittings) that the pipe could be secured so it doesn't blow off even if not fully inserted, although it would leak.

    I am certainly not an expert on plumbing but I used to be a hydraulics engineer so I think I have a tiny bit of knowledge to back up my reasoning.... However feel free to shoot me down in flames :)
     
  16. Agile

    Agile

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    Discussion of fittings leaking is irrelevent in this case.

    Its apparently a case of the pipe pulling out of the tube.

    Thats why I would normally use soldered copper for all pressurised pipework.

    Yet another example of why NOT to use plastic !

    Tony
     
  17. Softus

    Softus

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    It isn't an olive, not by any stretch of the imagination, so I don't know why you're calling it one. It's a grab wedge, sometimes called a grab ring. On some push-fit fittings the pipe reaches the O ring before the grab ring.

    I have to admit to being a little distracted each time you use the words "blow off", because it implies something dramatic that you don't have any evidence of happening. However, setting that to one side, if you don't push the pipe in as far as the manufacturer stipulates, then you risk a problem. I don't see any virtue in analysing what that problem might be, because there's only one way of doing it right, and if you don't do it right then all bets are off.

    I don't why anything needs shooting down with anything, since all of your points can be addressed calmly and rationally.

    In fact, I'm still not sure what point you are making.
     
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