Beware the plastic isolation valve!

Why just the valves, though? Maybe, all their fittings ae about to disintegrate after 25 years?

Tim+ snipped-for-privacy@yahoo.co.youkay> wrote in news: snipped-for-privacy@news.individu al.net:

You do know the Speedfit guarantee is 25yrs right ;-?

I tend to avoid using a joint that is weaker than the material of the pipe on the grounds that any forces on the pipe will be transmitted to weaker the jointing piece. Could th ejoints have been under stress?

Actually when I used 15mm speedfit for my individually room zoned heating system I used compression fittings on that too. All fine until I added a

For copper I generally solder.

Possibly, but these have both fractured in exactly the same place. It would seem to be a design flaw. I have other Speedfit straight connectors that have been fine (so far). ;-)

Tim

Actually…

I must have used hundreds of those over the years when I used to install drink dispense systems mainly on cooling circuits some of which had a percentage of glycol in the solution while most we had no problems with a few failed at that point after only a short time. IIRC while plain connectors bodies are moulded as a whole component the isolation valves bodies have been assembled from two that was either glued or heat welded together around a washer that seals the joint, as seen in your first photo. I took quite a few with me when I retired and have happily used them on non critical projects such as pond water features or garden and greenhouse irrigation arrangements where they have been fine. But I would never use one inside where a leak could do damage.

GH

Certainly won’t use one indoor again.

Tim

As a materials scientist, the mode of failure is suggestive of ESC as in Environmental Stress Cracking...... Google it!

The design life of the O-rings is 25 years (which is where the 25 years came from), so I'm sceptical.

I only ever used them once (they came with a shower mixer), and they lasted 11 years.

I do keep a handful of their stop-ends in my plumbing tool box for temporary use.

I use their plastic pipe occasionally (e.g. if I have to feed it through somewhere and couldn't get rigid copper through), but always with compression fittings (and pipe inserts).

So far, I've taken the view I might still be around in 25 years, but I definitely won't want to be fixing worn out plumbing. So I always do soldered copper.

The phenomenon of these valves fracturing like they did sounds very much like a very well known failure mode of ESC (Environmental Stress Cracking)

Having read your link I think you’re absolutely right. I’m pretty amazed though how after 25ish years my two valves failed within months of each other.

I contacted the makers who came back with the response that they were only warrantied for 12 months from the time of sale (which doesn’t sound right). Not that I thinking of making any sort of claim but I’d have been really upset if the only lasted 10 years say…

Tim

Were they properly supported? The pipes do have a fair bit of give. I'd have thought many years of thermal movement (even with cold water) and shutting on/off would put extra stress on the fitting if there's little/no support.

I mention this as I've just redone a bathroom where none of the plastic pipes had any support beyond resting on whatever was nearby, with some quite jaunty angles and unsupported runs >1m. Clear signs of leaks at two joints, but nothing catastrophic.