Can I use a plastic stopper to close off a hot water pipe?

[IainJ]

I am having a new shower fitted with a pumped shower sited in the loft. The old shower was fed by hot and cold pipes directly from the loft tanks via standard gravity system. My plumber has used plastic stoppers to block the old pipes. Is this a safe and durable method? Or should these pipes be blocked if in a different / more permanent way (perhaps welded shut)?

Clearly these stoppers need to have a life span of decades - but will they last that long?

Thanks for any advice.

Iain

 

[dextrous]

If it were me, I'd be inclined to solder end-caps on for a fraction of the price of push-fit fittings used. Or you could use compression fittings. Others may disagree, but there's something about the longevity of plastic fittings that I don't trust.

 

[kirkgas]

as dextrus said, soldered blanks for me every time, perhaps i'm a dinasaur but i KNOW soldered fittings last cause i've been using them for over 30 years, i only use plastic push fit caps as temp fittings, say when we are fitting a new kitchen and want to leave the water on in the rest of the house, push fit is great as you can simply compress the insert ring and remove, i think the manufacturer will tell you they have one on test in their factory at a constant 65 degrees and it hasnt failed etc etc but it hasnt been subjected to constant expansion/contraction etc which is where the prob will arise. i was at a training course years ago where the rep said they had run a boiler for over a year 24/7 and it hadnt failed once, but again it is all the expansion/contraction, turning on/off/up/down and misuse by all the tenants that causes all the problems but he wasnt lying just not telling us anything that is relevant

 

[dextrous]

As kirk implies, a manufacturer's claims doesn't always tell the whole story. If it did, then how come those clever machines demonstrating umpteen opening and closing of drawers in IKEA doesn't quite match with the reality of furniture when you get it home. Mine come off the runners well before the 191,258 that the machine has managed to perform without a problem.

In my own mind, rubber being heated and cooled and witholding changing pressures and natural expansion/contraction and vibration of pipes does not give me full confidence. The space shuttle blew up due to rubber seals being exposed to variations of temperature - it may be an extreme comparison, but the principles are the same.