v simple q: will a compression joint handle mains pressure?

[Jim]

need to cut off a water mains pipe inside my attic (no tap).

Will a compression joint do this?

Will the plastic types be ok?

thanks

[Lobster]

Not sure exactly what you're wanting to do, but if you're simply asking whether plastic (or brass) compression fittings will take mains water pressure, then the answer is yes, in both cases.

David

[Jim]

thanks :)

[Set Square]

I assume that you're talking about cutting off the flow once the pipe has been severed. Clearly, a compression joint won't actually cut the pipe - you need a pipe cutter. I assume further that you have some means of temporarily turning off the water while you do this - otherwise you'll have a flood!

Any main-stream pipe fitting will hold against mains pressure - solder, compression, plastic push-fit, copper push-fit. My preference would be the last of these - something like

turn the water off, cut the pipe with a pipe cutter, clean up the end of the pipe with wire wool, push on one of these fittings, turn water back on - job's a good 'un!

[david lang]

You will have to turn the water off before you fit it, or use a freezer kit while you do.

Dave

[Jim]

thanks for all the replies. Yes, I do have a pipe cutter, and a bucket :) just in case.

Thanks for all replies, I was mainly concerned as to whether compression joints (or their plastic equivalents) would handle mains pressure vs tank pressure (which I have experience of).

Whatever, thanks for all replies. I'll do it tomorrow.

Best wishes all. :)

[Jim]

oh- and I forgot to mention.... I have a tap to turn off the mains.... which I will be doing obviously... thanks again :)

[Dave Fawthrop]

Please explain exactly what you want to do.

Cutting pipes under mains water pressure is ***spectacular***. IMO not to be done in an attic. =20 Been there done that in the *underdrawing* and survived. =20

--=20 Dave Fawthrop

17,000 free e-books at Project Gutenberg! Yorkshire Dialect go to

[Gordon Henderson]

I have a mix of plastic push-fit type and compression jointing on my mains sode of things - out incoming pressure is about 8.5bar and so-far so good...

Fortunately[1] the flow-rate is very low so if we do get a leak it won't be a torrent...

Gordon

[1] Mutter/grumble/whinge I wish it were more than 9l/min, but I'll have to dig up a tarmac path to find out where the blockage is. Mains leaks in our street can be spectacular!

[Chris Bacon]

If it's a metal fitting on a metal pipe, then yes, easily.

No idea.

[Doctor Drivel]

under high pressure and imbed themselves into the opposite wall and then a full open end of water. Get a normal compression cap.

[Set Square]

Well, if you will insist on cutting the pipe with a hacksaw, what do you expect?!

Push-fit are *fine* if used properly.

[Doctor Drivel]

You have limited to no experinece of these, which means you are botty talking as usual. Nothing worse than a know-it-all who knows sweet eff all. Avoid push fit stop ends on high pressure mains pipes. Normal compression is simple and a sound joint.

[Christian McArdle]

With that set of stats, if you've got room, consider fitting an accumulator. You'll probably also need a pressure reducing valve if you don't have one already.

With an accumulator, you'll get lashings of mains pressure water with no pump or digging.

Even when you get the blockage fixed in the future, the accumulator will give you a bit of water during mains failure...

Christian.

[sPoNiX]

Out of interest, assuming the pire doesn't give way first, which can withstand the most pressure?

sponix

[Set Square]

I don't know - but the copper push-fit fitting which I suggested is rated at

16 bar - which should be sufficient for most people - unless you're Dr Drivel, who has the capacity to generate hot air at a considerably higher pressure than that!

[Chris Bacon]

ISRT compression fittings, but it's a long time since I had anything to do with high-pressure stuff.We didn't use solder, anyway.

[Doctor Drivel]

Brazed then solder.

[Ed Sirett]

I've not dealt with accumulators to date but I would expect them to have a restricted max working pressure ( 3 -6 bar?). Anyway they would certinaly be a bit to lot cheaper than digging the garden up.

[Andy Wade]

Err, what _is_ an accumulator? It's not something I've heard of before in the context of /water/, and I'm imagining something like a giant expansion vessel, a sort of sealed-system equivalent of a cold water storage cistern...