Possible to push a push-fit fitting back on a pipe at 3 bar?

[michcosg]

Hi Folks

I am considering a job in council block flat which involves amending 15mm copper pipework under 3 bar of pressure. The problem is the local council seem to a bit hard to get a hold of to turn off the water! Thus my plan was to freeze the pipe with an electrical freezing kit and do the work. My concern is that if I subsequently get a leak, will I be able to cut the pipe and get a push-fit fitting on a pipe spouting water under 3 bar of pressure so that I maybe able to repeat the freezing and the repair?

Alternatively I could of course put 2 stopcocks on the pipework: one where the customer wants it and one just after where I am cutting and freezing it behind some boxing so that if subsequently have a leak can shut it off there.

 

[Scott_D]

Have you seen the video of someone trying a similar thing?
I think its American and the plumber is under the basin with water flying out. Think of the damage 30 seconds of water can cause, some jobs just aren't worth the risk.

If you were to try I would suggest an open compression valve with a hose pipe into the toilet. Cut and put the valve on allowing water to pass through, tighteen the valve and shut off.

 

[Keefy]

I recently had a similar scenario where the only option was to 'snatch it'. I got a Speedfit isolation valve ready (closed position!) on one end of a length of pipe, took a deep breath and calmly cut the pipe with my head under a towel while leaning over it. This was in a living room and despite a few scary seconds of high pressure water shooting out I was the only think that got wet. Also done it with a compression iso in the past. The trick is to take a few deep breaths and double check the iso is in the off position.

It's worked for me so far but I honestly don't know what Plan B would be if say, the pressure of the water sent your fitting across the room. Go on, dare you!

 

[Ric2013]

Definitely put an extra full bore isolator in!

Personally, If I were working live and connecting an isolator onto a flowing pipe using pushfit, I'd prefer to have my full-bore isolator open (and ideally discharging somewhere it doesn't matter even if that's out a window). Then there is minimal pressure to have to fight. I never rely on my strength because I don't have that much to rely on!

If there are other taps available on the pipe wou are working on, I'd open everything to reduce the pressure from the static pressure to the working pressure too (make sure overflows can cope if using basin taps for this purpose).

 

[ShaunCorbs]

I recently had a similar scenario where the only option was to 'snatch it'. I got a Speedfit isolation valve ready (closed position!) on one end of a length of pipe, took a deep breath and calmly cut the pipe with my head under a towel while leaning over it. This was in a living room and despite a few scary seconds of high pressure water shooting out I was the only think that got wet. Also done it with a compression iso in the past. The trick is to take a few deep breaths and double check the iso is in the off position.

It's worked for me so far but I honestly don't know what Plan B would be if say, the pressure of the water sent your fitting across the room. Go on, dare you!

Have the isolator open and a hose pipe on the end your not dealing / having the pressure fight you trying to get the fitting on

 

[SimonG]

Have done it with a leadlock on an old lead line with no isolation. It was in a garage though. Valve attached and hose to outside. I was soaked.

Freeze it, valve in and work at your leisure.

 

[Chuck]

I assume you want to move the existing stopcock for the flat? If so, ...

Does the flat owner even have the block owners permission to move the incoming stopcock? This will normally require the council's permission as it affects 'their' side of the plumbing.

Even if you do get hold of the council, there will be a protocol for turning off the water supply to the whole block that will be hugely expensive to comply with. You'll need to pay for the whole block to be given proper notice and the impact on vulnerable occupants assessed and mitigated, etc., then when the supply is restored, you'll be paying for the council's own approved contractors to flush and bleed the system, check pumps, etc. and visit every affected flat to check for correct operation and leaks.

I'd recommend that you get the flat owner to reconsider their plans so that the existing stopcock stays undisturbed. There are some nice hidden access panels available that may help devise and acceptable solution. If the client not happy with this approach walk away.

 

[michcosg]

Brilliant guys. I think I will do the job but fit a full bore isolator if possible shortly after where I cut the pipe and have a second isolator (open) to hand with a hose attached just in case that fails. Thank you very much.

 

[michcosg]

I assume you want to move the existing stopcock for the flat? If so, ...

Does the flat owner even have the block owners permission to move the incoming stopcock? This will normally require the council's permission as it affects 'their' side of the plumbing.

Even if you do get hold of the council, there will be a protocol for turning off the water supply to the whole block that will be hugely expensive to comply with. You'll need to pay for the whole block to be given proper notice and the impact on vulnerable occupants assessed and mitigated, etc., then when the supply is restored, you'll be paying for the council's own approved contractors to flush and bleed the system, check pumps, etc. and visit every affected flat to check for correct operation and leaks.

I'd recommend that you get the flat owner to reconsider their plans so that the existing stopcock stays undisturbed. There are some nice hidden access panels available that may help devise and acceptable solution. If the client not happy with this approach walk away.

Thanks for the well informed sensible heads up Chuck. Maybe I will reconsider my previously advised plan!