Connecting MDPE to iron/steel pipe

[Hilldes]

The job in the next couple of days is to sever water supply to the house before demolition and to retain the supply to caravans and outbuildings. I've located what I believe to the the water supply pipe - see pic. The upper pipe, broken with yellow plastic insert is the gas pipe, the rusty metal pipe below this must be the water pipe? At the bottom is the newly diverted electric supply cable. 

 

If this is the water pipe, its outside diameter is 28mm (0.93 inches). A couple of questions please:

 

• What size MDPE to iron connector do I need please (the iron pipe size)?
• How do I cut and prepare the the pipe - sand area to but cut to remove loose rust, cut with angle grinder, the remove burs inside and out with files?

 

I'm also considering connection right back at the water meter/stop cock at the boundary - see other pic. Yet to dig to explore the type of pipe connection here. I'm guessing this is a later addition to the 1950's supply in the other pic. 

 

This is a bit just-in-time for demolition staring Monday, so looking for a quick solution for now and something longer term for the build later next week. I can easily isolate supply at the stop cock, but can't be without water on site.

[joe90]

After a friend of mine had so much trouble (leaks) with an old iron water pipe I would go right back to the water meter, job done, and piece of mind.

[PeterW]

Looks like 1” iron but you won’t get a decent connection to that. I would go back to the boundary and excavate that Toby and you’ll find an MDPE connector on it most likely. That would be my starting point for any connection. 
 

Crossed with @joe90..!

Edited December 4, 2020 by PeterW

[Hilldes]

Thanks @joe90 and @PeterW this needs to work quickly and reliably so I'll dig by the meter and see what's there to connect to. On question on the "Toby" (I'm guessing this is the unit containing the water meter and stop cock) Peter this is technically on the verge at the boundary, can I connect direct to this or does this need the water company?

[joe90]

1 minute ago, Hilldes said:

can I connect direct to this

yes (well I did ours!!,).

[PeterW]

46 minutes ago, Hilldes said:

On question on the "Toby" (I'm guessing this is the unit containing the water meter and stop cock) Peter this is technically on the verge at the boundary, can I connect direct to this or does this need the water company?

Everything after the meter / isolator is yours so yes you can. Make sure you dig around and under the join and clean it all off before you try undoing any connections though as you will have a steel pipe full of water trying to drain back into the hole ..! 

[Bitpipe]

Agree - we had a 1" iron pipe from the meter to the original '50s house and separately to the more recent (70s) garage extension, then feeding garden taps up to 30m away.

 

When we demolished the garage we ran a feed to the caravan from an exposed bit of MPDE that was in that mix somewhere but it caused an exposed bit of iron pipe to go live again - we managed to get a steel fitting that connected to that and 32mm copper at the other end and put and end cap on it as a temp measure. 

 

When we fully demolished we ran new MPDE all the way from the meter as the iron was rotten, slightest movement would pull it out of the next joint.

 

I tried to reuse the coupler to service the taps at the back garden but could not get a good seal. Plan to run 50m of MPDE at some point (should have done it before laying the lawn a few years back).

 

 

[Conor]

If you do need to connect to the iron pipe, eveno on a temp basis, I highly recommend this:

 

https://www.speedy-plastics.co.uk/shop/mdpe-watermains/mdpe-plasson/universal-coupler-10017/plasson-25mm-mdpe-pipe-to-universal-pipe-coupler-24mm-28mm/?gclid=Cj0KCQiA2af-BRDzARIsAIVQUOfmvTGn2QEJz5OXWoFE2Q5Y-M2IGEZF57V9tSl_cs7tCZkI6u68Eg0aAmSqEALw_wcB

 

I used similar for connecting to our old lead pipe.. dead easy and no leaks.

 

Edited December 4, 2020 by Conor

[Bitpipe]

I found the hard part was getting a clean fit to the iron pipe that had been in ground for along time and the surface was very corroded.

 

Did my best to try and get  the iron pipe's exterior smooth but was an impossible job given the access.

[Hilldes]

So the good news is there is MDPE at the Toby.  Haven't measured it yet but looks about 20mm. The question is how to sever and connect the new pipe. In the new pic the white connector goes into the Toby - the stopcock. The lower part of the pic shows the blue MDPE starting to go downhill and going into some form of solid tar like substance which I guess might be a seal around the join to the iron pipe.

 

Can I just disconnect the white connector and put in the new MDPE pipe?

[Conor]

Yes, just remove the existing adaptor and use a 20-25mm MPDE coupler and attach your new 25mm pipe.

[Hilldes]

6 minutes ago, Conor said:

Yes, just remove the existing adaptor and use a 20-25mm MPDE coupler and attach your new 25mm pipe.

Thanks @Conor will dig out a bit more around the connector to see what's what. I'll only get one shot at this because I'll need to remove the existing section of MDPE in order to get the right angle into the Toby. If the white connector is a full coupler then I can see how I can remove the whole coupler and fix a new coupler to the remaining pipe into the stop cock. If the white coupler is more an integral part of the stock cock/Toby then I guess I'll need to reuse it and insert my own pipe into it?

[Conor]

2 minutes ago, Hilldes said:

Thanks @Conor will dig out a bit more around the connector to see what's what. I'll only get one shot at this because I'll need to remove the existing section of MDPE in order to get the right angle into the Toby. If the white connector is a full coupler then I can see how I can remove the whole coupler and fix a new coupler to the remaining pipe into the stop cock. If the white coupler is more an integral part of the stock cock/Toby then I guess I'll need to reuse it and insert my own pipe into it?

 

That bit of pipe you have exposed is the 1-1.m "tail" that comes out of the box that the contractor fits, that is then connected to the customers pipe. The boundary box itself usually has a push-fit connection on either side for the supply pipes. You can cut that length of MDPE wherever suits you to get the right angle for connecting to your own pipe.

[PeterW]

As @Conor said just make all your prep up and then cut that MDPE with a pair of pipe shears, put the insert into the tail then put your connection onto it. Don’t muck about trying to amend what is on the Toby. 

[Bitpipe]

£12 will get you a razor sharp pipe cutting tool from Screwfix - will give you a clean straight cut on that blue MPDE.

 

https://www.screwfix.com/p/0-26mm-manual-plastic-pipe-shears/59590

 

Don't forget your pipe stiffener inserts when you use the coupler.

[Bitpipe]

Also, don't cut too close to the white fitting as you need enough space to get the collar of your own coupler far enough away from the body of the coupler to make the join and then screw it back on (and be able to take it off again in the future).

 

 

 

[Hilldes]

Ah @Conor  and @PeterW got it. The new pics shows the full connection to the Toby. So basically I won't open the white connector. I'll just sever the blue MDPE and connect to it with a new coupler. I measured the MDPE and its nearer 21mm actual O/D so assume that is 20mm pipe.

 

Thanks also @Bitpipe I'll need to dig a bit more around the 'tar ball' to get enough room for the new coupler on the existing MDPE. Got the inserts and cutters.

[PeterW]

Give yourself at least 2-300mm of blue to work with off that Toby just in case you have to cut and redo the joint. 

[Hilldes]

2 hours ago, PeterW said:

Give yourself at least 2-300mm of blue to work with off that Toby just in case you have to cut and redo the joint. 

 

Thanks @PeterW I've been carefully prising away some of the 'tar ball' it is very tough and has started to seep where the blue MDPE goes into it so I stopped. I have about 8 inches of MDPE to play with and some of that goes through a good 45 degree bend down into the tar ball - which may have deformed as it curved and I guess may not make a good joint. 

 

I plan to sever the MDPE as close to the tar ball as I can. If the coupler join leaks leaks because the pipe is deformed, then I'll cut some off and join closer to the Toby.

 

Last resort would be to try to remove the white nut at the toby and push the new MDPE pipe straight in there.

[Hilldes]

Two interesting events on site today.

1. Fortuitously, some idiot (who shall remain nameless) snapped the main stock cock lever off by over-tightening in the off direction. So had to call out Affinity water who temporarily turned back on again so we have caravan and site supply, but still have not diverted from the house to be demolished. Affinity will try to schedule a new stop cock fitting tomorrow so we can proceed to sever supply to the house. In the nameless person's defence, turning the stop cock off with normal torque did not fully isolate the supply, so kept turning more until the metal T piece snapped off the tap. All I could think is the dribble that was still coming from the pipe may have been from the pipework in the house even though the stock cock in the house was firmly turned off - or the main stop cock at the boundary really did not seal in the off position.
2. Secondly you are probably wondering why I started the above with "fortuitously", given its a bit of a PITA. The other thing the water engineer said was if I had severed that blue pipe (in pics in previous posts) as planned I'd have got wet. Why I asked? Because that is the LIVE side he replied. It turns out the blue MDPE in pics from 'tar ball' to Toby is the live feed into the stop cock and the feed to the property comes out the other side of the Toby and doubles back into our driveway. Phew that was a narrow escape! Will hopefully locate the pipe on the correct side of the Toby when Affinity Water dig to replace the stop cock.

@PeterW, @Conor, @Bitpipe, @joe90

[joe90]

OOPS, well who would have thought that, lucky escape. Can you not turn the Toby round a bit so it’s pointing more in the right direction?

[Hilldes]

17 minutes ago, joe90 said:

OOPS, well who would have thought that, lucky escape. Can you not turn the Toby round a bit so it’s pointing more in the right direction?

Yeah I think the way to tell is look at the sequence, should be: live supply, stop cock, meter, then to house. I could see the blue MDPE went into the stop cock ?. 

 

Will ask Affinity Water if we can change orientation of the Toby when they replace the stop cock, I guess they will need to remove the Toby to replace the stop cock anyway. It may be  as it is because the Toby is on the road side of the water main and it would need to move from what is technically the verge onto our drive to reconfigure it.

[Mr Punter]

Gosh that would have been a lot of water if you cut straight through with the pipe shears.

[Mr Punter]

Incidentally if you need to work on MDPE where there is no upstream stopcock you can get a squeeze-off tool to stop the flow.

[Bitpipe]

Wow - that was a lucky escape!