Can't find the right stopcock (copper to mdpe)

[ProDave]

I'm trying to order some pipe fittings to get some basic water services into the house. And I can't find the right stopcock I need.

 

25mm MDPE main in to copper services. That one is easy. A brass stopcock with 25mm in and 22mm out.

 

But the one that has got me stumped is copper IN to 20mm mdpe OUT to an outside tap.

 

If I use this one http://www.screwfix.com/p/poly-stop-cock-20mm-x-15mm/98486?_requestid=101742#product_additional_details_container

The water will be going the wrong way and it probably won't work at all.

 

I need copper IN (don't care what size but would choose 22mm if I had a choice) and 20mm mdpe OUT

 

Surely I can't be the first to want to do that?

 

Yes I know I can do it with equal mdpe in / out stopcock but I hate those horrible mdpe / copper insert things that go with them.

 

I did this on my last house, 14 years ago, so I know it can be done, but I don't recall where I eventually found the right stopcock from. Tries BES, T'stn, and screweys so far.

[TerryE]

Who says you need to use a stopcock?  What's with a full bore 15mm ball valve + lever where you T off the rising main?  Then convert the 15mm to 20mm MDPE with a standard insert like this. 

[PeterW]

My thought is why go MDPE for the outside tap ..?? 

[ProDave]

I am trying to avoid those mdpe to copper adapters. I have used one, once, and to be fair it sealed first time and never leaked. It just did not inspire confidence. It was a "rubber bung" in essence and when fitted you could flex the copper pipe where it fitted into the mdpe fitting.

 

So on the present house I used brass stopcocks that take a 25mm mdpe in one end and a 22mm copper out the other, both secured and sealed with a compression ollive, that inspires confidence and gives a solid joint.

 

The reason for mdpe to the outside taps (yes there are 2 of them) Well I have wood fibre and render cladding, and my philosophy is not to make penetrations in the external cladding that might be a source of water getting into the wood fibre. So in both cases the outside taps are piped in 20mm mdpe. One under the floor and into the garage, the other out through the blockwork wall under the sole plate and then back up the outside of the wall to the outside tap.  Try that in copper and it would not last a winter.

 

The best compromise I can find is a brass stopcock with two female 1/2" BSP fittings, then a 15mm to 1/2" BSP male on the input and 1/2" BSP male to 20mm mdpe on the output. That's 2 more fittings and 2 more joints than I would like if only I could find the correct stopcock.

[TerryE]

1 hour ago, ProDave said:

 

I am trying to avoid those mdpe to copper adapters.

 

So why not try the JG Speedfit MDPE PE - Copper Coupler 20 x 15mm and a 15/15 ball valve?

[ProDave]

10 hours ago, TerryE said:

So why not try the JG Speedfit MDPE PE - Copper Coupler 20 x 15mm and a 15/15 ball valve?

I could use one of those and a 15/15 brass stopcock. I might go for that option.

 

I guess that's another of my prejudices, I hadn't looked at pushfit stuff.

[TerryE]

Dave, just out of interest can you explain your rationale for wanting a traditional stopcock?  It's just that with the exception of the main 25 MDPE  to 22mm stopcock,  I've gone down the lever operated full bore ball valve route for all of my internal water valves: easy to operate with a 90° twist and no impediment to water flow when open. OK, I've stuck with a boring WRAS-approved stopcock for the main entry, but to me the ball-valve approach is just so much easier.

 

Surely the internal valve to the external taps is just another valve?

 

The main reason that I suggested the push fit post is that I couldn't find the EF or compression equivalent.  I also prefer solder joints for main lines, with the odd compression to allow you Brad it into sub-assemblies for maintenance, but the push fit stuff, especially the Pegler Texture Classic look very good.

[ProDave]

Again that's the dinosaur in me. Certain things "should" have a stopcock not a ball valve. Ball valves will be used for local isolation of things like taps for maintenance.

[Jeremy Harris]

I'd just use a ball valve, which is what I've done.  Easier to turn on and off and just as reliable.  I went a bit OTT and used stainless steel ones to isolate the outside taps, and they seem fine. 

 

As an aside, I've found that MDPE for outside taps (we have three, two run of one pipe, one off another) is pretty frost-tolerant.  I used it primarily because experience on the farm was that whenever anything froze up solid the MDPE pipe never seemed to come to any harm from it.  The same seems true here, I've got a tap fitted to a post with an uninsulated run of MDPE and it's frozen a few times now but seems to just tolerate it without damage.

[TerryE]

2 hours ago, ProDave said:

Again that's the dinosaur in me. Certain things "should" have a stopcock not a ball valve. Ball valves will be used for local isolation of things like taps for maintenance.

 

Dave, IMO, the modern ball and socket valves are milled and polished to such a tolerance that they really are a trouble free way of ensuring on/off flow control.

[Nickfromwales]

Outside taps are 'accessories' to the main, UNLESS you have teed into the incoming main mdpe as it comes up the drive to the house, at which point you would indeed be right to fit stopcocks as they would then be spurs off the rising main. 

For outgoing supplies AFTER the stopcock you deffo should use 1/4 full bore as @TerryE has done. Click on my profile and you'll see the blue handled one I fitted for attic isolation on an UVC multi-block. Near silent in operation too. 

[Gone West]

@Nickfromwales Could you clarify this for me. Are you saying that the 'stopcock' where the incoming main first enters the inside of the house has to be a conventional stopcock even if there are other stopcocks on that MDPE pipe between where the MDPE pipe enters your land and your house? I was hoping to use a 'Push Fit Full Bore Lever Isolation Valve', as mentioned above, instead of a conventional stopcock.

[Jeremy Harris]

A proper "stop cock" is also a non-return valve, as the piston and washer is "supposed" to be able to float up and down when the handle is fully open, so preventing backflow that could contaminate the main supply.  If you take a proper one apart, then you should find that the washer is fitted to a small floating piston than is located in a drilling in the part that rotates and is screwed down.  The idea was that with no incoming flow, or under backflow, the little piston would drop down and close off the connection from the possibility of reverse flow.

 

In practice I doubt that these old-design stop cocks ever really worked well as NRVs after a few years, every one I've ever taken apart has had the small piston pretty much jammed in place.  Now you're usually required to fit a proper NRV (a double check valve) on the incoming supply after the stop cock  for back flow prevention anyway, most probably because it's well known that the standard design of stop cock doesn't work as an NRV very well, as it's a very old design that goes back to the early days of mains water supplies.  Given this, I'm not sure why there is still insistence that a conventional stop cock is used as the main isolating valve.  My personal view is that a ball valve would be just as reliable (maybe more so) but a ball valve isn't a proper stop cock as far as the water regs are concerned as it's classed as a non-serviceable valve i.e, you can't repair it if it fails (barking mad logic, when you're dealing with a ball valve design that's inherently far more reliable, but rules are rules.............). 

[TerryE]

@PeterStarck, I think that you will find that it is Water Regs as much as Buiding Regs.  Certainly Anglian require you to have a stopcock (that is a proper stopcock) and DCV and draincock on all direct connections to the water supply.  So

• If the outside tape is on a spur before the supply enters the house then it must essentially be configured as a standpipe (search for standpipe to see the thread on this).
• If it is on a spur between the main stockcock and the DCV then it must be protected by a DCV
• If it is on a spur after the main stockcock and then it should still be protected by a DCV.

In these last two cases AFAIK, it is up to you what type of isolation valve you need to fit if any.

[Nickfromwales]

2 hours ago, PeterStarck said:

@Nickfromwales Could you clarify this for me. Are you saying that the 'stopcock' where the incoming main first enters the inside of the house has to be a conventional stopcock even if there are other stopcocks on that MDPE pipe between where the MDPE pipe enters your land and your house? I was hoping to use a 'Push Fit Full Bore Lever Isolation Valve', as mentioned above, instead of a conventional stopcock.

If you tick the boxes, so.....

1) incoming mains into propery

2) stoptap of whatever guise

3) double check NRV

4) drain off cock 

....then I doubt if any BCO would fail you, but the water company may. 

Can you give details of your supply from the road in please?

[ProDave]

I've been through the NRV thing with Scottish Water. Aparaently the NRV in their boundary box does not count as it's only a single NRV. Neither does the NRV in my own boundary box count as that too is only a single NRV. And neither did the NRV built into the tap on my stand pipe count, as that's only a single NRV. So before they would pass me for connection I had to fit an in line double NRV in the pipe to the stand pipe, the feed to the static caravan, and have a third one ready to connect in the feed to the house.

 

Madness.

 

ALL could be avoided if thy just supplied a boundary box with a double NRV built in instead of the apparently useless single one.

[Jeremy Harris]

The water regs require that the stopcock be a "serviceable valve", hence the reason for ball valves being non-compliant, whereas a conventional stopcock is compliant because you can take it apart to repair it.  Quite why one would ever want to repair a stopcock, rather than just replace it, is beyond me, but the regs seem to have just inherited that definition from the days when changing washers, replacing packing glands etc was normal for domestic-scale stuff.

 

The way some water companies interpret the water regs into their own rules seems to vary a lot.  The water regs are as Nick describes, with no requirement for any particular configuration on the consumer side, beyond the incoming stopcock, double check valve etc.  Having read through the wording in the water regs, it's not exactly 100% clear, and I think some water companies have taken the view that there needs to be additional double check valves all over the place.  All three of the outside taps we fitted had double check valves anyway - they are easy to spot as they have an inter-valve drain plug on the underside and seem to be marked as WRAS approved.

[Oz07]

Me and a friend have only passed a water supply connection first inspection 1/2 times each. Built over 20 houses between us. They put a new main in for him recently and they were at 600mm. They make it up as they go along

[Gone West]

12 hours ago, Nickfromwales said:

Can you give details of your supply from the road in please?

 

First stopcock is on my land next to the lane. The second stopcock is a metre inside my hedge which is where the water meter is. The next one is inside the house. I don't have any outside taps running off the mains water supply because I have a borehole.

[Nickfromwales]

9 hours ago, Oz07 said:

Me and a friend have only passed a water supply connection first inspection 1/2 times each. Built over 20 houses between us. They put a new main in for him recently and they were at 600mm. They make it up as they go along

Yup. Last one I did they wanted 750mm ! One before that they made me core a 100mm hole through breeze block footings and slide a sleeve through to the ground outside. 

Theres more sense and reasoning for electric cables than there is for water pipes.

 

[Nickfromwales]

28 minutes ago, PeterStarck said:

First stopcock is on my land next to the lane. The second stopcock is a metre inside my hedge which is where the water meter is. The next one is inside the house. I don't have any outside taps running off the mains water supply because I have a borehole.

I'd be shocked if they pulled you over tap type tbh, unless you get a jobsworth. As long as you have a D-C NRV, you should be ok. Have you been given written criteria for the new connection, or are you just picking up on a existing feed and altering it? If the latter then will anyone actually visit / call to inspect it?

[ProDave]

It's 900mm deep up here now (present house is 600 and has never frozen)

[Nickfromwales]

How much cheaper would insulation be vs deep excavations? . 

 

[TerryE]

11 hours ago, Nickfromwales said:

Yup. Last one I did they wanted 750mm

 

Anglian mandated that our internal trench and pipe from the boundary to the house was at 750mm depth, and then the gang that connected us up put the main in the road at around 600 coming up to maybe 400mm at the water meter for the pipe to dive back down to 750mm in our trench.

 

A bit of a farce really.

[Jeremy Harris]

43 minutes ago, Nickfromwales said:

How much cheaper would insulation be vs deep excavations? . 

 

 

I doubt you need to go down more than about 300mm to eliminate the risk of pipes freezing, based on some measurements I did for fun some years ago.  I built a weather station, with a wireless link to the house, and had a couple of spare temperature sensor inputs.  As the thing was sat on a post hammered into the ground, I decide to fit a sensor about 300mm into soil, just to see how cold it got.  This was a few years ago, and the soil at that depth never dropped below about 6 deg C, even when we'd had a spell of very cold weather (well below zero) for a few days.  My guess would be that perhaps the top 100mm or so of  soil might possibly freeze in prolonged cold weather.