New gas supply - distance from U6 meter

[Jonast]

Dear all,


I’d be most grateful for your thoughts and advice.

I am a self-builder converting anagricultural shed to a small studio-type house. Its near Sevenoaks in Kent inthe middle of an orchard. I started it four years ago and am still nowhere nearcomplete - I am learning the hard way!

At the outset, Southern Gas Networks installeda service on the site which remains unused. They terminated their supply with ashut off valve in a meter box I had fitted in a garage on the site.

This is a straight 28m run away from thehouse. A further 2-3m should be allowed for entry to the house and connectionto a Worscester Bosch combi (24kW) and a gas hob (9kW).

The trench for the pipe run has already been dug


British Gas were due to fit a U6 meteryesterday whereupon I would have had the gas supply run on to the house.However I put this on hold following a telephone call with them in which theysuggested I take further advice before committing to it. This was on the basisthat they install meters free of charge but upgrade them if needs be atconsiderable charge!

I think their concern was that a U6 metermight not be large enough to provide the appliances with sufficient gas giventhe likely pressure drop over 30m.

Three questions arise from this upon whichI have been given completely contradictory answers, mostly, I must confess, bypub experts and Google!

I’m hoping somebody here can provide some clarity as follows:

1. Is a U6 meter man enough tosupply 24kW + 9kW of appliances?
2. What diameter yellow MDPE pipeshould be specified given a run of about 30m after the meter?
   
   
3. How would the supply best bebrought into the house? Note that the construction is a timber frame sitting ona single skin, brick plinth wall with a solid floor. I have provided a100/110mm duct through the foundations and up through the floor to run all ofthe services from underground though I recognize now that this might not be appropriate for gas.
   

Once again, many thanks for reading thisand for any thoughts you may have. Needless to say, if any of you are local andcan issue a Gas Safe Certificate, there is a job here for you!

Best regards,


Jonathan

 

[kris]

110 is a bit excessive as only need 32 mm sleeve . It would require 28 mm copper for defonate and the meter is large enough but we would need to know distance the hob n boiler is from the meter to ascertain how far the 28mm goes. Chances are 28mm would have to go to the first tee piece.
Best you get a gassafe registered engineer into measure up and check.
Welcome to the forum.

 

[village idiot]

Kris, he says the 110mm is for all the services (I assume gas, water, cable tv and electricity, to name a few.
But as you say, better the OP gets someone to have a look

 

[kris]

Oops sorry. Village. I shouldve gone to spec savers lol. Can't have all utilities in same duct.

 

[rpm]

Oops sorry. Village. I shouldve gone to spec savers lol. Can't have all utilities in same duct.

Never knew that kris after all they put them all in the same ruddy trenches in London lol

 

[snowhead]

Never knew that kris after all they put them all in the same ruddy trenches in London lol

It's alright if they go bang in the street, but not in your house, apparently..

 

[rpm]

It's alright if they go bang in the street, but not in your house, apparently..

I`ve seen some of the videos of pavements exploding, very scary indeed!

 

[Ollieg]

They are ment to be at different depths in the street. I think 750, 600,450.

 

[Reg Man]

The gas meter is capable of providing the likely demand. The gas installation pipe will have to be sized according to the pressure drop over the run, which can be calculated by the gas safe registered engineer. The gas installation pipe must not be ducted under foundations. You can bring it up on the outside wall and then pass through above ground fitting an emergency control valve at point of entry. Hope this helps in your decision.

 

[Ermintrude]

That's what I thought. 32mm PE would be service of choice.

 

[tamz]

1. Plenty big enough
2. 32mm PE
3. Not up through that duct you have fitted. Its not allowed for pe to enter below a building in that way and the other way is specialised.

Apart from running the PE in a track, this is not a diy job. Any suitably qualified gas registered engineed "should" be able to keep you right.
Btw you are very near the limit for pressure drop and what can legally be worked upon with a domestic ticket.

 

[Jonast]

Thanks to everybody who has replied to mypost.

I am reassured by what everyone says aboutthe G6 since a larger meter wouldn’t fit the meterbox I have painstakinglybuilt into a garage wall.

I will specify 32mm PE for the 30m run tothe boiler.

I provided a below ground entry for all ofthe services to be run through and Building control didn’t baulk when I pointedthis out to them. However I can’t push 25mm blue PE through the duct because ofa small radius 90 deg bend in it so would never get 32mm through even if itwere allowed! As I said, I am learning the hard way.

I will need a GSR installer to fit an aboveground entry for gas and to make the connection to the meter.

This will doubtless take time to arrange –you guys are always busy - but that’s not the problem. It’s not a problem thatI can’t have a hot bath in there either though I look forward to the day..

The problem is that I need to backfill about8m of the 28m trench thats been dug as soon as possible. This is because it’s completelyobstructing access to the building which is causing me all sorts of unrelatedheadaches. The trench is also starting to collapse.

So, would it be permissible for unqualifiedme to simply lay the 32mm PE pipe across the area I need to backfill, and then backfillleaving the ends free for the GSR installer to make the connection at each end? Or would I then find nobody prepared todo this?

Be interested in your thoughts on this. Also, what is meat by running PE in a track?


As a side, my recent experience might amusesome of you:

• SGN will not do the pipeworkbecause it is after the meter
  
• The BG meter boys will not fitthe pipework also because the run would be more than 5m.
  
• The BG boiler installation boyswill not quote for fitting the boiler because there is currently no gas supplyto the building and they will not provide it.

It’s a mad world!

 

[Reg Man]

As an engineer, I would be looking at depth of cover and infill material. but get a gas safe registered fitter to check it over.

 

[tamz]

You need at least 450mm deep ' preferably on a layer of sand and cover it with a layer of sand then put a marker tape on top around 150mm above. Get a GSR to have a look before you backfill.

Terminate the PE at the house wall onto steel or copper and fit an AECV (an emergency control valve)
Run a suitably protected 1" mi (steel) pipe in your floor screed to your appliances (you can reduce it for the hob but bigger is better at very little extra cost).

Steer away from the gas board for your boiler.
A local GSR engineer will do as good a job much cheaper.

 

[Jonast]

I cant find any GSR engineer willing (or perhaps able?) to work with yellow MDPE! I understand they need to use specialist fittings at each end.

Could somebody please give me a steer in the right direction?

 

[Reg Man]

MDPE transition coupling, no special tools required, well within the capability of a GSR engineer.

 

[snowhead]

You need someone who works with MDPE all the time, like these;

Gas Services | Gas Connections | Gas Meters | Gas Utility | Crown Utilities


Go to the Gasafe website
Use advanced search and search for MDPE Fusion in AREA OF WORK in your Local area;

Find a Registered Business

 

[Reg Man]

Does not require electro fusion jointing, so ok for joe average.

 

[snowhead]

Does not require electro fusion jointing, so ok for joe average.

I know, but anyone who does Electrofusion does MDPE, and finding someone confident to do MDPE is the O.P's problem.

 

[Ermintrude]

I use philmac

 

[tamz]

There are a variety of compression type fittings suitable for gas/

OR

Bung the SGN guys a few quid and i'm sure they will stick a couple of draw locks on the ends.

 

[Reg Man]

MDPE easier than copper.

 

[Jonast]

Hi Guys,

Thanks to all who have commented so far!

Today BG fitted a shiny new U6 gas meter to the service provided by SGN.Actually, it's a reconditioned one but it looks very nice nonetheless.

Standing pressure at the meter was 23.5mbar.

I took the opportunity to measure the run of SGN’s service pipe which is nowburied. It's longer than I thought. Effective length is actually 30m and it's32mm yellow PE.

The difficulty remains what size pipe to specify to connect the meter tothe house which is a further 30m away (allowing for upstands andbends at each end). The supply will feed a 24kW WB combi and a 9kW gashob.

My instinct is to have it run in 63mm yellow PE despite it being five timesmore expensive than 32mm. My layman's logic is that if this doesn't provideenough gas flow at the house, then it will be down to SGN to upgrade their 32mmservice. Or am I being naiive in believing this?!

Also, this assumes there is a way of checking the gas flow rate withoutany of the appliances being fitted. Am I correct in believing that there is?

As ever, your comments and advice would be much appreciated. Having made somany costly mistakes elsewhere on the build, I am determined to getthis aspect right first time!

Cheers, Jonathan

 

[Reg Man]

A 32mm at 30m will supply 5m3 of gas with the minimum 1mbar differential from end to end. With what you are proposing as long as there are not massive length of runs within the property it should meet the requirements. If you go for 55mm PE it has the capacity to deliver 21m3, which is way above what the meter can deliver (6m3). Get your Gas Sae engineer to check it out.

 

[Ermintrude]

But will also render installation as non domestic due to the static volume of gas present in the system.

 

[anz]

Hi Guys,

Thanks to all who have commented so far!

Today BG fitted a shiny new U6 gas meter to the service provided by SGN.Actually, it's a reconditioned one but it looks very nice nonetheless.

Standing pressure at the meter was 23.5mbar.

I took the opportunity to measure the run of SGN’s service pipe which is nowburied. It's longer than I thought. Effective length is actually 30m and it's32mm yellow PE.

The difficulty remains what size pipe to specify to connect the meter tothe house which is a further 30m away (allowing for upstands andbends at each end). The supply will feed a 24kW WB combi and a 9kW gashob.

My instinct is to have it run in 63mm yellow PE despite it being five timesmore expensive than 32mm. My layman's logic is that if this doesn't provideenough gas flow at the house, then it will be down to SGN to upgrade their 32mmservice. Or am I being naiive in believing this?!

Also, this assumes there is a way of checking the gas flow rate withoutany of the appliances being fitted. Am I correct in believing that there is?

As ever, your comments and advice would be much appreciated. Having made somany costly mistakes elsewhere on the build, I am determined to getthis aspect right first time!

Cheers, Jonathan

The standing pressure at the outlet is regulated by the meter governor.
Changing the service would not give you any extra. The main is usually fed under a higher pressure anyway.

You should have really got the meter installed closer to the boiler.

 

[Reg Man]

30m of 32mm pipe has a volume of 0.048m3 plus meter plus other pipework. Probably still below 1m3 volume and less than 35mm so UP/1/B domestic test ok.

 

[Ermintrude]

30m of 32mm pipe has a volume of 0.048m3 plus meter plus other pipework. Probably still below 1m3 volume and less than 35mm so UP/1/B domestic test ok.

Was referring to 65mm

 

[Reg Man]

Standing pressure tells you very little other than the governor is working and locking up to prevent the medium pressure getting though the equipment.

 

[Reg Man]

63mm at 30m is capable of 28m3 within 1mbar differential. on a U6 meter laughable.

 

[tamz]

I told you the sizes in post 11 and 14.
I didn't just have a guess at these sizes.

 

[Reg Man]

Far to much information supplied, get a qualified gas safe engineer in to delivery what is required.

 

[Ermintrude]

I told you the sizes in post 11 and 14.
I didn't just have a guess at these sizes.

As did I in post 10[emoji12]

 

[Jonast]

Sorry guys, I have read all of your postsand have tried to digest all you have said.

What prompted my last post and what’s stillbugging me is that I realize now that the supply to the house from the gas mainin the street will actually be 60m.

The meter is half way along and I can’t doanything about SGN’s supply to it which is 32mm. It’s buried with all the otherservices and I’m sure that upgrading it now would cost SGN - or more likely me -thousands. So that isn’t going to happen.

With the benefit of hindsight, I’d have hadthe meter fitted nearer to the house as anz suggested, but the garage seemed theobvious place to put it at the time. I didn’t want a gas meter in the house or onein the ground outside.

So, for ermintrude and tamz, given thelength of the service pipe, do you still think that 32mm PE would suffice?

My worry is that if 32mm doesn’t work, SGNwill blame me when I would rather blame them for not providing an adequateservice!

Thanks again to all for the feedback

Jonathan

 

[Reg Man]

The gas transporters bit up to the meter is medium or high pressure so it will not effect your side of the meter.

 

[Masood]

Sorry guys, I have read all of your postsand have tried to digest all you have said.

What prompted my last post and what’s stillbugging me is that I realize now that the supply to the house from the gas mainin the street will actually be 60m.

The meter is half way along and I can’t doanything about SGN’s supply to it which is 32mm. It’s buried with all the otherservices and I’m sure that upgrading it now would cost SGN - or more likely me -thousands. So that isn’t going to happen.

With the benefit of hindsight, I’d have hadthe meter fitted nearer to the house as anz suggested, but the garage seemed theobvious place to put it at the time. I didn’t want a gas meter in the house or onein the ground outside.

So, for ermintrude and tamz, given thelength of the service pipe, do you still think that 32mm PE would suffice?

My worry is that if 32mm doesn’t work, SGNwill blame me when I would rather blame them for not providing an adequateservice!

Thanks again to all for the feedback

Jonathan

I understand that you don't want to make costly mistakes but you're trying to do a GSR's work for him/her, and second-guess trained professionals, without having the knowledge to do so. Get a GSR in who can do site-specific measurements and calculations and tell you what's what.

 

[wetdrip]

Forum member: King Billy and his crew are based in Maidstone, thirty minutes away. You could do worse than send K.B. a P.M. on the forum.

 

[Dotty]

As stated, you are now trying to do the work of a gsr. we will not size this for you.

Get someone in.

 

[Dotty]

Jonast would like to thank you all who have issued advice on this matter.