GAS mdpe service pipe underground. One for the experts.

[Hugh Jaleak]

Gas installations inside a building will come under completely different regs to those externally, and the Gas Safe guys have enough to comply with let alone worry about the pre meter supply! I suspect regs are not widely published to prevent unauthorised works to the supply, e.g. if a 3rd party excavation hits a gas pipe, they are not allowed to attempt a repair themselves.

Gas is a different world when outside in the ground, leaks can be notoriously difficult to locate, pipelines can be at different pressures, (you DO NOT want to be rupturing a HP gas line!), and I also believe some large industrial gas supplies (e.g. to a power station) can be unodourised. (Natural gas has no smell, the odour is added to allow leaks to be detected.)

Anyone carrying out this type of work will need to be qualified, they don't just let anyone loose with a jackhammer these days. All operatives will have to be trained under the National Roads and Streetworks Act, (NRSWA) before putting a spade in the ground, and additionally have the required knowledge to work on gas supplies..... National Grid have their own training establishment at their Hitchin site to train these guys how to operate correctly and safely.

Then the reinstatement in a trade in itself, the guys who 'make good' will be trained in using materials and plant to a high standard. Get the reinstatement wrong and the company will be made to redo it at their own cost!

I agree with Dextraneous, NG have the power to enter private property in emergencies, if they are unable to access your property to maintain, repair and/or improve the gas supply then you will probably leave them little option but not reconnect your supply until such a time as you comply with their requirements! Have a look at National Grid's website, it's pretty comprehensive and may answer a lot of your questions.

 

[Richardthe3rd]

The OPs attitude is of someone with too much time on their hands, the well healed retired civil servant or public servant employee living a long retirement at the cost of the tax payer, a curtain twitcher & Nosey Parker type.

It's so unfair when most OAPs can only look forward to a winter where their choice is heat or eat.

I do hope I'm wrong!!

 

[slpj]

Richard the 3rd. You know what your names rhymes with, and it exactly matches the daft comments you made about my status.

Advice? I wasn't asking for advice, I was asking if someone could answer some questions.

Hugh Jaleak.
Thankyou for your more helpful and comprehensive answer. I was wondering if the situation is exactly as you describe. I've been able to download a free copy of the gas safety reg's, and the pipeline installation guidance. But neither answer my questions. However I have also spoken to an mdpe manufacturer and they are going to send me some blurb on their recomendations about safe installation underground in various circumstances, and the types of joints used. Yes I can see what you are saying about not wanting to give clues to people who might otherwise be tempted to do the work themselves. However, SGN amongst others, publish a leaftlet, that explains that if in the course of having your gas meter moved -- at your own request -- you wish to do some of the work yourself, you are liberty to do it. Hence they would obviously explain exactly what they wanted and why, which would very likely include some information about joints, the whereabouts of them, if they were asked those questions. Perhaps I'll ring them up too.

Yes of course they can enter in an emergency. I said that. But this is NOT an emergency. They are simply upgrading/replacing the main in the road, and consequently replacing the service pipes if need be. I'm happy for them to do that, but not to suit themselves alone.

And I can update this now. I told them that I wasn't going to let them dig up my drive, unless they had a compelling reason to do that, rather than dig my gargage floor and reinstate the meter where it is now. They didn't, and the meter will remain where it is. So I no longer need to find out in advance how the pipe is going to be connected underground. I will see exactly how it is done tomorrow, if they are able to keep to time. (They've hit a lot more concrete in the road, and it's slowed them up). It seems they are going to use a "tranistion"? coupling, to go from mdpe to steel, and I presume run a new steel or copper riser to the meter.

What I still can't quite understand, is why they need to do anything to my service pipe at all. It's been leak tested and passed. It's already mdpe. they are not going to replace it. Instead, in the pavement they will disconnect it from the existing old DM, extend it and reconnect it to the new DM in the road. Then they are going to dig my garage floor less then a metre away from the steel riser going to my gas meter, cut the mdpe, and replace the existing steel riser with a new steel or copper riser. Now this may make perfect sense. Pray tell me, what's wrong with my questioning that?

Why don't I wan't my drive dug up? Well not that it's anyone elses business to know. However, since the question is one that I can answer, I see no reason not to answer it. The Gas company have contracted to the blokes digging and replacing the main, who have in turn contracted the reinstatement to another company to make good in the road, and peoples houses. Initially, although the road was laid with steel reinforced concrete under tarmac, the resinstaters were not putting the steel back. Then one of my neighbours told the council, and now they are, but not untill after half the road has started to sink under the weight of traffic. You may all trust everybody to do a decent job. But I know that is not always the case. My drive was laid and tarmaced properly with harcore under it. I don't want some lazy sod simply backfilling and laying tarmac over the hole, only for it to sink some months later, as is frequently the case after the pavements have been dug up. In the garage, 6 or so inches of concrete will far more likely to be done properly -- because it's so easy to do -- and I also won't have the eyesore of a patched drive. Additionally, I'm intending to extend the front of my garage, If I have a service pipe stuck on the front of it, I'll then have the expense of having to pay the gas company to move it again. Happy? Probably not. But I am, and that's what counts. .

 

[Hugh Jaleak]

As I pointed out in a previous post, the Utility Companies do actually 'own' any reinstatements carried out as a result of works in the highway on their assets. Regardless of the construction of the existing carriageway, if the backfill has been carried out correctly, then it should not sink.

It is permissible to carry out a temporary reinstatement, especially with deep excavations or for example following a burst water main, where the backfill may need longer to consolidate due to depth or surrounding soil drying out. However, I believe the Highway Authority has to be notified it is a temporary job and has to be informed when the permanent reinstatement is completed. Either way, should it sink in the future then the Highways people can insist it is done again!

Some joints are made using fusion techniques. The fittings contain a coil of fine wire, once the pipes to be connected are inserted, an electrical current is passed through the coil of wire, causing it to heat up and melt the surrounding plastic, thus fusing the joint together. (Although Transco (as was) have been known to forget to fuse joints, for Murphy's then to come a couple of days later to reopen the excavation, find out Transco didnt fuse the joint and fuse it themselves to stop the escape....)

Larger pipes are often 'Butt Welded'. The ends of the 2 pipes to be joined are 'shaved' to ensure the plastic is clean. Then the pipes are clamped and forced against a very hot 'plate'. Once sufficient time has elapsed for the plastic to soften to almost melting, the pipes are pulled back slightly, the hotplate removed and the pipes forced together under pressure. As the plastic cools it fuses together making the joint.

I think the work you can do yourself would be limited to digging and reinstatement on your own property, and possibly running pipework. All connections would have to be done by National Grid or their agents.

 

[slpj]

Hi Hugh Jaleak.

" --- if the backfill has been carried out correctly, then it should not sink. " Exactly the point I was making. The filling wasn't carried out correctly, and was supposed to be the final result. Anybody honest enough to admit it, will admit that many corners are cut on both private and public works if it can be got away with.

And, I now know the reason for the reluctance to dig my garage floor and keep the meter in it's original location. Time and money. The people doing the job are self employed. They have been given a price/time to replace the service pipe and connect the meter. It's qucker to lift block paving or dig through tarmac, than to dig up the concrete in my garage. And meanwhile, the meter connector has to be in attendance, standing around until he can get on with his bit. It appears that they both lose money if it takes too long, so the customer has to accept what he's given. Except that I wouldn't. Not very fair on them it seems to me, but equally not fair on the customer.

Anyway. Exactly as you said. Joints fused with heat. Neat machine. I'm of the opinion that it would have been better to pull in a new length of mdpe, rather than have joints in it where it needed to be extended. But I would imagine that the joints, if done properly, are as good as a continous length of pipe.

So why did my steel riser need to be replaced?
It was yellow plastic sleeved steel, which ran part way under my garage concrete floor to where it was joined to the mdpe. The sleeve if intact, prevents rust on the pipe. Where there wasn't sleeve it was supposed be coated/wrapped in something else to prevent rusting. My pipe was, and when taken out, there was no rust. However, on some pipes the sleeve is either damaged or the wrapping is insufficient to prevent rust. Result, gas leak and or explosion.

So the mdpe has now been run -- sleeved in GALVANISED steel for mechanical protection -- under the garage floor, and up the wall a foot or so, where it terminates to a copper pipe, which connects to the ECV and meter.

Why couldn't they have told me about the non galvanised reasons? I have no idea.

Now I'm just waiting for the blokes to come around and fill the hole with concrete.

As for doing the work yourself. I didn't mean to say that you would be permitted to lay the pipe or make the joints. I really meant that you could dig the hole, and that you would be told the whys and wherefores of it, as there is no good reason not to tell you.

But having seen how it was done, I'm pretty sure I could have done the bit under my garage floor, and the reconnection of my meter at least as well.

Why do I say that? Because, when the meter was reconnected, and the service pipe tested, there was no leak. Then the ECV was opened and the system tested for leaks. There was a leak on the meter side of the ECV. It was boldly stated that I had a leak im my house somewhere. I disagreed, since the leak I was told was a significant one, so I'm pretty sure I would have noticed. I suggested that his "U bend gauge" -- which looked like it had seen better days, was at fault/had a leak. No not possible I was told. Guess what? There was a hole in the rubber pipe used to connect the U bend to the meter nipple. Is that the standard bit of kit to test these days? Well that's all they're issued with it seems. And as for finding the leak. Soapy water. Great if the leak is visible. Not great if the leak is out of sight. Anyway, in this case, you could smell the gas leak and a fiddle with the rubber pipe made it worse. So the leaking end was cut off and the pipe reconnected. No more leak.

I'm not impressed.

 

[Dan Robinson]

Problem with sounding like a smartarse is that when you get something basic wrong in your ramblings it just makes you sound like a bit of a dick.


It's not called a U-bend guage.

 

[slpj]

And the problem with being Dan_Robinson, is that you obviously don't understand the "" used around my description of the gauge used to test for gas tightness. This makes you sound like an idiot.

But let's say I have made a mistake. Under your posts it says, and I quote, -- "A person who never made a mistake never tried anything new."

That particular platitude, in this particular context, proves that you are a DICK, and not a dan at all.

Back to the "U bend gauge" . Well leave out the word bend, and you get U gauge, of which there are many advertised for sale. Now where do you suppose it gets the name? From the U bend obviously.

So if I sound like I'm a smartarse, it's because I'm a damn sight smarter than you are.

 

[Richardthe3rd]

Problem with sounding like a smartarse is that when you get something basic wrong in your ramblings it just makes you sound like a bit of a dick.


It's not called a U-bend guage.

There's nothing worse than some old fart of a 'know-it-all' looking over your shoulder eh Dan? I bet the guys doing his job loved him??!!!
"I don't bloody believe it"

I loved 'One Foot in the Grave' when it was on the telly & it's such a relief that Victor has turned up here on DIYdoughnuts Plumbing forum!!.......

 

[sooey]

Another happy customer.

 

[Richardthe3rd]

And the problem with being Dan_Robinson, is that you obviously don't understand the "" used around my description of the gauge used to test for gas tightness. This makes you sound like an idiot.

But let's say I have made a mistake. Under your posts it says, and I quote, -- "A person who never made a mistake never tried anything new."

That particular platitude, in this particular context, proves that you are a DICK, and not a dan at all.

Back to the "U bend gauge" . Well leave out the word bend, and you get U gauge, of which there are many advertised for sale. Now where do you suppose it gets the name? From the U bend obviously.

So if I sound like I'm a smartarse, it's because I'm a damn sight smarter than you are.

No, no he's the Dan I'm the Dick. See, you're not so smart!!

 

[doitall]

There's nothing worse than some old fart of a 'know-it-all' looking over your shoulder eh Dan? I bet the guys doing his job loved him??!!!
"I don't bloody believe it"

I loved 'One Foot in the Grave' when it was on the telly & it's such a relief that Victor has turned up here on DIYdoughnuts Plumbing forum!!.......

Care with your choice of words Sir Dick

 

[Dan Robinson]

Making the same mistake twice precludes you from the jist of my signature OP .


And putting in speech marks could infer that what you wrote was a direct quote from you.



BTW - U-bends go under sinks - just saying .

 

[onlyfitidealboilers]

Lol 👍😉

 

[Steelmasons]

So if I sound like I'm a smartarse, it's because I'm a damn sight smarter than you are.

Doubt it....@ least Dan refers to it as a manometer.

.......U bend gauge?????? bet those guys were having a laugh at your expense.

A little info is fookin dangerous.

 

[Richardthe3rd]

There's nothing worse than some old fart of a 'know-it-all' looking over your shoulder eh Dan? I bet the guys doing his job loved him??!!!
"I don't bloody believe it"

I loved 'One Foot in the Grave' when it was on the telly & it's such a relief that Victor has turned up here on DIYdoughnuts Plumbing forum!!.......

Care with your choice of words Sir Dick