Mains gas pipe query

  CurlyWhirly 21:02 28 Nov 2010

I live in an old house that has no physical DPC installed and I have recently had a problem with rising damp but it's sorted now - I hope !

However I've noticed that the mains gas pipe is corroding as the part of the pipe that is coming through the wall on the inside has a ring of damp around it.

As that particular wall has now been damproofed I should be okay but I'm just curious as to what would happen if gas was leaking out of a corroded pipe as the section of pipe that I'm referring to comes BEFORE the gas shut-off valve and so shutting off this valve would serve no purpose !

I wonder what Transco would do in this situation ?

Outside the gas pipe goes directly into the ground so I'm assuming that there must be some sort of on/off valve underground ?

p.s. I can't be certain that the damproofing will be successful on this particular section of wall (aprox 3 ft in length) as my stone walls are 18 inches thick and should really be pumped from both sides but, due to the gas meter cupboard being in the way, it was only possible to pump that particular section of wall from the outside.

  uk-wizard 21:17 28 Nov 2010

"I wonder what Transco would do in this situation?"

Stuff a yellow plastic pipe through the old metal one if possible.

  Forum Editor 23:13 28 Nov 2010

is that any gas pipe that passes through a wall must be enclosed in a section of non-corrosive pipe - usually plastic.

Your pipe is obviously the older iron type - what used to be referred to as 'barrel', and it will corrode, although it takes a very long time to corrode to the point where the gas will leak.

The National grid is now responsible for all underground gas pipes up to the pre-meter terminal valve. If you're concerned about corrosion you should talk to them.

  Dragon_Heart 01:59 29 Nov 2010

Both uk-wizard & FE are correct.

In our case they pushed a new yellow pipe ( indicates it's gas ) through the old pipework. Made a new connection at the main AND put our gas meter on the outside wall. ( The metrer reader still left 'not in' cards several times despite the large white blob with a gas symbol on the wall ).

Even if you have copper pipework it is best NOT to have brickwork render or motar in contact with it.

  BT 09:09 29 Nov 2010

We had a gas leak just outside our front gate under the pavement.
The gas company replaced the whole pipe from the main to the house by driving a 'Mole' underground the whole 20 yds right up to the house. They just had to dig one small hole where the pipe came up next to the house, and one halfway up the driveway.
At the same time they moved the meter to a white box outside and replaced all the pipework into the house.

  skeletal 11:02 29 Nov 2010

For reasons known only to the great and the good, as soon as a water pipe crosses your boundary, it becomes your responsibility, but as others have said, this is not true of gas pipes. It is the Network owner that is responsible for all gas equipment up to and including the ECV (Emergency Control Valve), the valve that in domestic situations is positioned just before the meter installation. In most cases the Network owner is National Grid.

As usual, there is a mountain of legal and technical issues surrounding this.

If you are really really interested in this, including all the variations for industrial and commercial premises, the Institution of Gas Engineers and Managers have a published Procedure: “Defining the end of the Network, a meter installation and installation pipework (1733)” for the bargain price of £70.

Or, the simple answer is that if you have any worries, contact National Grid and let them sort it out.


  namtas 14:03 29 Nov 2010

If you think about it, having full control up to the valve is perfectly sensible to me. It really would not be a good idea for a gas company to have to seek authority to deal with a gas leak where the customer was either not available or not cooperative.

  skeletal 14:28 29 Nov 2010

I have to say I think it’s sensible as well! Back to water companies, if there is a leak underneath your drive, it could go on for ages, and provided you aren’t paying for the water via an upstream meter, the water company would have quite a job to persuade you to cough up the cash to repair what in my book is “their” leak.

I suppose they “get you” in the end, by threats...I’m not sure.


  Forum Editor 17:30 29 Nov 2010

No, don't phone Transco. As I said earlier, the National Grid is responsible for transporting gas on the underground pipe network, and up to the meter terminal valve.

If you're worried about the safety of a gas pipe outside your house, or if you smell gas, there's a National Grid help number which you call for advise and assistance:-

0800 111 999

  Forum Editor 17:35 29 Nov 2010

You are entirely responsible for the mains water supply pipe that runs under the ground on your property, once the pipe leaves the water supplier's shut-off valve.

If there's a leak you are obliged by law to have it repaired to prevent a waste of water, although some water suppliers will repair it for you, free of charge. They aren't obliged to do it, however.

  Forum Editor 17:37 29 Nov 2010

In the case of a leak on a gas supply pipe, The National Grid has a right of entry onto your property for the purposes of making a repair.

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