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.

  Dragon_Heart 21:11 30 Nov 2010

How can you tell it's not leaking ?

One solution is to get some washing up liquid and squirt it around the pipe / hole in the wall, if bubbles appear you've got a leak.

Transco old name, National Grid new name !

  Forum Editor 21:21 30 Nov 2010

but on the surrounding area of brickwork where the pipe emerges from the wall internally."

That's almost certainly because the pipe is colder than the air in the room, and moisture is condensing out onto the pipe, and the surrounding brickwork is wicking it away.

  Dragon_Heart 02:41 01 Dec 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 "

The water supplier's shut-off valve is on the public highway 99.9999% of the time.


"So that when the gas pipe causes an explosion that destroys your house you can prove to your insurers that you weren't negligent - you'll have details of the call you made."

That's if your still in one piece ! Sleep well !

  CurlyWhirly 19:48 01 Dec 2010

Leaking ?

How can you tell it's not leaking ?
Because I had my boiler sefviced last week and after he had finished the Gas safe registered plumber used a device that detects gas leaks also there's no smell of gas ;)

  CurlyWhirly 19:53 01 Dec 2010

That's almost certainly because the pipe is colder than the air in the room, and moisture is condensing out onto the pipe, and the surrounding brickwork is wicking it away.
I hope your right!

I wonder if you can buy something that absorbs moisture from the gas meter cabinet like what is used when you buy a pair of new shoes!

I think they are called silicate crystals ?

This would help me with the diagnosis.

p.s. just thought, I could paint the pipe with anti-condensation paint or would this be frowned upon by the National Grid ?

  namtas 20:35 01 Dec 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.

Unsure what prompted FE to remind me of this. As a ex Domestic Systems Corgi registered engineer I am well aware of the regulations.

  oresome 20:43 01 Dec 2010

Under the circumstances may I suggest that CurlyWhirly keeps the record of the phone conversation some distance from the property!

  CurlyWhirly 20:49 01 Dec 2010

Yes and as I live in a terraced house, it would take out my neighbours houses either side of mine too !

  spuds 21:45 01 Dec 2010

Approximately 18 months ago, sub-contractors for the National Grid changed all the underground gas pipes and fittings in my area. Out went the old wrought or cast iron and was replaced with plastic or copper piping.

Work done on my property consisted of the meter being removed from inside the property, to a new location at the front of the house. From the newly located meter to the interior of the house, and previous wrought iron pipe, a copper pipe was installed on the outside of the wall, plus insertion through the wall. The seal at that point was by a mastic sealant. All very unsightly, and perhaps (in my opinion) considered hazardous, due to the copper pipes fragile nature.

Reading an earlier posting, I note that someone had a drive replaced due to underground workings. We had a similar experience, and due to the contractor's bonus scheme, we had to 'demand' the sub-contractor's back twice, even though the original notification papers stated that a 'specialist team' would replace-repair as in before state'. This was not true, so be aware if the National Grid and their sub-contractor's are working in your area.

  Dragon_Heart 22:07 01 Dec 2010

.... not you're bonus :-(

This is down to cost cutting and lack of supervision by the National Grid and other utility companies.

This thread is now locked and can not be replied to.

Elsewhere on IDG sites

Apple unveils first ‘pro’ iPhone 11 Pro and 11 Pro Max

IBC 2019: new video tools from Adobe, Blackmagic, Lenovo and more

iOS 13 release date, time & new features

Les meilleurs appareils connectés compatibles avec Google Home (2019)