Gas pipe camera inspection ?

[Deleted User] · 9 June 2017 at 5:03PM

Long story short.
Built house.Originally laid 3/4" gas pipe under concrete.
Come to hook up the boiler and not enough pressure to fire it up.Engineer suggests kink or blockage in pipe. We're going to try air compressor to blast out the pipe with air but ....

Question: Is there the technology available to put a camera down the 3/4" pipe to detect anything before having to drill everything up and lay again.Can I hire someone to come and do this ?

Thanks in advance.

FreeBear · 10 June 2017 at 1:06PM

You can get cameras for inspecting pipes internally - A company close to me makes pipeline cameras for the oil & gas industry (mega bucks)..

For a small pipe, assuming a straight run, a cheap endoscope from ebay would probably do the job. https://www.ebay.co.uk/sch/i.html?_nkw=10m+usb+endoscope

DaftyDuck · 10 June 2017 at 1:26PM

Replace pipe! Kink or bend under concrete equals weakened pipe. Gas pipe, too. Under concrete!!! Few more!!!! for emphasis.

Even if it is semi-sorted for now, it will fail later.

Get pipe replaced.

Oh, it was properly covered to protect it from the concrete, wasn't it?

Furts · 11 June 2017 at 6:02AM

I second DaftyDuck. Over the years I have been told do not put gas pipes in floor slabs, nor duct them under, or through, concrete slabs.

A new pipe seems the proper way forward to me.

southcoastrgi · 11 June 2017 at 1:50PM

3/4 or 22mm ?
The pipe might not be big enough for the boiler anyway
It would have to be really kinked or damaged to not let the boiler fire at all

[Deleted User] · 12 June 2017 at 4:58AM

Furts wrote: »

I second DaftyDuck. Over the years I have been told do not put gas pipes in floor slabs, nor duct them under, or through, concrete slabs.

A new pipe seems the proper way forward to me.

How else are you supposed to lay a gas pipe under a house from street meter to boiler ?
It's standard practice here in Ireland to lay pipe in a new build between the insulation and poured concrete floor.
It's a 3/4" copper pipe in white plastic casing which is industry standard.
The pipe was clipped down onto insulation boards before the concrete was poured.
We find it hard to believe there's an obstruction or link because of the care we took and also because when one person blows down one end of the 50 foot pipe it's possible to feel the air coming out of the other end.

Anyway the compressed air has produced nothing so camera is the next option.
The pipe is drawing 20 bars of pressure but when the boiler attempts to kick in this instantly drops to 10.
That and getting the new meter checked by the gas board appear to be our only options other than laying a new pipe which is going to be hugely problematic because the house build has been completed.

Le_Kirk · 12 June 2017 at 9:48AM

Maybe it is the distance from supply point to boiler that is the issue and the pipe is not big enough!

firefox1956 · 12 June 2017 at 10:21AM

It sounds to me as though your problem might NOT be your pipe.
As you say it would nearly have to be squashed flat to be that restricted &
if you laid the pipe yourself you would have noticed a kink that bad.
Sounds to me more like a problem at the meter or the boiler.
I would be investigating at either end before starting ripping floors up !!
HTH

ComicGeek · 12 June 2017 at 10:57AM

Deleted_User wrote: »

How else are you supposed to lay a gas pipe under a house from street meter to boiler ?
It's standard practice here in Ireland to lay pipe in a new build between the insulation and poured concrete floor.
It's a 3/4" copper pipe in white plastic casing which is industry standard.
The pipe was clipped down onto insulation boards before the concrete was poured.
We find it hard to believe there's an obstruction or link because of the care we took and also because when one person blows down one end of the 50 foot pipe it's possible to feel the air coming out of the other end.

Anyway the compressed air has produced nothing so camera is the next option.
The pipe is drawing 20 bars of pressure but when the boiler attempts to kick in this instantly drops to 10.
That and getting the new meter checked by the gas board appear to be our only options other than laying a new pipe which is going to be hugely problematic because the house build has been completed.

It is commonplace to run the gas pipe in screed above insulation as you have done - I think the previous posters were concerned that it had been laid in a concrete slab without protection, which would have been an issue.

When you say 20 bars of pressure, I assume this is actually mbars? More likely that the installed pipe is damaged somehow, as 50 foot pipe for a large 38kW combi in a 22mm copper pipe with a couple of bends would probably only be about 2 mbar loss, not 10 mbar.

Still very close to the limit though as some boiler will need 18mbar or higher to work. I would definitely have used 28mm pipe instead of 22mm, with a loss of less than 1mbar. Personally I think you need to look at options for running a new gas pipe internally (with suitable ventilation in voids).

ComicGeek · 12 June 2017 at 11:06AM

Actually, just looking at the figures again, are you 100% it wasn't 15mm copper pipe, not 22mm. I've just done a rough calc with 50 ft 15mm copper on a 38kW combi, and come up with a pressure drop of 10 mbar......

[Deleted User] · 12 June 2017 at 2:42PM

Definitely 3/4"

Gas pipe camera inspection ?

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