protect a Gas pipe in screed

Yarn · 12 Jan 2012

Hello, I would like to know if it is ok for a Gas pipe in a screed channel to be 'gaffa taped' / duct taped to protect it from the concrete corrosion?

Not work i have done my self but have this situation and am concerned its not up to regs.

Could i beef up the protection with some DPM polythene (if im careful not to make a cavity)?

Thanks.

dcawkwell · 12 Jan 2012

best stuff will be conduit.

Agile · 12 Jan 2012

The correct protection for metal pipe in/near concrete is a kind of Denso tape.

We used to be able to use Denso tape but now have to use what looks the same but is sole for more but packaged for gas pipe use!

I assume that your pipe is in an open channel within concrete.

Normally has to be removed to wrap the tape.

Tony

Yarn · 12 Jan 2012

Thanks, I have to say that i already knew both of these answers. What i would like to know is, if it currently does not comply, and i need to insist that it is changed (or if it does comply, can i add some DPM for my own peace of mind).

Agile, you are right, i cant add denzo myself as its now fitted in the channel. It would be easy for me to slide some polythene strips along the pipe and tape them up though.

Dan Robinson · 12 Jan 2012

Your set up is not compliant and your solutions wouldn't be either.

It needs to be done properly.

Yarn · 12 Jan 2012

Thanks so much.

Can i confirm what i should insist it is re-done with? does this need to be Denzo tape, to screed straight over it?

Dan Robinson · 12 Jan 2012

It needs to have 25mm minimum, ideally 50mm minimum of screed above it.

And wrapped in a suitable materials. Denzo, for example. With a 50% overlap. Really the tube used should have been sheathed with the joints wrapped.

If there are cars etc.,, travelling over the pipe it needs to be covered with 375mm.

Pedestrian traffic 40mm.

Yarn · 12 Jan 2012

This is in my kitchen.

Interesting that you use the words 'suitable material'. I can imagine this is where the argument will occur later with the fitter.

For that matter why is some DPM polythene not suitable material.

I am not disagreeing with you, but i already know the response im giong to get later.

Agile · 12 Jan 2012

You are not giving us the full and correct information!

If this channel is now to be filled with concrete it must have sufficient cover lime 40mm as well as being wrapped in the CORRECT petroleum jelly impregnated tape.

Dan is out of date ( or having another early senior moment ) and now we can only use the protection tape sold for gas use! It has been a recent ACS question!

Wrapping with plastic sheet may be better than nothing but does not comply with the regulations!

Of course if its to remain a duct then it does not specific protection but preventing direct contact with concrete is advisable. Also the duct will need ventilating in accordance with the regulations.

Tony

Yarn · 12 Jan 2012

I want to fill with screed. Have at least 50mm clearance above the pipe. sounds like i just need the tape?

didnt understand "sufficient cover lime 40mm"

Dan Robinson · 12 Jan 2012

I thought Denzo wasn't allowed in walls.... Floors were OK, but happy to be corrected.

Agile · 12 Jan 2012

Sorry that was a typo. Should have read "like 40 mm".

Again Dan has forgotten as the instruction for pedestrian traffic is a minimum of 40 mm with 50 mm being advised.

Its very naughty of a lazy installer not wrapping pipe ( with the correct product ) if he knows its to be burried in concrete.

If it was reported to Gas Safe he would be required to dig it up and do it properly all at his own expense.

Although the tape is expensive at about £10 for 10m of 50mm tape from Plumb Centre its false economy for an installer to not use it when the consequences could be so severe in terms of cost and remedial work required.

Untitled

Agile
12 Jan 2012
1

Tony

Dan Robinson · 12 Jan 2012

Shows how often i bury gas pipes in screed

muggles · 12 Jan 2012

Should really have been run in plastic-coated copper pipe, with the plastic removed in the vicinity of the joints and taped with a suitable tape after testing. The suitable tape would either be the anticorrosion tape mentioned, or I believe self-amalgamating silicone tape is also permitted

Yarn · 12 Jan 2012

Thanks all. I shall have a word and let you know.

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protect a Gas pipe in screed

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