Earthing

[sedgy34]

Just starting a debate this is what happened!!
i had an assessment on 1 of 6 newbuild houses we had done, the outgoing pipe off the gas meter had been bonded in 10mm earth the water incoming main was bonded too at point of entry in the utility area.
i was told by the electrical inspector he would have to revisit because at each point a gas pipe comes out the floor there should be 10mm bond on it!!!! in response i said you got no chance of me doing such works now theses are new houses.
now there should be 2 responses to my dilema i will give you the rest of the story when ive read your responses.

 

[Strima]

Take it all the gas is in copper pipe? Did he class this as supplementary bonding?

Sounds a bit silly to me.

 

[sedgy34]

new house all in copper

 

[Guest111]

Well it would be copper,you aren,t allowed to use plastic on gas.

 

[sjm]

Test from main bonding point to each place where a gas pipe comes out of the floor. The reading should be below 0.05 ohms if so then all pipework can be considered to be bonded.

 

[sedgy34]

just to reitterate the gas was bonded at the meter, he wanted 10mm earths where the gas pipes come out the floors in different areas round the ground floor ie by boiler,gas fire,gas hob.

 

[Guest123]

just to reitterate the gas was bonded at the meter, he wanted 10mm earths where the gas pipes come out the floors in different areas round the ground floor ie by boiler,gas fire,gas hob.

Well either he had good reason to suspect they may introduce a potential of their own or....the chap was a cretin!!!

A test to prove either 1. the pipework is effectively connected to earth already or 2. to prove that it is not an extraneous conductive part 'should' appease him.

 

[sjm]

Can't remember exactly where I saw it but I believe that re-emerging pipework should be bonded. So the answer is to test as per my previous post then mark it as a deviation on your EIC.

 

[Guest123]

Can't remember exactly where I saw it but I believe that re-emerging pipework should be bonded. So the answer is to test as per my previous post then mark it as a deviation on your EIC.

The only doubt regarding the pipework is the electrical continuity of the underground joints.

Technically the re-emerging pipework could be classed as a seperate extraneous conductive part in it's own right, but as we said, a test would confirm this.

 

[sedgy34]

The assessor was from another area filling in for the normal guy i have making a name for himself suppose he also had another guy with him who was learning to be an assessor. he raised the issue relating to corrosion of pipes in the ground reg and was adamant it needed doing and i will pay for a revisit.

 

[sedgy34]

i seemed to question my knowledge and ability at this stage for a second, then realised this guy was off his rocker afterall this was a new house new pipework would take 40 yrs to corrode i guess

 

[Guest123]

As I said, this is the only issue that may arise.

Are you able to speak to the plumber regarding the joints themselves i.e, are they just bare copper buried in the floor or did he use the insulated type copper pipeing??? would he offer you some sort of written confirmation on thier installation???

Confirming electrical continuity now is one thing, guaranteeing it for 30-40 years is quite another.

 

[Geoffsd]

To confirm, as it hasn't actually been said -

This is a concrete floor?

Is it a Building Inspector or a Scheme Assessor?

 

[sedgy34]

he was a scheme assessor
you can imagine at this stage it was a high topic and you ask all sparkies you know and have the debate in the wholesalers
the floor was concrete with block and beam below that
the copper pipework carcass was as you would expect in a new house laid in the block and beam floor concreted afterwards perfect job from a plumbers point of view.
i did raise this topic with the plumbing contractor noting it was the assessor asking this question and not me!! you can imagine it went down like a lead balloon

 

[sedgy34]

The issue went back to his HQ i took it up with the regional area manager who couldnt decide who was correct!!
the regional manager then asked his good friend assessor who i should have had originally to assess our work who favoured us
logic prevailed in the end!!!

 

[GLENNSPARK]

well theres 411.3.1.2 in the OSG...
it is also necessary to consider not just metallic supply pipework but also internal metallic pipework which may have been buried in the ground for convenience, for example, central heating pipework cast into the concrete or buried in the screed of a floor at ground level. Such metallic pipes would normally be considered to be extranious-conductive-parts.....

 

[brman]

Are you going to spill the beans on which scheme so we can all avoid them?

 

[morph]

if the pipework was buried in the ground and through the concrete i can see the assessors point but a quick continuity test would confirm whether the extra bonding is not needed or not

 

[sedgy34]

Mentioning no names but I'm Nic approved lol

 

[Geoffsd]

I realise the matter has been resolved but an interesting subject.

Is a beam and block floor "the ground". Is it not suspended?

The OSG is just that - a guide.
The regulations state that a service should be bonded where it enters the property (external meter) if extraneous.
If the floor is considered part of the property then the pipes do not re-enter as they did not leave.
No different, in my opinion than being buried in the wall.
Anyway, wouldn't the pipes have been lagged/wrapped to allow for movement?

Remember that the assessor was insisting on 10mm bond, ie. Main Bonding.
So, in his opinion, every gas, water and CH pipe on the ground floor should have been Main Bonded with 10mm G/Y - back to the MET ?

What about upstairs flats with concrete floors? The same?

Also, we cannot be responsible for corrosion after thirty or forty years.
Our meters measure the values today and that is what we use.

It's good that common sense has prevailed but with a less obvious mistake what would have happened?

 

[Engineer54]

This Assessor is either a fool, or wants to make-up his own rules!! What was his reasoning behind his statement?? Hell you could end up with 30mm or more, bonding this gas pipe!! lol!!!

 

[sedgy34]

I understand your comments but if you raise an issue of corrosion the install would have to be some years old not 1month

 

[Edd]

I can imagine all the future work this assesor inspects.. insisting 10mm's running from the MET out to every tap, gas outlet, pipe. boiler etc..
it would be like a spiders web. Bet he came up with the idea, spurted it out, and then relised what a pratt he had been but couldnt back track and make himself look a fool!

 

[drew35]

If the gas pipe in the ground corrodes than an earth bond is the least of their worries. Ask him to show you where this regulations is written.

 

[Guest111]

If the gas pipe in the ground corrodes than an earth bond is the least of their worries. Ask him to show you where this regulations is written.

as far as I am aware you are not supposed to bury gas pipes in concrete floors these days.

 

[telectrix]

if that gas pipe corrodes, then there won't be much left after the gas explosion anyway.

 

[Engineer54]

as far as I am aware you are not supposed to bury gas pipes in concrete floors these days.

Can't see a problem with gas pipes laid in the screed of a concrete floor, so long as it's been wrapped in that grease impregnated tape, (it always used to be) there is very little chance of corrosion!!

I can remember a friend of mine many years ago now, running his kitchen gas pipes in a larger PVC sleeve in the screed, when he renovated/extended his kitchen...

 

[Guest111]

Can't see a problem with gas pipes laid in the screed of a concrete floor, so long as it's been wrapped in that grease impregnated tape, (it always used to be) there is very little chance of corrosion!!

I can remember a friend of mine many years ago now, running his kitchen gas pipes in a larger PVC sleeve in the screed, when he renovated/extended his kitchen...

Idont think it was to do with the corrosion,I seem to remember it being something to do with damage from drilling or fracturing if concrete flexes as it could have a shearing effect on pipe.

 

[Engineer54]

I can understand the drilling through, with these kitchen fitters these day's, but not damage due to Screed flexing. as screed sits on top of the concrete floor. They have been installing gas/water pipes in the screed for donkey's years, especially in commercial/industrial premises...

 

[Des 56]

The plumbers I know still bury it,here is some info I found,it seems eng 54 is spot on with his facts

Pipe in Screed, Corrosion protected pipe
Soft copper tube in plastic sleeve

Installing tube in walls and floors,where copper tube is to be buried in solid floors or walls, the number of joints should be kept to a minimum.
Ideally the tube should be run in a preformed duct (If its in ducting the ducting has to be sealed with a suitable PTFE tape 50% overlap)

If its "ideally" in a duct,it goes to say, it can be done otherwise

 

[Spark1979]

You can't bury gas pipe work in the concrete foundations of premises due to movements it's in the gas regulations, you can lay in screed as long as it has manufacturers protection on and is at correct depth

 

[Guest111]

You can't bury gas pipe work in the concrete foundations of premises due to movements it's in the gas regulations, you can lay in screed as long as it has manufacturers protection on and is at correct depth

new there was something about not burying it cheers mate.

 

[Des 56]

This is from the European copper board

. Use plastic sheathed copper laid on top of the base concrete and soundness test the installation piping before wrapping any joints and covering with a suitable screed.

Alternatively, pass plastic sheathed soft coiled copper through a larger tube that has been previously set into the concrete.

http://www.ukcopperboard.co.uk/lite...on-Tips/Domestic-gas-installation-testing.pdf

Seems like we need a plumber to decide :wink5:

 

[Spark1979]

As an Niceic approved electrician who is now doing his igq in gas bs6891:2005 states under 8.8.1: installation pipe work shall not be buried in concrete slabs. 8.8.2: rigid stainless steel pipework shall not be buried in concrete screeds. Where a pipe is buried in a concrete screed there shall be a minimum of 25mm of cover above pipe
8.8.3: pipes buried in concrete grounds floors shall be protected against failure caused by movement. Joints shall be kept to a minimum. No compression fittings.

Hence gas pipework must be laid in the screed not concrete foundation!

 

[Des 56]

As an Niceic approved electrician who is now doing his igq in gas bs6891:2005 states under 8.8.1: installation pipe work shall not be buried in concrete slabs. 8.8.2: rigid stainless steel pipework shall not be buried in concrete screeds. Where a pipe is buried in a concrete screed there shall be a minimum of 25mm of cover above pipe
8.8.3: pipes buried in concrete grounds floors shall be protected against failure caused by movement. Joints shall be kept to a minimum. No compression fittings.

Hence gas pipework must be laid in the screed not concrete foundation!

This all Bananas and custard to me, because I know little if anything about the subject

, but your quotation seems to suggest the opposite of your conclusion.
I have underlined what appears to contradict

 

[Spark1979]

Concrete ground floors are the entire floor as a whole. See http://www.greenspec.co.uk/ground-floor-insulation.php for break down of a floor

 

[Engineer54]

I don't know what the building regulations in the UK state now, but screed cover used to be min 4''. So there should not be much of a problem of achieving a min 25mm cover over any pipe or conduit work laid in the screed.

By the way Screed is NOT a concrete mix, it's purely a sand and cement mix, generally a weak one at that!!!

 

[sedgy34]

The floor was block and beam and I think a wet screed but hasn't block and beam got a cavity
The pipes were as 1 branched off and soldered joints wrapped in yellow tape then stabs coming out of the floor were the gas appliances are
The gas regs may have changed now

 

[Engineer54]

Think they use a membrane on block and beam work, and pour the screed mix in top of that!!! Pretty sure that's what they do on the projects i've worked on, but i'll ask our Civil Engineer tomorrow...