Gas pipe question(s)

[Bodgitnscarper]

Please can any qualified gas plumbers give me some advice?
This is NOT for DIY purposes, I just want to know what options are/could have been for the gas supply to our new extension.

The extension walls are block work and are not plastered yet.

We had the main incoming gas supply moved to an external meter box by a utilities company.
We then had a company come round to fit us a new boiler.
The chosen position for the boiler is approx 6 meters from the meter box on the same wall, but is the other side of the external side door and window.
So the gas plumber took the gas pipe straight through the back of the meter box, then vertically upwards (surface mounted on the block work).
He then ran it horizontally right under the joists and against the wall (surface mounted on clips).
The pipe is 28mm for the first 3.5m, where it tees off in 22mm to the boiler, for a further 2meters. The branch coming off in 22mm goes into the existing house and is capped under the floor for a possible future gas fire.
The joists are 8"/195mm.
The plumber reckoned he couldn't fit the pipe through the joists (which run perpendicular to the pipe run to the boiler) because it's 28mm.
However, I have researched the rules on drilling joists and, as far as I can see, holes could be drilled to a maximum of the middle third of the joist depth (so approx 65mm max).
So as long as there are 3 diameters between holes, could he not have drilled 30mm(ish) holes and joined a series of short lengths together? Is there a reason why he couldn't have hid the pipe rather than leaving it in the top corner? It looks a bit naff!
The walls will be dry lined with dot and dab but I doubt it will be deep enough to hide the 28mm pipe on its clips and Id assume this would be dodgy anyway if it was hidden in the top of the wall?
The floor is suspended block and beam and the insulation & screed haven't gone in yet. Would I be better having the pipe moved into a floor channel or something?
Would there be a better way to get the pipe to the boiler?
Thanks.

 

[rochdalegas]

I might be wrong but I think its 12.5 % of the joist depth so it would be over. also a bad idea to cut neat the end of joists. Is re routing outside an option to consider if not a neat boxing job and it will soon be forgotten I tend to only notice things when they are done then soon forget about them 6 months down the line.

 

[Bodgitnscarper]

Thanks for your swift reply.
I suppose once the ceiling and walls are boarded it won't be so obvious.
Are there any requirements not to hide/bury it?
I'd always know it's there but not so obvious should I sell the house on in the future.

I suppose external would be ok as long as the copper didn't get nicked!

 

[John D v2.0]

If you put it outside you can always put it inside a 32mm waste pipe for disguise against thieves!
Need to seal inside but not out though in case of a leak.

 

[Bodgitnscarper]

Rochdalegas - I've just checked again and the 12.5% is correct for notches.
I was wrong about the hole sizes though, the max size diameter it is a quarter of the joist depth.
Thanks again.

 

[FiremanT]

Picture?

 

[Elkato531]

the max size diameter it is a quarter of the joist depth

True, but the allowed position for drilling is between 0.25 and 0.4 times the span, so you can't drill a joist close to the wall. Also threading 28mm copper through successive joists is not easy. You'd have to chop it into short pieces and then solder it back together again.

 

[bernardgreen]

I suppose once the ceiling and walls are boarded it won't be so obvious.
Are there any requirements not to hide/bury it?

There are regulations about gas pipes in enclosed cavities. I seem to recall that any cavity in which there is a gas pipe has to be ventilated to prevent to build up of gas should the pipe develop a leak.

and joined a series of short lengths together?

more joints = more risk of a leak.

 

[John D v2.0]

. I seem to recall that any cavity in which there is a gas pipe has to be ventilated to prevent to build up of gas should the pipe develop a leak.

Yes or you can sleeve the pipe so it's not open to the cavity