Routing 28mm Gas Pipe Through 7 Inch Joists

[M25]

What is the current best practice for routing a 28mm copper gas pipe in the void between a ceiling and a floor where 7 inch joists are used, assuming this can be done?

I understand that the maximum "permissible" notch depth for such a joist is only 22mm so that would not be enough, however holes can be up to 44mm (provided they are between 1/4 and 2/5 of span and on the joist centerline vertically).

In the case I am considering the pipe would need to go through three or four joists and could be fed into the space at the right level from the outside of the property (as it would enter via a sleeved hole in the wall). So it seems reasonable that it could be threaded through holes in the joists without much practical difficulty.

Is installation via holes in the joists acceptable? What would be the ideal hole size, and would any sleeving through the joists be advisable? Also, would this create a ventilation requirement for this area or any other issues?

This question is for advance planning and interest only, gas pipes will be installed by a gas safe registered contractor when the time comes and I'm sure he/she will also know the answer! Thanks in advance for any helpful responses.

 

[bernardgreen]

Holes midway between top and bottom of the joist are the best option as they have the least effect on the load bearing capacity of the joist. Notches top or bottom have a far greater effect on reducing the load bearing capacity.

 

[snb]

a use for trac pipe

 

[dilalio]

a use for trac pipe

+1.

Recently did exactly this on three barn-style new builds. Trac pipe is fully sleeved throughout, thus making it perfect for voids. I’m sure you can find installation information on their website or data sheets.

 

[oilboffin]

+1 here too.Bob

 

[M25]

Thanks all, I do agree holes in the centre of the joists is the way to go to maintain their strength and also the trac pipe looks like a good option.

Seems like 15m of trac pipe might be about 210 pounds inc vat compared to 120 for copper, so not bad at all.

Still would like to know whether the copper pipe would be allowed in holes though. I have an old uk domestic gas manual which says "pipes should be laid across the underside of joists" .... "where this is not possible they *must* be laid across the top of the joists with the joists notched to accommodate the pipe". So this lead me to thinking that somehow holes might not be allowed, whereas notches were OK. But of course my joists are not big enough for 28mm notches!

Is there such an issue or am I just taking it too literally? Presumably the trac pipe is fine in holes, although those holes would need to be bigger for the same internal diameter.

 

[dilalio]

Trac pipe through holes.
It’s also about gas pipe in void - not just about structural integrity of joists.

 

[FiremanT]

Trac pipe through holes.
It’s also about gas pipe in void - not just about structural integrity of joists.

No venting required in ceiling/floor space installations.But agree TP is a damn sight easier to run through joists than copper.

OP: Not sure about old rules, but you should not notch the bottom of the joisyts, if that is what you mean - drilling is preferable, and you can buy a 80 degree drill attachment to make it easier:

 

[M25]

That looks like a useful tool, I'd not thought about whether you could get a drill in there at the right angle...

It's helpful if there is no venting needed (or inspection points etc...). Of course assuming either no joints or just properly soldered joints in the case of copper.

 

[Dan Robinson]

or just properly soldered joints in the case of copper.

Irrelevant.

 

[John D v2.0]

It's helpful if there is no venting needed

Between floor and ceiling is not usually ventilated at all, only below ground floor and in the loft is ventilated to protect the timbers.
You would need sleeved and sealed appropriately, or make sure the joist space is open to the rooms.

 

[M25]

There seems to be some differing opinion on venting. It's correct that there is no actual vent to my knowledge (e.g air brick or whatever) but it's not going to be very well sealed either with lots of pipework entering and exiting all around the house.

There are already 22mm copper gas pipes in this space, not that that makes it right, and these will be disconnected anyway as I need 28mm.

Is there a definitive reference or building regulation on this point? I could put in a vent in the hall ceiling say, but without seeing an associated regulation I would not know how big to make it.

Tracpipe told me no venting was required for the tracpipe option, and that that was the case up to a certain pipe size but 28mm was OK. So it's just the 28mm copper option I'm unsure about.

 

[John D v2.0]

If it's not part of the room and doesn't have ventilation provided then it's a building void.
Someone might seal round all the pipes to stop noise or something. At least less likely with proper vents to outside

 

[FiremanT]

There seems to be some differing opinion on venting. It's correct that there is no actual vent to my knowledge (e.g air brick or whatever) but it's not going to be very well sealed either with lots of pipework entering and exiting all around the house.

There are already 22mm copper gas pipes in this space, not that that makes it right, and these will be disconnected anyway as I need 28mm.

Is there a definitive reference or building regulation on this point? I could put in a vent in the hall ceiling say, but without seeing an associated regulation I would not know how big to make it.

Tracpipe told me no venting was required for the tracpipe option, and that that was the case up to a certain pipe size but 28mm was OK. So it's just the 28mm copper option I'm unsure about.

Between floor and ceiling is not usually ventilated at all, only below ground floor and in the loft is ventilated to protect the timbers.
You would need sleeved and sealed appropriately, or make sure the joist space is open to the rooms.

If it's not part of the room and doesn't have ventilation provided then it's a building void.
Someone might seal round all the pipes to stop noise or something. At least less likely with proper vents to outside

M25: John regularly oversteps the mark in giving "advice". To be fair, you cannot be expected to find out everything with a quick Google

The space between a ceiling and a floor does not need to be vented, and no special precautions (sleeving etc) are necessary for copper. To be honest, I have never used Tracpipe, so I will err on the side of caution, and say to check the instructions, or get further definitive advice here (but not from JohnD, or God help you, Bernard Green when he pops up).

 

[John D v2.0]

To be fair, I forgot to point out I am not a qualified gas engineer. Thanks for the reminder

The space between a ceiling and a floor does not need to be vented,

Agreed, in fact venting it would be very thermally inefficient.

and no special precautions (sleeving etc) are necessary for copper

So how about the law? How do you interpret gsiur 19 (6) "Where any installation pipework is not itself contained in a ventilated duct, no person shall install any installation pipework in any shaft, duct or void which is not adequately ventilated. "
I don't see any exemption for the void described.