Just a quick question, hope somebody can help. I know gas pipe installations with pipes through walls have to be sleeved, but I am unsure about the following:
TIA.
Alex
The overall effect is to prevent the copper of the pipe, and this applies to water pipes too, from coming into contact with mortar or plaster.....there are several ways of doing this, but with existing pipes through walls, the easiest way has to be expanding foam - this creates a barrier and prevents the alkalis attacking the copper, with new installations, any plastic tubing, denzo tape(the greasy stuff), PVC tape, then point over, plaster as normal etc.
I doubt if anyone is interested in your pipes and whether they are up to regulations etc, but I have seen copper pipes almost corroded through within
10 years in areas of constant damp where the alkalis are leeching out of the plaster/mortar....in very dry conditions it's a rarity to see any corrrosion at all.
There is a probability in the future that I would be renting the property, in which case as Landlord I would require a gas safety certificate. I don't want to do work now for myself that will require re-doing in order to obtain the certificate. As for existing pipework being sleeved, if it will require it to be certified, then it makes sense to remove it and re-do now rather than later.
Alex
IIUC, only when installing or altering the pipework.
Yes. See BS 6891:
"8.9.5 Solid walls Every pipe passing through a solid wall shall be sleeved."
The purpose of the sleeve is to contain any escape of gas such that it is vented outside the building (preventing corrosion of the pipe is a welcome fringe benefit, but not the primary motivation).
Section 8.10 of the above BS describes it:
"8.10 Sleeves
8.10.1 Sleeves shall be of a material capable of containing gas, e.g. copper, steel, polyethylene or polyvinyl chloride (PVC). 8.10.2 Sleeves shall pass through the full width of the wall or the full thickness of the floor. Sleeves shall not impair the fire resistance of a building. The annular space between the pipe and the sleeve shall be sealed at one end to the pipe with a flexible fire resistant compound. Where a sleeve passes through an exterior wall, the seal shall be on the inside of the wall.COMMENTARY AND RECOMMENDATIONS ON 8.10.2 The internal diameter of any sleeve should allow for an annular space around the pipe to enable satisfactory insertion of the pipe into it and be of sufficient diameter to allow adequate sealing between the pipe and the sleeve. Additional information on the installation of polyethylene pipe can be found in the Institute of Gas Engineers and Managers publication IGE/TD/4 [6], Gas Services.
8.10.3 Screwed, push-fit and compression joints shall not be located within a sleeve. 8.10.4 The outside of the sleeve shall be secured and sealed at each end to the structure of the building with a suitable building material, e.g. cement mortar."I am not sure what the most favoured "flexible fire resistant compound" is however...
Pity whoever installed the bottled gas system in my house didn't read this... The bottles are outside and the 15mm copper pipe just comes straight through the wall. No sleeving.
Just walk down any road of houses, and you'll see a number of tell-tale signs of sealed system boilers, i.e. a flue terminal, pressure relief pipe, and gas pipe all going through the wall within a few feet of each other. It's remarkably rare to see the gas pipe is actually sleaved, yet these will nearly all have been installed by CORGIs. I often wonder why this particular regulation is so universally ignored by the profession.
Needless to say, if you look at my own DIY installation, they're all sleaved (even the water pipes, so as they exand and contract, they don't eventually rub a hole through the pipe), although I must admit I didn't bother with the PRV outlet.
Heat resistant silicone. Itumescent mastic
It makes the job harder and needs bigger tools. To be fair the sleeving might not be easily visible from a distance.
There is much better inspection and montioring of gas work than there was a few years ago.
As to what to do if the existing installation is sub standard.
If the pipes are dry and not leaking then the most any fitter would likely categorise unsleeved pipework would be "At Risk".
I would have though any (real) silicone was pretty heat resistant?
Yeah, but have a look at the spec of "Heat Mate".
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