Alex wrote:

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:

1. Do existing installations that are not sleeved now have to be
re-sleeved to comply? Most of the gas pipes in the house were
installed 30+ years ago.

IIUC, only when installing or altering the pipework.

2. Does the sleeving apply to non-cavity walls?

Yes. See BS 6891:

"8.9.5 Solid walls
Every pipe passing through a solid wall shall be sleeved."

3. What should the sleeve be sealed to the pipe with, and also what
should you seal the sleeve into the wall with?

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...

--
Cheers,

John.

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