Had a corgi regged gas fitter in to estimate putting in a new stove, whilst there he said I must get the pipes through the wall from the meter refitted as they are not sleeved. Had another fitter came also corgi registered and he said it was not necessary. Anyone know the real facts?
Really they should, but if there is no sign of corrosion or damage and its not a meter box were the pipe comes through the wall, there should be no problem. Its what is called "Not to current standards" the lowest classification on unsafe situations.
ANY gas pipe passing through a cavity wall must be sleeved with a gas tight sleeve to prevent the possibility of a corrosion or damage caused leak to the pipe resulting in the cavity filling with gas. Its also currently expected practice to sleeve through all walls (even solid or single brick/block) to protect the pipe from mechanical or corrosion damage. As a pre-existing installation its NCS (not to current standards) and therefore at risk. Your first installer is right. I'd suggest you go with his advice and have the sections of pipe passing through the walls sleeved. Certainly you should beware of corrosion leaks developing slowly within the wall.
Yup, they must be sleeved, partly to protect the copper pipe from corrosion due to its being in contact with brickwork which may have various salts and other stuff in it which could attach the metal, and partly to protect it from mechanical damage due to movement of the masonry itself. If it's possible to make enough of a gap around the pipe to slip maybe a slit length of plastic pipe or cut up squeezy liguid bottle[1] over the pipe that'd do. You need to seal the gap between the pipe and the sleeve at the indoors end: any non-cracking filler should do e.g. frame filler, decorator's caulk, silicone, plumber's mait.
[1] and here's one we made before the programme. :-)
ISTR that it is a must for cavity walls in case the pipe should develop a leak mid cavity so a build up of gas might go bigga banger should it light up!.
Other than that doesn't seems like a bad idea just to allow for movement..
To allow for structural movement, shouldn't the sleeving be strong enough to protect the copper gas pipe. I think that the plastic bottle would fail in these circumstances, however, a deformable plastic sleeve would still allow an escape path for leaking gas. Tom
There's no requirement in the standards (BS6891 IIRC) for the sleeving to have any particular strength. I think the idea is just that it allows some space between the pipe & masonry whereas if the pipe's fitted in tightly any movement will damage it.
Corrosion from mortar?
.andy
To email, substitute .nospam with .gl
Indeed. Many cements attack copper when damp. I have been to more than one 70's flat where the CW pipes were not adequately wrapped and the pipes have sprunk a leak.
AIUI the sleeve allows for two problems: One: it lets the building settle a little without straining the pipe. Two: if a leak did occur it will encourage it to vent outside.
As a further precaution pipes go through cavities directly and without joints.
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