hob gas supply

i have moved the hob in my kitchen to a different wall.
i have made up a new length of pipe that runs across the ceiling and down the wall with the hob on. the length that runs down the wall has a dog leg in and runs about 20 cms from the side of the hob, then goes below the hob level and runs along to the hob below the work top.
my plan was to get my plumber to cut into the old hob supply and tie in my new pipe then connect up at the hob.
my pipe runs down a brize block wall which it is clipped too. the wall has plasterboard stuck to it and the pipe is just below flush with the board so i was going to cover the pipe with tape and then fill over the channel with plaster, the plaster board is then going to have 13mm splash back fitted over it..
when my plumber saw it he said
1) the gas pipe can only run vertically down the wall straight to the hob (this seems ridiculous as access would be a nightmare)
2) he says the pipe can't run in plasterboard, it must be sunk into the wall
and protected and then the plasterboard goes over it.
3) hes not happy i put the pipe in and does not want to put his name to it. surely a leak test is more than enough to satisfy him or would he only be happy if he could dig out every bit of gas pipe in the house just in case!

is he right in what he says or is he just either thick or being awkward

There is no reason why your pipework has to be buried into the wall.(it will look better aesthetically) but it can be surface mounted as long as it is clipped properly.When you say you have `made up some pipework` have you just run some pipework without touching your gas supply pipework? Is your `plumber a gas fitter`. Are you a gas fitter? I don`t see any problem with him connecting the old gas supply into your pipe supply as long as he carries out a full tightness test before & after he connects it up, otherwise how will he know (if his guage registers a drop) if the leak is on the new pipework or the existing? I take it he is Corgi registered?

hi,
the pipe wont be wall mounted it will be buried in the plasterboard.
the plumber is corgi registered.
i have just run new pipe work and havent touched the old pipework i was going to get him to do all the tieing in.

hope that helps.

When you say buried in plasterboard, I take it you mean it is behind the plasterboard.

Now imagine there is a leak in this pipe. The gas (from the leak) starts filling up the unventilated cavity (gap behind the plasterboad). You will not need all that much gas for the volume (5%) and you have a potential bomb.

All I can say is behave yourself and run the pipe surface. In fact messing with the gas pipe and let the gasman install the pipe. I would certainly ask for sight of his CORGI card. If he is not seeing the potential hazard in running the gas pipe in unventillated cavity, he should be pulled up on this hazardous practice.

If he`s Corgi then your idea won`t be a problem. From what you say I believe your gas pipe will just be below surface, so no probs. As for the cavity wall bomb theory, I think I`d better take up all gas lines I have installed beneath floorboards in the last 100 houses I have had to re-run the Gas carcass then

Corgi book shows for your situation, pipe must be corrosion protected (eg Denso or Premtape) then dot&dab cement to stop gas from any future leak getting behind the pboard. It shows the board continuous across the front of the pipe, which would be neater.

By the way What the corgi book says re pipes under floorboards, is nonsense!