installing gas hob

Do you need a certificate at all?

We did ours in a single run of 10mm-ish bendable copper. In the wall it ran through a bit of plastic pipe. The bottles + changeover valve are in a little hut (keeping the rain off, but open enough so there's no chance for the gas to pool) next to the house.

A gas installer told me to use the next size copper pipe up (in your case 15 mm I guess if using 10 mm) to line the hole through which the 10 mm pipe goes. I used 15 mm with a 22 mm sleeve. Usual pipe supports on the inside. Best to pay him to connect up. You might need to change the jets to bottled rather than main gas and maybe then adjust them. Said nothing about my bottles being against the house.

Peter Scott

Thanks, but thats why I'm asking :-)

Where the pipe goes through a cavity wall it will need a continuous sleeve of material that won't rot the pipe installed right through the wall, both ends sealed.

sealed only on the inside end the other outside end should be left open

This prevents a gas escape into the cavity. It will need to be done in rigid pipe with any joints done with approved joint compound. Bottled gas is more dangerous than natural gas because of it's density. I think if you aren't aware of these simple things,you better leave it to a gas safe fitter.