Running a new gas pipe - help please Information, help and advice on many gas related subjects from gas fires to domestic appliances

[George22]

I wonder if anyone can help me.
First of all, I intend to engage a CORGI engineer to do the work but I am trying to save a little time and head scratching first.
I have what seems to be a common problem in that I am trying to run a gas extension from and understairs cupboard to the kitchen at the other side of the house. The floors are concrete and running around the outside of the house is impractical.
I have identified a possible route, which is to follow the C/H boiler feed pipes into the floor void of the bedroom above. These pipes run out of the U/S cupboard and have been boxed into the corner in the adjacent room. This boxing I assume would be classed as a duct but is less than 100 x 100mm so assume is ok.
Once in the floor void, the gas pipe would then follow the floor joists in the room above, with no need for any notching. They would run through the bedroom floor, into the bathroom and then down into the kitchen. Bedroom floor is nailed chipboard (I dont think it is glued) covered with laminate flooring and the house around 30 years old.
I have read many of the questions and answers on this forum about this issue but am still unsure if what I want to do would meet the regs. In the bathroom, the pipe will run underneath the bath. If need be, I can leave the floor open here or fit a ventilation grid to evacuate anything that may be trapped. Any views/advice on this?
As an alternative, there was a copper gas pipe installed when the house was built and this is buried in the concrete floor. It has never been used and I assume that no-one will touch it wit a barge pole? Or could this be pressure tested to check it's integrity?
Hope someone can help with this.
Thanks

[plastic_man77]

@ George22

It's too difficult to give you a definitive answer on this site. The best thing you can do is call a gas engineer to your property to help you make a decision. They will inevitably throw a spanner in the works if you plan everything in advance, so you will have to bite the bullet, think on your feet and take advice-just point out to the engineer what you aren't happy with while he's there- for instance, if he wants to run the pipework outside, which you don't appear to think is practical or you simply don't want, then say so.

The engineer will want to know what appliance you intend to supply and it's heat input requirement, because it may not be possible to extend the pipework you are talking about if it is not large enough to provide the correct quantity of gas at the right pressure- they may need to take a seperate branch directly from the gas meter- especially if the branch you are hoping to extend feeds other appliances, possibly with high demands.

[George22]

@ plastic_man 77.

Hi and thanks for your response.
I take on board what you have advised. I really need to talk to the guy who has to sign it off.
Just as additional info, the feed is to supply a gas cooker only, which is a Leisure Rangemaster. I understand that I may need to fit a wide bore pipe however this would be possible using the route I have selected. Also, the gas meter is also located on the external wall behind the understairs cupboard so a direct feed would be relatively straightforward.
I suppose my main concern is whether the underfloor route I have chosen in the floor void constitutes a 'duct'. I have read various conflicting posts on this.

Thanks again for replying.