Oil pipe in the floor

[DIYinBerks]

I want to replace my oil pipe which goes about 2m under the kitchen floor before going out the house. It is unprotected copper and since my cold water pipe burst under the floor recently (also unprotected copper) I thought I would replace the oil line before it too corrodes away.
My OFTEC engineer will do the plumbing part and recomission the boiler but he wants me to do the civil engineering part. My problem is that he has suggested that "ideally" the pipe should be 400mm below floor level which would mean cutting into our foundation slab. I think the old pipe is probably in the screed - can I put plastic-sheather copper (as suggested by our engineer) at that depth? (about 50-75mm) Or if not directly, in either plastic or metal conduit? I have found references on the web to OFTEC publications that should contain the answer but these seem to be hidden from non-OFTEC people. Can anyone direct me to a specification that I can access? (Or just give an opinion?)
Thanks!

 

[Jezclayton]

No problem with putting pipe in the screed, but note:-

1) Use plastic coated pipe with no hidden joints. Better still run the coated pipe within a length of 22mm plastic pipe to facilitate removal at a later date;
2) Try and maintain 300 mm separation from other services run in the same direction;
3) You will also most likely need another 22mm buried conduit within which to run the fire valve capillary;
4) Pipe should be visible where it enters the building with fire valve installed at this point externally;
5) All joints must be mechanical (preferably flared) with no soldered joints.

The 400mm to which you have been guided relates to external pipe runs and are to avoid mechanical damage from gardening tools in particular. If your technician is unsure of the above, just get him to phone OFTEC and they will confirm.

 

[DIYinBerks]

Thanks, that's more like what I thought. I was hoping to use the flexible plastic conduit so that sounds perfect. My engineer also recomended a separate conduit for the fire valve in case of replacement..
Is there a specific minimum depth I need to meet? I did find some posts about Gas that said it is 25mm minimum of screed or concrete.
Definately no joints if I have my way!

 

[Jezclayton]

The idea is to protect the pipe from accidental mechanical damage, such as nails from carpet gripper etc. Only you can assess the risks and will be footing the bill if such damage occurs.

I recommend channelling the screed to full depth, (ie to floor slab level). You have already intimated this is 50-75mm which is normal.