Yes Yes and YES!!!!!!!!! protect all copper pipes under concrete slabs – use denso tape or similar wrapping tape designed to prevent acids etc coming into contact with the copper, make sure you cover every exposed bit of any copper pipe when you wrap it around the pipe.
Any joints under the concrete floor should be welded using silfos or silberloy welding rods.
Selgas Services Ltd
Craftsman Gasfitters, Plumbers, Electrical Service Technicians