Determining pipes in council flat

[Just_back_from_the_pub]

My mate has recently bought a flat in an old council block in East London. He wants me to give him a hand installing a new bathroom suite. There are currently some 22mm copper pipes (surface mounted and painted) that supply water to the bathroom. In addition to this there is a larger pipe around 40mm or more also painted. It is difficult to determine the source/purpose of this pipe. I don't think it is lead as it doesn't have that sound when tapped. Any idea what it is likely to be used for?

Any help appreciated. Apologies if I am unable to acknowledge any responses immediately. Thanks.

 

[big-all]

things to keep in mind in flats is services for the other flats may pass through his flat

 

[Bahco]

Could be a gas pipe.
Are the pipes accessed thru a service duct which is removable?
Try tracing it back but leave well alone if you are unsure.
Only touch pipework that you know their exact function

 

[kevplumb]

sure its not a drain

 

[ChrisR]

An iron riser for water or gas? Try heating it(hair dryer). If it gets hot then gas.

 

[kevplumb]

good point chris
missed that one

 

[Just_back_from_the_pub]

Thanks for the very helpful and sensible advice chaps. I will keep you informed as to our progress. Thanks again!