Only guessing, but it would be logical - though not necessarily the only logical solution - to think that the "conduite d'immeuble" is one that runs from the mains to a building.

service pipe - A fairily horizontal gas or water pipe from the street main to the premises receiving the supply. It is called the communication pipe up to the boundary, then becomes the supply pipe ...

riser, rising main - A vertical distribution pipe or cable, usually run inside a services riser shaft or duct, to bring electrical power, cold water, or gas to the upper storeys of a building
[Scott/Penguin Dict of Bldg]