Our team is working on a project of a whole 2-storey (to be) newly constructed office building.

I wonder (1) whether we can apply both floors to ID+C rating system or it has to be a single part of the building.

The owner has ownership and control of the whole building as well as the regular occupants are owner's employees.

(2) If apply a part of one floor or part of both floors, how can water faucet and/or HVAC fixtures are supposed to be included or excluded from project boundary?

(3) How fixtures outside project boundary affect indoor water use calculation? For example, there is a water treatment outside the project boundary, if part of the project's water use comes from that source, can that part calculated as project's water use reduction?