The core of the building including (parts of) its shell. Base buildings provide serviced space for occupancy. The base building normally includes the building’s primary structure including foundations; the building envelope (roof and facade) in whole or part; (semi-) public circulation and fire egress (lobbies, corridors, elevators and public stairs); and primary mechanical and supply systems (electricity, heating and air conditioning, telephone, water supply, drainage, gas, etc.) up to the point of contact with individual occupant spaces.