Ideas for tracking individuals in a building
Systems such as this one use actual wrist worn transmitters with proximity constrained receivers located at various points in the building, typically at doors and elevators. The receivers are configured to detect a wrist worn tag when it is within about 3 meters. In your case a system like this could get expensive quite quickly (for a given value of 'expensive'...) since you'd want receivers in many places. It might give you some ideas though. There are several companies that make similar systems and target the same market. None of these have quite what I would describe as a network back-end as you describe, but that's the easy part. (Speaking as a software developer who has recently integrated one of these into something very much like this.) 

The RFID badges that I'm familiar with need to be within about 10cm of a sensor to trigger it, and are expected to be used intentionally, i.e., to unlock a mag-lock and allow access to a room, etc. My impression is that you'd like to track personnel movement without requiring the personnel to have to think about it.