Range
The Philips Hue Bridges and Sensors communicate using Zigbee (2.4GHz) so are short-range devices i.e. similar to 2.4 GHz WiFi.
The range will therefore depend on office layout and construction. If the range issues are experienced additional bridges may be required.
Bridge Capacity
There is a theoretical limit of 63 Hue accessories per bridge but a Motion Sensor is in fact 3 sensors in one so reduces the limit to 21. We do however recommend working well within this limit so performance is not affected.