A building management system monitors and controls a building’s mechanical and electrical plant: heating, ventilation, cooling, lighting and sometimes metering. It runs on a network of controllers and sensors. Because it often shares infrastructure with security devices, its access rules and network segmentation matter to the security plan.
A BMS is about comfort, energy and equipment life, not security. The two disciplines meet at the network closet, where the same cabling and switches may serve both.
What a BMS controls
Typical points include air handlers, boilers, chillers, valves, dampers, lighting schedules and meters. Controllers run local logic and report to a supervisory server, and the front end shows trends and alarms. Much of the value comes from scheduling and from noticing equipment that has drifted out of range.
Where security meets the BMS
Access control, cameras and the BMS frequently sit on one network, and a BMS account with weak credentials is a route into the building’s systems. Segment the networks, keep vendor remote access documented and limited, and make sure firmware updates are planned rather than skipped.