BMS and building controls: the key role of the commissioning engineer

Building Management Systems (BMS, known in France as GTB) and centralised technical management systems (GTC) supervise and control HVAC systems, lighting, openings and other building services. For the commissioning engineer, the BMS is both a verification tool and a performance lever.

GTC vs GTB: what is the difference?

• • GTC (centralised technical management): supervision of a single building service (e.g. HVAC only). Displays statuses and alarms and allows remote control.
• • GTB (full Building Management System): supervises ALL building services (HVAC, lighting, access control, etc.) and includes energy optimisation functions. It is the higher level.

Communication protocols

• • BACnet (Building Automation and Control Network): an open protocol and the most widespread in commercial buildings. Enables interoperability between manufacturers.
• • Modbus RTU/TCP: a simple, robust industrial protocol, widely used for substations and energy meters.
• • LON (LonWorks): a legacy protocol still found in older installations. Increasingly being replaced by BACnet.
• • KNX: the European standard for home automation and lighting, increasingly integrated into multi-service BMS.

The commissioning engineer's role on the BMS

• • Point-to-point checks: every sensor, valve and fan must report the correct value to the BMS.
• • Testing control sequences: start-up, shutdown, fallback modes, heating/cooling changeover.
• • Validating alarms: every fault must trigger the right alarm at the right priority level.
• • Optimising time schedules: matching operating schedules to how the building is actually used.
• • Checking data logging: trend logs must be usable for energy monitoring.

Mastering the BMS turns an HVAC technician into the person who drives the building's performance. Commissioning engineers who develop this skill become the preferred contacts of facility operators and energy managers.