Building Management Systems: Functions and Integration

A building management system (BMS) collects technical information and coordinates selected building services through a central interface. Its scope depends on the building, equipment and agreed integration design.

Systems that may be integrated

• Heating, ventilation and air conditioning.
• Lighting and energy metering.
• Electrical distribution and backup power.
• Security-system interfaces.
• Lift status and location monitoring.
• Approved interfaces to fire and life-safety systems.

Integration with a life-safety system must preserve its required independent functions and approved control priorities. A BMS does not automatically replace a dedicated fire alarm or safety controller.

Information and records

The BMS can collect environmental measurements, equipment status and system operating information. Data storage, trend processing and retention periods are defined by the project and management needs.

Alarms and supervision

A graphical interface presents technical alarms and equipment faults. Audible alerts can draw an operator’s attention to conditions requiring a response. Alarm priorities, acknowledgement and escalation should be configured for the building’s operations.

Control and scheduling

Authorized operators may control supported points through equipment graphics or floor plans. Schedules can coordinate operation with daily, weekly or longer-term building needs and help reduce unnecessary energy use.

Changes to schedules and control commands should be made within the permitted operating limits. Available commands depend on the connected equipment and integration design.

Access control and accountability

Operators can be assigned different monitoring and control permissions according to their responsibilities. Logs record access and actions, helping the management team investigate changes and operating events.

Architecture and resilience

The BMS design includes two servers, automatic backup and distributed building controllers connected through a LAN. Redundancy, failover and backup are project features that must be specified and tested; they are not guaranteed in every BMS.

Controllers may retain programmes, parameters and trend data during particular interruptions, subject to their memory, power arrangements and configuration. Local operation during a network outage also depends on the designed access method and controller capabilities.

Communication and integration

Interfaces such as BACnet and Modbus can connect compatible systems. Controllers are commonly located near the plant they serve, such as electrical rooms or HVAC equipment rooms.

Typical monitoring and control points

• Transformers, standby generators, main and floor distribution boards, and UPS systems.
• Chillers, chilled-water pumps, cooling towers and air-handling units.
• Extract fans and approved staircase-pressurization interfaces.
• Status information from fire pumps, gaseous suppression systems and the fire alarm panel.
• Security and lift-system information within the agreed integration scope.

Planning a useful BMS

Define the points list, operating sequences, alarm strategy, access permissions, data retention and failure response before implementation. Proper commissioning and operator training help turn integrated information into more effective building management and better control of operating costs.