BOC Building Automation and Controls Flashcards

What communication protocol is most widely used for interoperability between BAS devices from different manufacturers?

Answer: BACnet (Building Automation and Control Networks)

BACnet is the ASHRAE/ANSI/ISO standard open protocol that allows devices from different manufacturers to communicate on a common network, enabling integrated building automation.

What is an 'alarm management' feature in a BAS used for?

Answer: Notifying operators when a monitored point exceeds normal operating limits

Alarm management monitors designated points and generates notifications when values exceed defined thresholds, alerting operators to faults, equipment failures, or unsafe conditions.

What is 'demand-controlled ventilation' (DCV) and what sensor drives it?

Answer: Ventilation rate modulated based on occupancy using CO₂ sensors

DCV uses CO₂ sensors as a proxy for occupancy; when CO₂ levels rise (more people), outdoor air flow increases, and when levels drop, ventilation is reduced to save energy.

In building controls, what does an 'economizer' control strategy do?

Answer: Uses cool outdoor air for free cooling instead of mechanical refrigeration when conditions allow

An economizer control opens outdoor air dampers when outdoor conditions are cool enough to meet cooling needs without running the compressor, reducing chiller or DX cooling energy.

What is the purpose of 'optimal start' programming in a BAS?

Answer: To calculate the latest start time that still brings the building to setpoint by occupancy

Optimal start uses historical data and outdoor temperature to calculate the latest possible start time that allows the HVAC system to reach comfort setpoints just as occupancy begins.

What is 'load shedding' in the context of building electrical demand management?

Answer: Temporarily reducing non-critical electrical loads to avoid exceeding demand charge thresholds

Load shedding strategically turns off or reduces non-critical loads (such as non-essential lighting or HVAC zones) during peak demand periods to stay below costly demand charge thresholds.