BOC Building Automation and Controls Flashcards

What does 'commissioning' of a building automation system involve?

Answer: Verifying that all BAS hardware, software, sequences, and setpoints function as designed

BAS commissioning systematically tests and verifies every point, sequence, alarm, and schedule to confirm the system operates as designed and meets the owner's project requirements.

In a variable air volume (VAV) system, what does the VAV box controller modulate to maintain zone temperature?

Answer: The damper position to vary airflow to the zone

The VAV box controller adjusts the damper opening to increase or decrease airflow to the zone, maintaining the zone temperature setpoint with a fixed supply air temperature.

What is a 'fault detection and diagnostics' (FDD) tool in a BAS designed to identify?

Answer: Equipment malfunctions and degraded performance before they cause failure or comfort complaints

FDD algorithms analyze BAS data to detect anomalies such as stuck valves, sensor drift, or economizer faults that reduce efficiency or indicate impending failures.

Which BAS setpoint strategy is used to reduce heating or cooling energy during unoccupied nighttime hours?

Answer: Setback (or setup) temperature scheduling

Setback reduces the heating setpoint (or raises the cooling setpoint) during unoccupied periods, allowing the building to drift closer to outdoor conditions and saving conditioning energy.

In a BAS control network, what is the function of a router or gateway device?

Answer: To translate between different communication protocols or network segments

A BAS gateway or router bridges different protocols or network segments, allowing devices using BACnet/IP, BACnet MS/TP, Modbus, or other protocols to communicate with the central system.

What is the purpose of a 'night purge' or 'pre-cool flush' mode in a BAS?

Answer: To flush cool nighttime outdoor air through the building before occupancy to reduce morning mechanical cooling load

Night purge uses cool outdoor air during late-night or early-morning hours to pre-cool the building's thermal mass, reducing the cooling load when mechanical systems ramp up at occupancy.