Building Systems & Maintenance Flashcards
7 cards from real AFE practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Building Systems & Maintenance flashcards as text
Under ASHRAE Standard 90.1, what is the primary purpose of demand-controlled ventilation (DCV)?
Answer: Reduce outdoor air intake when occupancy is low, saving heating and cooling energy
DCV uses CO₂ sensors to modulate outdoor air intake based on actual occupancy, reducing energy wasted conditioning unnecessary outdoor air in partially occupied spaces.
A facility engineer is sizing a domestic hot water heater. What parameter is most critical for determining peak demand capacity?
Answer: Peak hourly draw rate and recovery rate
Peak hourly demand determines the required storage and recovery rate; undersizing based on average use leads to inadequate hot water during high-demand periods.
Which lubrication method is most suitable for a high-speed centrifugal pump bearing operating continuously at elevated temperatures?
Answer: Oil mist lubrication or circulating oil system
Circulating oil or oil mist systems provide continuous cooling and contamination removal for high-speed, high-temperature bearings where grease would degrade rapidly.
When performing a roof infrared scan to detect moisture intrusion, when should the scan be conducted for best results?
Answer: Shortly after sunset while the roof is cooling and wet areas retain heat
After sunset, dry roofing materials cool faster than moisture-saturated areas, creating thermal contrast detectable by infrared cameras.
A building's water treatment program specifies maintaining 300–500 ppm total dissolved solids (TDS) in the cooling tower basin. What control method is most commonly used to manage TDS?
Answer: Blowdown (bleed-off) of concentrated tower water and replacement with fresh makeup water
Blowdown removes concentrated water from the system, lowering TDS and cycles of concentration, and is replaced by fresh makeup water to dilute dissolved solids.
What does a high differential pressure reading across an air handler's supply fan indicate when airflow has decreased?
Answer: The supply air filters are loaded and need replacement
A clogged filter increases resistance on the suction side, raising the pressure differential across the fan section while reducing actual airflow delivered.
A facility manager is implementing an energy audit per ASHRAE Level II standards. Which deliverable distinguishes a Level II from a Level I audit?
Answer: Detailed energy analysis with capital cost estimates and savings for specific measures
A Level II audit goes beyond the walk-through by providing engineering analysis, detailed energy savings calculations, and capital cost estimates for each identified energy conservation measure.