AFE Building Systems & Maintenance 4

Question 1

Under ASHRAE Standard 90.1, what is the primary purpose of demand-controlled ventilation (DCV)?

Accepted Answer

Reduce outdoor air intake when occupancy is low, saving heating and cooling energy

Answer

DCV uses CO₂ sensors to modulate outdoor air intake based on actual occupancy, reducing energy wasted conditioning unnecessary outdoor air in partially occupied spaces.

Question 2

A facility engineer is sizing a domestic hot water heater. What parameter is most critical for determining peak demand capacity?

Accepted Answer

Peak hourly draw rate and recovery rate

Answer

Peak hourly demand determines the required storage and recovery rate; undersizing based on average use leads to inadequate hot water during high-demand periods.

Question 3

Which lubrication method is most suitable for a high-speed centrifugal pump bearing operating continuously at elevated temperatures?

Accepted Answer

Oil mist lubrication or circulating oil system

Answer

Circulating oil or oil mist systems provide continuous cooling and contamination removal for high-speed, high-temperature bearings where grease would degrade rapidly.

Question 4

When performing a roof infrared scan to detect moisture intrusion, when should the scan be conducted for best results?

Accepted Answer

Shortly after sunset while the roof is cooling and wet areas retain heat

Answer

After sunset, dry roofing materials cool faster than moisture-saturated areas, creating thermal contrast detectable by infrared cameras.

Question 5

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?

Accepted Answer

Blowdown (bleed-off) of concentrated tower water and replacement with fresh makeup water

Answer

Blowdown removes concentrated water from the system, lowering TDS and cycles of concentration, and is replaced by fresh makeup water to dilute dissolved solids.

(AFE) Association for Facilities Engineering Certification Practice Test

(AFE) Association for Facilities Engineering Certification Practice Test

AFE Building Systems & Maintenance 4