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
A variable air volume (VAV) system reduces airflow to a zone when cooling demand drops. What risk does this create if not properly managed?
Answer: Inadequate outdoor air ventilation below ASHRAE 62.1 minimums
At minimum airflow positions, VAV boxes may supply less outdoor air than required, violating ASHRAE 62.1 ventilation standards and degrading indoor air quality.
Which insulation material is most appropriate for a chilled water pipe operating at 42°F in a humid environment?
Answer: Fiberglass with vapor retarder jacket
Fiberglass with a continuous vapor retarder jacket prevents condensation on below-ambient piping by blocking moisture diffusion from the warm, humid surrounding air.
What NFPA standard governs the inspection, testing, and maintenance of fire protection systems including sprinklers?
Answer: NFPA 25
NFPA 25 is the Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems.
A cooling tower's approach temperature is defined as:
Answer: The difference between leaving water temperature and ambient wet-bulb temperature
Approach temperature is the leaving water temperature minus the ambient wet-bulb temperature; a smaller approach indicates a more efficient tower.
What is the correct torque sequence when retightening large flange bolts on a pressurized piping joint?
Answer: Sequential in a star or cross pattern to ensure even gasket compression
A star or cross-pattern torque sequence distributes load evenly across the gasket, preventing leaks caused by uneven compression or gasket deformation.
Which term describes the ratio of actual evaporation water loss to circulating water flow in a cooling tower, expressed as a percentage?
Answer: Evaporation rate
The evaporation rate (typically 1–2% of circulating flow) represents water lost to the atmosphere as vapor, which is the primary cooling mechanism.
A facility's 480V three-phase distribution panel shows a voltage unbalance of 4.5%. What is the most likely consequence for connected three-phase motors?
Answer: Reduced torque output and excessive heat in rotor windings
NEMA MG-1 states that a 3.5% voltage unbalance can cause a temperature rise of approximately 25%, significantly reducing motor life and torque output.