Technical Measurements Flashcards
7 cards from real BOC practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Technical Measurements flashcards as text
Which formula estimates sensible heat transfer for standard air in Btu/h?
Answer: Q = 1.08 × CFM × ΔT
Sensible heat for standard air is 1.08 × CFM × temperature difference.
A hot water coil has 10 GPM with a 10°F temperature drop. What is the heat transfer?
Answer: 50,000 Btu/h
Q = 500 × GPM × ΔT = 500 × 10 × 10 = 50,000 Btu/h.
An AHU mixes 25% outside air at 40°F with 75% return air at 72°F. What is the mixed air temperature?
Answer: 64°F
Mixed air = (0.25 × 40) + (0.75 × 72) = 10 + 54 = 64°F.
What does dew point temperature indicate?
Answer: The temperature at which moisture begins to condense from air
Dew point is the temperature at which air becomes saturated and water vapor starts to condense.
A Pitot traverse shows a velocity pressure of 0.25 in. w.c. for standard air. What is the approximate velocity?
Answer: 2,000 fpm
V = 4,005 × √VP = 4,005 × 0.5 ≈ 2,000 fpm.
On a day with an average outdoor temperature of 45°F, how many heating degree days accrue (65°F base)?
Answer: 20
Heating degree days = 65 − 45 = 20.
A facility draws 80 kW of real power and 100 kVA of apparent power. What is the power factor?
Answer: 0.80
Power factor = kW ÷ kVA = 80 ÷ 100 = 0.80.