HVAC Design Engineer Interview MCQs – Answers & Explanations

A curated set of 75+ advanced questions covering fundamentals, loads, duct/piping design, hydronics, VRF, controls, energy, codes, acoustics, and commissioning.

Fundamentals and thermodynamics 15 questions

1. What is the primary law governing heat transfer in HVAC systems?

1. a. Newton’s Law
2. b. Pascal’s Law
3. c. Fourier’s Law
4. d. Bernoulli’s Law

Answer & explanation

Answer: c. Fourier’s Law. Governs conductive heat transfer, central to envelope and insulation calculations.

2. Which type of heat changes the temperature of a substance without changing its phase?

1. a. Latent heat
2. b. Sensible heat
3. c. Hidden heat
4. d. Specific heat

Answer & explanation

Answer: b. Sensible heat. Used in sensible load calculations and supply air temperature sizing.

3. What is the unit of thermal conductivity in the Imperial system?

1. a. W/m·K
2. b. Btu/hr·ft·°F
3. c. J/kg·K
4. d. Btu/lb·°F

Answer & explanation

Answer: b. Btu/hr·ft·°F. Used to quantify material insulation performance.

4. Which psychrometric property remains constant during adiabatic cooling?

1. a. Dry bulb temperature
2. b. Wet bulb temperature
3. c. Relative humidity
4. d. Enthalpy

Answer & explanation

Answer: d. Enthalpy. No heat added/removed; evaporative cooling follows constant enthalpy.

5. What is the typical indoor design temperature for cooling in ASHRAE comfort design?

1. a. 72°F
2. b. 75°F
3. c. 78°F
4. d. 80°F

Answer & explanation

Answer: b. 75°F. Common comfort setpoint for offices; exact value depends on climate and program.

Load calculation and standards 10 questions

6. Which standard governs HVAC load calculation procedures?

1. a. NEC
2. b. ASHRAE 62.1
3. c. ASHRAE 90.1
4. d. ASHRAE 183

Answer & explanation

Answer: d. ASHRAE 183. Provides methods for calculating building heating and cooling loads.

7. Which factor most affects solar heat gain through windows?

1. a. U-value
2. b. SHGC
3. c. R-value
4. d. Emissivity

Answer & explanation

Answer: b. SHGC. Determines fraction of incident solar radiation admitted.

8. Recommended outdoor air ventilation rate baseline for offices (people component) per 62.1?

1. a. 5 cfm/person
2. b. 10 cfm/person
3. c. 15 cfm/person
4. d. 20 cfm/person

Answer & explanation

Answer: c. 15 cfm/person (plus area component). Actual values depend on occupancy category.

9. Which software is commonly used for detailed load analysis?

1. a. AutoCAD
2. b. HAP
3. c. Revit
4. d. SolidWorks

Answer & explanation

Answer: b. HAP. Hourly Analysis Program aligns with ASHRAE methods.

10. Diversity factor in HVAC design refers to:

1. a. Ratio of actual to peak load
2. b. Ratio of sensible to latent heat
3. c. Ratio of total to design airflow
4. d. Ratio of outdoor to indoor temperature

Answer & explanation

Answer: a. Ratio of actual to peak load. Used to avoid oversizing equipment.

Duct and piping design 10 questions

11. Which duct shape is most efficient for airflow?

1. a. Round
2. b. Square
3. c. Rectangular
4. d. Oval

Answer & explanation

Answer: a. Round. Lowest friction per CFM and less noise.

12. Recommended maximum velocity for main supply ducts (comfort applications):

1. a. 500 fpm
2. b. 1000 fpm
3. c. 1500 fpm
4. d. 2000 fpm

Answer & explanation

Answer: c. 1500 fpm. Balances pressure drop and noise; exact depends on program.

13. Which fitting typically causes the highest pressure loss?

1. a. Elbow
2. b. Reducer
3. c. Tee
4. d. Damper

Answer & explanation

Answer: c. Tee. Major turbulence and loss coefficients.

14. Purpose of a balancing damper:

1. a. Reduce noise
2. b. Control temperature
3. c. Adjust airflow
4. d. Increase pressure

Answer & explanation

Answer: c. Adjust airflow. Used during TAB to meet design flows.

15. Preferred pipe material for large chilled water mains:

1. a. PVC
2. b. Copper
3. c. PEX
4. d. Carbon steel

Answer & explanation

Answer: d. Carbon steel. Strength, cost, and availability for large diameters.

Equipment selection and system design 15 questions

16. Most efficient chiller type for large commercial buildings:

1. a. Air-cooled
2. b. Water-cooled
3. c. Absorption
4. d. Scroll chiller

Answer & explanation

Answer: b. Water-cooled. Lower condensing temperatures yield higher efficiency.

17. Typical COP range for modern centrifugal/screw chillers:

1. a. 2–3
2. b. 3–4
3. c. 5–6
4. d. 7–8

Answer & explanation

Answer: c. 5–6. Depends on load, leaving temps, and tower approach.

18. Best system for high-rise buildings with many zones:

1. a. Split AC
2. b. VRF/VRV
3. c. Window AC
4. d. Packaged rooftop

Answer & explanation

Answer: b. VRF/VRV. High zoning flexibility and part-load efficiency.

19. Primary advantage of DOAS (Dedicated Outdoor Air System):

1. a. Lower installation cost
2. b. Independent humidity control
3. c. Smaller duct sizes
4. d. Reduced refrigerant charge

Answer & explanation

Answer: b. Independent humidity control. Decouples ventilation and sensible loads.

20. Most common cooling tower configuration in HVAC:

1. a. Crossflow
2. b. Counterflow
3. c. Induced draft
4. d. Natural draft

Answer & explanation

Answer: c. Induced draft. Efficient heat rejection; widely adopted.

21. What does a VFD primarily control?

1. a. Voltage
2. b. Current
3. c. Motor speed
4. d. Temperature

Answer & explanation

Answer: c. Motor speed. Reduces fan/pump energy at part load.

22. Sensor type used for demand-controlled ventilation via CO₂:

1. a. Humidity
2. b. Thermistor
3. c. Infrared
4. d. Pressure transducer

Answer & explanation

Answer: c. Infrared CO₂ sensors. Robust and widely used for IAQ control.

23. Primary function of a BMS:

1. a. Reduce duct size
2. b. Monitor/control HVAC
3. c. Increase cooling capacity
4. d. Replace thermostats

Answer & explanation

Answer: b. Monitor/control HVAC equipment and systems.

24. Control strategy that reduces energy in VAV systems:

1. a. Constant volume
2. b. Supply air reset
3. c. Fixed setpoint
4. d. Manual dampers

Answer & explanation

Answer: b. Supply air reset. Matches SAT to load, reduces reheat/fan energy.

25. Typical control voltage for thermostats:

1. a. 12V
2. b. 24V
3. c. 48V
4. d. 120V

Answer & explanation

Answer: b. 24V. Common for residential/light commercial controls.

26. Eco-friendlier refrigerant (lower GWP) among the options:

1. a. R-22
2. b. R-134a
3. c. R-410A
4. d. R-32

Answer & explanation

Answer: d. R-32. Lower GWP than R-410A; rising adoption.

27. LEED certification primarily evaluates:

1. a. Structural safety
2. b. Energy & environmental performance
3. c. Fire resistance
4. d. Acoustic comfort

Answer & explanation

Answer: b. Energy & environmental performance. Multi-category sustainability credits.

28. ASHRAE standard for minimum energy efficiency requirements:

1. a. 62.1
2. b. 55
3. c. 90.1
4. d. 183

Answer & explanation

Answer: c. 90.1. Baseline for energy codes and performance.

29. Advantage of HRV/ERV systems:

1. a. Lower duct pressure
2. b. Reduced refrigerant charge
3. c. Energy savings via exhaust heat/moisture recovery
4. d. Smaller equipment

Answer & explanation

Answer: c. Transfers heat/moisture between exhaust and supply airstream.

30. Cooling equipment seasonal efficiency rating (residential):

1. a. COP
2. b. SEER
3. c. EER
4. d. HSPF

Answer & explanation

Answer: b. SEER. Seasonal metric; EER is point condition.

Advanced design and troubleshooting 10 questions

31. Primary cause of compressor short cycling in packaged systems:

1. a. Oversized equipment
2. b. Undersized ductwork
3. c. Low refrigerant charge
4. d. Dirty filters

Answer & explanation

Answer: a. Oversized equipment. Hits setpoint too fast, cycling losses.

32. Common compressor type in large chillers:

1. a. Scroll
2. b. Screw
3. c. Reciprocating
4. d. Centrifugal

Answer & explanation

Answer: d. Centrifugal. High capacity, good efficiency.

33. Typical chilled water supply temperature (comfort cooling):

1. a. 42°F
2. b. 44°F
3. c. 46°F
4. d. 48°F

Answer & explanation

Answer: b. 44°F. Paired with ~54°F return for ΔT ≈ 10°F.

34. Main function of air-side economizer:

1. a. Reduce duct size
2. b. Use outdoor air for free cooling
3. c. Increase refrigerant charge
4. d. Control humidity

Answer & explanation

Answer: b. Free cooling when ambient permits.

35. Device that protects compressors from liquid slugging:

1. a. Filter drier
2. b. Suction accumulator
3. c. Expansion valve
4. d. Oil separator

Answer & explanation

Answer: b. Suction accumulator. Holds returning liquid, feeds vapor.

36. Standard for minimum ventilation rates & IAQ:

1. a. ASHRAE 55
2. b. ASHRAE 62.1
3. c. ASHRAE 90.1
4. d. ASHRAE 183

Answer & explanation

Answer: b. ASHRAE 62.1. Defines outdoor air requirements.

37. Standard defining thermal comfort ranges:

1. a. ASHRAE 55
2. b. ASHRAE 62.1
3. c. ASHRAE 90.1
4. d. ASHRAE 183

Answer & explanation

Answer: a. ASHRAE 55. Temp, humidity, air speed, clothing, metabolic rate.

38. Minimum ventilation rate for bathrooms in motels:

1. a. 25 cfm
2. b. 35 cfm
3. c. 50 cfm
4. d. 75 cfm

Answer & explanation

Answer: c. 50 cfm. Typical code/standard value.

39. Minimum clearance for access panels on oil-fired units:

1. a. 6 in
2. b. 10 in
3. c. 12 in
4. d. 16 in

Answer & explanation

Answer: c. 12 in. Safe access and maintenance space.

40. Primary composition of natural gas:

1. a. 65% methane
2. b. 75% methane
3. c. 85% methane
4. d. 95% methane

Answer & explanation

Answer: d. 95% methane. Remainder ethane, propane, CO₂, nitrogen.

Practical design scenarios 10 questions

41. Instrument for measuring wet and dry bulb temps:

1. a. Thermocouple
2. b. Sling psychrometer
3. c. Manometer
4. d. Hygrometer

Answer & explanation

Answer: b. Sling psychrometer. Enables psychrometric analysis.

42. Compression ratio if discharge is 235 psig and suction is 35 psig:

1. a. 5:1
2. b. 6:1
3. c. 7:1
4. d. 10:1

Answer & explanation

Answer: d. 10:1 (approx). Accounting for absolute pressures; typical practice answer.

43. Oil compatible with R‑410A:

1. a. Mineral
2. b. Alkylbenzene
3. c. POE
4. d. PAG

Answer & explanation

Answer: c. POE (Polyolester). Required for HFCs like R-410A.

44. Typical supply air temperature in comfort cooling:

1. a. 50°F
2. b. 55°F
3. c. 60°F
4. d. 65°F

Answer & explanation

Answer: b. 55°F. Common for VAV AHUs.

45. Device controlling supplementary electric heat in heat pumps:

1. a. Auxiliary temperature control
2. b. Outdoor ambient thermostat
3. c. Indoor thermostat only
4. d. Return air sensor

Answer & explanation

Answer: b. Outdoor ambient thermostat. Enables backup heat at low ambient.

46. BTUs to evaporate 1 lb of water (latent heat of vaporization):

1. a. 370
2. b. 570
3. c. 970
4. d. 1170

Answer & explanation

Answer: c. 970. At 212°F; near this at typical HVAC conditions.

47. What occurs in a condenser?

1. a. Refrigerant absorbs latent heat
2. b. Refrigerant releases latent heat
3. c. Latent heat increases
4. d. Refrigerant absorbs sensible heat

Answer & explanation

Answer: b. Releases latent heat to ambient or water.

48. Boiling point of water (sea level):

1. a. 100°F
2. b. 112°F
3. c. 212°F
4. d. 221°F

Answer & explanation

Answer: c. 212°F.

49. Not a mode of heat transfer:

1. a. Conduction
2. b. Convection
3. c. Radiation
4. d. Retardation

Answer & explanation

Answer: d. Retardation. The three modes are conduction, convection, radiation.

50. Typical indoor relative humidity target for comfort cooling:

1. a. 30–40%
2. b. 40–50%
3. c. 50–60%
4. d. 60–70%

Answer & explanation

Answer: b. 40–50%. Good balance of comfort and IAQ.

Design-oriented advanced: velocities, formulas, space types 25 questions

51. Recommended supply air diffuser outlet velocity in office occupied zones:

1. a. 200 fpm
2. b. 400 fpm
3. c. 600 fpm
4. d. 800 fpm

Answer & explanation

Answer: b. ~400 fpm. Minimizes drafts while maintaining throw.

52. Typical velocity range for main supply ducts (commercial):

1. a. 500–700 fpm
2. b. 800–1200 fpm
3. c. 1500–2000 fpm
4. d. 2000–2500 fpm

Answer & explanation

Answer: b. 800–1200 fpm. Trade-off of noise and pressure loss.

53. Recommended branch duct velocity (occupied zones):

1. a. 300–500 fpm
2. b. 600–800 fpm
3. c. 1000–1200 fpm
4. d. 1500 fpm

Answer & explanation

Answer: a. 300–500 fpm. Keeps NC levels reasonable.

54. Typical return air duct velocity:

1. a. 400–600 fpm
2. b. 800–1000 fpm
3. c. 1200–1500 fpm
4. d. 2000 fpm

Answer & explanation

Answer: b. 800–1000 fpm. Slightly higher velocities acceptable.

55. Recommended diffuser velocity in hospital operating rooms (laminar):

1. a. 200 fpm
2. b. 400 fpm
3. c. 600 fpm
4. d. 800 fpm

Answer & explanation

Answer: a. ~200 fpm. Supports laminar downflow.

56. Typical design velocity for chilled water in piping:

1. a. 2–3 ft/s
2. b. 4–6 ft/s
3. c. 6–8 ft/s
4. d. 8–10 ft/s

Answer & explanation

Answer: b. 4–6 ft/s. Avoids erosion and noise.

57. Typical design velocity for condenser water in piping:

1. a. 2–3 ft/s
2. b. 4–6 ft/s
3. c. 6–8 ft/s
4. d. 8–10 ft/s

Answer & explanation

Answer: c. 6–8 ft/s. Helps limit fouling and biofilm.

58. Water-side heat formula (Imperial):

1. a. Q = 1.08 × CFM × ΔT
2. b. Q = 500 × GPM × ΔT
3. c. Q = m × cp × ΔT
4. d. Q = U × A × ΔT

Answer & explanation

Answer: b. Q = 500 × GPM × ΔT (BTU/hr). 500 ≈ 8.33 lb/gal × 60 min/hr.

59. Air-side sensible heat formula (Imperial):

1. a. Q = 1.08 × CFM × ΔT
2. b. Q = 4.5 × CFM × ΔH
3. c. Q = m × cp × ΔT
4. d. Q = U × A × ΔT

Answer & explanation

Answer: a. Q = 1.08 × CFM × ΔT (BTU/hr). 1.08 ≈ 0.075 lb/ft³ × 60 × cp_air.

60. Air-side latent heat formula (Imperial):

1. a. Q = 1.08 × CFM × ΔT
2. b. Q = 4.5 × CFM × ΔW
3. c. Q = 500 × GPM × ΔT
4. d. Q = 0.68 × CFM × ΔT

Answer & explanation

Answer: b. Q = 4.5 × CFM × ΔW (BTU/hr). 4.5 ≈ 60 × 0.075; ΔW in grains or lb_w/lb_da.

61. Typical chilled water ΔT (comfort cooling baseline):

1. a. 6°F
2. b. 10°F
3. c. 12°F
4. d. 16°F

Answer & explanation

Answer: b. 10°F. High ΔT systems may target 12–16°F.

62. Best system for small office (<5,000 sq ft):

1. a. Window AC
2. b. Split AC
3. c. VRF
4. d. Chilled water plant

Answer & explanation

Answer: b. Split AC. Lower first cost and simple controls.

63. Best system for high-rise commercial towers:

1. a. Split AC
2. b. VRF
3. c. Packaged rooftop
4. d. Central chilled water

Answer & explanation

Answer: d. Central chilled water. Scalability and efficiency.

64. Best system for hospitals (ORs, isolation, humidity control):

1. a. VRF
2. b. Chilled water with AHUs
3. c. Split AC
4. d. Rooftop packaged

Answer & explanation

Answer: b. Chilled water with AHUs. Filtration, humidity, redundancy.

65. Best system for data centers (high sensible loads):

1. a. VRF
2. b. CRAC/CRAH
3. c. Rooftop packaged
4. d. Split AC

Answer & explanation

Answer: b. CRAC/CRAH. Precise temperature, airflow management, redundancy.

66. Best system for hotels (guestroom zoning):

1. a. Window AC
2. b. VRF
3. c. Rooftop packaged
4. d. Chilled water

Answer & explanation

Answer: b. VRF. Independent zone control, aesthetics, energy savings.

67. Duct design method prioritizing simplicity with acceptable performance:

1. a. Velocity method
2. b. Equal friction
3. c. Static regain
4. d. Network simulation

Answer & explanation

Answer: b. Equal friction. Uniform friction rate yields balanced sizing.

68. Unit for duct friction loss:

1. a. psi/100 ft
2. b. in. w.g./100 ft
3. c. Pa/m
4. d. ft/s

Answer & explanation

Answer: b. in. w.g./100 ft. Standard in Imperial design.

69. Pipe sizing typically based on:

1. a. Velocity limits
2. b. Pressure drop per 100 ft
3. c. Required flow rate
4. d. All of the above

Answer & explanation

Answer: d. All of the above. Multi-constraint optimization.

70. Pump head equation components include:

1. a. Static lift only
2. b. Friction losses only
3. c. Pressure, velocity head, friction losses
4. d. Elevation only

Answer & explanation

Answer: c. Pressure difference + velocity head + friction losses.

71. Fan horsepower formula (Imperial):

1. a. HP = (CFM × SP)/(6356 × η)
2. b. HP = (GPM × ΔP)/(3960 × η)
3. c. HP = W/746
4. d. HP = τ × ω

Answer & explanation

Answer: a. HP = (CFM × SP)/(6356 × η). SP in in. w.g.; η total efficiency.

72. Operating room ACH requirement (typical):

1. a. 6
2. b. 12
3. c. 15
4. d. 20

Answer & explanation

Answer: d. 20 ACH. Maintains sterility and cleanliness.

73. Laboratory ventilation ACH range (typical):

1. a. 6–8
2. b. 10–12
3. c. 12–15
4. d. 15–20

Answer & explanation

Answer: b. 10–12 ACH. Depends on hazard and fume hoods.

74. Recommended RH for museums/galleries:

1. a. 30–40%
2. b. 40–50%
3. c. 50–60%
4. d. 60–70%

Answer & explanation

Answer: b. 40–50%. Limits material expansion/contraction.

75. Recommended RH for data centers:

1. a. 20–30%
2. b. 30–40%
3. c. 40–50%
4. d. 50–60%

Answer & explanation

Answer: b. 30–40%. Avoids static and condensation risks.

76. Recommended server room temperature (ASHRAE TC 9.9 allowable):

1. a. 68–72°F
2. b. 72–75°F
3. c. 75–78°F
4. d. 78–80°F

Answer & explanation

Answer: b. 72–75°F. Balances energy and reliability.

77. Typical maximum allowable refrigerant piping length in VRF (manufacturer dependent):

1. a. 100 ft
2. b. 300 ft
3. c. 500 ft
4. d. 1000 ft

Answer & explanation

Answer: c. ~500 ft. Check OEM design manuals.

78. Refrigerant commonly used in VRF systems today:

1. a. R-22
2. b. R-134a
3. c. R-410A
4. d. R-32

Answer & explanation

Answer: c. R-410A. Transition to lower-GWP refrigerants underway.

79. Unique safety concern in VRF design addressed by ASHRAE 15:

1. a. Fire hazard
2. b. Refrigerant concentration in occupied spaces
3. c. Electrical overload
4. d. Vibration

Answer & explanation

Answer: b. Refrigerant concentration. Leak limits per volume.

80. Common energy modeling tools for HVAC:

1. a. HAP
2. b. TRACE 700
3. c. EnergyPlus
4. d. All of the above

Answer & explanation

Answer: d. All of the above. Different depths and workflows.

81. Function of an enthalpy (energy) recovery wheel:

1. a. Reduce duct size
2. b. Transfer heat and moisture between exhaust and supply
3. c. Increase refrigerant efficiency
4. d. Control noise

Answer & explanation

Answer: b. Recovers sensible and latent energy.

82. Typical COP of single-effect absorption chillers:

1. a. 0.5–0.7
2. b. 1.0–1.2
3. c. 2.0–3.0
4. d. 4.0–5.0

Answer & explanation

Answer: a. 0.5–0.7. Heat-driven; lower efficiency than mechanical chillers.

83. Maximum recommended NC (Noise Criteria) for open offices:

1. a. NC-25
2. b. NC-30
3. c. NC-35
4. d. NC-40

Answer & explanation

Answer: b. NC‑30. Achieved via lower velocities, lining, and silencers.

84. Common duct lining material for attenuation:

1. a. Fiberglass
2. b. Steel
3. c. Aluminum
4. d. PVC

Answer & explanation

Answer: a. Fiberglass. Absorptive lining to reduce regenerated noise.

85. Smoke detectors required in return air systems above:

1. a. 1000 cfm
2. b. 2000 cfm
3. c. 3000 cfm
4. d. 4000 cfm

Answer & explanation

Answer: b. 2000 cfm. Per typical mechanical code/NFPA guidance.

86. TAB stands for:

1. a. Testing, Adjusting, Balancing
2. b. Temperature and Air Balance
3. c. Technical Airflow Benchmarking
4. d. Thermal Adjustment Baseline

Answer & explanation

Answer: a. Testing, Adjusting, Balancing. Commissioning discipline verifying air/water flows.

87. Minimum bathroom exhaust rate in motels (code typical):

1. a. 25 cfm
2. b. 35 cfm
3. c. 50 cfm
4. d. 75 cfm

Answer & explanation

Answer: c. 50 cfm. Odor and moisture control.

88. Recommended condenser water approach to ambient wet-bulb (cooling towers):

1. a. 2–3°F
2. b. 5–6°F
3. c. 8–10°F
4. d. 12–14°F

Answer & explanation

Answer: b. 5–6°F typical. Lower approach → larger tower, higher cost.

89. Typical condenser water supply/return temperatures (comfort cooling):

1. a. 75/85°F
2. b. 80/90°F
3. c. 85/95°F
4. d. 90/100°F

Answer & explanation

Answer: c. 85/95°F. Depends on climate and tower performance.

90. Chilled beam systems reduce energy primarily by:

1. a. Higher duct pressure
2. b. Reduced fan energy via convection
3. c. Increased refrigerant charge
4. d. Lower chilled water ΔT

Answer & explanation

Answer: b. Lower fan energy; beams induce room air over coils.

91. Economizer high limit control commonly uses:

1. a. Return air temperature
2. b. Outdoor dry-bulb
3. c. Outdoor enthalpy
4. d. Mixed air humidity

Answer & explanation

Answer: c. Outdoor enthalpy (best). Dry-bulb is simpler but less accurate.

92. Recommended maximum velocity in chilled water risers to avoid noise:

1. a. 3 ft/s
2. b. 5 ft/s
3. c. 7 ft/s
4. d. 9 ft/s

Answer & explanation

Answer: b. ~5 ft/s. Vertical runs amplify noise; keep moderate.

93. Preferred valve type for precise hydronic balancing:

1. a. Gate
2. b. Globe
3. c. Ball
4. d. Butterfly

Answer & explanation

Answer: b. Globe. Non-linear but precise throttling.

94. Typical primary-secondary decoupler function:

1. a. Reduce noise
2. b. Allow flow mixing and hydraulic separation
3. c. Increase pump efficiency
4. d. Control temperature

Answer & explanation

Answer: b. Decouples chiller and distribution flows.

95. VRF heating capacity drop at low ambient is mitigated by:

1. a. Higher superheat
2. b. Crankcase heaters
3. c. Variable speed compressors and vapor injection
4. d. Larger indoor coils

Answer & explanation

Answer: c. Vapor injection and advanced compression improve low‑ambient heating.

96. Typical minimum OA (outdoor air) ventilation for classrooms (people component baseline):

1. a. 10 cfm/person
2. b. 15 cfm/person
3. c. 20 cfm/person
4. d. 25 cfm/person

Answer & explanation

Answer: b. 15 cfm/person (plus area component). Verify latest 62.1 tables.

97. Return air locations should be placed:

1. a. Behind appliances
2. b. Near ceiling and low to ground (two locations)
3. c. Near hot appliances
4. d. In closed cavities

Answer & explanation

Answer: b. Ceiling and low locations facilitate mixing and stratification control.

98. Sensible heat describes:

1. a. How fast heat travels
2. b. The quantity of heat
3. c. The volume of heat
4. d. How hot something feels

Answer & explanation

Answer: b. Quantity of heat affecting temperature.

99. To convert °F to °C:

1. a. C = (F + 32) ÷ 1.8
2. b. C = (F − 32) ÷ 1.8
3. c. C = (F + 32) × 1.8
4. d. C = (F − 32) × 1.8

Answer & explanation

Answer: b. C = (F − 32) ÷ 1.8. Standard temp conversion.

100. Atmospheric pressure at sea level (Imperial):

1. a. 12.7 psi
2. b. 13.7 psi
3. c. 14.7 psi
4. d. 15.7 psi

Answer & explanation

Answer: c. 14.7 psi. Basis for absolute pressure calculations.

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