HVAC Indoor Air Quality and Filtration

Question 1

What does MERV stand for in air filter ratings?

Accepted Answer

Minimum Efficiency Reporting Value; higher = more efficient at capturing smaller particles

Answer

Maximum Efficiency Rated Value

Answer

Measured Environmental Reduction Volume

Answer

Most Effective Rating Variable

Question 2

What is 'sick building syndrome' (SBS)?

Accepted Answer

Occupants experiencing health symptoms linked to time spent in a building, primarily caused by poor ventilation and indoor air contaminants

Answer

Building structural failure due to foundation problems

Answer

Legal liability from building code violations

Answer

Mold growth in building materials only

Question 3

What is the primary purpose of outdoor air ventilation in commercial HVAC systems according to ASHRAE Standard 62.1?

Accepted Answer

To dilute indoor contaminants and provide fresh air for occupant health and comfort

Answer

To cool the building during mild weather (free cooling)

Answer

To maintain positive building pressure and prevent infiltration

Answer

To reduce humidity in the building

Question 4

What CO2 concentration is generally considered the threshold above which occupant comfort begins to decline?

Accepted Answer

1,000 ppm

Answer

800 ppm

Answer

2,000 ppm

Answer

5,000 ppm

Question 5

What is 'bioaerosol' contamination in HVAC systems?

Accepted Answer

Airborne biological particles (mold spores, bacteria, viruses) generated by HVAC system components or building sources

Answer

Chemical contamination from refrigerant leaks

Answer

Static electricity buildup creating particle attraction

Answer

Ozone from UV systems reacting with dust particles

Question 6

What type of filter is required to achieve HEPA filtration?

Accepted Answer

True HEPA filter rated at 99.97% efficiency on particles ≥0.3 μm

Answer

MERV 13 filter rated at 85% efficiency

Answer

MERV 16 filter rated at 95% efficiency on all particles

Answer

Any filter rated MERV 14 or above

Question 7

What is the purpose of a UV germicidal irradiation (UVGI) system in an air handling unit?

Accepted Answer

To inactivate microorganisms by disrupting their DNA using UV-C light

Answer

To generate ozone for air purification

Answer

To ionize particles so they are captured by the filter

Answer

To heat the air to kill bacteria during winter operation

Question 8

What is a 'volatile organic compound' (VOC)?

Accepted Answer

Carbon-based chemical gases emitted from materials and products, with common indoor sources including new carpet, paint, and cleaning products

Answer

Odors from outdoor vehicle exhaust only

Answer

Biological contaminants from mold growth only

Answer

Moisture-related compounds from plumbing systems

Question 9

How does an energy recovery ventilator (ERV) improve indoor air quality while reducing energy consumption?

Accepted Answer

By transferring heat and moisture between outgoing and incoming air streams, conditioning fresh air with minimal energy

Answer

By filtering outdoor air before it enters

Answer

By recirculating indoor air more efficiently than traditional systems

Answer

By generating its own energy through heat recovery to power UV purification

Question 10

What does 'demand-controlled ventilation' (DCV) do?

Accepted Answer

Modulates outdoor air intake based on actual occupancy, typically using CO2 sensors

Answer

Varies supply air temperature based on occupancy using motion sensors

Answer

Controls ventilation fan speed based on outdoor air temperature

Answer

Schedules ventilation only during occupied hours using time clocks