Introduction: This quiz set on Air Filtration and Plenum Ventilation is designed for M.Pharm students studying Bioprocess Engineering and Technology. It focuses on core concepts relevant to pharmaceutical cleanrooms and controlled environments: HEPA/ULPA filter function, filter ratings and media, plenum design and pressurization, airflow patterns (laminar vs turbulent), testing and certification methods, and routine maintenance considerations. The questions aim to deepen understanding of how air cleanliness is achieved and validated in production and aseptic areas, linking theory to practical HVAC and quality-control practices encountered in pharmaceutical manufacturing and regulatory compliance.
Q1. What particle size is the HEPA filter efficiency rating (99.97%) traditionally based upon?
- 0.1 micrometer
- 0.3 micrometer
- 0.5 micrometer
- 1.0 micrometer
Correct Answer: 0.3 micrometer
Q2. Which specification best describes an ULPA filter compared with a HEPA filter?
- Lower efficiency but higher airflow than HEPA
- Typically 99.999% efficiency for particles around 0.12 µm
- Used only for gaseous contaminants, not particles
- Has larger fiber diameter than HEPA media
Correct Answer: Typically 99.999% efficiency for particles around 0.12 µm
Q3. What does a higher MERV rating indicate for an air filter?
- Better removal efficiency for smaller particles
- Lower pressure drop at the same airflow
- Increased tolerance to moisture only
- Preferential removal of gaseous contaminants
Correct Answer: Better removal efficiency for smaller particles
Q4. Which statement best defines a supply plenum in cleanroom HVAC?
- An exhaust duct that removes contaminated air from the room
- A chamber used to mix outdoor air with exhaust air
- A pressurized distribution chamber that feeds filtered air to the room
- A storage compartment for spare HEPA filters
Correct Answer: A pressurized distribution chamber that feeds filtered air to the room
Q5. Which airflow pattern is described as unidirectional, low-turbulence and commonly used for aseptic zones?
- Displacement airflow
- Plenum turbulence flow
- Unidirectional (laminar) airflow
- Mixed-mode recirculating airflow
Correct Answer: Unidirectional (laminar) airflow
Q6. Typical HEPA face velocity in a laminar flow hood is approximately which value?
- 0.05 m/s
- 0.45 m/s
- 2.0 m/s
- 5.0 m/s
Correct Answer: 0.45 m/s
Q7. As a HEPA filter loads with particulate matter during service, what happens to the pressure drop across it?
- Pressure drop decreases
- Pressure drop remains constant
- Pressure drop increases
- Pressure drop fluctuates randomly without trend
Correct Answer: Pressure drop increases
Q8. Where is a pre-filter typically located in relation to a final HEPA filter?
- Downstream of the HEPA filter
- Upstream of the HEPA filter
- Side-by-side with the HEPA filter
- Farther along the exhaust duct only
Correct Answer: Upstream of the HEPA filter
Q9. What is the most penetrating particle size range (MPPS) for mechanical HEPA filters?
- >1.0 micrometer
- Approximately 0.1–0.3 micrometer
- <0.01 micrometer
- 0.5–1.0 micrometer
Correct Answer: Approximately 0.1–0.3 micrometer
Q10. Which instrument is commonly used to perform HEPA filter leak scanning during commissioning?
- Optical particle counter only
- Temperature-humidity meter
- Aerosol photometer (PAO/DOP detector)
- Sound level meter
Correct Answer: Aerosol photometer (PAO/DOP detector)
Q11. Which standard largely superseded FED STD 209E for cleanroom classification and is used internationally?
- ASTM E10
- ISO 14644-1
- CE 1023
- BS 5295
Correct Answer: ISO 14644-1
Q12. What is the primary role of a HEPA filter in an AHU serving a pharmaceutical cleanroom?
- To adjust temperature setpoint
- To remove airborne particles and contaminants from supply air
- To dehumidify air
- To neutralize chemical vapors
Correct Answer: To remove airborne particles and contaminants from supply air
Q13. Which aerosol is commonly used today for HEPA filter efficiency and leak testing as a non-toxic substitute for DOP?
- Sulfur hexafluoride (SF6)
- Polyalphaolefin (PAO)
- Isopropyl alcohol vapor
- Compressed air tracer
Correct Answer: Polyalphaolefin (PAO)
Q14. Why are cleanrooms usually maintained at a positive pressure relative to adjacent less-clean areas?
- To increase airborne particle generation inside the cleanroom
- To drive contaminants from the cleanroom into corridors
- To prevent infiltration of contaminated air into the cleanroom
- To save energy by reducing HVAC workload
Correct Answer: To prevent infiltration of contaminated air into the cleanroom
Q15. Which instrument is used to measure particle counts and size distribution during routine cleanroom monitoring?
- Manometer
- Optical particle counter
- Aerosol photometer (for leak scanning only)
- Hygrometer
Correct Answer: Optical particle counter
Q16. Typical HEPA filter media is made from which material?
- Woven polyester fabric
- Pleated activated carbon
- Microglass (borosilicate glass fiber) media
- Stainless steel mesh
Correct Answer: Microglass (borosilicate glass fiber) media
Q17. When should a prefilter in a pharmaceutical HVAC system be replaced?
- Only when the final HEPA fails an efficiency test
- After a fixed calendar period regardless of condition
- When differential pressure across the prefilter exceeds the recommended limit
- Only when visible dust falls from the filter
Correct Answer: When differential pressure across the prefilter exceeds the recommended limit
Q18. One important benefit of air recirculation through HEPA filters in a plenum system is:
- Increasing raw makeup air consumption
- Reducing particle load and aiding thermal control
- Eliminating the need for primary filtration
- Preventing any need for maintenance
Correct Answer: Reducing particle load and aiding thermal control
Q19. In plenum ventilation design for cleanrooms, the term “plenum” most accurately refers to:
- A sealed storage area for HEPA filters
- An occupied workspace requiring special PPE
- An air handling chamber used to distribute conditioned air to the space
- A type of microbial sampling device
Correct Answer: An air handling chamber used to distribute conditioned air to the space
Q20. Which airflow arrangement best minimizes cross-contamination between operators and product in aseptic processing?
- Non-directional mixing airflow
- Downward unidirectional (laminar) airflow over the product
- Horizontal recirculating turbulence across the workbench
- Exhaust-only flow without supply filtration
Correct Answer: Downward unidirectional (laminar) airflow over the product
