Air circulation maintenance in sterile and non-sterile areas MCQs With Answer

Air circulation maintenance in sterile and non-sterile areas MCQs With Answer

by

Introduction
Maintaining proper air circulation in sterile and non-sterile areas is critical for pharmaceutical manufacturing, compounding, and quality assurance. This set of MCQs focuses on principles of HVAC design, filtration, pressure cascades, airflow patterns, monitoring, validation, and routine maintenance specific to controlled environments. Questions emphasize practical knowledge—HEPA filter performance, differential pressure practice, air changes, laminar versus turbulent flow, contamination control strategies, and common testing methods used during commissioning and periodic checks. These items are designed to strengthen understanding for M.Pharm students preparing for exams or working in pharmaceutical production, ensuring safe, compliant, and contamination-controlled processes.

Q1. Which statement best describes the primary purpose of establishing a pressure cascade in pharmaceutical cleanrooms?

  • To maximize energy efficiency by recirculating return air between adjacent rooms
  • To ensure airflow direction from cleaner to less-clean areas, minimizing contamination ingress
  • To equalize temperature and humidity across all production areas
  • To reduce sound transmission between rooms with different activities

Correct Answer: To ensure airflow direction from cleaner to less-clean areas, minimizing contamination ingress

Q2. Which characteristic is most typical of a HEPA filter used in sterile manufacturing?

  • Removes 99.97% of particles ≥0.3 µm
  • Designed to remove gaseous chemical vapors only
  • Rated by MERV scale only and cannot be integrity-tested
  • Effective primarily for particles >10 µm

Correct Answer: Removes 99.97% of particles ≥0.3 µm

Q3. What is the preferred airflow pattern inside a Grade A laminar flow workbench when preparing sterile products?

  • Unidirectional vertical downward flow across the critical area
  • Recirculating turbulent flow to dilute contaminants
  • Horizontal flow directed from operator toward product
  • Bidirectional flow to balance temperature gradients

Correct Answer: Unidirectional vertical downward flow across the critical area

Q4. Which monitoring parameter is most commonly used continuously to ensure cleanroom pressurization is maintained?

  • Particle count of ≥0.5 µm particles in real time
  • Differential pressure between adjacent rooms
  • Carbon dioxide concentration in the room
  • Sound level measured in decibels

Correct Answer: Differential pressure between adjacent rooms

Q5. During HEPA filter installation and qualification, which test is typically used to detect leaks in the filter media or seals?

  • DOP/PAO aerosol challenge and downstream particle scanning
  • Thermal imaging of filter surface temperature
  • Airflow smoke visualization without particle measurement
  • Visual inspection for dust accumulation only

Correct Answer: DOP/PAO aerosol challenge and downstream particle scanning

Q6. For sterile compounding areas, why is control of air changes per hour (ACH) important?

  • To ensure rapid dilution and removal of airborne contaminants and maintain environmental stability
  • To control the rate of ceiling condensation and prevent structural damage
  • To guarantee that solvents evaporate faster for process acceleration
  • To minimize the amount of supply air required for HVAC filters

Correct Answer: To ensure rapid dilution and removal of airborne contaminants and maintain environmental stability

Q7. What is the main rationale for using recirculated air through HEPA filtration in cleanrooms?

  • Recirculation reduces outdoor air intake and stabilizes particle counts while conserving energy
  • Recirculated air increases humidity to required levels for microbial growth control
  • It eliminates the need for regular environmental monitoring
  • Recirculation lowers the requirement for pressure differentials between rooms

Correct Answer: Recirculation reduces outdoor air intake and stabilizes particle counts while conserving energy

Q8. Which practice is most appropriate when an adjacent non-sterile area contains hazardous operations and a sterile area must be protected?

  • Maintain the sterile area at positive pressure relative to the hazardous area with an airlock buffer
  • Maintain both areas at equal pressure to simplify HVAC control
  • Keep the sterile area at negative pressure to contain hazardous emissions
  • Disable recirculation and rely solely on supply air for the sterile zone

Correct Answer: Maintain the sterile area at positive pressure relative to the hazardous area with an airlock buffer

Q9. Which particle size range is most critical to control because many bacteria and bacterial clumps fall within it and can carry into product?

  • 0.5–5 µm
  • 10–50 µm
  • 0.01–0.05 µm
  • 50–100 µm

Correct Answer: 0.5–5 µm

Q10. What is the primary benefit of periodically performing airflow smoke studies in a sterile zone?

  • To visually verify flow direction, turbulence, and potential dead zones around the critical area
  • To measure microbial counts produced by personnel
  • To quantify HEPA filter penetration at the molecular level
  • To determine the exact rate of air changes per hour using smoke density

Correct Answer: To visually verify flow direction, turbulence, and potential dead zones around the critical area

Q11. Which maintenance action is most important for sustaining HEPA performance and preventing microbial contamination?

  • Scheduled pre-filter replacement and differential pressure monitoring across HEPA modules
  • Spraying disinfectant directly onto HEPA media during routine cleaning
  • Bypassing HEPA filters intermittently to reduce operating costs
  • Only cleaning the intake grille annually without checking filters

Correct Answer: Scheduled pre-filter replacement and differential pressure monitoring across HEPA modules

Q12. For critical sterile zones, which environmental condition besides particle count is commonly included in routine monitoring to protect product quality?

  • Relative humidity and temperature
  • Ambient light intensity measured in lux only
  • Background ion concentration
  • Magnetic field strength in the room

Correct Answer: Relative humidity and temperature

Q13. What is the correct sequence of door openings to minimize contamination when moving from a less-clean corridor into a Grade A/B suite?

  • Enter the airlock, close exterior door, pass through gowning/airlock, then open inner door into clean suite
  • Open both doors simultaneously to reduce air pressure shock
  • Keep interior door open while passing through the exterior door quickly
  • Remove gowning prior to entering to reduce particulate shedding

Correct Answer: Enter the airlock, close exterior door, pass through gowning/airlock, then open inner door into clean suite

Q14. What is a common alarm setpoint strategy for differential pressure between a sterile room and its adjacent ante-room?

  • Set low/high alarms around a nominal positive differential (e.g., alarm if beyond ± specified Pa range)
  • Only alarm if differential pressure exceeds 100 Pa
  • Disable alarms because operator judgment is sufficient
  • Set alarms to trigger only during HVAC maintenance windows

Correct Answer: Set low/high alarms around a nominal positive differential (e.g., alarm if beyond ± specified Pa range)

Q15. During validation, which metric is most appropriate to demonstrate that a cleanroom quickly recovers following a challenge (e.g., door opening or disturbance)?

  • Recovery time to baseline particle count within the critical zone
  • Time to reach equilibrium humidity only
  • Duration for audible HVAC fan ramp-up
  • Length of time personnel remain in the room

Correct Answer: Recovery time to baseline particle count within the critical zone

Q16. When planning routine maintenance, which practice reduces contamination risk while servicing HVAC components in sterile manufacturing areas?

  • Isolating the supply to the affected zone, performing work from the non-product side, and re-certifying after completion
  • Opening HEPA housings and cleaning media in-situ without containment
  • Performing maintenance during active production to save downtime
  • Removing final HEPA filters and storing them in the sterile area until reinstallation

Correct Answer: Isolating the supply to the affected zone, performing work from the non-product side, and re-certifying after completion

Q17. Which filter stage is typically used upstream of a HEPA filter to protect the HEPA and extend its service life?

  • Pre-filter or coarse particulate filter
  • Activated carbon primary filter
  • Ultraviolet germicidal filter directly upstream
  • Electrostatic precipitator as a sole final stage

Correct Answer: Pre-filter or coarse particulate filter

Q18. Which control philosophy best minimizes cross contamination when both sterile and cytotoxic (hazardous) operations are present in adjacent areas?

  • Establish independent HVAC zones with appropriate pressure hierarchy and dedicated exhaust for hazardous areas
  • Share return air between zones to balance pressures
  • Use the same supply ducting but different filters to separate contaminants
  • Operate all areas at the same neutral pressure to simplify corridor access

Correct Answer: Establish independent HVAC zones with appropriate pressure hierarchy and dedicated exhaust for hazardous areas

Q19. Which routine test provides quantitative evidence of HEPA filter performance in service?

  • Downstream particle counting with a calibrated photometer or particle counter during a challenged leak test
  • Measuring sound level near the filter housing
  • Visual inspection of the exhaust grille for discoloration
  • Measuring amperage draw of the fan only

Correct Answer: Downstream particle counting with a calibrated photometer or particle counter during a challenged leak test

Q20. When addressing a persistent particle hot spot near a processing line, which corrective action is most appropriate?

  • Conduct airflow visualization, check HEPA integrity and balancing, correct disturbances or equipment placement causing turbulence
  • Increase room temperature to reduce particle buoyancy
  • Reduce the number of air changes to limit air movement
  • Routinely remove ceiling tiles to allow particles to escape

Correct Answer: Conduct airflow visualization, check HEPA integrity and balancing, correct disturbances or equipment placement causing turbulence

Leave a Comment