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Guide [Cleanroom]
Question 1. Which ISO 14644‑1 class permits the highest allowable particle concentration for particles ≥0.5 μm? A) ISO Class 5 B) ISO Class 7 C) ISO Class 9 D) ISO Class 1 Answer: C Explanation: ISO Class 9 allows up to 35 000 particles per cubic meter for particles ≥0.5 μm, the least stringent of the listed classes. Question 2. Federal Standard 209E Class 100 roughly corresponds to which ISO 14644‑ 1 class? A) ISO Class 4 B) ISO Class 5 C) ISO Class 6 D) ISO Class 7 Answer: B Explanation: FS 209E Class 100 (≤100 particles ≥0.5 μm per ft³) is approximately equivalent to ISO Class 5. Question 3. In cleanroom occupancy terminology, “At‑rest” refers to which condition? A) When equipment is operating but no personnel are present B) The state after cleaning and before any operation begins C) Full production with personnel and equipment running D) The condition during construction activities Answer: B
Guide [Cleanroom]
Explanation: “At‑rest” describes the cleanroom after cleaning and before any operational activity, used for baseline testing. Question 4. EU GMP Annex 1 Grade A environments must maintain which of the following air‑change rates? A) Minimum 10 ACH B) Minimum 15 ACH C) Minimum 30 ACH D) Minimum 60 ACH Answer: C Explanation: Grade A rooms (e.g., aseptic filling) require at least 30 air changes per hour to control particulate and microbial load. Question 5. USP <797> primarily addresses which type of cleanroom activity? A) Sterile compounding of pharmaceuticals B) Non‑sterile bulk drug manufacturing C) Packaging of medical devices D) Waste disposal in hospitals Answer: A Explanation: USP <797> sets standards for sterile compounding, requiring cleanroom design and practices to protect product sterility. Question 6. According to 21 CFR Part 211, which document is required to demonstrate cleanroom validation? A) Design Qualification (DQ) report B) Process Validation Master Plan C) Validation Protocol and Report (VMP)
Guide [Cleanroom]
B) Molecular (volatile) C) Biological D) Radiological Answer: B Explanation: Outgassing releases volatile organic compounds (VOCs) that are molecular contaminants, not particles. Question 10. The correct sequence for aseptic gowning is: A) Hair cover → shoe cover → gloves → gown → face mask B) Gown → hair cover → shoe cover → gloves → face mask C) Hair cover → gown → shoe cover → gloves → face mask D) Hair cover → shoe cover → gown → gloves → face mask Answer: D Explanation: Proper gowning starts with hair and shoe covers to protect the gown, followed by gown, gloves, and finally face mask. Question 11. To minimize turbulence, personnel should: A) Walk quickly across the room B) Use a rolling cart to transport items C) Move slowly and avoid sudden direction changes D) Open doors frequently for ventilation Answer: C Explanation: Slow, deliberate movements reduce air disturbance and prevent particle resuspension. Question 12. Molecular contamination on a surface is best reduced by:
Guide [Cleanroom]
A) High‑pressure water spray B) Solvent wiping with a lint‑free cloth C) Abrasive polishing D) UV irradiation only Answer: B Explanation: Solvent wiping removes molecular films without generating particles, unlike abrasive methods. Question 13. In HVAC design, a “laminar flow” system is characterized by: A) Random air circulation patterns B) Unidirectional airflow at low velocity C) High‑velocity turbulent jets D) Recirculating air through a single filter Answer: B Explanation: Laminar flow provides a uniform, unidirectional air stream that minimizes particle disturbance. Question 14. For a cleanroom requiring ISO Class 5, the recommended face velocity for HEPA filtration is: A) 0.1 m/s B) 0.3 m/s C) 0.5 m/s D) 0.8 m/s Answer: C Explanation: ISO Class 5 typically uses a face velocity of 0.5 m/s to achieve required cleanliness while controlling turbulence.
Guide [Cleanroom]
Explanation: Plain concrete is porous and prone to shedding, making it unsuitable for cleanroom floors. Question 18. The term “ULPA” stands for: A) Ultra‑Low Pressure Air B) Ultra‑Low Penetration Air C) Ultra‑Low Particulate Air D) Ultra‑Large Particle Air Answer: C Explanation: ULPA filters are rated to remove ≥99.999% of particles ≥0.12 μm, representing Ultra‑Low Particulate Air. Question 19. During Design Qualification (DQ), the primary focus is on: A) Verifying installation of equipment B) Confirming the design meets user requirements and standards C) Testing the cleanroom under operational conditions D) Calibrating all sensors and instruments Answer: B Explanation: DQ ensures that the design specifications fulfill all regulatory and functional requirements before construction. Question 20. Installation Qualification (IQ) typically includes which activity? A) Running product batches to assess performance B) Verifying that HVAC components are installed per design drawings C) Conducting microbiological sampling during operation D) Performing a full recovery test after a contamination event
Guide [Cleanroom]
Answer: B Explanation: IQ confirms that equipment and systems are installed correctly according to design documents. Question 21. Operational Qualification (OQ) for a cleanroom primarily tests: A) Product sterility outcomes B) System performance under “At‑rest” conditions, such as airflow and pressure C) Employee gowning compliance D) Long‑term filter degradation Answer: B Explanation: OQ assesses whether the cleanroom operates as intended in a controlled, non‑operational state. Question 22. Performance Qualification (PQ) differs from OQ by: A) Being performed before equipment installation B) Testing the cleanroom under real production (Operational) conditions C) Focusing solely on documentation review D) Excluding particle monitoring Answer: B Explanation: PQ validates that the cleanroom maintains required performance during actual manufacturing activities. Question 23. In airborne particle counting, the most common sampling location is: A) Center of the ceiling B) Near the air supply diffuser C) At the work zone height (0.8 m) in the critical area
Guide [Cleanroom]
C) The frequency of personnel gowning errors D) The durability of cleanroom walls under chemical exposure Answer: A Explanation: Recovery testing quantifies how quickly a cleanroom returns to compliance after a contamination event. Question 27. Continuous monitoring systems (FMS) typically do NOT monitor which parameter? A) Differential pressure B) Relative humidity C) Particle concentration in real time D) Staff attendance logs Answer: D Explanation: FMS focuses on environmental parameters; staff attendance is not part of environmental monitoring. Question 28. Active air sampling for microbiological monitoring commonly uses which principle? A) Impaction onto agar plates using a calibrated sampler B) Passive settling of airborne microbes onto open Petri dishes C) Swabbing of surfaces with sterile cotton D) UV fluorescence detection of spores Answer: A Explanation: Active sampling draws a known air volume onto agar media via impaction, enabling quantitative microbial analysis. Question 29. Passive air sampling (settle plates) provides data on:
Guide [Cleanroom]
A) Real‑time airborne particle counts B. Concentration of viable organisms that settle by gravity over a defined period C) Chemical vapor levels in the room D. Temperature gradients across the cleanroom Answer: B Explanation: Settle plates collect microorganisms that naturally settle, giving a qualitative measure of contamination. Question 30. The most appropriate disinfectant for routine cleaning of a Grade A cleanroom is: A) 70 % Isopropyl alcohol B. 0.5 % Sodium hypochlorite C. Quaternary ammonium compound (QAC) with sporicidal activity D. Hydrogen peroxide vapor (HPV) for periodic deep‑cleaning Answer: A Explanation: 70 % IPA provides rapid bactericidal action without leaving residues, suitable for routine cleaning; sporicidal agents are reserved for specific needs. Question 31. In preventive maintenance, fan filter units (FFUs) should be inspected for filter integrity at least every: A) 6 months B) 12 months C) 24 months D) 36 months Answer: B Explanation: Manufacturer guidelines and industry practice typically require annual FFU filter integrity testing.
Guide [Cleanroom]
Explanation: ISO 21501‑4 provides the methodology for calibrating optical particle counters to ensure measurement traceability. Question 35. A thermal anemometer measures air velocity by: A) Detecting the Doppler shift of laser light B) Measuring temperature change of a heated wire exposed to airflow C) Using a rotating cup assembly D. Calculating pressure drop across a restriction Answer: B Explanation: The heated wire cools proportionally to airflow; the change in resistance is converted to velocity. Question 36. Vane anemometers are best suited for: A) Low‑velocity laminar flow measurement B. High‑velocity turbulent flow measurement C. Measuring humidity levels D. Detecting particle size Answer: B Explanation: Vane anemometers rely on wind‑driven rotation, making them appropriate for higher velocities and turbulent conditions. Question 37. A photometer used for aerosol challenge testing of filters primarily measures: A) Particle size distribution B. Light attenuation caused by aerosol concentration C. Temperature of the aerosol stream D. Electrical charge of particles
Guide [Cleanroom]
Answer: B Explanation: Photometers assess aerosol concentration by measuring the reduction in light intensity passing through the aerosol. Question 38. Which of the following pressure cascade configurations is typical for a sterile fill line? A) Negative pressure in the fill area, positive pressure in the gowning area B. Positive pressure in the fill area, negative pressure in the adjacent warehouse C. Uniform pressure throughout all zones D. Positive pressure in the gowning area, neutral pressure in the fill area Answer: B Explanation: The fill area is kept at positive pressure to prevent ingress, while surrounding less‑critical zones may be at lower pressure. Question 39. When calculating required ACH for an ISO Class 7 room with a volume of 300 m³, the target airflow is 90 m³/min. What is the required ACH? A) 12 ACH B) 18 ACH C) 24 ACH D) 30 ACH Answer: B Explanation: ACH = (Airflow × 60) / Room volume = (90 × 60) / 300 = 18 ACH. Question 40. The most common cause of HEPA filter “blow‑through” is: A) Excessive face velocity exceeding design limits B. Filter media aging
Guide [Cleanroom]
A. Biological safety cabinet B. Clean bench (Class 100) C. HEPA‑filtered exhaust vent D. Positive pressure enclosure Answer: B Explanation: A laminar flow hood provides a unidirectional, HEPA‑filtered airflow over the work surface, commonly called a clean bench. Question 44. Which of the following practices helps to reduce molecular contamination on stainless‑steel surfaces? A. Polishing with abrasive pads B. Passivation with nitric acid C. Wiping with oil‑based lubricants D. Exposing to high‑temperature steam only Answer: B Explanation: Passivation removes free iron and forms a protective oxide layer, reducing surface reactivity and molecular contamination. Question 45. During a smoke study, a vortex observed near a door indicates: A. Adequate airflow distribution B. Potential turbulence caused by door operation C. Proper pressure differential maintenance D. No impact on particle control Answer: B Explanation: Vortices are signs of turbulent airflow, often generated by door movement, which can disturb particle control.
Guide [Cleanroom]
Question 46. The most appropriate method for verifying the integrity of a ULPA filter is: A. Water spray test B. DOP/PAO aerosol penetration test with flow reversal C. Visual inspection of filter media D. Measuring pressure drop only Answer: B Explanation: An aerosol challenge (DOP/PAO) with flow reversal detects leaks and confirms ULPA filter performance. Question 47. In a cleanroom, the term “gowning corridor” refers to: A. The main production area B. The transitional space where personnel don and doff garments C. The HVAC control room D. The storage area for raw materials Answer: B Explanation: The gowning corridor is designed for safe donning/doffing of cleanroom attire, separating it from the critical zone. Question 48. Which of the following is a key consideration when selecting sealants for cleanroom walls? A. High VOC emission for rapid curing B. Low outgassing and non‑particulate nature C. Ability to be painted over with any color D. Flexibility to allow wall movement Answer: B
Guide [Cleanroom]
D. Chemical fume hood Answer: D Explanation: Chemical fume hoods are separate containment devices, not standard HVAC components. Question 52. In cleanroom classification, “particle size” refers to: A. The diameter of the smallest detectable particle B. The average mass of airborne particles C. The geometric mean of particles present D. The nominal size used for counting (e.g., 0.5 μm) Answer: D Explanation: Classification tables specify limits for particles at defined nominal sizes, such as ≥0.5 μm. Question 53. The most effective way to reduce personnel‑generated particles is to: A. Increase room temperature B. Implement strict gowning and movement protocols C. Use higher‑speed fans D. Install additional lighting Answer: B Explanation: Proper gowning and controlled movement directly limit shedding and turbulence. Question 54. Which of the following cleaning agents is considered “sporicidal”? A. 70 % isopropyl alcohol B. 0.5 % sodium hypochlorite (bleach) C. Quaternary ammonium compounds (QAC) without additives
Guide [Cleanroom]
D. Mild detergent solution Answer: B Explanation: Sodium hypochlorite at appropriate concentration destroys bacterial spores, making it sporicidal. Question 55. The term “airborne molecular contamination” (AMC) is most closely associated with which monitoring technique? A. Particle counting B. Real‑time VOC sensor (e.g., PID) C. Settle plates D. Temperature probe Answer: B Explanation: AMC monitoring uses instruments like photo‑ionization detectors to track volatile organic compounds. Question 56. A cleanroom designed for semiconductor wafer processing typically requires: A. High humidity (>60 %) to prevent static B. Low humidity (<45 %) and temperature control to reduce electrostatic discharge C. Positive pressure relative to the outside environment only D. No filtration because wafers are already clean Answer: B Explanation: Low humidity reduces static buildup, which can damage delicate semiconductor devices. Question 57. Which of the following is the most common cause of pressure excursions in a cleanroom? A. Seasonal temperature changes
