Laminar flow equipment MCQs With Answer

Laminar flow equipment MCQs With Answer

Understanding laminar flow equipment is essential for B.Pharm students involved in pharmaceutical aseptic processing and sterile compounding. This introduction covers laminar airflow principles, HEPA/ULPA filtration, unidirectional vs turbulent flow, validation tests (smoke, particle count, filter integrity), pressure differentials, and cleanroom classification (ISO/USP). Emphasis is on practical aspects: correct hood selection, PPE and contamination control, routine certification, and maintenance practices that protect product sterility. Keywords: laminar flow equipment, laminar airflow hood, HEPA filter, cleanroom, aseptic technique, validation, B.Pharm. Now let’s test your knowledge with 50 MCQs on this topic.

Q1. What is the defining characteristic of laminar (unidirectional) airflow in laminar flow equipment?

• Air moves in a uniform, parallel stream with minimal turbulence
• Air is constantly mixed by fans to distribute particles evenly
• Airflow alternates direction periodically to clean the area
• Airflow relies on natural convection without filters

Correct Answer: Air moves in a uniform, parallel stream with minimal turbulence

Q2. What is the primary purpose of a laminar flow hood in pharmaceutical compounding?

• To protect the operator from hazardous aerosols
• To protect the product from particulate and microbial contamination
• To provide temperature control for formulations
• To sterilize equipment by UV radiation alone

Correct Answer: To protect the product from particulate and microbial contamination

Q3. What is the standard efficiency rating of a HEPA filter commonly used in laminar flow equipment?

• 99.97% removal at 0.3 micrometers
• 90% removal at 1.0 micrometers
• 99.0% removal at 5.0 micrometers
• 100% removal at 0.01 micrometers

Correct Answer: 99.97% removal at 0.3 micrometers

Q4. Which statement best differentiates laminar (unidirectional) flow from turbulent (non-unidirectional) flow?

• Laminar flow uses HEPA filters, turbulent flow does not
• Laminar flow moves air in parallel streams; turbulent flow mixes air and creates eddies
• Turbulent flow is always faster than laminar flow
• Laminar flow cannot be used in cleanrooms

Correct Answer: Laminar flow moves air in parallel streams; turbulent flow mixes air and creates eddies

Q5. What is the airflow direction in a vertical laminar flow hood?

• From top to bottom over the work surface
• From front to back under the work surface
• From bottom to top away from the work surface
• From left to right across the work surface

Correct Answer: From top to bottom over the work surface

Q6. Which of the following is true about laminar flow hoods compared to biological safety cabinets (BSC)?

• Laminar flow hoods protect both product and operator equally
• Laminar flow hoods primarily protect the product, while BSCs also protect personnel and environment
• BSCs do not use HEPA filters, but laminar flow hoods do
• Laminar flow hoods are used for hazardous material handling only

Correct Answer: Laminar flow hoods primarily protect the product, while BSCs also protect personnel and environment

Q7. Which class of biological safety cabinet provides both product and personnel protection?

• Class I
• Class II
• Class III
• Laminar flow bench

Correct Answer: Class II

Q8. ULPA filters differ from HEPA filters by providing which advantage?

• Higher efficiency, capturing ≥99.999% of smaller particles
• Lower airflow resistance and no need for fans
• Better removal of chemical vapors than activated carbon
• They are washable and reusable without replacement

Correct Answer: Higher efficiency, capturing ≥99.999% of smaller particles

Q9. Which international standard is most commonly used to classify cleanroom air cleanliness?

• ISO 14644‑1
• ASTM E11
• FDA 21 CFR Part 210
• WHO GMP Annex 2 only

Correct Answer: ISO 14644‑1

Q10. Which ISO class is approximately equivalent to a Federal Class 100 clean area?

• ISO 7
• ISO 6
• ISO 5
• ISO 3

Correct Answer: ISO 5

Q11. What is the purpose of a pre-filter in laminar flow equipment?

• To sterilize the air microbiologically
• To remove large dust particles and extend life of the HEPA filter
• To increase room temperature before HEPA filtration
• To replace HEPA filtration during maintenance

Correct Answer: To remove large dust particles and extend life of the HEPA filter

Q12. Typical recommended face velocity range for a laminar flow workbench is closest to which value?

• 0.3–0.5 meters per second
• 1.5–2.0 meters per second
• 0.01–0.05 meters per second
• 5–10 meters per second

Correct Answer: 0.3–0.5 meters per second

Q13. Which test is commonly used for HEPA filter integrity using an aerosol challenge and photometer?

• Smoke pattern test
• PAO/aerosol photometer filter integrity test
• Microbiological culture test
• Voltage leak test

Correct Answer: PAO/aerosol photometer filter integrity test

Q14. What does a smoke pattern test primarily evaluate in a laminar flow hood?

• Airflow pattern and presence of turbulence or dead zones
• Microbial contamination on surfaces
• HEPA filter chemical composition
• Electrical grounding of the cabinet

Correct Answer: Airflow pattern and presence of turbulence or dead zones

Q15. In aseptic processing, how should pressure be maintained between a cleaner room and an adjacent less-clean room?

• Negative pressure in the cleaner room relative to adjacent area
• Positive pressure in the cleaner room relative to adjacent area
• Equal atmospheric pressure to avoid airflow
• Pressure cycling between positive and negative hourly

Correct Answer: Positive pressure in the cleaner room relative to adjacent area

Q16. What is a commonly recommended differential pressure range between adjacent cleanroom zones?

• 5–15 Pascals (Pa)
• 50–150 Pascals (Pa)
• 0.1–0.5 Pascals (Pa)
• 500–1000 Pascals (Pa)

Correct Answer: 5–15 Pascals (Pa)

Q17. What distinguishes a recirculating laminar flow hood from a non-recirculating (exhaust) hood?

• Recirculating hoods return filtered air to the room; non‑recirculating hoods exhaust filtered air outside
• Recirculating hoods do not use HEPA filters; non-recirculating ones do
• Non-recirculating hoods are quieter and use no fans
• Recirculating hoods are intended for hazardous drug handling only

Correct Answer: Recirculating hoods return filtered air to the room; non‑recirculating hoods exhaust filtered air outside

Q18. What defines the “critical zone” inside a laminar flow hood?

• The outer edges of the cabinet where airflow is weakest
• The immediate work area where sterile manipulations occur
• The motor housing area for the blower
• The storage compartment underneath the bench

Correct Answer: The immediate work area where sterile manipulations occur

Q19. Laminar flow equipment is an essential engineering control in which pharmaceutical activity?

• Aseptic processing and sterile product compounding
• Tablet coating temperature control
• Packaging of non-sterile tablets only
• Bulk solvent storage ventilation only

Correct Answer: Aseptic processing and sterile product compounding

Q20. Which practice helps reduce particulate contamination introduced by operators working at a laminar flow bench?

• Wearing appropriate cleanroom gowning and strict aseptic technique
• Working faster without gloves
• Wearing street clothes under a lab coat
• Placing paperwork inside the hood during operations

Correct Answer: Wearing appropriate cleanroom gowning and strict aseptic technique

Q21. What is a common material used for the media of HEPA filter fibers?

• Glass microfiber
• Cotton wool
• Stainless steel mesh
• Plastic film

Correct Answer: Glass microfiber

Q22. Which factor most directly shortens the service life of a HEPA filter in laminar flow equipment?

• High particle loading and improper pre-filtration
• Low ambient humidity only
• No ultraviolet light exposure
• Using the filter for only sterile work

Correct Answer: High particle loading and improper pre-filtration

Q23. How does air change rate (ACH) relate to cleanroom cleanliness?

• Higher cleanliness generally requires higher air change rates
• Air change rate is unrelated to cleanliness
• Lower air change rates always improve cleanliness
• Air change rate only affects temperature, not particles

Correct Answer: Higher cleanliness generally requires higher air change rates

Q24. What design features of a biological safety cabinet (BSC) help protect personnel from biohazards?

• Downflow laminar air only, without front sash
• Directional airflow, sash and exhaust HEPA filtration
• Only UV lamps and no filtration
• Open-top design to increase operator comfort

Correct Answer: Directional airflow, sash and exhaust HEPA filtration

Q25. When should HEPA filter integrity testing be performed for laminar flow equipment?

• Only when the filter visibly appears dirty
• After installation, after relocation or repair, and at scheduled intervals (e.g., annually)
• Never, if the unit is new
• Only when a regulatory inspector requests it

Correct Answer: After installation, after relocation or repair, and at scheduled intervals (e.g., annually)

Q26. Which instrument is commonly used to measure HEPA filter leakage during a challenge test?

• Particle counter alone
• Aerosol photometer (PAO photometer)
• pH meter
• Thermocouple

Correct Answer: Aerosol photometer (PAO photometer)

Q27. Regulatory particle monitoring for many cleanroom classifications commonly tracks particles of what minimum size?

• 10 micrometers
• 5.0 micrometers
• 0.5 micrometers
• 0.01 micrometers

Correct Answer: 0.5 micrometers

Q28. Which tool is typically used to measure airflow velocity at the face or work surface of a laminar flow hood?

• Anemometer
• Oscilloscope
• Spectrophotometer
• Calorimeter

Correct Answer: Anemometer

Q29. What does a cleanroom ‘recovery test’ evaluate?

• How long it takes the environment to return to baseline particle counts after a disturbance
• The chemical resistance of the HEPA filter
• The electrical power backup time for the fan motor
• The microbial kill rate of disinfectants

Correct Answer: How long it takes the environment to return to baseline particle counts after a disturbance

Q30. What does the acronym HEPA stand for?

• High Energy Particulate Adsorbent
• High Efficiency Particulate Air
• High Efficiency Particle Absorber
• High Extraction Particulate Assembly

Correct Answer: High Efficiency Particulate Air

Q31. In a horizontal laminar flow cabinet, airflow travels in which direction relative to the operator?

• From the operator toward the back of the cabinet
• From the back of the cabinet toward the operator
• From top to bottom over the product
• From bottom to top away from the operator

Correct Answer: From the back of the cabinet toward the operator

Q32. Which of the following is a major source of contamination in laminar flow operations?

• Operators, materials, and incoming air
• Only the HEPA filter itself
• Only the flooring material under the bench
• Only UV lamps used intermittently

Correct Answer: Operators, materials, and incoming air

Q33. Which unit is commonly used to display differential pressure in cleanroom monitoring systems?

• Pascals (Pa)
• Liters per minute (L/min)
• Kelvin (K)
• Ohms (Ω)

Correct Answer: Pascals (Pa)

Q34. A filter leak test typically requires which two elements?

• A sonic detector and thermometer
• An aerosol challenge and a photometer to detect leakage
• A bacterial culture plate and UV light
• A pressure gauge and a stethoscope

Correct Answer: An aerosol challenge and a photometer to detect leakage

Q35. Compared to HEPA filters, ULPA filters are characterized by which performance trait?

• Lower initial cost and lower efficiency
• Higher particle capture efficiency for very small particles
• Ability to remove gases and vapors without additional media
• Reusable after washing with water

Correct Answer: Higher particle capture efficiency for very small particles

Q36. Sterile product quality assurance requires which combination of controls?

• Only laminar flow equipment, no personnel training
• Aseptic technique, validated laminar flow equipment, environmental monitoring
• Only batch testing of final products
• Only chemical filtration of raw materials

Correct Answer: Aseptic technique, validated laminar flow equipment, environmental monitoring

Q37. Which USP guidance specifically addresses sterile compounding and relevant environmental controls like laminar flow hoods?

• USP <797>
• USP <1116>
• USP <51>
• USP <661>

Correct Answer: USP <797>

Q38. ISO 14644 cleanroom classification is based primarily on what measurement?

• Number of personnel allowed in the room
• Particle concentration per volume of air for specified particle sizes
• Microbial load on surfaces only
• Room temperature and humidity levels

Correct Answer: Particle concentration per volume of air for specified particle sizes

Q39. If a laminar flow cabinet is non-recirculating and exhausts to the exterior, what is an important requirement?

• The exhaust should bypass all filtration to save energy
• The exhaust should be HEPA filtered before discharge to the environment
• The exhaust should be released directly into occupied corridors
• Exhaust location is unimportant for contamination control

Correct Answer: The exhaust should be HEPA filtered before discharge to the environment

Q40. When arranging supplies inside a laminar flow hood for aseptic work, what is best practice?

• Place as many items as possible to speed work
• Minimize items and place them to avoid disrupting unidirectional airflow
• Keep large boxes directly behind the work area to block drafts
• Store heavy equipment inside the hood permanently

Correct Answer: Minimize items and place them to avoid disrupting unidirectional airflow

Q41. What does the presence of eddies in a smoke visualization test indicate?

• Perfect laminar flow with no problems
• Localized turbulence or airflow disturbances that may compromise sterility
• That the HEPA filter is functioning better than expected
• That the cabinet is sterile and requires no monitoring

Correct Answer: Localized turbulence or airflow disturbances that may compromise sterility

Q42. What is the main operational difference between Class I and Class II biological safety cabinets?

• Class I protects product but not personnel; Class II protects personnel only
• Class I protects personnel and environment; Class II protects product, personnel, and environment
• Class I is used for chemical fume control; Class II is used for sterile compounding only
• Class I has HEPA filters on exhaust only; Class II has supply and exhaust HEPA filtration

Correct Answer: Class I has HEPA filters on exhaust only; Class II has supply and exhaust HEPA filtration

Q43. What operational sign often indicates a need to replace a HEPA filter?

• Decreased particle counts in the room
• Increased pressure drop across the filter and reduced airflow
• A sudden increase in room temperature by 10°C
• The color of the filter turning white

Correct Answer: Increased pressure drop across the filter and reduced airflow

Q44. How often is certification of laminar flow hoods commonly recommended in pharmacy practice?

• Every 6–12 months or after relocation/repair
• Once at installation and never again
• Daily by regulatory inspectors only
• Every 10 years regardless of use

Correct Answer: Every 6–12 months or after relocation/repair

Q45. What is the typical order of air filtration stages in a laminar flow system?

• HEPA filter followed by pre-filter
• Pre-filter followed by HEPA filter
• Activated carbon only
• No filtration stages are needed

Correct Answer: Pre-filter followed by HEPA filter

Q46. Which airflow configuration is typically recommended to ensure product protection during aseptic manipulations?

• Horizontal laminar flow bench providing unidirectional flow over the product
• Open bench with ceiling fans only
• Vertical airflow away from the product toward the operator
• Recirculating without HEPA filtration

Correct Answer: Horizontal laminar flow bench providing unidirectional flow over the product

Q47. Best practice for introducing materials into a controlled cleanroom area includes which approach?

• Bringing items directly from the street into the ISO 5 area
• Passing materials through appropriate gowning and airlock/anteroom procedures
• Wiping items with tap water at the workbench
• Allowing loose cardboard packages inside the laminar flow hood

Correct Answer: Passing materials through appropriate gowning and airlock/anteroom procedures

Q48. HEPA filters capture particles by which primary mechanisms?

• Interception, impaction, and diffusion
• Magnetic attraction only
• Chemical reaction with filter media only
• Absorption of gases only

Correct Answer: Interception, impaction, and diffusion

Q49. Why is airflow velocity uniformity important across a laminar flow work surface?

• To prevent temperature stratification only
• To avoid backflow, eddies, and contamination of the critical zone
• To increase noise levels for equipment testing
• Because non-uniform airflow consumes less energy

Correct Answer: To avoid backflow, eddies, and contamination of the critical zone

Q50. What is the primary function of an airborne particle counter in laminar flow validation?

• To measure airborne particle concentrations and verify cleanliness levels
• To detect chemical vapors and odors
• To sterilize air in the cleanroom
• To replace microbial surface sampling

Correct Answer: To measure airborne particle concentrations and verify cleanliness levels

G S Sachin

I am a Registered Pharmacist under the Pharmacy Act, 1948, and the founder of PharmacyFreak.com. I hold a Bachelor of Pharmacy degree from Rungta College of Pharmaceutical Science and Research. With a strong academic foundation and practical knowledge, I am committed to providing accurate, easy-to-understand content to support pharmacy students and professionals. My aim is to make complex pharmaceutical concepts accessible and useful for real-world application.

Mail- Sachin@pharmacyfreak.com