Validation of compressed air and nitrogen systems MCQs With Answer

Validation of compressed air and nitrogen systems MCQs With Answer

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Validation of compressed air and nitrogen systems MCQs With Answer

This quiz collection is designed for M.Pharm students to deepen their understanding of validation principles for compressed air and nitrogen systems used in pharmaceutical manufacturing. It covers regulatory requirements, ISO quality classes, filtration, drying technologies, contamination control, sampling strategies, and IQ/OQ/PQ approaches. Questions emphasize practical decision-making: selecting appropriate filters, setting monitoring points, interpreting dew point and particle counts, and designing risk-based validation protocols. By practicing these MCQs, students will build competence in ensuring gas purity, preventing cross-contamination, maintaining documentation, and complying with pharmacopeial and regulatory expectations for sterile and non-sterile processes.

Q1. Which ISO 8573 parameter defines the maximum allowed oil content (liquid and aerosol) in compressed air used for non-sterile pharmaceutical processes?

  • Class 1 for solid particles
  • Class 2 for water
  • Class 1 for oil
  • Class 3 for total microbial count

Correct Answer: Class 1 for oil

Q2. During qualification of a compressed air system, what is the primary purpose of establishing multiple representative sampling points?

  • To reduce the number of filters required
  • To demonstrate homogeneity of pressure only
  • To verify gas quality throughout the distribution network
  • To calibrate flow meters at each machine

Correct Answer: To verify gas quality throughout the distribution network

Q3. Which filtration strategy is most appropriate to remove oil aerosols and fine particles from compressed air prior to point-of-use in sterile processing?

  • Single-stage particulate filter (5 µm)
  • Coalescing filter followed by a final 0.01 µm sterile-rated filter
  • Activated carbon filter only
  • Bag filter with 50 µm rating

Correct Answer: Coalescing filter followed by a final 0.01 µm sterile-rated filter

Q4. Which drying technology provides the lowest achievable dew point for compressed air used in critical pharmaceutical applications?

  • Refrigerated dryer
  • Membrane dryer
  • Regenerative desiccant (dual-tower) dryer
  • Aftercooler only

Correct Answer: Regenerative desiccant (dual-tower) dryer

Q5. What is the most appropriate acceptance criterion for particulate contamination in compressed air used for filling non-parenteral liquid products according to risk-based approaches?

  • Zero particles >0.5 µm per cubic meter
  • Compliance with an agreed specification based on application risk and ISO 8573 particle class
  • Only oil content matters; particles are irrelevant
  • Any particle count is acceptable if pressure is stable

Correct Answer: Compliance with an agreed specification based on application risk and ISO 8573 particle class

Q6. Which parameter is most critical to monitor continuously for a nitrogen generation system used to blanket sterile product containers?

  • Compressor inlet temperature
  • Nitrogen purity (oxygen % or ppm)
  • Ambient humidity in the plant
  • Length of piping runs

Correct Answer: Nitrogen purity (oxygen % or ppm)

Q7. In an OQ for compressed air, which test demonstrates the system’s ability to maintain required gas quality under worst-case demand?

  • Visual inspection of piping supports
  • Flow-rate challenge at maximum process demand while monitoring quality parameters
  • Checking label compliance on nitrogen cylinders
  • Testing alarm lamps in the control room

Correct Answer: Flow-rate challenge at maximum process demand while monitoring quality parameters

Q8. Which of the following is a key reason to avoid oil-lubricated compressors when compressed air contacts sterile product or critical surfaces?

  • Oil-lubricated compressors are noisier
  • Risk of oil carryover leading to contamination and support for microbial growth
  • They cannot reach required pressures
  • They consume more electricity

Correct Answer: Risk of oil carryover leading to contamination and support for microbial growth

Q9. For validation sampling of compressed air for microbiological contamination, which sample collection method is recommended?

  • Capture air in sterile impingement liquid or use an impactor sampler onto agar plates at point-of-use
  • Draw air through a household vacuum cleaner bag
  • Use non-sterile cotton swabs rubbed on piping
  • Measure only particle counts and infer microbial levels

Correct Answer: Capture air in sterile impingement liquid or use an impactor sampler onto agar plates at point-of-use

Q10. Which regulatory document or pharmacopoeial guideline should be considered for establishing acceptance criteria for compressed gases used in pharmaceutical manufacturing?

  • USP and EP sections on gases and general chapters, plus regional GMP guidance
  • Only local fire safety codes
  • ISO 9001 quality manual exclusively
  • Consumer appliance standards

Correct Answer: USP and EP sections on gases and general chapters, plus regional GMP guidance

Q11. What is the purpose of a condensate separator with automatic drain in a compressed air system for pharmaceutical use?

  • To increase air temperature before filtration
  • To remove bulk liquid water and facilitate safe disposal of contaminated condensate
  • To sterilize the air via heat exchange
  • To compress additional air during demand peaks

Correct Answer: To remove bulk liquid water and facilitate safe disposal of contaminated condensate

Q12. When validating a PSA (pressure swing adsorption) nitrogen generator, which parameter is essential to demonstrate during PQ?

  • Stability of nitrogen purity over an extended production cycle and under variable load
  • Color of the adsorbent beds
  • Electrical wiring color codes
  • Brand of oxygen analyzer used in manufacture

Correct Answer: Stability of nitrogen purity over an extended production cycle and under variable load

Q13. Which maintenance control is critical to prevent backflow contamination from process lines into the compressed air distribution?

  • Periodic painting of pipelines
  • Installation and verification of backflow preventers and check valves with regular testing
  • Routinely increasing compressor pressure
  • Using longer piping runs to reduce velocity

Correct Answer: Installation and verification of backflow preventers and check valves with regular testing

Q14. Which dew point measurement is most relevant for assessing compressed air dryness for pneumatic conveying of hygroscopic powders?

  • Ambient dew point outside the plant
  • Compressed air dew point at point-of-use
  • Instrument room dew point
  • Gas cylinder headspace dew point

Correct Answer: Compressed air dew point at point-of-use

Q15. What is the primary validation concern when using membrane nitrogen generators for high-purity needs?

  • Membrane color fading over time
  • Capability to consistently meet oxygen ppm specification and sensitivity to ambient humidity and temperature
  • Generator footprint in the plant
  • Noise levels during operation

Correct Answer: Capability to consistently meet oxygen ppm specification and sensitivity to ambient humidity and temperature

Q16. Which control measure is most effective to prevent microbial contamination growth inside compressed air piping?

  • Maintaining low relative humidity by appropriate drying and regular condensate removal
  • Painting internal pipe surfaces
  • Running air at the lowest possible pressure
  • Using wider diameter pipes to slow flow

Correct Answer: Maintaining low relative humidity by appropriate drying and regular condensate removal

Q17. In a risk-based validation, when would routine microbiological monitoring of compressed air be most strongly justified?

  • Only when compressed air is used for cooling non-contact equipment
  • When compressed air directly contacts sterile product, open product, or critical surfaces
  • For compressed air used solely for pneumatic control signals outside cleanrooms
  • Never; microbes cannot survive in compressed air systems

Correct Answer: When compressed air directly contacts sterile product, open product, or critical surfaces

Q18. Which documentation component is essential to complete after PQ of a compressed air system?

  • Only supplier invoices
  • PQ report with test results, deviations, trending, and approved release criteria
  • Employee lunch schedules
  • Floor cleaning checklist

Correct Answer: PQ report with test results, deviations, trending, and approved release criteria

Q19. Which parameter is NOT typically specified in an acceptance criterion for pharmaceutical-grade nitrogen used for blanketing?

  • Maximum oxygen content (ppm or %) to ensure inertness
  • Maximum hydrocarbon/oil content if applicable
  • Required microbiological burden for liquid nitrogen
  • Pressure and flow availability at point-of-use

Correct Answer: Required microbiological burden for liquid nitrogen

Q20. Which periodic verification provides the best early warning that a compressed air filtration element is approaching end-of-life?

  • Monthly visual inspection of external filter housing paint
  • Upstream and downstream differential pressure monitoring across the filter
  • Recording compressor motor amperage only
  • Measuring room temperature fluctuations

Correct Answer: Upstream and downstream differential pressure monitoring across the filter

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