Recovery Test, Make-Up Air Test, and Test Frequency, here are interview preparation questions and answers tailored to HVAC and cleanroom validation in pharmaceuticals:
PHARMACEUTICAL INTERVIEW QUESTIONS & ANSWERS
TOPIC: RECOVERY TEST, MAKE-UP AIR TEST & TEST FREQUENCY
1. What is a Recovery Test in cleanroom validation?
Answer:
The Recovery Test evaluates how quickly a cleanroom returns to its classified cleanliness level (for temperature or humidity) after a temporary contamination or disturbance. It ensures the effectiveness of non-unidirectional airflow systems.
2. What are the types of recovery tested?
Answer:
1. Humidity Recovery
2. Temperature Recovery
3. Describe the procedure for Humidity Recovery Test.
Answer:
Switch off the AC system.
Increase temperature to 40°C using a hot air blower.
Restart the AC system.
Monitor until humidity returns to design limits.
Record the time taken (as per ISO 14644-3).
4. What is the purpose of the Temperature Recovery Test?
Answer:
To verify how quickly the cleanroom can recover to acceptable temperature levels after an artificial rise in temperature (40°C) and resume temperature control efficiency.
5. What is Makeup Air in HVAC systems?
Answer:
Makeup air is the fresh air supplied into the cleanroom to replace the air lost due to exhaust, leakage, door openings, and maintain positive pressure and cleanroom air quality.
6. How is the Makeup Air CFM calculated?
Answer:
Make Up CFM = Velocity of Makeup Air × Makeup Air Grill Area
7. What is the acceptable pressure differential between cleanroom and adjoining area?
Answer:
The pressure differential should be 0.03 to 0.05 inches of water gauge, equivalent to 7.5 to 13 Pascals, to ensure positive pressurization.
8. Why is positive pressurization important in a cleanroom?
Answer:
Positive pressurization prevents entry of contaminated air from lower classified areas, maintaining cleanliness integrity of the cleanroom.
9. What is the frequency of cleanroom validation tests?
Answer:
Test Frequency
Air Velocity Test Half-yearly
Filter Integrity (PAO) Test Yearly
Non-Viable Particle Count Half-yearly
Recovery Test Half-yearly
Smoke Test / Airflow Pattern Yearly
Viable Count As per SOP (e.g., MU009)
Differential Pressure Monitoring Daily
Temperature & Humidity Monitoring Daily
10. Under what conditions is revalidation of HVAC systems required?
Answer:
Change in facility design or layout
Change in equipment
Major process modification
Impact on air classification