1. USER REQUIREMENT SPECIFICATION FOR AHU
2. SOP FOR OPERATION OF AHU
3. SAT FOR AHU
4. DESIGN QUALIFICATION FOR AHU
5. INSTALLATION QUALIFICATION FOR AHU
6. OPERATIONAL QUALIFICATION FOR AHU
7. PERFORMANCE QUALIFICATION FOR AHU
8. HANDOVER CERTIFICATE – HVAC
9. SOP FOR INTERLOCKING OF THE HVAC SYSTEM
10. SCHEMATIC DIAGRAM OF AHU

AHU Qualification in Pharma – Step-by-Step Guide

AHU Qualification in Pharma are the heart of HVAC systems in pharmaceutical facilities. They control temperature, humidity, air cleanliness, and pressure differentials – all critical for maintaining classified area conditions as per GMP.

Therefore, AHU Qualification is a mandatory activity to demonstrate and document that each AHU consistently performs as intended.

1. What Is AHU Qualification?

AHU Qualification is a documented process of:

• Verifying design and installation
• Testing operational performance
• Demonstrating consistent performance under routine conditions

It typically includes:

• DQ – Design Qualification (optional but recommended)
• IQ – Installation Qualification
• OQ – Operational Qualification
• PQ – Performance Qualification

Each phase generates protocols and reports approved by Quality.

2. Prerequisites Before AHU Qualification

Before starting AHU qualification, ensure:

1. Approved URS (User Requirement Specification)
   • Required temperature & humidity range
   • Cleanroom class (ISO / Grade A–D / Class 100000, etc.)
   • Differential pressure requirements
   • Air changes per hour (ACPH)
   • Fresh air percentage & return air concept
2. Approved Design Documents
   • HVAC design drawings and P&IDs
   • AHU data sheets (capacity, CFM, motor rating, filter grades etc.)
   • Airflow diagrams (supply, return, exhaust)
3. Completed Installation
   • AHU installed as per drawing
   • Ducting, dampers, filters, drain lines, insulation completed
   • Electrical and BMS/instrumentation work completed
4. Approved SOPs
   • AHU start-up & shutdown
   • Filter handling & replacement
   • Cleaning and maintenance
   • Alarm handling and deviation management
5. Calibrated Instruments Available
   • Anemometer / velometer
   • Manometer / differential pressure gauge
   • Temperature & humidity sensors / data loggers
   • Particle counter (for room classification)
   • Sound level meter (if applicable)

3. Design Qualification (DQ)

Objective: To verify that AHU design meets user and regulatory requirements.

Key DQ checks:

• AHU capacity vs. room load calculation (CFM, TR, ACPH)
• Selected filter grades (e.g. prefilter, fine filter, HEPA) vs. required cleanroom class
• Fresh air quantity to meet indoor air quality & positive pressure
• Duct layout and velocities within limits to avoid noise/turbulence
• Drain pan design (slope, material, trap) for condensate removal
• Selection of materials (SS/Aluminium/GI) suitable for pharma use
• Availability of adequate monitoring and control (BMS / local indicators)

Output:

• DQ Protocol & DQ Report with documented verification and approved conclusion.

4. Installation Qualification (IQ)

Objective: To verify and document that the AHU is installed as per approved design, specification, and vendor recommendations.

4.1 IQ Checks & Documentation

1. Verification of Equipment Details
   • AHU tag number / ID
   • Make, model, serial number
   • Motor rating, fan type, coil details
   • Filter types and grades
2. Physical Installation
   • AHU location as per layout
   • Leveling, mounting, vibration isolators
   • Accessibility for maintenance & filter replacement
   • Adequate lighting and working space around AHU
3. Ducting & Accessories
   • Duct routing as per drawing
   • Proper sealing and insulation
   • Correct installation of volume control dampers, fire dampers, balancing dampers
   • Flexible connections at AHU discharge/suction if required
4. Filters & Coils
   • Correct filter sequence (e.g. prefilter → fine filter → HEPA at terminal)
   • Filter make, grade, efficiency, dimensions as per design
   • Coil type, number of rows, fin density as per specification
5. Drain & Condensate Management
   • Properly sloped drain pan
   • Non-corrosive drain piping
   • Water seal / trap provided to prevent air ingress
6. Electrical & Controls
   • Motor wiring and earthing verification
   • Overload + short circuit protection
   • Interlocks (if any) with other systems
   • BMS connections / local controllers, alarms
7. Documentation Check
   • Calibration certificates of inbuilt sensors & gauges
   • Operation & maintenance manuals
   • As-built drawings

Output:

• IQ Checklist with observation details
• IQ Report with “Pass/Fail” status and deviations, if any

5. Operational Qualification (OQ)

Objective: To verify that the AHU operates as intended throughout the specified operating ranges and conditions.

OQ tests are typically conducted without product, but with the system under normal operating configuration.

5.1 AHU Start-up & Safety Checks

• Check AHU start/stop operation from local/BMS panel
• Verify correct direction of fan rotation
• Verify safety interlocks (door interlocks, fire alarm trip, etc.)
• Check for abnormal noise, vibration, leakage

5.2 Airflow & Air Changes (ACPH)

1. Measure air velocity at supply diffusers / grilles using an anemometer.
2. Calculate air volume (CFM) for each outlet:
   • CFM = Average velocity (ft/min) × Area of diffuser (ft²)
3. Sum all CFM values to get total supply CFM.
4. Calculate Air Changes per Hour (ACPH):
   • ACPH = (Total CFM × 60) / Room Volume
5. Verify ACPH against design and regulatory requirements.

5.3 Differential Pressure

• Verify differential pressures between adjacent rooms:
  • Critical → less critical rooms should maintain positive pressure.
• Use calibrated manometers or Magnehelic gauges.
• Record pressure readings over a defined time (e.g. hourly for 8 hours).
• Acceptable limits as per URS / SOP (e.g. +10 to +15 Pa, etc.).

5.4 Temperature & Relative Humidity Control

• Run AHU in normal operating mode.
• Measure and record temperature and RH at defined locations within the room.
• Take readings at defined intervals (e.g. every 30–60 minutes) over a stipulated period.
• Check that values fall within specified limits (e.g. 22 ± 3 °C, 40–60% RH).

5.5 Recovery Test

Purpose: To demonstrate how quickly the cleanroom recovers to acceptable particulate levels after a contamination event.

• Intentionally disturb the air (e.g. door opening, personnel movement) or record after a simulated upset.
• Measure airborne particles immediately after disturbance and then at fixed intervals.
• Record time taken to return to the initial/acceptable classification level.
• Compare with predefined acceptance criteria.

5.6 Filter Integrity Testing (if applicable at OQ stage)

For terminal HEPA filters (often part of room qualification but linked to AHU performance):

• Perform HEPA filter integrity test (e.g. PAO/DOP test) as per standard.
• Check for leaks across filter face and seals.
• Record test method, equipment used, challenge concentration, and results.

5.7 Alarm & Interlock Verification

• Test high/low temperature, high/low pressure, and humidity alarms.
• Verify that AHU trips or responds as defined in design (e.g. fire alarm trip, fan failure).

Output:

• OQ Protocol with detailed test methods and acceptance criteria
• OQ Report with raw data, calculations, graphs, and conclusions

6. Performance Qualification (PQ)

Objective: To demonstrate that the AHU consistently maintains specified environmental conditions during routine operation (often with simulated or actual production).

PQ typically covers:

• Overall room performance (classification, environmental conditions)
• AHU’s ability to maintain control under normal load (equipment + personnel)

6.1 Environmental Monitoring

Over defined periods and shifts:

1. Temperature & RH Mapping
   • Place data loggers at representative locations in the room.
   • Record temperature and RH continuously over several days.
   • Verify that all points remain within specified limits.
2. Differential Pressure Trending
   • Monitor and trend differential pressures across critical rooms.
   • Confirm that pressures remain within defined range during typical operations – including door openings, equipment running, and personnel presence.
3. Airflow & Classification Verification
   • Confirm air velocities and ACPH at defined intervals (e.g. beginning and end of PQ).
   • Re-verify cleanroom class using particle counting (at-rest and/or operational as per strategy).

6.2 Operational Scenarios

Evaluate AHU performance under realistic conditions:

• Normal operation with defined number of personnel
• Typical equipment running
• Simulated worst case (maximum occupancy/equipment where applicable)

Assess:

• Whether temperature, RH, pressure, and classification are maintained
• Any trends or drifts over time

6.3 Data Review and Conclusion

• Review all data (graphs, trends, log sheets)
• Investigate any OOS/OOT results
• Document rationale for acceptance or need for corrective actions

Output:

• PQ Protocol and PQ Report
• Final conclusion that AHU and associated areas are “Qualified for intended use”

7. Requalification of AHU

Requalification is required:

• Periodically (e.g. annually or as per site SOP)
• After major changes, such as:
  • AHU capacity change
  • Filter replacement with different grade / specification
  • Duct modifications
  • Change in room classification or usage
  • Significant maintenance repairs

Requalification scope may include selective IQ checks and full/partial OQ & PQ, based on change impact.

8. Documentation & GMP Compliance

All AHU qualification activities must be:

• Planned via approved protocols
• Executed by trained personnel
• Reviewed by Engineering and Quality
• Concluded in a formal report with:
  • Objective
  • Scope
  • Responsibilities
  • Test results & deviations
  • Attachments (raw data, calibrations, diagrams)
  • Final conclusion and approval signatures

Properly executed AHU qualification supports:

• Compliance with GMP / cGMP, WHO, EU, USFDA guidelines
• Robust room qualification & environmental control
• Assurance of product quality and patient safety

9. Suggested Website Structure (SEO-Friendly)

You can structure your web page like this:

1. H1: AHU Qualification in Pharma – Complete Step-by-Step Guide
2. H2: What Is AHU Qualification and Why Is It Important?
3. H2: Prerequisites for AHU Qualification
4. H2: Design Qualification (DQ) of AHU
5. H2: Installation Qualification (IQ) – Checklist
6. H2: Operational Qualification (OQ) – Tests & Acceptance Criteria
7. H2: Performance Qualification (PQ) – Room Performance Under Load
8. H2: AHU Requalification – When and How
9. H2: Documentation Requirements for GMP Compliance
10. H2 (optional): FAQs on AHU Qualification in Pharmaceuticals

10. Sample FAQs for Your Website

Q1. How often should AHUs be requalified in pharma facilities?
Generally, AHUs are requalified annually or as defined in site SOPs, and always after major changes or repairs that may impact performance.

Q2. Is HEPA filter integrity testing part of AHU qualification?
Yes. HEPA integrity testing is a critical part of cleanroom/HVAC qualification and is directly linked to AHU performance, especially in classified areas.

Q3. What are the key parameters monitored during AHU qualification?
Key parameters include temperature, relative humidity, differential pressure, air changes per hour (ACPH), airflow direction, particle counts, and HEPA filter integrity.

Q4. Are OQ and PQ both mandatory for AHU qualification?
Yes. OQ verifies operation across specified ranges, while PQ demonstrates consistent performance under routine conditions. Both are needed to claim full qualification.