Sterile area validation has different tests like air supply, air velocity, air changes, flow pattern, filter integrity, pressure test, particle count, temperature, recovery test, microbial count, relative humidity etc.
The below is brief about the tests required for sterile area qualifications:
1. Air supply capacity:
The purpose of this test to demonstrate that the air system is balanced and capable of delivering sufficient air volumes (as per design) to maintain required air change (NLT 20) in the defined area.
2. Air velocity/uniformity:
The purpose of this test to demonstrate that the air system is balanced and capable of delivering sufficient air volumes to maintained a minimum cross-section velocity under HEPA terminal filter modules. For LAF air flows velocity to be 0.36-0.54 m/s.
3. Air change:
There is no minimum GMP requirement for air changes per hour. A minimum 20-air changes will be maintained with 15 Pascal pressure differentials to the adjacent area.
4. Air flow pattern:
To determine the airflow interaction with machinery and equipment, in the critical area protected by a unidirectional flow the clean air system in the sterile area. This test determines the airflow pattern.
5. HEPA filter integrity:
All HEPA filter installed in the facility will test for filter integrity test and filter leak test at the At-Rest Phase by using PAO (Poly-alpha-olefin) aerosol into supply duct to the HEPA filter. it's used to demonstrate the filter integrity and leak test.
6. Particle count:
The number of particles of size equal to 0.5 microns and larger and number of particles of size equal to 5 microns and larger at each designated location.
7. Temperature:
Room temperature may be a critical parameter for both open and closed operations. Most products, materials and processes can handle a wide range in temperature. Temperature working environment of 68°F - 77°F (20°C - 25°C) based on the design.
8. Recovery test:
To determine the capabilities of the system to recover from internally generated contamination to normal range within reasonable time period.
Recovery test will be demonstrated by following the test of:
- Measure the particle counts at room air return outlets and establish “At rest” level.
- Generate the smoke to room until particle counts is high and constant and switch off the smoke generator.
- Record the particle counts each minute until counts return “At Rest” level.
- Recovery time should be approximately 15-20 minutes (EU GMP guide Annex-1)
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