The Impact of PAO Aerosol Generation Methods on Air Filter Testing | Cold Generation vs. Thermal Generation

How does PAO aerosol testing affect the integrity testing of high-efficiency filters (HEPA/ULPA)?

PAO (Polyalphaolefin) aerosol testing is an essential standard for cleanroom and high-efficiency filter (HEPA/ULPA) integrity testing. It ensures the filtering performance of the filter and complies with GMP cleanroom validation regulations. The generation methods of PAO aerosols can be divided into thermal generation and cold generation. Different methods affect the aerosol’s particle size distribution, concentration stability, and the accuracy of test results, which in turn impacts the integrity assessment of the filter. This article will explore the effects of these two PAO generation methods and their applications in Taiwan’s semiconductor industry, medical biotechnology, electronics manufacturing, chemical, and food industries.

Generation Methods and Testing Impact of PAO Aerosol

1. Thermal Generation of PAO Aerosol

  • Principle: PAO liquid is evaporated using high temperatures and then cooled and condensed into fine aerosol particles.
  • Particle Size: Approximately 0.1–0.2 μm, meeting the MPPS (Most Penetrating Particle Size) standard for HEPA/ULPA filters.
  • Advantages:
  • The particles are finer, allowing for precise testing of the high-efficiency filter’s integrity.
  • Aerosol concentration is stable, making it suitable for testing in large cleanroom environments.
  • It can be used in high-standard industries such as Taiwan’s semiconductor, pharmaceutical, and optoelectronics industries, ensuring compliance with ISO 14644, GMP, and FDA standards.
  • Impact:
  • The equipment is more expensive, suitable for high-end testing environments.
  • Regular maintenance is required to ensure stable PAO aerosol output.

Applications of Thermal Generation PAO Aerosol

  • Semiconductor Manufacturing Industry (Wafer Fab, Packaging and Testing Plants)
  • Pharmaceutical and Medical Industry (GMP Cleanrooms, Pharmaceutical Production Lines)
  • Optoelectronics and Precision Electronics Manufacturing (LCD, OLED, PCB Plants)
  • Biotechnology and Food Industry (Cleanroom Food Processing, Biotechnology R&D Laboratories)
  • Medical and P3/P4 Biosafety Laboratories

2. Cold Generation of PAO Aerosol

  • Principle: PAO liquid is atomized into larger aerosol particles using airflow atomization techniques (such as compressed air or ultrasonic atomization).
  • Particle Size: Typically larger than 0.3 μm, making it harder to meet the MPPS standard.
  • Advantages:
  • Lower equipment cost, suitable for testing general industrial-grade HEPA filters.
  • Does not require high-temperature heating, making it suitable for temperature-sensitive environments.
  • Impact:
  • Larger aerosol particles lead to lower precision in the integrity testing of HEPA/ULPA filters.
  • Aerosol concentration is harder to maintain stably, potentially affecting the consistency of the test.

Applications of Cold Generation PAO Aerosol

  • HVAC Commercial Air Conditioning Systems (Office Buildings, Hospitals, Schools)
  • Chemical and Steel Industries (Industrial Factory Exhaust Systems, Ventilation Equipment)
  • Warehousing and Logistics (Food Cold Chain Storage, Pharmaceutical Logistics Centers)
  • Automotive and Paint Manufacturing (Spray Paint Factories, Electronic Coating Equipment)

Choosing the Suitable PAO Aerosol Generation Method

When choosing between thermal generation or cold generation of PAO aerosol, the following factors should be considered:

  1. Industry Requirements: For industries such as Taiwan’s semiconductor and medical biotechnology sectors, the “thermal generation” method should be chosen to meet cleanroom standards; for general HVAC or industrial-grade filter testing, the “cold generation” method can be selected.
  2. Testing Accuracy: For ISO 14644 cleanroom or FDA/GMP certification, the thermal generation method ensures compliance with strict filter testing requirements.
  3. Equipment Budget: The cold generation method has a lower equipment cost, suitable for general industrial manufacturing environments, while the thermal generation method is more suitable for high-end precision industries.

The Importance of PAO Testing for High-Efficiency Filters

PAO aerosol testing is crucial for ensuring the effectiveness of air filtration equipment, and choosing the appropriate aerosol generation method directly affects the accuracy of the test results. For industries that require high levels of cleanliness, such as semiconductor, pharmaceutical, and optoelectronics industries, the thermal generation PAO aerosol method should be used to ensure compliance with MPPS testing standards. For general HVAC systems, industrial manufacturing, and automotive painting industries, the cold generation method can be chosen for basic filter testing.

Through the appropriate PAO aerosol testing mechanism, not only can the filter performance be improved, but it can also comply with environmental ESG carbon emission standards, enhance energy efficiency, and ensure that companies meet the latest environmental regulations, achieving higher clean air quality requirements.

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