TEST AEROSOLS

Test aerosols are substances used in various testing scenarios to evaluate the performance of filtration systems, air purification devices, and other air-handling equipment. These aerosols can be natural or synthetic and are selected based on their ability to simulate the properties of particles that the equipment will encounter in real-world applications.

Key Applications of Test Aerosols

1. Filter Efficiency Testing

   • Test aerosols are widely used to determine the efficiency of air filters, including HEPA (High-Efficiency Particulate Air) and ULPA (Ultra-Low Penetration Air) filters. The aerosol particles are introduced into the system, and the concentration of particles upstream and downstream of the filter is measured to calculate the filter's efficiency.
   • Common standards that utilize test aerosols include ASHRAE Standard 52.2 and EN 1822.

2. Cleanroom Certification

   • In cleanroom environments, test aerosols help in certifying the performance of cleanroom HVAC systems. This ensures that the air quality meets the stringent requirements for particle concentration.
   • ISO 14644-1 provides guidelines on the classification of air cleanliness in cleanrooms and controlled environments using test aerosols.

3. Leak Testing

   • Test aerosols are used to detect leaks in containment systems, such as glove boxes and isolators. By introducing aerosol particles into the system and using particle counters or photometers, any leaks can be detected by identifying particle concentrations outside the containment area.

Common Types of Test Aerosols

1. DOP (Dioctyl Phthalate)

   • Historically used for HEPA filter testing, DOP aerosols are generated using a thermal generator that produces particles in the range of 0.3 micrometers, which are considered the most penetrating particle size (MPPS) for many filters.

2. PAO (Polyalphaolefin)

   • PAO is often used as a safer alternative to DOP for filter testing. It produces particles of a similar size and distribution but without the health hazards associated with DOP.

3. Polystyrene Latex (PSL) Spheres

   • PSL spheres are monodisperse particles that are often used for calibrating particle counters and for specific types of filter testing. They provide precise and consistent particle sizes.

4. Sodium Chloride (NaCl)

   • NaCl aerosols are commonly used for respiratory protective device testing. These particles are generated from a salt solution and can be used to simulate the performance of filters in real-world conditions.

Standards and Guidelines

1. ISO 14644-1:2015

   • This standard specifies the classification of air cleanliness in terms of the concentration of airborne particles in cleanrooms and controlled environments.

2. EN 1822

   • This standard outlines the testing methods for high-efficiency air filters, including HEPA and ULPA filters, using test aerosols to determine their efficiency.

3. ASHRAE Standard 52.2

   • Provides methods for testing the performance of air-cleaning devices as a function of particle size. Test aerosols are used to measure the removal efficiency of filters.

References

• ISO 14644-1:2015 - Cleanrooms and associated controlled environments
• EN 1822 - High efficiency air filters (EPA, HEPA and ULPA)
• ASHRAE Standard 52.2

These references provide comprehensive guidelines on the use and application of test aerosols in various testing scenarios, ensuring the reliability and effectiveness of filtration systems and controlled environmen