Learn more about DOP and PAO testing: the core technology of air filter performance testing

With the increasing global requirements for air quality standards and clean environments, DOP (Dioctyl Phthalate) and PAO (Polyalphaolefin) testing have become two key methods for performance testing of high-performance air filters (HEPA and ULPA). These inspections play an integral role in ensuring cleanroom environments in industries such as pharmaceutical, electronics manufacturing, and medical. This article will introduce you to the principles, applications, and importance of these two detection methods in industry and commerce.

What are DOP and PAO tests?

Both DOP testing and PAO testing essentially use specific aerosols to test the efficiency of high-performance air filters. The core principle of both methods is to challenge the filter by generating aerosols of a specific concentration and particle size (0.3 microns is considered the most difficult particle size) and then measure the amount of aerosols before and after the filter to determine the filtration efficiency of the filter.

DOP testing: a traditional but effective method

The DOP test is performed using an oily aerosol called dioctyl phthalate. This method has long been used in the nuclear and pharmaceutical industries because of its ability to accurately measure the removal efficiency of high-performance air filters.

• How it works: During DOP detection, the instrument generates a certain concentration of DOP particles and uses a photometer to detect the difference in aerosol concentration before and after the filter. This method is especially tested for particles with a particle size of 0.3 microns, as this is the most difficult particle size to be filtered by air filters.
• Advantages and Challenges: DOP assays have been widely used and accepted, with results with a high degree of accuracy and reliability. However, as DOP is a potential carcinogen, it needs to be strictly controlled in use and ensure that the operating environment has a good ventilation system.

PAO Testing: A Modern Alternative to Safer

With the improvement of safety standards, PAO testing is gradually replacing DOP as the mainstream method. PAO (poly α-olefin) is a synthetic oil with strong particle stability, harmless to humans, and is widely used in applications that require highly clean air environments, such as electronics manufacturing and pharmaceutical industries.

• How it works: PAO detection works similarly to DOP and uses a light scattering photometer to detect aerosol concentration differences. PAO aerosols have higher stability and uniformity, providing more accurate and reliable test results. During the test, PAO particles are evenly distributed in the air stream, and the filtration efficiency is evaluated by decreasing the concentration of particulates after the filter.
• Advantages and Challenges: The main advantage of AO is its increased safety and test stability. Compared with DOP, PAO is non-volatile and does not pose a carcinogenic risk, and has less health impact on workers and the environment during use. However, the cost of instruments and materials for PAO testing can be higher.

Advantages of our testing equipment

In our company, we are equipped with DOP and PAO testing instruments, which can provide accurate and fast high-performance air filter testing services. Our instruments produce stable aerosol particles, and together with precision light scattering photometers, ensure that every test result meets or exceeds international standards such as ISO 14644-3 and EN 1822.

Why choose our testing services?

• Comprehensive solutions: Whether it’s DOP or PAO testing, we have the right solution for your needs. From instrument selection and installation to regular calibration and maintenance, we provide professional support every step of the way.
• Safe and reliable operation: Our team strictly adheres to safe operating practices and employs instruments and materials that meet international standards to ensure the accuracy and reliability of every test.
• Experienced and professional team: Our technicians have extensive industry experience and expertise to quickly and effectively solve any problem in the inspection process.

DOP and PAO testing plays a very important role in air filter performance testing. We are committed to providing our customers with the highest standards of testing services to ensure that your production environment meets the latest air quality and safety standards. When you choose our high-efficiency HEPA products, you get a testing service to keep your air filter performing at its best.