My daily equipment diary

In 1950 these filters were called “absolute filters” after 1950 these filters were named “HEPA filters”. They were commercialized in 1950 and within fifty years it becomes a technology breakthrough in air cleanliness, where the highest level of air cleanliness is required in all fields such as the pharmaceutical industry, hospitals, aerospace, data manufacturing, photographic film manufacturing, etc. Its uses expanded to residential areas also where prevention from dust mites, bugs, lead, mold spores, pet dander, smoke, pollens, hair, etc. is required the most. Moving towards high standards, the cleanroom areas are getting more precise day by day from hospitals to industrial production where air quality matters a lot, the Hepa Filters are essential. From making to maintaining a cleanroom set methods for checking the efficiency of these filters is needed regularly.

Standards for testing Hepa Filter Efficiency

3.ISO has issued a new standard in 2011 i.e. ISO 29463 that includes the old classification with additional criteria thus making it internationally acceptable. It has now extended filter classes to compromise between all current classifications.

It is clear from above table that all standards are now compromised by moving towards more precision classification of filters according to MPPS in ISO 29463.

This standard has obsoleted the use of traditional methods using photometric and polydisperse aerosol and focusing on discrete particle counting with MPPS(Most Penetrating Particle Size).

This method includes a five-step procedure for checking Hepa filters efficiency.

Originally published at on March 10, 2021.




A passionate writer, a science equipment expert, content writer , blogger, and a cool human

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Huma Aslam

Huma Aslam

A passionate writer, a science equipment expert, content writer , blogger, and a cool human

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