ISO 29463 originates from EN1822, which defines EPA, HEPA and ULPA filters commonly used in industry. While ISO 29463 maintains the classification of EPA, HEPA and ULPA.But replace E10-E12, H13-H14 and U15-U17 with the following 13 filter levels. The ISO 29463 can't replace EN 1822, EN 1822 will continue to be valid.
It is generally believed that as airflow increases, face velocity increases, and filtration efficiency decreases. In other words, lower airflow (lower velocity) should lead to higher filtration efficiency. However, in actual testing—such as at 500 m³/h—the opposite is sometimes observed: efficiency decreases when airflow is reduced. This article aims to analyze the underlying reasons. Notably, this phenomenon has also been observed by experienced professionals in the filtration industry, and we share our findings and discussion here.
EN 1822, ISO 29463, and IEST-RP-CC003.4 are three key standards for classifying and testing HEPA (High-Efficiency Particulate Air) and ULPA (Ultra-Low Penetration Air) filters. While they share similarities, they differ significantly in testing methods, particle size considerations, classification, and application scope. Below is a comprehensive comparison.
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