Since 1 July 2018 the standard for testing air filters for general ventilation is ISO 16890. Along with the introduction of new filter classes there are also new requirements for the test. One example is the electrical discharging of the filter: it is now performed with vaporized isopropyl alcohol (IPA) in a conditioning chamber. The previous method in Europe was the dipping of filter media into liquid IPA (EN 779). The reason for change was the observation that efficiencies of electret filter media treated with saturated IPA vapor resulted in significant lower efficiencies compared to measurements of filter media treated with liquid IPA (Cai 2010). Other changes include the use of DEHS (0,3 µm to 1,0 µm) and KCl (1,0 µm to 10,0 µm) aerosols to measure the filtration efficiency and the elimination of a dust-loading test (except for filters with ePM10 values below 50 % in which case a gravimetric efficiency has to be determined). To specify the reproducibility and to evaluate the test method according to ISO 16890 a round robin test was performed.
Eleven laboratories participated in the round robin test. One of them provided the filters which were equally manufactured and consisted of polypropylene fibers. Each laboratory was free to use their equipment with the exception that it had to fulfill the specifications laid out in ISO 16890. This resulted in the use of different optical particle counters (OPC), different atomizers, different conditioning chambers and so on – a perfect situation to evaluate a test method.
The measurements of the pressure differences and the filtration efficiency before and after IPA treatment showed...
Session: G8 - Short Oral Presentations
Day: 23 October 2019
Time: 14:45 - 16:00 h