Filtration performance of particulate air filters for general ventilation - Dust loading in real life tests vs. lab testing

摘要

Particulate air filters made of glass or synthetic fibres (F7 bag filters and F9 filter cassettes) were used in regular air ventilation systems and demounted after 3 up to 21 month. At the different loading stages these filters were tested in the lab and installed again. Pressure drop and DEHS-efficiencies were measured and compared to results according to EN 779:2012. The highest pressure loss was around 200 Pa for one single filter type. This value is much lower than the end pressure of the classification which is 450 Pa for fine filter. The measured efficiencies were significantly lower than the average efficiencies of the standard. Filters relying on electret effects showed efficiencies about the minimum efficiency of a discharged filter media. In addition field testing was performed for in situ removal efficiency by particle size. The unsteady particle concentration and size distribution lead to uncertainty of measurements in the ultrafine size range.