高性能エアフィルタのか酷時健全性試験 ＩＩ ダスト負荷試験

Abstract

Performance of high efficiency particulate air (HEPA) filters loaded high concentration of dusts was examined to experimentally show the effectiveness of the filters under these conditions. Decontamination factors (DF) for dioctyl phthalate (DOP) aerosol before and after the dust loading, and for the loaded dusts; the JIS No.11 dust (mass median diameter 1.2μm) and NaCl aerosol (MMD 0.2μm) were measured by a laser particle spectrometer.Dust holding capacity of HEPA filters was proportional to the MMD of the loaded dusts. Decontamination factor for the dusts increased with the pressure drop which also increased by the dust loading and two or three orders of magnitude higher values were obtained at the pressure drop in 1.5 times of the initial one. This trend continued until the limit pressure of the filters, 250mmAq. After the dust loading stopped, DF decreased gradually due to the change of structure of loaded dusts. The DF of pinholed filters loaded dusts decreased with increasing pressure drop but still the higher enough values were obtained compared with the regulated DF.From the results mentioned above, it was shown experimentally that the effectiveness of HEPA filters loaded high concentration of dusts was enough for the regulated one.