高效過濾器多久必須更換？

高效過濾器多久必須更換？
How often do HEPA Filters have tobe changed?
高效過濾器多久必須更換？
Inthe pharmaceutical industry, HEPA filters are used as terminal filters for theprocessing or filtration of air in production spaces. They are mandatory insterile production, although they are sometimes also used in the manufacture ofsolid or semisolid dosage forms. Amongst the HEPA or high-efficiencyparticulate air filters are Filter Classes H13 to H14 (DIN 1822), the latterwith a retention rate of 99.995%. But how often do they need to be changed?
在制藥行業(yè)，高效過濾器用于生產(chǎn)空間處理和過濾空氣終端過濾器。高效過濾器在無菌生產(chǎn)中是必須使用的，當(dāng)然有時也會用于固體和半固體劑型的生產(chǎn)。H13至H14（DIN1822）是高效過濾器的兩種，后者截留率為99.995%。但多久必須更換一次呢？
Onecan frequently find internal company guidelines according to which the filtersshould be changed annually, regardless of monitoring results. Is that sensible?An exact number, meaning the maximum duration of use for HEPA filters inmonths, cannot be found in the relevant GMP guidelines. According to GMP, thefilter has to be free of leaks. This is verified by qualification and regularlyperformed leak tests as per ISO 14644-3, which are mandatoryfor sterile facilities. According to the technical interpretation of the Annex1 (PIC/SPI 032-2), leak tests are to be performed every six monthsin A/B zones and every twelve months in C/D zones. The FDA Aseptic Guidedemands a regular inspection. The requirements of Annex 1 can be applied hereas well. Leaks may be repaired; those repaired areas may only take up 0.5% ofthe filter surface per filter.
我們經(jīng)常會看到在公司內(nèi)部文件中，要求每年更換過濾器，而不管監(jiān)測結(jié)果如何。這合理么？在相關(guān)的GMP指南中其實并沒有高效過濾器可以使用時長的具體數(shù)字。根據(jù)GMP的要求，過濾器必須無泄漏，通過確認(rèn)和定期執(zhí)行ISO14644-3泄漏測試就能進行核對，無菌車間來說這是必須的。根據(jù)附錄1（PIC/S PI032-2）的技術(shù)詮釋，A/B區(qū)每6全月要進行泄漏測試，C/D級區(qū)則為12個月。FDA無菌指南要求進行定期檢查。附錄1的要求在這里也可以應(yīng)用。泄漏是可以修補的，但修補的面積不能超過單個過濾器面積的0.5%。
However,not only the integrity of the HEPA filter is relevant. The load of the filter(layer) and thus the pressure drop at the filter is also important. If thepressure drop at the filter rises, the energy demand of the ventilation systemincreases to maintain the necessary air change rates. This pressure drop at thefilter can increase to the performance limits of the ventilation system. Toprotect the HEPA filters, preliminary filters are used - usually fineparticulate air filters like F7 und F9 filters (EN779). Those have to bereplaced regularly and protect the HEPA filters from clogging.
當(dāng)然，高效過濾器并不只有完整性一件事情。過濾器（層）的負(fù)載以及壓力降也很重要。如果過濾器壓降升高，則送排風(fēng)系統(tǒng)的能量需求會增加，用以維持必須的換氣率。這樣的過濾器壓降可能會增加通風(fēng)系統(tǒng)的性能限制。為了保護高效過濾器，就要使用前端過濾器---通常是像F7和F9過濾器（EN779）這樣的精細(xì)過濾器。這些過濾器必須定期更換以保護高效過濾器避免堵塞。
Froma practical viewpoint, one could say that the maximum duration of use dependsdirectly on the pressure drop. Changing the filters only makes sense if thepressure drop gets too high for the performance of the ventilation system or ifthe cost of energy demand lies above the cost of a filter change. The filtersdo have to pass the leak tests (see above), of course. In practice,several companies do not use a filter for more than eight years. As mentionedbefore, though, this is not a legally binding value, but merely based onexperience.
從實踐角度來看，我們可以說長使用時長直接取決于壓降。只有在壓降達到一定高值影響到通風(fēng)系統(tǒng)的性能，或者是能量需求超過過濾器更換成本時，過濾器更換才有意義。當(dāng)然，過濾器必須能通過泄漏測試（見上）。尤其是，幾個公司并不會使用一個過濾器超過8年。正如前述，并沒有法規(guī)規(guī)定這樣的值，這都只是根據(jù)經(jīng)驗得來的。ZxEHvjqa5