高效過濾器泄漏率測試：≤0.01%是否必須

1、高效過濾器泄漏率測試：0.01%是否必須What is the Acceptance Criteria of HEPA?acceptance criteria什么是高效過濾器的接受標(biāo)準(zhǔn)？acceptance criteriaultimately determined by thetest leak size limit of greaterThe approach most test standards take regarding ultimately determined by thetest leak size limit of greatercustomerand supplier.

2、However, a scan than or equal to0.01% has generally been adopted for many applications utilizing HEPA flters orclean areas of varying classifcations.Although the 0.01% leak size has beenused historically and has its origins linked to early generation analog photometertest equipment, establishing a l

3、eak size limit of 0.01% as an acceptancecriteria without performing a science and risk-based assessment can result inissuesrelating to leak testing and can contribute to signifcantoperationalcosts if an out of tolerance or failed condition is identifed ina low riskarea. As previouslynoted in Section

4、 6.5, flters are not 100%efcient and areexpected to have some naturalor integral penetrationof particles near theMPPS. Test acceptance limits become more controversial or problematic whenutilizing lower-rated HEPA flters where the acceptable factory penetration ator near MPPS can be comparable to or

5、 larger than the feldtest leak sizeacceptance criteria.This is especially true where the bleed through e ?ectcan occur (seeSection 6.9).When purchasing a flter, it is thereforeimportant toconsider a flter s rating as well as how it will be tested afterinstallationin order to avoid unnecessary feld t

6、est failures.大多數(shù)測試標(biāo)準(zhǔn)關(guān)于高效過濾器泄漏率的接受標(biāo)準(zhǔn)是，可接受的泄漏限度最終由客戶和供應(yīng)商共同確定。但是，對于使用HEPA過濾器或不同級別潔凈區(qū)的許多應(yīng)用，大多數(shù)采用0 0.01 %的掃描測試泄漏標(biāo)準(zhǔn)。盡管0.01 %的泄漏率在歷史上已經(jīng)使用過，并且其起源與早期的模擬光度計(jì)測試設(shè)備相關(guān)聯(lián)，但在沒有進(jìn)行科學(xué)和基于風(fēng)險(xiǎn)的評估的情況下，將0.01 %的泄漏率標(biāo)準(zhǔn)作為可接受標(biāo)準(zhǔn)將導(dǎo)致與泄漏測試有關(guān)的問題，并且如果在低風(fēng)險(xiǎn)區(qū)域發(fā)現(xiàn)超限或失敗情況，將可能會帶來巨大的運(yùn)營成本。過濾器不是100 %截留的，并且預(yù)計(jì) MPPS附近的粒子在過濾器局部或整體可以穿透。當(dāng)使用較低級別的HEPA過濾器

7、時(shí),工廠進(jìn)行的 MPPS或MPPS附近粒子的可接受泄漏率標(biāo)準(zhǔn)可能等于或大于現(xiàn) 場泄漏率測試的接受標(biāo)準(zhǔn)，測試接受標(biāo)準(zhǔn)會變得更具爭議和困難。在可能發(fā)生 泄漏的地方尤其如此。因此，在購買過濾器時(shí)，考慮過濾器的等級以及安裝后 如何進(jìn)行測試非常重要，以避免不必要的現(xiàn)場測試失敗。ISO 14644-333 gives guidance on how alternative leakacceptancecriteria can be implemented. In a risk-based approach, it may be ideal to haveacceptance criteria that t

8、rends with the eficiency of the flters being used orthecleanliness of the room being tested. ISO 14644-3 uses the factory flter efciency rating as the basis of acceptancecriteria negotiation. The leak acceptancecriteria for a photometer leak test and a particle counter based leaktestshould be the sa

9、me, as the theory and methodology behind leak sizing isidenticalfor both methods.If performedproperly,a leak test withfor both methods.If performedproperly,a leak test withphotometeranda particle counter will result in the same leak size (Meek, et al., 2011121).photometerandISO 14644-333提供了有關(guān)如何實(shí)施泄漏替

10、代標(biāo)準(zhǔn)的指南。在基于風(fēng)險(xiǎn)的方法中，理想的接受標(biāo)準(zhǔn)是，該接受標(biāo)準(zhǔn)可以反映所使用過濾器的效率或所測試房間的潔凈度。ISO 14644-3 使用工廠過濾效率等級作為接受標(biāo)準(zhǔn)協(xié)商的基礎(chǔ)。光度計(jì)泄漏測試和基于粒子計(jì)數(shù)器的泄漏測試的泄漏接受標(biāo)準(zhǔn)應(yīng)該相同，因?yàn)閮煞N方法背后的理論和方法是相同的。如果執(zhí)行得當(dāng)，使用光度計(jì)和粒子計(jì)數(shù)器進(jìn)行的泄漏測試將得到相同的泄漏率結(jié)果(Meek等，2011 121)A leak detected in excess of 0,01 % of the upstream massconcentration is deemed to exceed themaximum allowab

11、le penetration. However,for filter systems of an integral efficiency at MPPS 99,95 %and less than99,995 %, theacceptance criterion is 0,1 %.如果檢測到的泄漏量超過上游濃度的0.01 %, 一般認(rèn)為該泄漏率超過最大允許標(biāo)準(zhǔn)。但是，對于整體效率 MPPS為99.95 %且小于99,995 %的過濾器系統(tǒng)（如H13過濾器），接受標(biāo)準(zhǔn)為0.1%。If filter systems of an integral efficiency lower than 99,95

12、 %at MPPS are to be tested, a different acceptance criterion are necessary, basedon agreement between customer and supplier.如果要測試MPPS整體效率低于99.95%的過濾系統(tǒng)，則根據(jù)客戶和供應(yīng)商之間的協(xié)議，需要不一樣的接受標(biāo)準(zhǔn)。The flters for depyrogenation tunnel用于去熱原隧道的高效過濾器The flters ftted to a depyrogenation tunnel are subject toprolongedperiods

13、 of high temperature operation, so standard flters are notsuitable. Special flters rated to 350 C are available with a manufacturerguarantee d efciency of 99.99% for 0.3(i m particles (notethat the FDA defnitionof a HEPA is 99.97% at 0.3 m) at a temperature of 350 C) with a ceramicmaterial used for

14、the media to frame seal. Recently there have been advances inthe materials available and ?exible sealants are being introduced that canreduce the heat up time and reduce the risk of sealant cracking. Traditionalflters need to have a controlled heat up and cool down time (typically not toexceed 1C pe

15、r minute; the rate shouldbe confrmedwith the flter supplier)toprevent heat stress damageto the seals. Often the systems aremaintained hotduring periods of non-use to reduce the heat cycling on the flter.安裝到去熱原隧道中的過濾器需要經(jīng)受長時(shí)間的高溫操作，因此不適用標(biāo)準(zhǔn)過濾器。廠家使用陶瓷材料用于濾材與邊框的密封可提供耐受350 C的對0.3顆粒的效率為 99.99 %的特殊過濾器(注， FDA

16、對HEPA的定義為 99.97 % 0.3 m m)。最近，可用的材料有了進(jìn)步，并且引入了柔性密封劑，可以減少 加熱時(shí)間并降低密封劑開裂的風(fēng)險(xiǎn)。傳統(tǒng)的過濾器需要具有受控的加熱和冷卻速度(通常不超過1 C/分鐘；應(yīng)與過濾器供應(yīng)商確認(rèn)該速率)，以防止熱應(yīng)力 損壞密封件。通常，在不使用期間，系統(tǒng)會保持高溫，以減少過濾器的加熱循Filters used for depyrogenation tunnel are generally H14. Theseflters canbe full facescan leak testedoninstallation,but aftertheinitialheat

17、ing cycle (burning in the flter, which usually results in the fltergradebecoming equivalent toH13) traditionaltesting isnotrecommended. The oilaerosol (if it is Polyalphaolefn (PAO) will load onto the flter and burn o ? ,giving o ? unhealthy fumes, and may load the flter media; this is usually more fragileafter burn in as the binder holding the media together has o ?-gassed.DEHS (Di