BS/EN 1822-1-2019 pdf download.High efficiency air filters (EPA, HEPA and ULPA) Part 1: Classification, performance testing, marking.
7.4.2 Step 1: Testing sheet filter medium
The efficiency of flat sheet filter medium test samples shall be determined for a range of particle sizes at the nominal filter medium velocity. From the efficiency versus particle size curve, generated this way, the most penetrating particle size (MPPS) shall be determined.
See 2.5J..
7.4.3 Step 2: Leak test of the filter element
Filter elements of Groups H and U shall be individually tested for absence of leaks at their nominal air volume flow rate. Filter elements of Group H shall be leak tested using either the reference scanning method or the Oil Thread Test (EN ISO 29463-4:2018, Annex A). H13 may also be tested according to EN ISO 29463-4:2018, Annex F. Filter elements of Group U shall be leak tested using the MPPS scanning method, described in EN ISO 29463-4, only.
See Z52.
7.4.4 Step 3: Efficiency test of the filter element
Using the MM’S test aerosol (the same as used in step 2), the integral efficiency of the filter element shall be determined at its nominal air volume flow rate.
For filters of Group E, this shall be done on statistical bases (see EN ISO 29463-5:2018, 4.2). For filters of Groups Ft and U, this shall be done on each individual filter, except for filters tested as per EN ISO 29463-4:2018, Annex A, where testing on statistical bases is acceptable.
See Z.5.3.
The use of the aerosol photometer filter scan leak test is not allowed.
7.4.5 Remarks
On the basis of the value(s) determined for integral efficiency and for filters of Groups H and U also for local efficiency (= absence of relevant leaks), filter elements shall be assigned to a filter class as specified in ,5. This assignment is only valid if the fixed test conditions are met.
In all three procedural steps it is permissible to use either a monodisperse or a polydisperse test aerosol. The particle counting method used may be a total count method (CNC) or a method involving particle size analysis (OPC).
Since total count particle counting methods provide no information about the particle size, they may only be used to determine the efficiency in procedural step 1 with monodisperse test aerosols of a known particle size.
For the determination of the minimum efficiency of the flat sheet filter medium (step 1) the test method using a monodisperse test aerosol shall be considered as the reference test method. Care shall be taken for the correlation with the reference test method If using a polydisperse aerosol for steps 2 and 3.
For production testing, filter manufacturers may use data of their filter medium supplier for procedural step 1, instead of doing these test themselves, as long as these data are fully traceable and documented and the tests are done in full accordance with this standard, and in particular with EN ISO 29463-3.
However, it is necessary to be aware that, in any case, it remains the responsibility of the filter manufacturer to ensure the correctness in accordance with this standard, traceability and documentation of the data. This can be accomplished by maintaining a quality management system, e.g. EN ISO 9000, including supplier audits and regular cross-checking of the data provided by the filter medium supplier or verified by third-party measurements. The cross-checking of the filter medium data shall be done using an accepted statistical method, which can be the skip lot procedure as described in ISO 2859-1 or any equivalent alternative method.
7.5 Test procedures
7.5.1 Testing sheet filter media
7.5.1.1 General
The fractional efficiency curve of flat sheets filter medium samples shall be determined in new condition (material as supplied by the medium manufacturer) and in discharged condition (see EN ISO 29463-5:2018, Annex C). If these measurements reveal that the filter medium is having a significant charge. the filter elements shall be classified on the bases of the discharged flat sheet efficiency or penetration measurements as per EN ISO 29463-5:20 18, Annex C.
7.5.1.2 Test samples.BS/EN 1822-1-2019 pdf download.