1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 779:2012Particulate air filters forgeneral ventilation Determination of the filtrationperformanceBS EN 779:2012 BRITISH STANDARDNational forewordThis British Standard is th
2、e UK implementation of EN 779:2012. Itsupersedes BS EN 779:2002 which is withdrawn.BS EN 779:2012 provides a system of checking the filtrationperformance of air filters used in air conditioning systems. The useof this revised version of BS EN 779 will ensure a more rigorouscheck of the quality and p
3、erformance of air filters used in airconditioning systems. This in turn will result in improved air qualityin indoor working environments.The test procedures used in this standard are based on establishedtechniques developed over decades, but using modern digitalinstrumentation. The multiple mechani
4、sms involved in air filtrationare complex and difficult to model, and consequently the testingtechniques themselves have also become complex.A result of this is that the performance grading of air filters cannotbe carried out reproducibly in terms of their effectiveness in theremoval of atmospheric
5、particulate air pollution. Tests using artificial(synthetic) particulate contamination are used to grade these filters. The BS EN 779:2012 test system grades (ranks) air filters accordingto their particulate removal capability. This varies and mayincrease or decrease significantly during the lifetim
6、e of the filter.Users of this standard need to be aware that the term averageefficiency, which occurs in the classification table and in otherplaces, is a test parameter that relates only to tests using artificialtest contamination in artificial test conditions. The value of thisparameter obtained i
7、n the test procedures does not correspondwith or relate directly to the installed performance of air filters inventilation systems. This value cannot be used to estimate or predictthe effectiveness of these filters in removing particulate atmosphericpollution.Conversely, the minimum efficiency is a
8、minimum performancecriterion. Under normal operating conditions the particulateremoval capability of the filter will not fall below this value.BSI experts, together with experts in CEN and ISO, are activelysupporting an ISO project to develop new performance criteriafor air filters for use in genera
9、l ventilation. The new standard isscheduled for publication in 2015 and will rank filters in terms oftheir performance in the removal of particulate air pollution.The UK participation in its preparation was entrusted to TechnicalCommittee MCE/21/3, Air filters other than for air supply for I.C.engin
10、es and compressors.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Publis
11、hed by BSI StandardsLimited 2012ISBN 978 0 580 67231 6ICS 91.140.30Compliance with a British Standard cannot confer immunity fromlegal obligations. BS EN 779:2012 BRITISH STANDARDThis British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 April 2012.Am
12、endments issued since publicationDate Text affectedBS EN 779:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 779 April 2012 ICS 91.140.30 Supersedes EN 779:2002English Version Particulate air filters for general ventilation - Determination of the filtration performance Filtres air de ventil
13、ation gnrale pour llimination des particules - Dtermination des performances de filtration Partikel-Luftfilter fr die allgemeine Raumlufttechnik - Bestimmung der Filterleistung This European Standard was approved by CEN on 14 April 2011. CEN members are bound to comply with the CEN/CENELEC Internal
14、Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
15、member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official version
16、s. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slove
17、nia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide fo
18、r CEN national Members. Ref. No. EN 779:2012: EBS EN 779:2012EN 779:2012 (E) 2 Contents Foreword 4Introduction . 51 Scope 72 Normative references 73 Terms and definitions . 74 Symbols and abbreviated terms 115 Requirements . 126 Classification 147 Test rig and equipment . 157.1 Test conditions 157.2
19、 Test rig 157.3 Aerosol generation DEHS Test Aerosol . 177.4 Aerosol sampling system . 187.5 Flow measurement 197.6 Particle counter 197.7 Differential pressure measuring equipment . 197.8 Dust feeder . 198 Qualification of test rig and apparatus 238.1 Air velocity uniformity in the test duct 238.2
20、Aerosol uniformity in the test duct 238.3 Particle counter sizing accuracy 248.4 Particle counter zero test 258.5 Particle counter overload test 258.6 100 % efficiency test 258.7 Zero % efficiency test 258.8 Aerosol generator response time 268.9 Pressure equipment calibration . 268.10 Pressure drop
21、checking 268.11 Dust feeder air flow rate 268.12 Summary of qualification requirements 278.13 Apparatus maintenance 289 Test materials . 289.1 Test air - cleanliness, temperature and humidity . 289.2 Test aerosol 289.3 Loading dust 299.4 Final filter 2910 Test procedure for the filter 3010.1 Prepara
22、tion of filter to be tested 3010.2 Initial pressure drop 3010.3 Initial efficiency 3010.3.1 General 3010.3.2 Efficiency measurement . 3010.4 Dust loading . 3110.4.1 Dust loading procedure 3110.4.2 Arrestance 3210.4.3 Efficiency 3310.4.4 Average efficiency . 3310.4.5 Test dust capacity 33BS EN 779:20
23、12EN 779:2012 (E) 3 11 Test method for discharging of filter material 3411.1 General 3411.2 Equipment 3411.3 Preparation of test samples . 3511.4 Measurement of the filter medium efficiency . 3511.4.1 General 3511.4.2 Isopropanol test . 3511.4.3 Expression of results 3611.5 Report . 3612 Uncertainty
24、 calculation of the test results 3713 Reporting 3813.1 General 3813.2 Interpretation of test reports 3913.3 Summary 3913.4 Efficiency 4113.5 Pressure drop and air flow rate 4113.6 Arrestance and test dust capacity . 4213.7 Marking . 42Annex A (informative) Shedding from filters 51A.1 General 51A.2 S
25、hedding 51A.2.1 Particle bounce 51A.2.2 Release of fibres or particulate matter from filter material . 51A.2.3 Re-entrainment of particles 51A.3 Testing 52A.4 References . 52Annex B (informative) Commentary 53B.1 General 53B.2 Classification . 53B.3 Test 53B.3.1 Test aerosol 53B.3.2 Loading dust 54B
26、.3.3 Distribution and sampling of aerosols 54B.3.4 Particle counter characteristics . 54B.3.5 Flat sheet test . 54B.4 Filtration characteristics . 55B.4.1 General 55B.4.2 Pressure drop 55B.4.3 Discharged efficiency 55Annex C (informative) Pressure drop calculation 56Annex D (informative) Example of
27、a completed test report 58D.1 Example of test reports . 58D.2 Examples of calculations 66D.3 Final results at 450 Pa . 69Bibliography 70BS EN 779:2012EN 779:2012 (E) 4 Foreword This document (EN 779:2012) has been prepared by Technical Committee CEN/TC 195 “Air filters for general air cleaning”, the
28、 secretariat of which is held by UNI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by October 2012, and conflicting national standards shall be withdrawn at the latest by October 2012. Attention i
29、s drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 779:2002. EN 779:2012 is based on the test method according to EN 779
30、:2002. It contains extensive test rig qualification procedures together with procedures which give some information regarding the real life behaviour of particulate air filters (see ”Introduction”). Annexes A to D are informative. According to the CEN/CENELEC Internal Regulations, the national stand
31、ards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, P
32、oland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 779:2012EN 779:2012 (E) 5 Introduction General The procedures described in this standard have been developed from those given in EN 779:2002. The basic design of test rig given in EN 779:20
33、02 is retained. A challenge aerosol of DEHS (or equivalent) is dispersed evenly across the duct upstream of the filter being tested. Representative upstream and downstream air samples are analysed by an optical particle counter (OPC) to provide filter particle size efficiency data. Classification Th
34、e EN 779:2002 classification system (comprising groups F and G filters) has been changed to three groups (F-, M- and G-filters). Filters found to have an average efficiency value of less then 40 % of 0,4 m particles will be allocated to group G and the efficiency reported as “ 500 in order to reduce
35、 the statistical error. BS EN 779:2012EN 779:2012 (E) 24 Dimensions in millimetres Figure 8 Air velocity and aerosol uniformity Sampling points for measuring uniformity of air velocity and aerosol dispersion A sample is taken successively at each measuring point. This procedure shall be repeated unt
36、il five samples from each measuring point are obtained. The five values for each point shall be averaged for all size ranges of the particle counter and the coefficient of variation CVishall be calculated for each for size range “i” as follows: i/iimeanCV = (2) where iis the standard deviation (of t
37、he nine measuring points) for size range “i”; meaniis the mean value of the nine measuring points for size range “i”. The CVishall be less than 15 % for 0,25 m3/s, 1,0 m3/s and 1,5 m3/s. 8.3 Particle counter sizing accuracy Optical particle counters (OPCs) measure the particle concentration and the
38、equivalent optical particle size. The indicated particle size is strongly dependent on the calibration of the OPC. To avoid effects caused by different aerodynamic, optical and electronic systems of various types of OPCs, measurements both upstream and downstream of the filter shall be made with the
39、 same instrument. The OPC shall be calibrated prior to initial system start-up and thereafter in regular intervals of not longer than one year and shall have a valid calibration certificate. The calibration of the OPC shall be done by the OPC manufacturer or any similarly qualified organisation acco
40、rding to established standardised procedures (e.g. IEST-RP-CC014; ISO 21501-1; ISO 21501-4) with spherical, isotropic particles of polystyrene latex (PSL) in single dispersion, having a refractive index of 1,59. The calibration has to be performed for at least 3 channels of the OPC, distributed over
41、 the measuring range of 0,2 m to 3,0 m, including the channels containing 0,2 m and 3,0 m. A good indication of the OPC calibration may be obtained by checking upstream distribution of the test aerosol at each test. A quick calibration check, performed frequently according to the recommendation of t
42、he particle counter manufacturer, is strongly recommended. In this calibration check it is sufficient to verify that PSL particles of varying size appear in the corresponding size class(es) of the OPC to which they belong. Checks with PSL particles at the low and the high end of the OPCs size range
43、are especially meaningful. BS EN 779:2012EN 779:2012 (E) 25 The sampling flow rate is the volumetric flow rate through the Optical particle counter (OPC). Any error in the volume flow will affect the reported particle number concentration with a proportional relationship. The error in the sampling f
44、low rate shall be within 5 %, in compliance with one established standardised procedure (e.g. IEST-RP-CC014). 8.4 Particle counter zero test The count rate shall be verified to have less than 10 total counts per minute in the 0,2 m to 3,0 m size range when operating with a HEPA or ULPA filter direct
45、ly attached to the instruments inlet. This also includes the sampling system. 8.5 Particle counter overload test OPCs may underestimate particle concentrations if their concentration limit CL is exceeded. Therefore it is necessary to know the CL of the OPC being used. The maximum aerosol concentrati
46、on used in the tests should then be kept sufficiently below the CL, so that the counting error resulting from coincidence does not exceed 5 %. Operating OPCs above their CL will cause efficiency results to be lower then they really are. If the upstream concentration in the test duct cannot be reduce
47、d, a dilution system may be used to reduce the aerosol concentrations below the OPCs CL. It is then necessary to take upstream and downstream samples via the dilution system in order to eliminate errors arising from uncertainty in the dilution factors value. 1) Either one of the two following proced
48、ures may be used to determine whether the data values are influenced by the efficiency of a reference filter shall be measured at different concentrations. At a concentration above the OPCs CL, efficiency starts to decrease; 2) An upstream particle concentration distribution shall be measured. Afterward, the concentration shall be uniformly reduced or diluted (this can be done by a known or an unknown factor) and the measurement of the particle concentration distribution repeated. If the shape of the latter particle size distribution curve shifts towards smaller particles, this is a
