ISO 29463-2-2011 High-efficiency filters and filter media for removing particles in air - Part 2 Aerosol production measuring equipment and particle-counting st.pdf

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1、 Reference number ISO 29463-2:2011(E) ISO 2011INTERNATIONAL STANDARD ISO 29463-2 First edition 2011-10-15 High-efficiency filters and filter media for removing particles in air Part 2: Aerosol production, measuring equipment and particle-counting statistics Filtres haut rendement et filtres pour lli

2、mination des particules dans lair Partie 2: Production darosol, quipement de mesure et statistique de comptage de particules ISO 29463-2:2011(E) COPYRIGHT PROTECTED DOCUMENT ISO 2011 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any for

3、m or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09

4、47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2011 All rights reservedISO 29463-2:2011(E) ISO 2011 All rights reserved iiiContents Page Foreword iv Introduction . v 1 Scope 1 2 Normative references 1 3 Terms and definitions . 2 4 Aerosol production . 2 4.1 Aerosol substa

5、nces 2 4.2 Producing mono-disperse aerosols 3 4.3 Generating poly-disperse aerosols . 6 4.4 Neutralization of aerosols 8 4.5 Minimum performance parameters for aerosol generators 8 4.6 Sources of error . 8 4.7 Maintenance and inspection 8 5 Measuring devices 9 5.1 Optical particle counters 9 5.2 Con

6、densation particle counter 11 5.3 Differential mobility analyser . 14 5.4 Particle size analysis system on the basis of differential mobility analysis . 16 5.5 Dilution systems 16 5.6 Aerosol photometer 17 5.7 Differential pressure measuring equipment . 19 5.8 Absolute pressure measuring equipment 1

7、9 5.9 Thermometers 19 5.10 Hygrometer 20 6 Maintenance and inspection intervals 20 7 Particle counting statistics . 21 Annex A (informative) Mean size of particle size distributions 22 Bibliography 24 ISO 29463-2:2011(E) iv ISO 2011 All rights reservedForeword ISO (the International Organization for

8、 Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the

9、right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. Internatio

10、nal Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication a

11、s an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. I

12、SO 29463-2 was prepared by Technical Committee ISO/TC 142, Cleaning equipment for air and other gases. ISO 29463 consists of the following parts, under the general title High-efficiency filters and filter media for removing particles in air: Part 1: Classification, performance, testing and marking P

13、art 2: Aerosol production, measuring equipment, particle-counting statistics Part 3: Testing flat sheet filter media Part 4: Test method for determining leakage of filter element Scan method Part 5: Test method for filter elements ISO 29463-2:2011(E) ISO 2011 All rights reserved vIntroduction ISO 29

14、463 (all parts) is derived from EN 1822 (all parts) with extensive changes to meet the requests from non-EU p-members. It contains requirements, fundamental principles of testing and the marking for high- efficiency particulate air filters with efficiencies from 95 % to 99,999 995 % that can be used

15、 for classifying filters in general or for specific use by agreement between users and suppliers. ISO 29463 (all parts) establishes a procedure for the determination of the efficiency of all filters on the basis of a particle counting method using a liquid (or alternatively a solid) test aerosol, an

16、d allows a standardized classification of these filters in terms of their efficiency, both local and overall efficiency, which actually covers most requirements of different applications. The difference between ISO 29463 (all parts) and other national standards lies in the technique used for the det

17、ermination of the overall efficiency. Instead of mass relationships or total concentrations, this technique is based on particle counting at the most penetrating particle size (MPPS), which, for micro-glass filter mediums, is usually in the range of 0,12 m to 0,25 m. This method also allows testing

18、ultra-low penetration air filters, which was not possible with the previous test methods because of their inadequate sensitivity. For membrane filter media, separate rules apply, and are described in ISO 29463-5:2011, Annex B. Although no equivalent test procedures for testing filters with charged m

19、edia is prescribed, a method for dealing with these types of filters is described in ISO 29463-5:2011, Annex C. Specific requirements for test method, frequency, and reporting requirements can be modified by agreement between supplier and customer. For lower efficiency filters (group H, as described

20、 below), alternate leak test methods noted in ISO 29463-4:2011, Annex A, can be used by specific agreement between users and suppliers, but only if the use of these other methods is clearly designated in the filter markings as described in ISO 29463-4:2011, Annex A. There are differences between ISO

21、 29463 (all parts) and other normative practices common in several countries. For example, many of these rely on total aerosol concentrations rather than individual particles. For information, a brief summary of these methods and their reference standards are provided in ISO 29463-5:2011, Annex A. I

22、NTERNATIONAL STANDARD ISO 29463-2:2011(E) ISO 2011 All rights reserved 1High-efficiency filters and filter media for removing particles in air Part 2: Aerosol production, measuring equipment and particle- counting statistics 1 Scope This part of ISO 29463 specifies the aerosol production and measuri

23、ng equipment used for testing high- efficiency filters and filter media in accordance with ISO 29463-3, ISO 29463-4 and ISO 29463-5, as well as the statistical basis for particle counting with a small number of counted events. It is intended to be used in conjunction with ISO 29463-1, ISO 29463-3, I

24、SO 29463-4 and ISO 29463-5. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies

25、. ISO 29463-1, High-efficiency filters and filter media for removing particles in air Part 1: Classification, performance, testing and marking ISO 29463-3, High-efficiency filters and filter media for removing particles in air Part 3: Testing flat sheet filter media ISO 29463-4:2011, High-efficiency

26、 filters and filter media for removing particles in air Part 4: Test method for determining the leakage of filter element Scan method ISO 29463-5:2011, High-efficiency filters and filter media for removing particles in air Part 5: Test method for filter elements ISO 29464 1) , Cleaning equipment for

27、 air and other gases Terminology 1) To be published. ISO 29463-2:2011(E) 2 ISO 2011 All rights reserved3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 29463-1, ISO 29464, and the following apply. 3.1 counting efficiency expression of that proportion

28、of the particles of detectable size suspended in the volume flow under analysis that make their way through the measured volume and are counted by the particle counter EXAMPLE The ratio of the concentration measured to actual aerosol concentration. NOTE The counting efficiency depends on the particl

29、e size, and decreases progressively in the proximity of the lower detection limit of the particle counter. 4 Aerosol production When testing a filter, a test aerosol with liquid particles shall be used as reference test method in accordance with ISO 29463-1. Alternatively, a solid PSL aerosol may be

30、 used for local efficiency (leak) testing (see ISO 29463-4:2011, Annex E). The testing of high-performance filters (ISO 65 U and higher) requires methods of aerosol production with high production rates (10 10s 1to 10 11s 1 ), in order to provide statistically significant measurements downstream of

31、the filter. By adjusting the operating parameters of the aerosol generator, it shall be possible to adjust the mean particle diameter of the aerosol so that it is equal to the MPPS. The concentration and the size distribution of the aerosol produced shall remain constant throughout the test. 4.1 Aer

32、osol substances A suitable aerosol substance for the reference test method is a liquid with a vapour pressure that is so low at the ambient temperature that the size of the droplets produced does not change significantly due to evaporation over the time scale relevant for the test procedure (in the

33、order of a few seconds). 4.1.1 Possible substances include, but are not limited to, DEHS, PAO, paraffin oil (low viscosity). 4.1.2 The most critical properties of a possible aerosol substance are the following, which should not differ significantly from the values given for the three substances sugg

34、ested in Table 1: index of refraction; vapour pressure; density. Standard laboratory safety regulations shall be observed when handling these substances. It shall be ensured by means of suitable exhaust systems and air-tight aerosol ducting systems that the test aerosols are not inhaled. In case of

35、doubt, the safety data sheets for the appropriate substances shall be consulted. ISO 29463-2:2011(E) ISO 2011 All rights reserved 3Table 1 Important data for aerosol substances at 20 C Trivial name DEHS PAO aParaffin oil (low visc.) Chemical designation Sebacic acid-bis(2-ethylhexyl) ester (e.g. CAS

36、 No. 122-62-3) Poly-alpha-olefin (e.g. CAS bNo. 68649-12-7) Mixture (e.g. CAS # 64742-46-7) Trivial name Diethylhexylsebacate Polyalphaolefin Paraffin oil Density, kg/m 3912 800 to 820 (820 c ) 843 Melting point, K 225 280 259 Boiling point, K 529 650 to 780 (674 c ) 526 Flash point, K 473 445 to 50

37、0 453 Vapour pressure at 293 K, kPa 1,9 0,1 kPa at 423 K 0,1 to 0,13 0,1 Dynamic viscosity, kg/m s 0,022 to 0,024 0,003 1 to 0,003 4 at 373 K 0,014 at 313 K c0,026 0,0025 to 0,0038 at 313K Kinematic viscosity, mm 2 /s 3,8 to 4,2 at 373 K 3,0 to 4,5 at 313 KIndex of refraction/wavelength, nm 1,450/65

38、0 1,452/600 1,4535/550 1,4545/500 1,4585/450 1,475/400 (1,455 6 c ) (1,466 c ) aUS Patents 5,059,349, 5,059,352, and 5,076,965 describe and restrict the use of PAO for filter testing. Material properties of PAO are as given in Japan JACA Standard No. 37-2001 and ISO 14644-3. bCAS #, Chemical Abstrac

39、t Service Registry Number, substances have been registered in Chemical Abstract, issued by American Chemical Society. cData for “Emery 3004” as a specific example of a PAO. Source: Crosby, David W., Concentration produced by a Laskin nozzle generator, a comparison of substitute materials and DOP, 21

40、st DOE/NRC Nuclear Air Cleaning Conference. 4.2 Producing mono-disperse aerosols 4.2.1 Condensation methods Condensation methods are preferred for the creation of mono-disperse aerosols, i.e. the particles are formed by condensation from the vapour phase. It is necessary to distinguish between heter

41、ogeneous and homogeneous condensation. 4.2.1.1 Heterogeneous condensation In the case of heterogeneous condensation, the vapour condenses at a relatively low level of super-saturation onto very small particles that are already present, the so-called condensation nuclei. The size distribution of the

42、resultant aerosol has a geometrical standard deviation between g 1,05 and g 1,15. One type of aerosol generator that operates using the principle of heterogeneous condensation and that is suitable for testing filters in accordance with this part of ISO 29463 is the Rapaport-Weinstock generator (see

43、Figure 1). ISO 29463-2:2011(E) 4 ISO 2011 All rights reserved4.2.1.1.1 Rapaport-Weinstock generator NOTE See Figure 1. An aerosol substance is nebulized through a nozzle, either as a pure substance or in solution, and the resultant poly-disperse aerosol is then vaporized along the heated section of

44、a glass tube. Residual nuclei of the impurities in the material remain. Key 1 liquid reservoir 2 nebulizer 3 vaporization section 4 thermostat 5 condensation section aCompressed air. bAerosol. Figure 1 Structure of the Rapaport and Weinstock aerosol generator In the subsequent condensation section,

45、the aerosol substance then condenses on these nuclei to form a mono-disperse aerosol (see also Reference 1). The particle diameter of this aerosol is determined by the mixing ratio of aerosol substance and solvent. The final aerosol contains the solvent used (e.g. propanol) as a vapour. Generators o

46、f this type achieve particle production rates of 10 9s 1 ; the particle diameter can be adjusted between approximately 0,1 m and 1,5 m. ISO 29463-2:2011(E) ISO 2011 All rights reserved 54.2.1.2 Homogeneous condensation At higher levels of super-saturation, clusters of vapour molecules form spontaneo

47、usly without the presence of condensation nuclei, and these then grow to particles that are some nanometres in diameter (homogeneous condensation). Larger particles then form as a result of coagulation of these particles with one another. The resultant size distribution has a standard deviation of g

48、 1,5 independent of the median particle size, and can thus only be referred to as quasi-mono-disperse. On the other hand, rates of production of particles achieved can be as much as two orders of magnitude larger than those possible using heterogeneous condensation (more than 10 11 s 1 ). Figure 2 s

49、hows the structure of a free-jet condensation aerosol generator that makes use of this principle. b a 1 2 3 4 5 6 8 7 9 10Key 1 DEHS tank 2 pump 3 flow controller 4 ultra-sonic nebulizer 5 thermostat 6 vaporization pipe with heater and insulation 7 sheath air 8 nozzle 9 sintered metal plate 10 coagulation section aNitrogen. bAerosol. Figure 2 Set-up of a free-jet condensation aerosol generator ISO 29463-2:2011(E) 6 ISO 2011 All rights reservedA pump delivers aerosol