DIN EN ISO 28439-2011 Workplace atmospheres - Characterization of ultrafine aerosols nanoaerosols - Determination of the size distribution and number concentration using differenti.pdf

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1、July 2011 Translation by DIN-Sprachendienst.English price group 12No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 1

2、3.040.30!$sH“1803727www.din.deDDIN EN ISO 28439Workplace atmospheres Characterization of ultrafine aerosols/nanoaerosols Determination of the size distribution and number concentration usingdifferential electrical mobility analysing systems (ISO 28439:2011)English translation of DIN EN ISO 28439:201

3、1-07Arbeitsplatzatmosphre Charakterisierung ultrafeiner Aerosole/Nanoaerosole Bestimmung der Grenverteilung und Anzahlkonzentration mit differentiellenelektrischen Mobilittsanalysesystemen (ISO 28439:2011)Englische bersetzung von DIN EN ISO 28439:2011-07Air des lieux de travail Caractrisation des ar

4、osols ultrafins/nanoarosols Dtermination de la distribution granulomtrique et de la concentration en nombre laidede systmes danalyse diffrentielle de mobilit lectrique (ISO 28439:2011)Traduction anglaise de DIN EN ISO 28439:2011-07www.beuth.deDocument comprises pagesIn case of doubt, the German-lang

5、uage original shall be considered authoritative.2106.11 DIN EN ISO 28439:2011-07 National foreword This document has been prepared by Technical Committee CEN/TC 137 “Assessment of workplace exposure to chemical and biological agents” (Secretariat: DIN, Germany) in collaboration with Technical Commit

6、tee ISO/TC 146 “Air quality”, Subcommittee SC 2 “Workplace atmospheres” (Secretariat: ANSI, USA), in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna Agreement). The responsible German body involved in its preparation was the Normenausschuss Sicherheitstechnische Gr

7、undstze (Safety Design Principles Standards Committee), Working Group NA 095-03-01-01 AK Staub of Working Committee NA 095-03-01 AA Messstrategien und Anforderungen an Messverfahren. For the International Standards referred to in Clause 2 there are no national standards available. 2 EUROPEAN STANDAR

8、D NORME EUROPENNE EUROPISCHE NORM EN ISO 28439 April 2011 ICS 13.040.30 English Version Workplace atmospheres Characterization of ultrafine aerosols/nanoaerosols Determination of the size distribution and number concentration using differential electrical mobility analysing systems (ISO 28439:2011)

9、Air des lieux de travail Caractrisation des arosols ultrafins/nanoarosols Dtermination de la distribution granulomtrique et de la concentration en nombre laide de systmes danalyse diffrentielle de mobilit lectrique (ISO 28439:2011) Arbeitsplatzatmosphre Charakterisierung ultrafeiner Aerosole/Nanoaer

10、osole Bestimmung der Grenverteilung und Anzahlkonzentration mit differentiellen elektrischen Mobilittsanalysesystemen (ISO 28439:2011) This European Standard was approved by CEN on 10 March 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions

11、 for giving this EuropeanStandard 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 member. This European Standard exists in th

12、ree 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 versions. CEN members are the national standards b

13、odies 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, Slovenia, Spain, Sweden, Switzerland and United K

14、ingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 28439:2011:

15、EContents Page Foreword .3 Introduction.4 1 Scope5 2 Normative references5 3 Terms and definitions .5 4 Symbols and abbreviated terms 6 4.1 Symbols6 4.2 Abbreviated terms.7 5 Principle .7 6 Equipment 8 6.1 General .8 6.2 Sampling line .8 6.3 Pre-separator .9 6.4 Particle charge conditioner 9 6.5 DEM

16、C 9 6.6 Aerosol particle detector 9 7 Measurement strategy 10 8 Measuring procedure10 8.1 Preparation.10 8.2 Sampling 11 9 Presentation and evaluation of data11 10 Check of DMAS performance.12 10.1 Check on particle classification.12 10.2 Check on particle number-counting efficiency 12 11 Problems a

17、nd errors .12 11.1 CPC (CNC) counting efficiency12 11.2 Particles with multiple charges13 11.3 Sampling losses 13 11.4 Uncertainties14 11.5 Overloading15 11.6 Sampling of fibres .15 11.7 Humidity .15 11.8 Maintenance.15 Annex A (informative) Methods for determining exposure 16 Annex B (informative)

18、List of manufacturers (non-comprehensive)17 Bibliography18 EN ISO 28439:2011 (E) DIN EN ISO 28439:2011-07 2Foreword This document (EN ISO 28439:2011) has been prepared by Technical Committee CEN/TC 137 “Assessment of workplace exposure to chemical and biological agents”, the secretariat of which is

19、held by DIN, in collaboration with Technical Committee ISO/TC 146 “Air quality“. 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 2011, and conflicting national standards shall be withdrawn

20、 at the latest by October 2011. Attention is 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. According to the CEN/CENELEC Internal Regulations, the

21、 national standards 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, Netherl

22、ands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN ISO 28439:2011 (E) DIN EN ISO 28439:2011-07 3Introduction Within occupational hygiene, aerosol concentrations have been traditionally measured in terms of mass concentrations. For some

23、ultrafine aerosols and nanoaerosols, other exposure metrics such as the number and surface area concentration are likely to become important for predicting health effects, depending on chemical and physical properties. This International Standard provides a method for determining the number concentr

24、ation and size distribution of ultrafine aerosols and nanoaerosols at workplaces by using differential mobility analysing systems (DMASs). This can be used by occupational hygienists and researchers to measure the concentration at some workplaces. The system is generally not suitable for personal ex

25、posure measurements. EN ISO 28439:2011 (E) DIN EN ISO 28439:2011-07 41 Scope This International Standard provides guidelines for the determination of the number concentration and size distribution of ultrafine aerosols and nanoaerosols by use of mobility particle sizers (also called differential mob

26、ility analysers). Only the particle fraction of the aerosol is considered. For ultrafine aerosols and nanoaerosols, exposure metrics such as the number and surface area concentration are important. This International Standard also gives guidelines for the determination of workplace exposure to ultra

27、fine aerosols and nanoaerosols. Specifically, the differential mobility analysing system (DMAS), now available from several vendors, is discussed. Principles of operation, problems of sampling in the workplace environment, calibration, equipment maintenance, measurement uncertainty, and reporting of

28、 measurement results are covered. Potential problems and limitations are described, which need to be addressed when limit values are fixed and compliance measurements carried out. 2 Normative references The following referenced documents are indispensable for the application of this document. For da

29、ted references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO/TR 27628, Workplace atmospheres Ultrafine, nanoparticle and nano-structured aerosols Inhalation exposure characterization and assessment 3 Ter

30、ms and definitions For the purposes of this document, the terms and definitions given in ISO/TR 27628 and the following apply. 3.1 critical electrical mobility Zcritelectrical mobility of particles that in the differential electrical mobility classifier are transferred from the sample air flow to th

31、e exiting monodisperse aerosol flow NOTE Due to the finiteness of the DEMC, the exiting monodisperse flow is not strictly monodisperse, but corresponds to a range of electrical mobilities for each voltage. EN ISO 28439:2011 (E) DIN EN ISO 28439:2011-07 53.2 particle charge equilibrium charging condi

32、tion for aerosol particles that is stable after exposure to positive and negative ions for a sufficiently long period of time NOTE 1 Bipolar ions are produced by either a radioactive source or a corona discharge. NOTE 2 The electrical charge on individual particles of an aerosol at charge equilibriu

33、m is not neutral. NOTE 3 Adapted from ISO 15900:20091, 2.11. 3.3 (equivalent) particle electrical mobility diameter diameter of a sphere with the same electrical mobility as the particle in question 4 Symbols and abbreviated terms 4.1 Symbols B particle mechanical mobility s/kg C Cunningham correcti

34、on factor 1 CNaerosol number concentration 1/m3d particle diameter nm dpequivalent particle electrical mobility diameter m pd average equivalent particle electrical mobility diameter m D particle diffusion coefficient m2/s e basic unit of charge (elementary charge) 1,602 177 1019C q1DEMC sample air

35、flow rate m3/s q2DEMC filtered sheath air flow rate m3/s q3DEMC excess air flow rate m3/s q4DEMC exiting air flow rate to particle detector m3/s k Boltzmann constant 1,38 1023Nm/K L length of sampling line m n number of charges 1 p penetration through sampling line 1 t (coagulation) time s tscanscan

36、 time s T absolute temperature at which the DEMC is operated K Vvvolume of buffer vessel for the sample air flow rate m3Z electrical mobility of a charged airborne particle m2/Vs Zcritcritical electrical mobility of a charged airborne particle m2/Vs gas viscosity Pas parameter for diffusion losses 1

37、 EN ISO 28439:2011 (E) DIN EN ISO 28439:2011-07 64.2 Abbreviated terms CNC condensation nuclei counter CPC condensation particle counter DEMC differential electrical mobility classifier DMAS differential mobility analysing system NOTE A DMAS is also known as a differential mobility particle sizer (D

38、MPS) or scanning mobility particle sizer (SMPS). HEPA high efficiency particle arrestor 5 Principle The aerosol is sampled in the workplace at a position representative of the atmosphere to which a worker might be exposed. Larger particles than approximately 1 m are precipitated and the particles sm

39、aller than approximately 1 m drawn into the instrument. After charge conditioning, the aerosol particles are separated in the electrical field of the DEMC (see References 6 and 7) according to their electrical mobility, which is given by Equation (1). p3ZneBCBd= =(1) where Z is the electrical mobili

40、ty, in metres squared per volt second, of a charged aerosol particle; n is the number of electrical charges; e is the basic unit of charge (elementary charge), 1,602 177 1019C; B is the particle mechanical mobility, in seconds per kilogram; C is the Cunningham correction factor; is the gas viscosity

41、, in pascal seconds; dpis the equivalent particle electrical mobility diameter, in metres. The critical particle electrical mobility, Zcrit, is directly related to the geometric dimensions of the DEMC. The equivalent particle electrical mobility diameter, dp, can be determined from equations provide

42、d by the instrument manufacturer. Particles of a certain size or size interval are counted in a condensation nuclei counter (CNC) also known as a condensation particle counter (CPC) or electrometer, and the particle number concentration for each size or size interval is determined. By scanning or st

43、epwise changing the voltage of the DEMC, a number size distribution is obtained. The size range from 3 nm to 1 000 nm in electrical mobility diameter can be partly covered by different instruments (see Reference 8). The DEMC has the advantage that the electrical mobility diameter is approximately eq

44、uivalent to the projected-area diameter of particles (defined as the diameter of a sphere with the same projected area as the particles being sized) with compact geometries. The entire number concentration is obtained by adding or integrating all size channels. Though the composition of the sampled

45、particles cannot be obtained, the distribution of surface area and volume concentration in some instances, e.g. if the particles are known to be spherical, can be estimated from calculations provided by the manufacturer or in the literature. EN ISO 28439:2011 (E) DIN EN ISO 28439:2011-07 76 Equipmen

46、t 6.1 General A DMAS consists of different instrument sections (see Figure 1): a) pre-separator; b) particle charger or particle charge conditioner; c) differential electrical mobility classifier (DEMC), with flow control and high voltage control; d) particle detector; e) system controller, with dat

47、a acquisition and data analysis (typically built-in firmware or dedicated software on a personal computer). Figure 1 Major parts of a DMAS 6.2 Sampling line The aerosol is often sampled with a flexible tube in order to access the breathing zone of a worker. The material of the tube shall be an elect

48、rical conductor. Particle diffusion losses should be minimized. This can be accomplished by using tubes of short length. For example, the application of flexible rubber tubes of conducting material of length up to a few metres with an inner diameter of 4 mm or 6 mm ensures a short residence time in the tube (see 11.3.2). The flow in the sampling line shall be laminar. When sampling highly fluctuating aerosols like welding fumes it is recommended additionally that