1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58particle light interaction methods Part 3: Light extinction liquid-borne particle counterICS 19.120
2、Determination of particle size distribution Single BRITISH STANDARDBS ISO 21501-3:2007BS ISO 21501-3:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 August 2007 BSI 2007ISBN 978 0 580 55677 7Amendments issued since publicationAmd. No.
3、Date CommentsThis publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard is the UK implementation of
4、ISO 21501-3:2007. Together with BS ISO 21501-2:2007 and BS ISO 21501-4:2007, it supersedes BS ISO 13323-1:2000 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee LBI/37, Sieves, screens and particle sizing.A list of organizations represented on this comm
5、ittee can be obtained on request to its secretary.Reference numberISO 21501-3:2007(E)INTERNATIONAL STANDARD ISO21501-3First edition2007-05-15Determination of particle size distribution Single particle light interaction methods Part 3: Light extinction liquid-borne particle counter Dtermination de la
6、 distribution granulomtrique Mthodes dinteraction lumineuse de particules uniques Partie 3: Compteur de particules en suspension dans un liquide par extinction de la lumire BS ISO 21501-3:2007ii iiiContents Page Foreword iv Introduction v 1 Scope . 1 2 Terms and definitions. 2 3 Requirements 2 3.1 S
7、ize calibration 2 3.2 Verification of size setting . 2 3.3 Counting efficiency. 2 3.4 Size resolution 2 3.5 Maximum particle number concentration 3 3.6 Sampling flow rate 3 3.7 Sampling time . 3 3.8 Sampling volume 3 3.9 Calibration interval . 3 3.10 Test report . 3 4 Test method. 4 4.1 Size calibra
8、tion 4 4.2 Verification of size setting . 6 4.3 Counting efficiency. 6 4.4 Size resolution 6 4.5 Maximum particle number concentration 7 4.6 Sampling flow rate 8 4.7 Sampling time . 8 4.8 Sampling volume 8 4.9 Calibration . 8 Annex A (informative) Uncertainty of particle size calibration 9 Annex B (
9、informative) Size resolution 11 Bibliography . 12 BS ISO 21501-3:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO tech
10、nical committees. Each member body interested in a subject for which a technical committee has been established has the 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
11、 with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International 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 I
12、nternational Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as 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
13、 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 21501-3 was prepared by Technical Committee ISO/TC 24, Sieves, sieving and other sizing methods, Subcommittee SC 4, Sizing by methods other than sieving. This first edition of I
14、SO 21501-3, together with ISO 21501-2 and ISO 21501-4, cancels and replaces ISO 13323-1:2000, which has been technically revised. ISO 21501 consists of the following parts, under the general title Determination of particle size distribution Single particle light interaction methods: Part 2: Light sc
15、attering liquid-borne particle counter Part 3: Light extinction liquid-borne particle counter Part 4: Light scattering airborne particle counter for clean spaces The following part is under preparation: Part 1: Light scattering aerosol spectrometer BS ISO 21501-3:2007vIntroduction Monitoring particl
16、e contamination levels is required in various fields, e.g. in the electronic industry, in the pharmaceutical industry, in the manufacturing of precision machines and in medical operations. Particle counters are useful instruments for monitoring particle contamination in liquid. The purpose of this p
17、art of ISO 21501 is to provide a calibration procedure and verification method for particle counters, so as to minimize the inaccuracy in the measurement result by a counter, as well as the differences in the results measured by different instruments. BS ISO 21501-3:2007blank1Determination of partic
18、le size distribution Single particle light interaction methods Part 3: Light extinction liquid-borne particle counter 1 Scope This part of ISO 21501 describes a calibration and verification method for a light extinction liquid-borne particle counter (LELPC), which is used to measure the size and par
19、ticle number concentration of particles suspended in liquid. The light extinction method described in this part of ISO 21501 is based on single particle measurements. The typical size range of particles measured by this method is between 1 m and 100 m in particle size. Instruments that conform to th
20、is part of ISO 21501 are used for the evaluation of the cleanliness of pharmaceutical products (e.g. injections, water for injections, infusions), as well as the measurement of number and size distribution of particles in various liquids. The following are within the scope of this part of ISO 21501:
21、 size calibration; verification of size setting; counting efficiency; size resolution; maximum particle number concentration; sampling flow rate; sampling time; sampling volume; calibration interval; test report. BS ISO 21501-3:20072 2 Terms and definitions For the purposes of this document, the fol
22、lowing terms and definitions apply. 2.1 calibration particles mono-disperse spherical particle with a known mean particle size, e.g. polystyrene latex (PSL) particle, that is traceable to an international standard of length, and where the standard uncertainty of the mean particle size is equal to or
23、 less than 2,5 % NOTE The refractive index of calibration particles is close to 1,59 at a wavelength of 589 nm (sodium D line). 2.2 counting efficiency ratio of the measured result of a light extinction liquid-borne particle counter (LELPC) to that of a reference instrument using the same sample 2.3
24、 particle counter instrument that counts the number of particles and measures their size using the light scattering method or the light extinction method 2.4 pulse height analyser PHA instrument that analyses the distribution of pulse heights 2.5 size resolution measure of the ability of an instrume
25、nt to distinguish between particles of different sizes 3 Requirements 3.1 Size calibration The recommended procedure for the size calibration is described in 4.1. 3.2 Verification of size setting The reported particle size range setting error of LELPC shall be equal to or less than 10 % when the tes
26、t is carried out by the method described in 4.2. 3.3 Counting efficiency The counting efficiency shall be (100 20) % when the test is carried out by the method described in 4.3. 3.4 Size resolution The size resolution shall be equal to or less than 10 % when the test is carried out by the method des
27、cribed in 4.4. BS ISO 21501-3:200733.5 Maximum particle number concentration The maximum measurable particle number concentration shall be specified by the manufacturer. The coincidence loss at the maximum particle number concentration of an LELPC shall be equal to or less than 10 %. NOTE When the p
28、article number concentration is higher than the maximum particle number concentration, the number of uncounted particles increases because of an enhanced probability of multiple particles existing in the sensing volume (coincidence error) and/or saturation of the electronic system. 3.6 Sampling flow
29、 rate The manufacturer shall specify the standard uncertainty of the sampling flow rate. It shall be checked by the user prior to the measurement so that the sampling flow rate is within the range specified by the manufacturer. The standard uncertainty of sampling flow rate shall be within the manuf
30、acturers specification. If the LELPC does not have a flow rate control system this subclause does not apply, however the manufacturer shall specify the allowable flow rate range of the LELPC. 3.7 Sampling time The standard uncertainty in the duration of sampling time shall be equal to or less than 1
31、 % of the preset value. This subclause does not apply when the LELPC is not equipped with a sampling system. This subclause does not apply when the LELPC is equipped with a volumetric sampling system. 3.8 Sampling volume The standard uncertainty of sampling volume shall be equal to or less than 5 %
32、of the preset value. This subclause does not apply when the LELPC is not equipped with a volumetric sampling system. 3.9 Calibration interval It is recommended that the calibration interval of an LELPC be one year or less. 3.10 Test report The following minimum information shall be recorded: a) date
33、 of calibration; b) calibration particle sizes; c) verification of size setting; d) flow rate; e) size resolution (with the particle size used); f) counting efficiency; g) voltage limit or channel of an internal pulse height analyser (PHA). BS ISO 21501-3:20074 4 Test method 4.1 Size calibration Whe
34、n calibrating an LELPC with calibration particles of known size, the median voltage (or internal PHA channel), corresponds to the particle size (see Figure 1). The median voltage (or internal PHA channel) should be determined by using a particle counter with variable voltage limit (or internal PHA c
35、hannel) settings. The median voltage (or internal PHA channel) is the voltage (or internal PHA channel) that equally divides the total number of pulses counted. When a particle counter with variable voltage limit settings is not available, a PHA can be used in place of the counter. Key X pulse heigh
36、t voltage (or channel) Y density 1 pulse height distribution with PSL particles Vllower voltage limit Vmmedian voltage Vuupper voltage limit Figure 1 Pulse height distribution of PSL particle signals When noise signals appear as if there are many small particles in the sample, the median voltage (or
37、 internal PHA channel) shall be determined by discarding the pulses due to “false particles” see Figure 2 a). The discarding should only be done when the density at the peak due to real particles is more than twice the density at the valley that separates it from the pulses due to “false particles”
38、see Figure 2 b). In this case, Vuis the voltage greater than the median voltage, Vm, where the density is the same as Vl. The median is calculated using only the population between the voltage limits Vland Vu. BS ISO 21501-3:20075a) b) Key X pulse height voltage (or channel) Y density 1 pulse height
39、 distribution with PSL particles 2 noise (false particles, small particles and/or optical, electrical noise) Vllower voltage limit Vmmedian voltage Vuupper voltage limit Figure 2 Pulse height distribution of PSL particle signals with noise The voltages of channels corresponding to particle size shou
40、ld be determined in accordance with the calibration curve provided by the manufacturer (see Figure 3). Key X particle size Y median value of calibration particles 1 calibration curve Vm,1median voltage corresponding to particle size xm,1Vm,2median voltage corresponding to particle size xm,2Vm,3media
41、n voltage corresponding to particle size xm,3Figure 3 Calibration curve NOTE When the median voltage is determined by using an external PHA, the uncertainty in the voltage of PHA and the voltage uncertainty of the LELPC are included in setting the voltage limits of the LELPC (see Annex A). BS ISO 21
42、501-3:20076 4.2 Verification of size setting To test the verification of size setting of the LELPC, use the suspension of the certified reference material. Set the LELPC to count in the cumulative mode, collect counts, CC, at a setting greater than or equal to half particle size of the certified ref
43、erence, and a particle size of 50 % counts of CC. The size setting error is calculated as in Equation (1) below. s(%) 100xxx=% (1) where is the size setting error, in %; x is the particle size of the certified reference material of liquid-borne particle number concentration, in m; xsis the particle
44、size corresponding to 50 % counts of CC, in m. NOTE The certified reference material of liquid-borne particle number concentration is suspended mono-disperse particles, such as PSL particles in pure water, and the particle number concentration was certified with this uncertainty. 4.3 Counting effici
45、ency To test the counting efficiency of the LELPC, use the suspension of the certified reference material. Set the LELPC to count in the cumulative mode, collect counts at a setting greater than or equal to half particle size of the certified reference material. Calculate the counting efficiency by
46、means of Equation (2) below. LaR100CCC=% (2) where Cais the counting efficiency, in %; CLis the observed particle number concentration by the LELPC, in particles per cubic centimetre; CRis the particle number concentration of the certified reference material, in particles per cubic centimetre. 4.4 S
47、ize resolution A certified reference material should be used for this test. The standard deviation of the calibration particles should be a known quantity, P. Determine the median voltage (or channel), Vm, using calibration particles, as shown in Figure 4. The lower voltage limit, Vl, and upper volt
48、age limit, Vu, are defined as those corresponding to a density of 61 %. Using the calibration curve, determine the particle sizes corresponding to Vland Vu. Calculate the absolute value of the differences in particle size between PSL particle size and particle size corresponding to Vland Vu. The gre
49、ater of these is the observed standard deviation, . Calculate the percentage of size resolution, R, of the LELPC by Equation (3) below (see also Annex B). 22PP(%) 100Rx=% (3) BS ISO 21501-3:20077where R is the size resolution, in %; is the observed standard deviation of LELPC, in m; Pis the suppliers reported standard deviation of calibration particles, in m; xPis the particle size of the certified reference material, in m. Key X pulse height voltage (or channe
