BS ISO 16107-2008 Workplace atmospheres - Protocol for evaluating the performance of diffusive samplers《工作场所空气 扩散取样器性能评定协议》.pdf

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1、BRITISH STANDARDBS ISO 16107:2007Workplace atmospheres Protocol for evaluating the performance of diffusive samplersICS 13.040.30g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51

2、g60g53g44g42g43g55g3g47g36g58BS ISO 16107:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 February 2008 BSI 2008ISBN 978 0 580 57055 1National forewordThis British Standard is the UK implementation of ISO 16107:2007. It supersedes BS I

3、SO 16107:1999 which is withdrawn.The UK participation in its preparation was entrusted by Technical Committee EH/2, Air quality, to Subcommittee EH/2/2, Workplace atmospheres.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not p

4、urport 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.Amendments/corrigenda issued since publicationDate CommentsReference numberISO 16107:2007(E)INTERNATIONAL S

5、TANDARD ISO16107Second edition2007-10-15Workplace atmospheres Protocol for evaluating the performance of diffusive samplers Air des lieux de travail Protocole pour lvaluation de la performance des dispositifs de prlvement par diffusion BS ISO 16107:2007ii iiiContents Page Foreword iv Introduction v

6、1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 2 4 Symbols and abbreviated terms . 2 5 Summary of test protocol 3 5.1 Factors affecting performance 3 5.2 “Accuracy” as providing a single performance value linking to measurement uncertainty 4 5.3 Bias, intersampler variability and th

7、e effects of environmental uncertainty 4 5.4 Reverse diffusion 5 5.5 Capacity Control of effects from interfering compounds 6 5.6 Capacity overload detection 6 5.7 Desorption efficiency . 7 5.8 Atmospheric pressure 7 5.9 Wind direction . 7 5.10 Simplifications 7 6 Apparatus 7 6.1 Exposure chamber sp

8、ecifications 7 6.2 Controlled environmental conditions. 8 6.3 Inter-run variability . 8 7 Reagents and materials . 9 8 Procedure 9 9 Sampler performance classification. 9 10 Accuracy 10 10.1 General. 10 10.2 Accuracy range confidence limit 10 10.3 Expanded uncertainty 11 11 Test report . 11 Annex A

9、(informative) Worked example Program for diffusive sampler accuracy range calculation . 13 Annex B (informative) Calculation of variances 15 Bibliography . 16 BS ISO 16107:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

10、(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 right to be represented on that committee. International organizations, g

11、overnmental 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. International Standards are drafted in accordance with the rules given in the ISO/I

12、EC 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 as an International Standard requires approval by at least 75 % of the mem

13、ber 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. ISO 16107 was prepared by Technical Committee ISO/TC 146, Air quality, Sub

14、committee SC 2, Workplace atmospheres. This second edition cancels and replaces the first edition (ISO 16107:1999), which has been technically revised. BS ISO 16107:2007vIntroduction Gas or vapor sampling is often accomplished by actively pumping air through a collection medium such as activated cha

15、rcoal. Problems associated with a pump, such as inconvenience, inaccuracy and expense, are inextricable from this type of sampling. The alternative covered by this International Standard is to use diffusion for moving the compound of interest onto the collection medium. This approach to sampling is

16、attractive because of the convenience of use and low total monitoring cost. However, previous studies have found significant problems with the accuracy of some samplers. Therefore, although diffusive samplers may provide a plethora of data, inaccuracies and misuse of diffusive samplers may yet affec

17、t research studies. Furthermore, worker protection may be based on faulty assumptions. The aim of this International Standard is to counter the uncertainties in diffusive sampling through achieving a broadly accepted set of performance tests and acceptance criteria for proving the efficacy of any gi

18、ven diffusive sampler intended for use. This International Standard is intended specifically for the large-scale evaluation of many diffusive sampler/analyte pairs of practical application and is complementary to EN 838. An affordable, experimental evaluation determines a single performance value in

19、dicating how a sampler performs in a typical situation. A sampler can thereby be quickly judged as to acceptability. Additionally, sufficient data are obtained to predict performance in many atypical situations. For example, although sampling may normally be done at room temperature, a particular ne

20、ed may call for use in extreme cold. In such a case, the single performance value would be superseded by the particular needs. BS ISO 16107:2007blank1Workplace atmospheres Protocol for evaluating the performance of diffusive samplers 1 Scope This International Standard specifies methods for evaluati

21、on of sampler performance in terms of workplace conditions: wind speed, humidity, temperature, atmospheric pressure, and analyte variation. The concise set of experiments specified aims to minimize cost to the user. The evaluation is limited to conditions commonly encountered in personal sampling in

22、 the indoor workplace setting, namely wind speeds of up to 0,5 m/s and for sampling periods typically from 2 h to 8 h. Static or area sampling, unlike personal sampling where movement of the subject is significant, may sometimes be subject to sampling-rate reduction due to stagnation at very low win

23、d speeds. This International Standard therefore does not apply to wind speeds of less than 0,1 m/s relative to static samplers. Samplers are also tested for compliance with the manufacturers stated limits on capacity, possibly in the presence of interfering compounds. Given a suitable exposure chamb

24、er, the sampler evaluation protocol can be extended to cover sampler use for other sampling periods and conditions. This International Standard indicates how to measure diffusive sampler uncertainty for characterizing concentration estimates obtained subsequent to the evaluation. It is impractical c

25、ontinually to re-evaluate diffusive sampler performance under various environmental conditions prevailing during application. NOTE 1 In this International Standard, the confidence level for the initial method evaluation becomes an integral part of the measurement uncertainty. This approach slightly

26、broadens the statistical protocols given in ISO Guide 98:1995. Furthermore, the possibility of sampler errors related to correctible sampler bias is addressed. NOTE 2 This International Standard is an extension of previous research on diffusive samplers (References 1 to 17 inclusive and EN 838). 2 N

27、ormative 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. EN 838, Workplace atmospheres

28、 Diffusive samplers for the determination of gases and vapours Requirements and test methods ISO Guide 98:1995, Guide to the expression of uncertainty in measurement. BIPM, IEC, IFCC, ISO, IUPAC, IUPAP, OIML BS ISO 16107:20072 3 Terms and definitions For the purposes of this document, the terms and

29、definitions given in EN 838 and ISO Guide 98:1995 and the following apply. 3.1 symmetric accuracy range A fractional range about the measurand concentration, c, within which 95 % of sampler measurements are found NOTE See References 18 to 21 inclusive. If the modulus of the bias is small, i.e. 0) re

30、present one-half the bias between estimates from a 0,5 h pulse at the end versus the beginning of the sampling period, relative to the mean of the estimates. Assume, conservatively (see, for example, Reference 6), that the bias in the estimates of 0,5 h pulse occurring at random within (for example,

31、 an 8 h sampling period ranges uniformly between tand +t. Then the variance, tR2, associated with sampling a 0,5 h pulse at random within the sampling period is given by Equation (3): ttR =2213(3) 5.5 Capacity Control of effects from interfering compounds 5.5.1 This International Standard provides a

32、 test for confirming a manufacturers claimed sampler capacity under stated conditions of use. Such conditions would normally refer to a specific sampling period and to environmental extremes, such as 80 % relative humidity at a temperature of 30 C. Additionally, a manufacturer may claim a value of c

33、apacity for sampling in the presence of specific interferences at stated concentrations. 5.5.2 For the purposes of this International Standard, capacity is defined as the sampled mass (or equivalently as the concentration for a specific sampling period) at which concentration estimates are 10 % low.

34、 Specifically, capacity is considered not exceeded if concentration estimates, corrected for correctable bias, are above 90 % of the true concentration at the 95 % confidence level. 5.5.3 An example of the test is as follows: eight diffusive and eight active samplers are exposed to the analyte of in

35、terest under the stated environmental conditions. Then, neglecting variability in the reference sampler mean, the 95 % confidence limit 95 %on the difference in the (unknown) mean concentration estimates is given by Equation (4): cst n =95% 0,95 ( )/ (4) where c is the estimated mean difference betw

36、een diffusive and active results; s is the estimated standard deviation characterizing intersampler variation, calculated from the eight diffusive sampler estimates; n is the number of samplers of each type (in this case, 8); is the number of degrees of freedom (n 1 = 7). Then 95 %shall be greater t

37、han 10 % c, where c is the mean concentration estimate from the reference samplers. EXAMPLE Suppose the diffusive sampler component of the true relative standard deviation, Rs= 5 %: 0,95(/) ()/ 3.3sc t n= (5) Therefore, in this case the mean value of the diffusive results shall be greater than 93,3

38、% of the reference concentration. NOTE As capacity strongly correlates with sampled mass, a capacity limit expressed as sampled mass at one stated sampling period is generally applicable to a range of sampling periods. 5.6 Capacity overload detection The capability to detect capacity overload (e.g.

39、by the use of a second sorbent or by employing paired samplers with different sampling rates) may be advantageous in some sampling situations. In the case of active samplers, such detection is easily effected through the use of back-up sections. Therefore, diffusive samplers with similar features wi

40、ll receive a specific classification. The point is that practicality precludes BS ISO 16107:20077testing of the samplers under all conditions of use, such as in an arbitrary multianalyte environment. The capability of voiding a sample when interferences become demonstrably problematic may therefore

41、be useful. At present, the efficacy of such breakthrough detection is not evaluated. However, evaluation tests may be developed in the future for this purpose. 5.7 Desorption efficiency 5.7.1 A further control of the effects from interfering compounds is afforded by restricting the permissible desor

42、ption efficiency. As in Reference 3, the desorption efficiency, in the case of solvent extraction, shall be 75 % at the concentration of intended application of the sampler. This requirement is expected to control the potential variation of the desorption efficiency induced by other interfering comp

43、ounds. The use of internal standards to compensate for the effect of desorbent evaporation is also generally recommended. 5.7.2 In the case of thermal desorption, the efficiency shall be 95 %. 5.8 Atmospheric pressure 5.8.1 Most diffusive sampler manufacturers provide a formula for correcting for th

44、e difference between atmospheric pressure at points of sampler application and calibration. Unlike the case with temperature, where sorbent properties may be temperature dependent, the formula is simple: for diffusion through air, the sampling rate is inversely proportional to the pressure, whereas

45、through a semi-permeable membrane, the rate is independent of pressure. The difference is because of the differing expansion coefficients of the media comprised of the scattering molecules. 5.8.2 If the correction formula for a given sampler type is suspected of error, then a simple experiment using

46、 eight samplers at a pressure shifted from the experiments of 5.1 will determine the effect. The test report see Clause 11 h) should give the correctable bias which would be expected under a 15 % shift in the atmospheric pressure. 5.9 Wind direction For use in personal sampling, the wind direction i

47、s expected to generally have an insignificant effect on concentration estimates, since the air flow near the body will usually be across the face of the sampler. Therefore, experiments are done with wind direction parallel to the sampler face. 5.10 Simplifications Knowledge of similarity between ana

48、lytes of interest can be used to expedite sampler evaluation. For example, interpolation of data characterizing the sampling of analytes at separated points of a homologous series of compounds is recommended. At present the procedure in Reference 9 is suggested: Following evaluation of a sampler in

49、use at a single homologous series member according to this International Standard, higher relative molecular mass members would receive partial validations considering sampling rate, capacity, analytical recovery and interferences. Similarly, testing for diffusive analyte loss can be omitted if the effect is found negligible for a given sampler or analyte series. 6 Apparatus 6.1 Exposure chamber specifications 6.1.1 Chamber capacity The chamber shall be capable of exposing at least eight samplers at a time together with re