1、BRITISH STANDARD BS6069-5.1: 1994 ISO 8756:1994 Characterization of air quality Part 5: General Section 5.1 Handling of temperature, pressure and humidity dataBS6069-5.1:1994 This British Standard, having been prepared under the direction of the Environment and Pollution Standards Policy Committee,
2、was published under the authority of the Standards Board and comes intoeffect on 15 August1994 BSI06-1999 The following BSI references relate to the work on this standard: Committee referenceEPC/35 Draft for comment92/56573 DC ISBN 0 580 23416 9 Committees responsible for this British Standard The p
3、reparation of this British Standard was entrusted by the Environment and Pollution Standards Policy Committee (EPC/-) to Technical Committee EPC/35, upon which the following bodies were represented: Association of Consulting Scientists British Cement Association British Coal Corporation Combustion E
4、ngineering Association Department of Health Department of the Environment (Her Majestys Inspectorate of Pollution) Department of Trade and Industry (Laboratory of the Government Chemist) Department of Trade and Industry (Warren Spring Laboratory) Engineering Equipment and Materials Users Association
5、 European Resin Manufacturers Association GAMBICA (BEAMA Ltd.) Health and Safety Executive Institute of Petroleum Institution of Environmental Health Officers National Society for Clean Air Royal Society of Chemistry The following bodies were also represented in the drafting of the standard, through
6、 subcommittees and panels: BCIRA British Steel plc Institute of Occupational Medicine Amendments issued since publication Amd. No. Date CommentsBS 6069-5.1:1994 BSI 06-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope 1 2 Procedures for adjustment of air qua
7、lity measurements for changes in atmospheric pressure, temperature and humidity during the sampling period 1 3 Reference conditions of temperature, pressure and humidity 2 4 Reporting results of air quality measurements 2 Annex A (informative) Bibliography Inside back coverBS6069-5.1:1994 ii BSI 06-
8、1999 National foreword This Section of BS6069 has been prepared under the direction of the Environment and Pollution Standards Policy Committee. It is identical with ISO8756:1994 Air quality Handling of temperature, pressure and humidity data, published by the International Organization for Standard
9、ization (ISO). ISO8756 was prepared by Technical Committee ISO/TC146 “Air quality”, Subcommittee4 “General aspects”, with the active participation and approval of the UK. BS6069 is being published in a series of Parts and Sections that will generally correspond to particular International Standards
10、arising from the UK participation in the work of ISO/TC146. This Section of BS6069 is one of several relating to Characterization of air quality General, published as a Section of Part5. Topics relating to other aspects of air quality characterization will be published as further Parts or Sections o
11、f BS6069. Methods for the determination of particular constituents of ambient air are being published as Parts of BS1747 Methods for the measurement of air pollution. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible
12、 for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 and 2, an inside back cover and a back cover. This standard has been updat
13、ed (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.ISO 8756:1994(E) BSI 06-1999 1 1 Scope This International Standard describes procedures for adjusting air quality measurements for changes in temperature, pressur
14、e and humidity during the sampling period. It also specifies the reference conditions of temperature, pressure and humidity to be used when reporting the results. The procedures and reference conditions are applicable to air quality measurement methods and apply to measurements made in ambient and w
15、orkplace atmospheres and to the measurement of stationary source emissions. 2 Procedures for adjustment of air quality measurements for changes in atmospheric pressure, temperature and humidity during the sampling period 2.1 Ambient and Workplace Atmospheres 2.1.1 General Atmospheric temperature, pr
16、essure and humidity may all change during the sampling period, which may be of a duration of several minutes or several weeks, depending on the location at which the air quality measurements are made (workplace or ambient) and the purpose for which they are required. Pressure and absolute humidity c
17、hange slowly, but temperature and relative humidity changes may be much more sudden. For example, a daily change in pressure may be of the order of approximately4000Pa taking place fairly smoothly at a rate of200Pa/h. Temperature changes may be approximately20C in the course of several hours, althou
18、gh in heated indoor workplaces the temperature is likely to remain fairly constant. Conversely, in some workplaces in industrial plants (e.g.near blast furnaces), changes may be very sudden and large. The effect of change in humidity will be different for different methods of air quality measurement
19、 and is not merely a correction for the volume of air sampled. For the effect of humidity, it is essential to refer to the specific air quality measurement method. 2.1.2 Sampling period of up to15min duration Atmospheric temperature, pressure and humidity are unlikely to change significantly in any1
20、5min period and corrections for changes are therefore unnecessary. In this case, the atmospheric temperature and pressure (where relevant, the absolute or relative humidity) should be noted at the time of sampling. 2.1.3 Sampling period of up to1h duration Atmospheric pressure is unlikely to change
21、greatly during a1h sampling period, but the temperature may change significantly during normal weather conditions. In this case, atmospheric pressure should be noted once during the sampling period, the temperature measured at the start and finish of sampling and the mean value recorded. Where relev
22、ant, the absolute or relative humidity should be noted once during the sampling period, preferably at the middle of the period. 2.1.4 Sampling period of up to12h duration Atmospheric temperature and pressure (and, where relevant, absolute or relative humidity) should be measured at the start of the
23、sampling period and then at intervals of1h. The mean values should be used in calculating air quality results. Sometimes, particularly when measuring ambient air quality, it may not be possible to measure temperature, pressure and humidity at hourly intervals. In such cases, the measurements should
24、be made as often as possible throughout the sampling period. The time-weighted average values should then be calculated for use in the air quality measurement. (See note1.) If it is impossible to make any temperature, pressure or humidity measurements during the sampling period, measurements should
25、be made at the commencement and conclusion of the sampling period and the mean values used in the subsequent air quality measurement calculation. However, this procedure is very much less accurate than that using time-weighted average values. The decision on the frequency of measurement of temperatu
26、re, pressure and humidity values during the sampling period should be made in the light of changes known to have occurred in similar situations and the magnitude of the error that can be tolerated for the purpose the measurements are being made. The relevance of the humidity measurement should be as
27、certained from the specific air quality measurement method. NOTE 1Time-weighted averages will not give the time-average value for the sampling period, but the difference between the true average and the time-weighted average will be small and, in nearly all cases, the error will be smaller than the
28、total error in the actual measurement of the air quality parameter.ISO 8756:1994(E) 2 BSI 06-1999 2.1.5 Sampling periods of greater than12h duration Where relevant, temperature, pressure and absolute or relative humidity should be measured at the beginning of the sampling period, and if possible, re
29、corded continuously, but if not, then at sufficiently frequent intervals(6h is the suggested duration) during sampling, to obtain a reasonably accurate mean value for the sampling period. The relevance of humidity measurements should be ascertained from the specific air quality measurement method. T
30、he frequency of the temperature and pressure measurements will depend on their variation expected from previous experience in similar situations and the degree of error acceptable in the final result. (See note1.) For very long sampling periods (e.g.one week or more) and when recording devices are u
31、navailable, maximum and minimum thermometers may be used to record the daily extreme values. 2.2 Stationary source emissions 2.2.1 General Changes in atmospheric pressure, temperature and humidity will have little effect on the results of emission measurements, bearing in mind the difficulties and u
32、ncertainties of sampling gas emissions from industrial plants. Volumes of sample gas should be corrected for temperature and pressure, and wet gas volumes corrected to a dry basis whenever the gas in the volume (or flow) measuring devices is not dry. 2.2.2 All sampling periods Sampling gaseous emiss
33、ions involves following very stringent procedures specified in particular measurement methods and the procedures should be followed exactly in respect of frequency and method of measurement of temperature, pressure and humidity of the emissions. 3 Reference conditions of temperature, pressure and hu
34、midity As measurements of air quality parameters are made at different temperatures, pressures and humidities, it is essential that results should be expressed with respect to standard reference conditions, so that reliable comparisons can be made of air qualities measured at different places and ti
35、mes and under different climatic conditions. For methods of measurement of air quality, the standard reference conditions recommended are as follows: reference pressure:101,3kPa; reference temperature:273K. Because of the difficulties of adjusting results for varying humidity values, as humidity doe
36、s not merely affect the sample volume and its effects are different for different measurement methods, a reference humidity value should only be used where applicable, for example in measurements of emissions from stationary sources. In these cases, the standard reference value should be 1) referenc
37、e humidity: zero (i.e.dry gas). 4 Reporting results of air quality measurements It is recognized that the reference values for temperature and pressure given in clause3 will not be typical of normal conditions found in many parts of the world, but the values are chosen simply to enable air quality m
38、easurements to be compared reliably, without variations being obscured by temperature and pressure differences. Therefore, in reporting air quality measurements all results should be a) given for the temperature and pressure (and where relevant, humidity) at which the measurements were made (see not
39、e2); b) corrected to the reference temperature and pressure (and where relevant, humidity) values, using the equation where (see notes2 and3); c) with reference to the specified reference conditions, for example20C or25 C and101,3kPa for workplace and ambient atmospheres, for compliance with nationa
40、l standards and regulations. NOTE 2The temperature and pressure at which the measurement was made may be single values, mean values, time-weighted averages, etc. as described in clause2. NOTE 3The humidity correction is not included. The calculation given in the specific method for the measurement o
41、f air quality should be used. 1) Thermodynamic properties of steam are tabulated, for example, in bibliographic references1,2 in Annex A. R 0 is the result, expressed in units of mass or number per unit volume of air at the reference temperature and pressure; R 1 is the result, expressed in units of
42、 mass or number per unit volume of air measured at temperature T 1 , in kelvins, and pressure p 1 , in kilopascals. R 0 R 1 1013 , p 1 - T 1 273 - =ISO8756:1994(E) BSI 06-1999 Annex A (informative) Bibliography 1 KEENAN, J.H., KEYES, F.G., HILL, P.G. and MOORE, J.G. Steam Tables; Thermodynamic Prope
43、rties of Water Including Vapour, Liquid and Solid Phases (International System of Units S.I.); New York, Chichester, Brisbane, Toronto: John Wiley 0 800C,0 1000bar;3rd, enl. print./ed. by Ulrich Grigull; Berlin, Heidelberg, New York: Springer; Mnchen: Oldenbourg,1982.BS6069-5.1: 1994 ISO8756:1994 BS
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