1、BRITISH STANDARD BS ISO 8573-6:2003 Compressed air Part 6: Test methods for gaseous contaminant content ICS 71.100.20 BS ISO 8573-6:2003 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 16 June 2003 BSI 16 June 2003 ISBN 0 580 42056 6 National
2、 foreword This British Standard reproduces verbatim ISO 8573-6:2003 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee MCE/8, Compressors, pneumatic tools, pneumatic machines and vacuum technology, which has the responsibility
3、to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards
4、Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This 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 does
5、 not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European develo
6、pments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii to v, a blank page, pages 1 to 12, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document wa
7、s last issued. Amendments issued since publication Amd. No. Date Comments Reference number ISO 8573-6:2003(E)NINRETOITALAN ADNATSDR ISO 83756- tide tsriFino 0-300210-5 Compressed air Part 6: Test methods for gaseous contaminant content Air comprim Partie 6: Mthodes dessai pour la dtermination de la
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9、58 O6:(3002)E ii BSISO85736:2003IS-3758 O6:(3002)E iiiContents Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms, definitions, units and symbols . 1 4 Selection guide and available methods 2 5 Sampling techniques 3 6 Measurement methods. 5 7 Reference conditions 5 8 Evalua
10、tion of test result . 5 9 Uncertainty. 5 10 Test report 6 Annex A (informative) Compressed air contaminant concentration report Example. 7 Annex B (informative) Measurement and sampling procedures on site and analysis in laboratory. 8 Annex C (informative) Analytical and on-line sampling systems 9 A
11、nnex D (informative) Equipment for on-site measurement Sampling and measurement procedures Sampling in gas detector tube . 11 Bibliography . 12 BSISO85736:2003IS-3758 O6:(3002)E iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodie
12、s (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,
13、 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. International Standards are drafted in accordance with the rules given in the ISO
14、/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 as an International Standard requires approval by at least 75 % of the m
15、ember 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 8573-6 was prepared by Technical Committee ISO/TC 118, Compressors,
16、pneumatic tools and pneumatic machines, Subcommittee SC 4, Quality of compressed air. ISO 8573 consists of the following parts, under the general title Compressed air: Part 1: Contaminants and purity classes Part 2: Test methods for aerosol oil content Part 3: Test methods for measurement of humidit
17、y Part 4: Test methods for solid particle content Part 5: Test methods for oil vapour and organic solvent content Part 6: Test methods for gaseous contaminant content Part 7: Test method for viable microbiological contaminant content Part 8: Test methods for solid particle content by mass concentrat
18、ion Part 9: Test methods for liquid water content BSISO85736:2003IS-3758 O6:(3002)E vIntroduction This part of ISO 8573 is one in a series of standards (planned or published) with the ambition of harmonizing air contamination measurements. It is also intended to be used for reference when stating pu
19、rity classes according to ISO 8573-1. In this part of ISO 8573, gaseous contamination of compressed air means that a sample of compressed air could contain small quantities of carbon monoxide (CO), carbon dioxide (CO 2 ), sulphur dioxide (SO 2 ), hydrocarbons and oxides of nitrogen (NO x ) the latte
20、r being a mixture of nitric oxide (NO) and nitrogen dioxide (NO 2 ), without a specified ratio between the two components. It is possible to obtain separate concentration values for NO and NO 2using either the laboratory equipment recommended here or on-site equipment, while under the recommended la
21、boratory analytical procedure, hydrocarbons are the sum of a variety of species assuming a ratio of C 1 H 1,85 . BSISO85736:2003blankINTENRATIONAL TSANDADR IS-3758 O6:(3002)E1Compressed air Part 6: Test methods for gaseous contaminant content 1 Scope This part of ISO 8573 provides a selection of sui
22、table test methods from those available for the measurement of contamination gases in compressed air. It specifies sampling technique, measurement and evaluation, uncertainty considerations and reporting for the applicable gaseous contaminants carbon monoxide, carbon dioxide, sulphur dioxide, nitric
23、 oxide, nitrogen dioxide and hydrocarbons in the range C 1to C 5(see ISO 8573-5 for C 6and above). The methods given are also suitable for other gases. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edi
24、tion cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 1219-1, Fluid power systems and components Graphic symbols and circuit diagrams Part 1: Graphic symbols ISO 2602, Statistical interpretation of test results Estimation of
25、 the mean Confidence interval ISO 2854, Statistical interpretation of data Techniques of estimation and tests relating to means and variances ISO 8573-1, Compressed air Part 1: Contaminants and purity classes 3 Terms, definitions, units and symbols For the purposes of this document, the terms and de
26、finitions given in ISO 8573-1, and the symbols given in ISO 1219-1 apply. See Table 1 for an explanation of the units and other symbols used. BSISO85736:2003IS-3758 O6:(3002)E 2 Table 1 Preferred units and symbols (and their non-preferred equivalents) used in this part of ISO 8573 Unit/symbol Explan
27、ation MPa bar 1 bar = 100 000 Pa = 0,1 MPa ml/m 3(= ppm V )aVolume fraction expressed in millilitres per cubic metre = one part per million (1 ppm) on a volume basis: 1/10 6(m 3 /m 3 )ml/m 3 (= ppm V ) C 1Volume fraction expressed in millilitres per cubic metre = one part per million (1 ppm) on a vo
28、lume basis: 1/10 6(m 3 /m 3 ), referred to a theoretical C 1 -molecule g/g (= ppm W ) Mass fraction expressed in micrograms per gram = parts per million on a weight basis b 1 % by volume Volume fraction of 1 %: 1/10 2(m 3 /m 3 ) MPa(e) bar(e) Effective pressure MPa(a) bar(a) Reference condition abso
29、lute pressure aParts per million (ppm) is a deprecated unit, i.e. not accepted by the International System of Units, SI. See, for example, ISO 31-0:1992, 2.3.3. bIn common parlance, the word “weight“ continues to be used to mean mass, but this practice is deprecated. See ISO 31-3. 4 Selection guide
30、and available methods There are two options for the measurement of contaminant content: a) sampling and analysis on-site; b) sampling on-site, analysis in the laboratory. The recommended methods and equipment within these options are given in Table 2. Table 2 Recommended measurement methods/equipmen
31、t Gaseous contaminant Measurement equipment Carbon monoxide (CO) Non-dispersive infrared (NDIR) absorption spectrometer Carbon dioxide (CO 2 ) Non-dispersive infrared (NDIR) absorption spectrometer Non-dispersive infrared (NDIR) absorption spectrometer Sulphur dioxide (SO 2 ) UV-fluorescence Hydro-c
32、arbons (HC) (C 1to C 5 ) Heated flame ionisation detector (HFID) Off-site Nitrogen oxides (NO x ) Chemiluminescent detector (CLD) with an NO 2 /NO converter, and in a heated version (HCLD) On-site All identified gases Gas detector tubes with colour change BSISO85736:2003IS-3758 O6:(3002)E 35 Samplin
33、g techniques 5.1 Gas sampling in bags The gas sample shall be taken at atmospheric conditions and collected in a special gas sampling bag made for the purpose. A sample of the compressed air shall be collected in a gas sampling bag for the evaluation of the contaminant concentration values. All meas
34、urements on the sample shall be carried out under atmospheric pressure conditions. Use of a commercially available gas sampling bag (e.g. one made of fluoroethylene propylene) to collect a sample of air for analysis should be made by the following method. The gas sampling bag should be of the type s
35、uitable for gas collection. Turbulent flow conditions are required in the main system pipe to ensure a mixing of the gaseous contaminants to give a representative sample of the air. Connect the gas sampling bag to the sampling point using a probe (see Figure 1), through a pressure reducing valve, by
36、 a polytetrafluoroethylene (PTFE) tube and a PTFE, or stainless steel, connector, depending upon the expected gas impurities. The piping should be protected from the possible formation condensation. The bag should have a vent valve to allow for flushing. Flushing should take place for 5 min with sys
37、tem air before taking the sample. Care should be taken to ensure that the bag is not over-inflated and of a size consistent with the sample required. The bag should only be re-used if permitted by the manufacturer. Together with the filled gas-sampling bag an empty unused gas-sampling bag shall be b
38、rought to the laboratory for a blind test. 5.2 On-line sampling The gas sample shall be taken at system pressure using a stainless steel probe (see Figures 1 and 2). The end of the probe outside the compressed air pipe shall have a valve, which shall be suitable for all pressure conditions of the co
39、mpressed air pipe. The probe shall be free from contaminants affecting the readings. See Annex C for the procedure. 5.3 Sampling in gas detector tube See Annex D for the procedure. BSISO85736:2003IS-3758 O6:(3002)E 4 Key 1 sampling probe in the main pipe 2 adjustable gland to allow adjustment of pro
40、be 3 direction of air flow amain pipe diameter, D bminimum straight length before probe, 10 D cprobe insertion point at minimum of 3 D dinternal probe diameter, d Figure 1 Equipment set-up of probe insertion for sampling Key 1 direction of flow 2 crevice-free joint 3 suitable pressure-tight thread c
41、onnection 4 to membrane holder Probe size A mm B mm C mm 1 7 9,6 200 2 10 12,6 200 3 17 19,6 400 Figure 2 Stainless steel sampling probe BSISO85736:2003IS-3758 O6:(3002)E 56 Measurement methods The recommended procedure for the evaluation of the contaminant concentration values in a laboratory is gi
42、ven in Annex C. The analytical equipment proposed for use by Annex C is based on the detector principles identified in Table 2. Consideration shall be given to the measurement system integrity and the calibration requirements of the measurement equipment, which shall be used in accordance with the a
43、pplicable instructions and to the degree of gaseous contamination measured. For the measurement of the concentration values, on-site gas detector tubes may be employed. This offers a direct reading from a scale via a chemical reaction with a colour change proportional to the actual contaminant conce
44、ntration in the actual compressed air sample taken. See Annex D. 7 Reference conditions Unless otherwise agreed, the reference conditions for gaseous contaminant concentration shall be in accordance with Table 3: Table 3 Reference conditions Air temperature 20 C Air pressure 0,1 MPa(a) 1 bar(a) Rela
45、tive water vapour pressure 0 8 Evaluation of test result The results of the measurements are given as concentration values of the contaminants as volume fractions or percentages by volume. See Table 1. 9 Uncertainty NOTE A calculation of the probable error according to this clause is not always nece
46、ssary. Due to the very nature of physical measurements it is impossible to measure a physical quantity without error or, in fact, to determine the true error of any particular measurement. However, if the conditions of the measurement are sufficiently well known, it is possible to estimate or calcul
47、ate a characteristic deviation of the measured value from the true value, such that it can be asserted with a certain degree of confidence that the true error is less than the said deviation. The value of such deviation (normally 95 % confidence limit) constitutes a criterion of the accuracy of the
48、particular measurement. It is assumed that all systematic errors that may occur in the measurement of the individual quantities measured and of the characteristics of the gas can be compensated for by corrections. A further assumption is that the confidence limits in errors in reading and integratio
49、n errors may be negligible if the number of readings is sufficient: the (small) systematic errors that could occur are covered by the inaccuracy of measurements. The information about asserting the uncertainty of measurement of individual quantities measured and on confidence limits of the gas properties are approximations. These approximations can only be improved by efforts of disproportionate expense
