1、BRITISH STANDARD BS ISO 12141:2002 Stationary source emissions Determination of mass concentration of particulate matter (dust) at low concentrations Manual gravimetric method ICS 13.040.40 BS ISO 12141:2002 This British Standard, having been prepared under the direction of the Health and Environmen
2、t Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 26 November 2002 BSI 26 November 2002 ISBN 0 580 40809 4 National foreword This British Standard reproduces verbatim ISO 12141:2002 and implements it as the UK national standar
3、d. The UK participation in its preparation was entrusted by Technical Committee EH/2, Air Quality, to Subcommittee EH/2/1, Stationary source emissions, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-referen
4、ces 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 Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Onl
5、ine. 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 not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsi
6、ble international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover,
7、 the ISO title page, pages ii to v, a blank page, pages 1 to 40, an inside back cover and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsINTERNATIONAL STANDARD ISO 12141 First edit
8、ion 2002-11-01 Reference number ISO 12141:2002(E) Stationary source emissions Determination of mass concentration of particulate matter (dust) at low concentrations Manual gravimetric method missions de sources fixes Dtermination dune faible concentration en masse de matires particulaires (poussires
9、) Mthode gravimtrique manuelleBSISO12141:2002 ii BSISO12141:2002 iii Contents Page 1 Scope . 1 2 Normative references . 1 3 Terms and definitions 1 4 Principle 4 5 Sampling plane and sampling points 5 6 Apparatus and materials (see summary annex E) . 7 7 Calculation of nozzle diameter to obtain weig
10、hable quantities of dust . 13 8 Weighing procedure . 14 9 Sampling procedure . 16 10 Thermal behaviour of dusts 18 11 Validation of results 20 12 Calculations 21 13 Performance characteristics of the method 22 14 Test report 23 Annexes A Requirements related to the working platform 25 B Determinatio
11、n of flow direction with Pitot tubes 26 C Determination of positions of sampling points in circular and retangular ducts 27 D Examples of suitable access ports for sampling equipment . 31 E Proven entry nozzle designs . 33 F Summary of apparatus requirements 35 G Sampling volume, flowrate and durati
12、on. 36 H Examples of weighing bias . 37 I Precision data. 39 Bibliography. 40 BSISO12141:2002 iv 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 car
13、ried 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, governmental and non-governmental, in liaison with ISO, also take part in the work.
14、 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/IEC Directives, Part 3. Draft International Standards adopted by the technical comm
15、ittees 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 International Standard may be the subject of patent rights.
16、ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 12141 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 1, Stationary source emissions. Annexes A, C, E and F form a normative part of this International Standard. A
17、nnexes B, D, G, H and I of this International Standard are for information only. BSISO12141:2002 v Introduction This method was developed from close liaison and cooperation between ISO/TC146/SC1/WG11 and CEN/TC264/WG5, resulting in the preparation of this International Standard and the European Stan
18、dard EN 13284-1. This International Standard is similar to EN 13284-1 with additional emphasis given on the use of high- volume sampling techniques for the measurement of dust at low concentrations. It also gives procedures for extending the range of measurement of ISO9096:1992 to lower concentratio
19、ns. As in ISO9096:1992, a representative, integrated sample is extracted from the flue gas and particulate matter entrained in the gas sample is separated by a filter. The pre-weighed filter is subsequently dried and weighed. Any increase in the mass is attributed to the collection of particulate ma
20、tter on the filter. To meet the specifications of this International Standard, the particulate sample must be weighed to a specified level of accuracy. At low dust concentrations, this level of accuracy may be achieved by: a) exercising extreme care in weighing, as per procedures of this standard, b
21、) extending the sampling time at conventional sampling rates, or c) sampling at higher rates for conventional sampling times (high-volume sampling). This International Standard in addition differs from ISO 9096:1992 by requiring the measurement of the mass of filter blanks, specifying weighing proce
22、dures. This method may be used for calibration of automated monitoring systems (AMSs) (see ISO 10155). If the waste gas contains unstable, reactive or semivolatile substances, the measurement will depend on the filtration temperature, and in-stack methods may be more applicable than out-stack method
23、s for the calibration of automated monitoring systems. BSISO12141:2002 1 Stationary source emissions Determination of mass concentration of particulate matter (dust) at low concentrations Manual gravimetric method 1 Scope This International Standard describes a reference method for the measurement o
24、f low dust content in ducted gaseous streams at concentrations below under standard conditions. This method has been validated with special emphasis on the region around . This International Standard has been developed and validated for gaseous streams emitted by waste incinerators. More generally,
25、it may be applied to emissions from other stationary sources, and to higher concentrations. If the gases contain unstable, reactive or semi-volatile substances, the measurement will depend on the sampling and filter treatment conditions. 2 Normative references The following normative documents conta
26、in provisions which, through reference in this text, constitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to in
27、vestigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 3966:1977, Me
28、asurement of fluid flow in closed conduits Velocity area method using Pitot static tubes ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results ISO 9096:1992, Stationary source emissions Determination of concentration and mass flow rate of particulate material in
29、gas-carrying ducts Manual gravimetric method ISO 10780:1994, Stationary source emissions Measurement of velocity and volume flowrate of gas streams in ducts 3 Terms and definitions For the purposes of this International Standard, the following terms and definitions apply. 3.1 particulate matter dust
30、 particles, of any shape, structure or density, dispersed in the gas phase under the sampling conditions NOTE In the method described, all the compounds that may be collected by filtration under specified conditions after sampling of the gas to be analysed, and which remain upstream of the filter an
31、d on the filter after drying under specified conditions, are considered to be dust (or particulate matter). However, for the purposes of some national standards, the definition of particulate matter may extend to condensibles or reaction products collected under specified conditions (e.g. temperatur
32、es lower than the flue gas temperature). 50 mg/m 3 5 mg/m 3 BSISO12141:2002 2 3.2 filtration temperature temperature of the sampled gas immediately downstream of the filter 3.3 in-stack filtration filtration in the duct with the filter in its filter holder placed immediately downstream of the sampli
33、ng nozzle 3.4 out-stack filtration filtration outside the duct with the filter in its heated filter holder placed downstream of the sampling nozzle and the suction tube (sampling probe) 3.5 isokinetic sampling sampling at a flowrate such that the velocity and direction of the gas entering the sampli
34、ng nozzle ( ) are the same as that of the gas in the duct at the sampling points, See Figure 1. NOTE The velocity ratio expressed as a percentage characterizes the deviation from isokinetic sampling. Figure 1 Isokinetic sampling in duct v n v s v n /v s BSISO12141:2002 3 3.6 hydraulic diameter chara
35、cteristic dimension of a duct cross-section (1) 3.7 sampling plane plane normal to the centreline of the duct at the sampling position See Figure 2. 3.8 sampling line line in the sampling plane along which sampling points are located, bounded by the inner duct wall See Figure 2. Key 1 Sampling lines
36、 2 Sampling plane 3 Access port 4F l o w 5 Top of duct Figure 2 Illustration of definitions in relation to a circular duct d h d h = 4 area of sampling plane length of perimeter of sampling plane BSISO12141:2002 4 3.9 sampling point the specific position on a sampling line at which a sample is extra
37、cted 3.10 standard conditions gas pressure and temperature constants and conditions to which volumetric calculations are referred NOTE For the purposes of this International Standard, standard conditions are rounded to ; rounded to ; dry gas. 3.11 overall blank test sample taken at the plant site in
38、 an identical manner to the normal samples in the series, except that no gas is sampled during the test duration NOTE The measured mass variation provides an estimation of the uncertainties. The overall blank value, divided by the average sampling volume of the measurement series, provides an estima
39、tion of the detection limit (milligrams per cubic metre) of the whole measurement process, as carried out by the operator. The overall blank includes possible deposits on the filter and on all parts upstream. 3.12 weighing control procedure for the detection/correction of apparent variations in mass
40、 due to possible changes between pre- and post-sampling weighing conditions, by using parts, identical to those to be weighed for dust measurements, pretreated and weighed under the same conditions of temperature and humidity (e.g. desiccator) as pre- and post- sampling NOTE The control parts are ke
41、pt free from contamination. 3.13 measurement series successive measurements carried out in the same sampling plane, and under the same process conditions 3.14 limit value average limit value dust concentration that is permitted by authorities for the plant process NOTE For purposes other than regula
42、tory uses, the measurement value is compared to a stated reference value. 3.15 high-volume sampling sampling at rates higher than typical in ISO 9096 by using larger-diameter nozzles and higher flowrates to maintain isokinetic sampling conditions NOTE Nozzle diameters are typically to , with corresp
43、onding flowrates of to . 4P r i n c i p l e A sample stream of the gas is extracted from the main gas stream at representative sampling points for a measured period of time, with an isokinetically controlled flowrate and a measured volume. The dust entrained in the gas sample is separated by a pre-w
44、eighed plane filter, which is then dried and re-weighed. Deposits upstream of the filter in the sampling equipment are also recovered and weighed. The increase in mass of the filter and the deposited mass upstream of the filter are attributed to dust collected from the sampled gas, which allows the
45、dust concentration to be calculated. Two different configurations of the sampling equipment may be used (see 6.2.1) depending on the characteristics of the gases to be sampled. 101,325 kPa 101,3 kPa 273,15 K 273 K 20 mm 50 mm 5 m 3 /h 50 m 3 /h BSISO12141:2002 5 Valid measurements can be achieved on
46、ly when: a) the gas stream in the duct at the sampling location has a sufficiently steady velocity (see 5.2); b) sampling is carried out without disturbance of the gas stream, under isokinetic conditions, using a sharp-edged nozzle facing into the stream; c) samples are taken at a preselected number
47、 of stated positions in the sampling plane, to allow for a non-uniform distribution of dust in the duct or stack; d) the sampling train is designed and operated to avoid condensation and chemical reactions, to minimize dust deposits upstream of the filter, and to be leak-free; e) dust deposits upstr
48、eam of the filter are taken into account; f) the overall blank value does not exceed of the daily limit set for the process; NOTE High-volume sampling techniques or an extension of the sampling time may be employed to satisfy this requirement. g) the sampling and weighing procedures are adapted to t
49、he expected dust quantities. A measurement series is validated only when the quantity of dust collected during the sampling is at least 5 times a corresponding positive difference in an overall blank. High-volume sampling techniques or an extension of the sampling time may be employed to satisfy this requirement. Any emission value determined in the test series that is less than the blank value is not valid. However, when measured concentrations are below , it ma
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