EN ISO 25140:2010

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.HQWUDFLMHEmissionen aus stationären Quellen - Automatisches Verfahren zur Bestimmung der Methan-Konzentration mit dem Flammenionisationsdetektor (FID) (ISO 25140:2010)Émissions de sources fixes - Méthode automatique pour la détermination de la concentration en méthane par détection à ionisation de flamme (FID) (ISO 25140:2010)Stationary source emissions - Automatic method for the determination of the methane concentration using flame ionisation detection (FID) (ISO 25140:2010)13.040.40Stationary source emissionsICS:Ta slovenski standard je istoveten z:EN ISO 25140:2010SIST EN ISO 25140:2010en,fr,de01-november-2010SIST EN ISO 25140:2010SLOVENSKI
STANDARD
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN ISO 25140
August 2010 ICS 13.040.40 English Version
Stationary source emissions - Automatic method for the determination of the methane concentration using flame ionisation detection (FID) (ISO 25140:2010)
Émissions de sources fixes -Méthode automatique pour la détermination de la concentration en méthane par détection à ionisation de flamme (FID) (ISO 25140:2010)
Emissionen aus stationären Quellen - Automatisches Verfahren zur Bestimmung der Methan-Konzentration mit dem Flammenionisationsdetektor (FID) (ISO 25140:2010)This European Standard was approved by CEN on 26 May 2010.
CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
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Reference numberISO 25140:2010(E)© ISO 2010
INTERNATIONAL STANDARD ISO25140First edition2010-08-01Stationary source emissions — Automatic method for the determination of the methane concentration using flame ionisation detection (FID) Émissions de sources fixes — Méthode automatique pour la détermination de la concentration en méthane par détection à ionisation de flamme (FID)
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ii © ISO 2010 – All rights reserved
ISO 25140:2010(E) © ISO 2010 – All rights reserved iii Contents Page Foreword.iv Introduction.v 1 Scope.1 2 Normative references.1 3 Terms and definitions.1 4 Symbols and abbreviated terms.5 5 Apparatus and principles of operation.6 6 Performance criteria and determination of the performance characteristics.9 7 Measurement procedure.11 8 Quality assurance and quality control procedures.13 9 Test report.17 Annex A (normative)
Operational gases.19 Annex B (normative)
Determination of the performance characteristics of an FID to be applied in the ongoing quality control (QA/QC) procedures.21 Annex C (normative)
Safety measures.27 Annex D (informative)
Results of comparison tests.28 Bibliography.31
ISO 25140:2010(E) iv © ISO 2010 – All rights reserved 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 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. 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 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 member 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 25140 was prepared by Technical Committee ISO/TC 146, Air quality, Subcommittee SC 1, Stationary source emissions. SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved v Introduction Methane (CH4) is a gas of relevance to the climate (greenhouse gas) and contributes directly to the atmospheric greenhouse effect. The emissions of methane originate from natural and anthropogenic sources. Significant sources are, for example, cattle breeding, cultivation of rice, extraction and transport of natural gas, and landfills. Other important sources contributing to emissions of methane are, for example, composting plants, the use of biogas and natural gas, and biomass firings. This International Standard specifies a method of measurement for the determination of methane emissions from stationary sources.
INTERNATIONAL STANDARD ISO 25140:2010(E) © ISO 2010 – All rights reserved 1 Stationary source emissions — Automatic method for the determination of the methane concentration using flame ionisation detection (FID) 1 Scope This International Standard specifies the principle, the essential performance criteria, and quality assurance and quality control procedures for an automatic method for measuring methane in the waste gas of stationary sources using flame ionisation detection. It is applicable to measurements of methane in dry or wet waste gases. The method allows continuous monitoring with permanently installed measuring systems as well as intermittent measurements of methane emissions. NOTE 1 This International Standard is specific to automatic methods for measuring methane in the waste gas of stationary sources using flame ionisation detection. It supplements the general requirements of other international or national standards on performance testing, QA/QC procedures, and the test report as specified, for example, in EN 15267-3[7], EN 14181[5], and EN 15259[6]. This International Standard does not specify an independent method of measurement. NOTE 2 An independent method of measurement, e.g. to calibrate or validate permanently installed measuring systems, is specified in ISO 25139[3]. NOTE 3 In EN 14181[5], “independent method of measurement” is called “standard reference method (SRM)”. 2 Normative 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. ISO 9169:2006, Air quality — Definition and determination of performance characteristics of an automatic measuring system ISO 14956, Air quality — Evaluation of the suitability of a measurement procedure by comparison with a required measurement uncertainty ISO 20988, Air quality — Guidelines to estimating measurement uncertainty 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 automatic measuring system AMS 〈air quality〉 measuring system interacting with the waste gas under investigation, returning an output signal proportional to the physical unit of the measurand in unattended operation NOTE 1 Adapted from ISO 9169:2006, 2.1.2. SIST EN ISO 25140:2010

ISO 25140:2010(E) 2 © ISO 2010 – All rights reserved NOTE 2 In the sense of this document, an AMS is a system that can be attached to a duct to continuously or intermittently measure and record the mass concentrations of methane passing through the duct. 3.2 analyser 〈stationary source emissions〉 analytical part in an extractive or in situ automatic measuring system NOTE Adapted from ISO 12039:2001[2], 3.3. 3.3 measurand particular quantity subject to measurement [ISO/IEC Guide 98-3:2008[4], B.2.9] EXAMPLE The mass concentration of methane in air. 3.4 mass concentration 〈stationary source emissions〉 concentration of a substance in an emitted waste gas expressed as mass per volume [ISO 12039:2001[2], 3.10] NOTE Mass concentration is often expressed in milligrams per cubic metre. 3.5 independent reading 〈stationary source emissions〉 reading that is not influenced by a previous individual reading by separating two individual readings by at least four response times 3.6 individual reading 〈stationary source emissions〉 reading averaged over a time period equal to the response time of the automatic measuring system 3.7 interferent interfering substance 〈air quality〉 substance present in the air mass under investigation, other than the measurand, that affects the response [ISO 9169:2006, 2.1.12] 3.8 adjustment 〈automatic measuring system〉 operation of bringing an automatic measuring system into a state of performance suitable for its use NOTE Adjustment can be automatic, semi-automatic or manual. [ISO 9169:2006, 2.1.5] 3.9 calibration 〈stationary source emissions〉 procedure for establishing the statistical relationship between values of the measurand indicated by the automatic measuring system and the corresponding values given by an independent method of measurement implemented simultaneously at the same measuring point SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved 3 NOTE 1 An independent method of measurement for the purpose of calibration of permanently installed methane measuring systems is specified in ISO 25139[3]. NOTE 2 In EN 14181[5], “independent method of measurement” is called “standard reference method (SRM)”. 3.10 interference 〈air quality〉 negative or positive effect upon the response of the measuring system, due to a component of the sample that is not the measurand 3.11 zero gas 〈stationary source emissions〉 gas or gas mixture used to establish the zero point on a calibration curve within a given concentration range [ISO 12039:2001[2], 3.4.2] 3.12 span gas gas or gas mixture used to adjust and check a specific point on a calibration curve NOTE Adapted from ISO 12039:2001[2], 3.4.1. 3.13 reference gas 〈stationary source emissions〉 gas of known, reliable and stable composition that may be used to check the response of an automatic measuring system and to calibrate the automatic measuring system 3.14 zero point 〈stationary source emissions〉 specified value of the output quantity (measured signal) of the automatic measuring system and which, in the absence of the measured component, represents the zero crossing of the calibration line 3.15 span point value of the output quantity (measured signal) of the automatic measuring system for the purpose of calibration or adjustment that represents a correct measured value generated by a reference material NOTE This concentration is often chosen to be around 80 % of the upper limit of the measuring range or around the emission limit value. 3.16 performance characteristic 〈air quality〉 one of the quantities assigned to equipment in order to define its performance NOTE Performance characteristics can be described by values, tolerances or ranges. 3.17 response time 〈air quality〉 time interval between the instant when a stimulus is subjected to a specified abrupt change and the instant when the response reaches and remains within specified limits around its final stable value, determined as the sum of the lag time and the rise time in the rising mode, and the sum of the lag time and the fall time in the falling mode [ISO 9169:2006, 2.2.4] SIST EN ISO 25140:2010

ISO 25140:2010(E) 4 © ISO 2010 – All rights reserved 3.18 lag time 〈air quality〉 by convention, time taken for the output signal to reach 10 % of the final change in the output signal when a step function is applied by applying a reference material to the automatic measuring system initially in the basic state [ISO 9169:2006, 2.2.2] 3.19 rise time 〈air quality〉 by convention, time taken for the output signal to pass from 10 % to 90 % of the final change in the output signal when a reference material is abruptly applied to the automatic measuring system initially in the basic state NOTE For instruments where transient oscillations occur in the approach to the final output signal, 90 % of the final change is considered as reached when the oscillations fall to less than 10 % of the final change in the output signal. [ISO 9169:2006, 2.2.3] 3.20 fall time 〈air quality〉 by convention, time taken for the output signal to pass from 90 % to 10 % of the initial output signal produced by a reference material applied to the automatic measuring system, when the application of this reference material is abruptly terminated to put the automatic measuring system in the basic state NOTE For instruments where transient oscillations occur in the approach to the final output signal, the 10 % of the initial output signal is considered as reached when the oscillations in the vicinity of the final output signal fall to less than 10 % of the initial output signal. [ISO 9169:2006, 2.2.1] 3.21 linearity 〈air quality〉 maximum deviation between a linear calibration curve and the true value of the measurand, evaluated in practice as the maximum lack of fit within the measuring range [ISO 9169:2006, 2.1.20] 3.22 lack of fit systematic deviation, within the range of application, between the accepted value of a reference material applied to the measuring system and the corresponding result of measurement produced by the measuring system [ISO 9169:2006, 2.2.9] 3.23 residence time 〈stationary source emissions〉 time period for the sampled gas to be transported from the inlet of the probe to the inlet of the measurement cell 3.24 period of unattended operation maximum interval of time for which the performance characteristics remain within a predefined range without external servicing, e.g. refill, adjustment [ISO 9169:2006, 2.2.11] NOTE The period of unattended operation is often called maintenance interval. SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved 5 3.25 uncertainty (of measurement) measurement uncertainty parameter associated with the result of a measurement, that characterises the dispersion of the values that could reasonably be attributed to the measurand [ISO/IEC Guide 98-3:2008[4], 2.2.3] 3.26 standard uncertainty uncertainty of the result of a measurement expressed as a standard deviation [ISO/IEC Guide 98-3:2008[4], 2.3.1] 3.27 expanded uncertainty quantity defining an interval about the result of a measurement that may be expected to encompass a large fraction of the distribution of values that could reasonably be attributed to the measurand NOTE 1 The fraction may be viewed as the coverage probability or level of confidence of the interval. NOTE 2 To associate a specific level of confidence with the interval defined by the expanded uncertainty requires explicit or implicit assumptions regarding the probability distribution characterized by the measurement result and its combined standard uncertainty. The level of confidence that may be attributed to this interval can be known only to the extent to which such assumptions may be justified. NOTE 3 Expanded uncertainty is termed overall uncertainty in paragraph 5 of Recommendation INC-1 (1980). [ISO/IEC Guide 98-3:2008[4], 2.3.5 and 0.7 for a translation of Recommendation INC-1 (1980)] 4 Symbols and abbreviated terms AMS automatic measuring system ei residual (lack of fit) at level i FID flame ionisation detection; flame ionisation detector i series element number MCH4 molecular mass of methane (16 g/mol) MH2O molecular mass of water (18 g/mol) mH2O, v mass of water vapour n number of measurements nneg number of interfering substances with a negative effect on the measured signal npos number of interfering substances with a positive effect on the measured signal QA/QC quality assurance and quality control sr repeatability standard deviation Spos sum of the positive interfering effects Sneg sum of the negative interfering effects SIST EN ISO 25140:2010

ISO 25140:2010(E) 6 © ISO 2010 – All rights reserved V0 volume of the dry gas sampled Vm standard molar volume (22,4 l/mol) x average of the measured values xi xi ith measured value ix average of the measured values at level i ˆix value estimated by the regression line at level i xi, neg ith negative deviation in units of the measurand (e.g. mass concentration) caused by an interfering substance with a negative effect on the measured signal xi, pos ith positive deviation in units of the measurand (e.g. mass concentration) caused by an interfering substance with a positive effect on the measured signal γCH4, s methane mass concentration at standard conditions of temperature and pressure (wet gas) γCH4, (H2O)0 methane mass concentration at reference conditions of water vapour (dry gas) γCH4, O2 methane mass concentration at reference conditions of oxygen γi test gas concentration at level i ρH2O, v density of water vapour ϕCH4, o methane content, as a volume fraction, at operating conditions ϕH2O, m measured water vapour content, as a volume fraction, in the waste gas ϕO2, m measured oxygen content, as a volume fraction, in the waste gas ϕO2, ref reference oxygen content, as a volume fraction 5 Apparatus and principles of operation 5.1 Measurement method 5.1.1 Analyser. The extractive analytical system consists of two elements: the flame ionisation detector (FID) and the associated sampling system. Measurement by FID is based on the ionisation of organically bound carbon atoms in a hydrogen flame. The ionisation current measured by the FID depends on the number of carbon-hydrogen bonds in the organic compounds broken during combustion in the fuel gas flame, the nature of bonding (straight chain or branched chain) and whether other bound elements are present. The main advantage of the FID is that it responds strongly to organic compounds and less to inorganic waste gas components, such as CO, CO2, NO, and H2O. To determine methane alone, the FID is equipped with a catalytic converter, which oxidises all organic compounds in the sample gas except methane. Care shall be taken to avoid poisoning or contamination of the converter by sulfur-, nitrogen-, and chlorine-containing compounds. To avoid memory effects (signal offsets caused by contamination of the tube system within the instrument) and response delays in the system, the catalytic converter should be located close to the FID and heated. SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved 7 NOTE 1 The catalytic converter usually consists of a heatable stainless steel tube filled with catalytic material. NOTE 2 Various manufacturers produce specific “methane FID” instruments with an integrated converter. Figure 1 is a schematic diagram showing the principle of operation of the FID.
Key 1 pressure regulator 2 fine dust filter 3 sampling gas pump 4 converter 5 back-pressure regulator 6 pressure gauge 7 flow meters 8 nozzle 9 combustion chamber 10 flame 11 electrode 12 heated housing 13 DC voltage a Fuel gas. b Combustion air. c Sample gas. d Gas outlet. e Bypass. Figure 1 — Schematic diagram of the principle of operation of the FID
5.1.2 Sampling system. Sampling is the process of extracting a small portion which is truly representative of the composition of the main gas stream from a large quantity of waste gas. A partial flow of the waste gas is directly fed into the FID analyser containing the catalytic converter via the sampling probe, the particle filter and the heated sampling line. An example of the set-up of the measuring system is shown in Figure 2. The sampling device, including the filter needed to remove fine particles, which could clog the burner, is heated to avoid sample condensation.
ISO 25140:2010(E) 8 © ISO 2010 – All rights reserved
Key 1 sampling probe, heated (if necessary) 6 bypass (optional) 2 zero and span gas inlet 7 test gas inlet for functional tests 3 particle filter (in-stack or out-stack), heated 8 FID including catalytic converter 4 sampling line, heated 9 data evaluation system 5 external sample pump (optional), heated Figure 2 — Schematic diagram of the measuring system set-up
The sampling device shall: a) be made of a material that is chemically and physically inert to the constituents of the waste gas under analysis; NOTE Stainless steel, perfluoroalkoxy, polytetrafluoroethylene and polypropylenefluoride are well-proven construction materials. b) be designed to ensure a sample residence time less than 60 s (with long sampling lines or high flow resistance, the use of an external pump with bypass is recommended); c) be heated throughout, and where measurements are taken in hot gases, the temperature of the coolest point shall be at least 20 °C above the waste gas temperature to avoid condensation of water vapour or other components of the waste gas, and should not exceed 200 °C; d) have a heated filtering device upstream of the sampling line to trap all particles liable to impair the operation of the apparatus; e) have an inlet for applying zero and span gases at or close to the entry nozzle of the sampling probe, upstream of the filter. 5.1.3 Data display and recording. The FID analyser shall have an output signal with a live zero and be able to show negative values. Automatic measuring systems (AMSs) for intermittent monitoring should have a means of averaging the continuous output signal of the FID over a stated reference time period (e.g. 30 min). The averaged output signal should then be converted to measured values in units of the measurand (mass concentration) by use of the calibration function. Where required, a means of converting the measured values to reference conditions of water vapour and oxygen content shall be available. The AMS should be capable of displaying and recording the measured methane mass concentrations. For permanently installed AMS for continuous monitoring, the plant electronic data evaluation system can be used for the calculation of the measured values at operating conditions, the conversion to reference conditions and for displaying and recording of the measured methane concentrations. NOTE The data display can be a separate device. SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved 9 5.2 Performance criteria fulfilment 5.2.1 General. The FID shall comply with the performance criteria specified in Table 1. These performance criteria are determined as specified in 5.2.2 to 5.2.4. 5.2.2 General performance test. The manufacturer of the AMS shall demonstrate in a general performance test that the relevant performance criteria listed in Table 1 are fulfilled by the instrument type. The test procedures of this general performance test shall comply with relevant international or national standards. 5.2.3 Ongoing quality assurance and quality control (QA/QC) in the laboratory. The user of the AMS shall demonstrate during regular laboratory tests conducted within the ongoing QC programme that the relevant performance criteria listed in Table 1 are fulfilled for the specific AMS. 5.2.4 Quality assurance during operation in the field. The user of the AMS has to check during field operation that the relevant performance criteria listed in Table 1 are fulfilled. 6 Performance criteria and determination of the performance characteristics 6.1 Performance criteria Table 1 specifies the performance criteria of the analyser and the measuring system to be evaluated at three levels: during general performance test; by means of ongoing QA/QC in the laboratory; and during field operation. Table 1 — Relevant performance criteria of the analyser and the measuring system to be evaluated during the general performance test and by means of ongoing QA/QC in the laboratory and during field operation Performance characteristic Performance criterion General
performance testQA/QC
in the laboratory Field
application Response time u 60 s ± ± ±f Repeatability standard deviation at zero point u 1,0 % of upper limit of the lowest measuring range useda± ± — Repeatability standard deviation at span point u 2,0 % of upper limit of the lowest measuring range useda± ± — Lack of fit u 2,0 % of upper limit of the lowest measuring range useda± ± — Influence of atmospheric pressureb, for a pressure change of ± 2 kPa u 1,0 % of upper limit of the lowest measuring range useda± — — Influence of sample volume flow u 2,0 % of upper limit of the lowest measuring range useda± — — Influence of sample gas pressure at span point, for a pressure change of 3 kPa u 2,0 % of upper limit of the lowest measuring range useda± — — Influence of ambient temperature, for a change of 10 °C u 2,0 % of upper limit of the lowest measuring range useda± — — SIST EN ISO 25140:2010

ISO 25140:2010(E) 10 © ISO 2010 – All rights reserved Table 1 (continued) Performance characteristic Performance criterion General
performance testQA/QC
in the laboratory Field
application Influence of voltage, at
−15 % below and at +10 % above nominal supply voltage
u 2,0 % of upper limit of the lowest measuring range useda± — — Influence of inorganic interference gasesc u 4,0 % of upper limit of the lowest measuring range useda± ± — Oxygen interference u 2,0 % of upper limit of the lowest measuring range useda± ± — Converter efficiency, tested with ethane W 98,0 % ± ± — Methane lossd u 15,0 % ± — — Zero drifte, within 24 h u 2,0 % of upper limit of the lowest measuring range useda± — ± Span drifte, within 24 h u 2,0 % of upper limit of the lowest measuring range useda± — ± Period of unattended operation for permanently installed AMS W 8 days ± — ± Losses and leakage in the sampling line and conditioning system u 2,0 % of upper limit of the lowest measuring range useda— — ± a The upper limit of the lowest measuring range used should be selected depending on the application such that the measured values lie within 20 % to 80 % of the analyser range. b The tested sample pressure is defined in the manufacturer's recommendations. c See Table B.1. d The temperature dependent methane loss is compensated for in the calibration process. e The frequency of zero and span checks is specified in Table 2. f If sampling line length exceeds the length applied in the general performance test.
6.2 Determination of the performance characteristics and measurement uncertainty 6.2.1 Performance test The performance characteristics of the AMS shall be determined during the general performance test in accordance with applicable international or national standards. The values of the performance characteristics determined shall meet the performance criteria specified in Table 1. NOTE Performance tests for automatic emission measuring systems are specified e.g. in ISO 9169 and EN 15267-3[7]. The ambient conditions applied during the general performance test shall be documented. The overall uncertainty of the AMS measured values shall be calculated in accordance with ISO 14956 on the basis of the performance characteristics determined during the general performance test and shall meet the uncertainty specified for the measurement objective. 6.2.2 Ongoing quality control The user shall check specific performance characteristics during ongoing operation of the measuring system with a periodicity specified in Table 2. The procedures for the determination of these performance characteristics are described in Annex B. Procedures for instruments for intermittent measurements differ from those for permanently installed AMS for continuous monitoring at plants. SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved 11 The measurement uncertainty during field application shall be determined by the user of the measuring system in accordance with applicable international or national standards. The uncertainty of the measured values under field operation is not only influenced by the performance characteristics of the analyser itself but also by uncertainty contributions due to: a) the sampling line and conditioning system; b) the site specific conditions; c) the calibration gases used. 7 Measurement procedure 7.1 General The AMS shall be operated according to the manufacturer’s instructions. The QA/QC procedures specified in Clause 8 shall be strictly observed. During the measurement, the ambient conditions should be in the ranges applied during the general performance test. 7.2 Choice of the measuring system It shall be checked that the chosen analyser is appropriate for the measurement task. To choose an appropriate analyser, sampling line and conditioning system, the following characteristics should be known before the field operation: a) ambient temperature range; b) temperature of the waste gas; c) water vapour content of the waste gas; d) dust load of the waste gas; e) expected concentration range of methane; f) expected concentration of potentially interfering substances, including at least those listed in Table B.1. To avoid long response times and memory effects, the sampling line should be as short as possible. If necessary, a bypass pump should be used. An appropriate heated filter shall be used. Before conducting field measurements, the user shall verify that the necessary QA/QC procedures have been performed. 7.3 Sampling location It is necessary to ensure that the gas concentrations measured are representative of the average conditions inside the waste gas duct. The measurement site, the measurement section and the sampling points shall be selected in accordance with applicable international or national standards. NOTE The selection of the measurement site, the measurement section and the sampling points are described, for example, in EN 15259[6]. In addition, the sampling location shall be chosen with regard to safety of personnel. SIST EN ISO 25140:2010

ISO 25140:2010(E) 12 © ISO 2010 – All rights reserved 7.4 Data collection The calibrated FID measured values at operating conditions of the waste gas shall be recorded by an internal or external data logging system and averaged in accordance with the measurement task. The volume content of water vapour and oxygen (if necessary) in the waste gas shall also be measured in parallel and averaged over the sampling period of the methane measurement to express the methane concentration for dry waste gas conditions and, if required, oxygen reference conditions. 7.5 Calculation Results of measurement shall be expressed as mass concentrations at reference conditions of water vapour (dry gas) and oxygen content, if required. If the methane concentration is provided as a volume fraction, Equation (1) shall be used to calculate the mass concentration at standard conditions of temperature and pressure (273 K, 1 013 hPa), γCH4, s: 444CHCH,sCH,omMVγϕ=⋅ (1) where ϕCH4, o is the methane volume fraction at operating conditions; MCH4 is the molecular mass of methane (16 g/mol); Vm is the standard molar volume (22,4 l/mol). If necessary, the measured methane mass concentration, γCH4,s, shall be corrected to the methane mass concentration at reference conditions of water vapour (dry gas), γCH4,(H2O)0, using Equation (2): 42042CH,(HO)CH,sHO, m100%100%γγϕ⎛⎞⎜⎟=⎜⎟−⎝⎠ (2) where γCH4,s is the methane mass concentration in the wet gas at reference conditions of temperature and pressure; ϕH2O, m is the measured water vapour content, as a volume fraction expressed as a percentage, in the waste gas (waste gas humidity). If the water vapour content is determined as a mass concentration, Equation (3) shall be used to calculate the water vapour content, as a volume fraction, ϕH2O, in the waste gas: HOHO222HOHO22,v,vHO,v,v0/(/)mmVρϕρ=+ (3) where mH2O, v is the mass of water vapour; ρH2O, v is the density of water vapour (0,8 g/l or 0,8 kg/m3), given by
HO22HO,vmMVρ=
in which MH2O is the molecular mass of water (18 g/mol); V0 is the volume of the dry gas sampled. SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved 13 If necessary, the measured methane mass concentration at standard conditions of temperature and pressure, γCH4, s, shall be corrected to reference conditions of oxygen, designated γCH4, O2, using Equation (4): 24242O,refCH,OCH,sO,m21%21%ϕγγϕ⎛⎞−⎜⎟=⎜⎟−⎝⎠ (4) where ϕO2, m is the measured oxygen content, as a volume fraction expressed as a percentage, in the waste gas; ϕO2, ref is the reference oxygen content, as a volume fraction expressed as a percentage. 8 Quality assurance and quality control procedures 8.1 General QA/QC is important in order to ensure that the uncertainty of the measured values for methane is kept within the limits specified for the measurement task. The following applications of the automatic measuring system have to be distinguished: a) AMS for intermittent measurements (8.3); b) permanently installed AMS for continuous monitoring (8.4). 8.2 Frequency of checks Table 2 shows the minimum required frequency of checks. The user shall implement the relevant standards for determination of performance characteristics or procedures described in Annex B. Table 2 — Minimum frequency of checks for QA/QC during the operation Minimum frequency Check AMS for intermittent measurements Permanently installed AMS Response time once a year once a year Repeatability standard deviation at zero point once a year once a year Repeatability standard deviation at span point once a year once a year Lack of fit once a year and after repair of the AMS once a year and after repair of the AMS
Calibration —
at regular time intervals specified, for example, in legislation or applicable standards by comparison with an independent method of measurement Interference check once a year once a year Converter check once for each measurement series once a year Sampling system and leakage check once for each measurement series once a year
ISO 25140:2010(E) 14 © ISO 2010 – All rights reserved Table 2 (continued) Minimum frequency Check AMS for intermittent measurements Permanently installed AMS Cleaning or changing of particulate filtersa at the sampling inlet and at the monitor inlet
once for each measurement series, if needed
once in the period of unattended operation Zero drift every 3 h and at the end of measuring period
once in the period of unattended operation Span drift every 3 h and at the end of measuring period
once in the period of unattended operation Regular maintenance of the analyser as required by the manufacturer
once in the period of unattended operation a The particulate filter shall be changed periodically depending on the dust load at the sampling site. During this filter change,the filter housing shall be cleaned.
The user shall implement a procedure to ensure that the zero gases and span gases used meet the uncertainty requirement specified in Annex A, e.g. by comparison with a reference gas of higher quality. 8.3 AMS for intermittent measurements 8.3.1 General AMS for intermittent measurements shall be adjusted and checked in accordance with 8.3.2 at frequencies specified in Table 2. The results of the QA/QC procedures shall be documented. 8.3.2 Adjustments and functional tests 8.3.2.1 Instrument adjustment Instrument adjustments with zero and span gases shall be carried out at least at the beginning of each measurement series. The safety procedures detailed in Annex C shall be followed. The zero and span gas shall be introduced under the same flow and pressure conditions using the sample port of the instrument or according to the manufacturer's instructions when using individual zero and span ports. The adjustment procedure shall be carried out as follows: a) feed zero gas into the FID and set the zero; b) feed span gas and adjust the instrument accordingly; c) feed zero gas into the FID once more and check that the reading returns to zero. Steps a) to c) have to be repeated, if the reading does not return to zero. 8.3.2.2 Response time The response time of the AMS response shall be checked in accordance with B.2 at least once a year. It shall be checked in the field application if the sampling line length exceeds the length applied in the general performance test. SIST EN ISO 25140:2010

ISO 25140:2010(E) © ISO 2010 – All rights reserved 15 8.3.2.3 Repeatability standard deviation at zero point The repeatability standard deviation at zero point shall be checked in accordance with B.3 at least once a year. 8.3.2.4 Repeatability standard deviation at span point The repeatability standard deviation at span point shall be checked in accordance with B.4 at least once a year. 8.3.2.5 Linearity check The linearity of the AMS response shall be checked in accordance with B.5 at least once a year. 8.3.2.6 Interference check The interference shall be checked in accordance with B.6 at least once a year. 8.3.2.7 Check of the converter efficiency The converter efficiency shall be checked in accordance with B.7 at least once for each measurement series. 8.3.2.8 Sampling system and leakage check The sampling system of the AMS shall be checked in accordance with B.8 at least once for each measurement series. 8.3.2.9 Cleaning or changing of particulate filters The particulate filter shall be checked at least once for each measurement series and changed if needed. During the filter change the filter housing shall be cleaned. 8.3.2.10 Zero and span drift The zero and span drift shall be checked in accordance with B.9 at least every 3 h and at the end of the measuring period. 8.3.2.11 Regular maintenance of the analyser The regular maintenance of the analyser shall be performed as required by the manufacturer. 8.3.2.12 Measurement uncertainty The uncertainty of measured values obtained by AMS for intermittent monitoring shall be determined in accordance with the principles laid down in ISO 20988. The measurement uncertainty shall be representative of the intended application of the AMS. It shall take into account all relevant sources of uncertainty. NOTE The uncertainty of measured values obtained by AMS for intermittent monitoring can be determined by a direct or by an indirect approach described in ISO 20988. The direct approach can be based on comparison measurements with an independent method of measurement under conditions of the intended operation of the AMS. ISO 20988 describes procedures to evaluate such comparison measurements. A detailed description of the indirect approach is given in ISO 14956. The uncertainty of the measured values shall meet the uncertainty criterion specified for the measurement objective. SIST EN ISO 25140:2010

ISO 25140:2010(E) 16 © ISO 2010 – All rights reserved 8.4 Permanently installed AMS 8.4.1 General Permanently installed AMS for continuous monitoring shall meet the performance criteria specified in Table 1. General QA/QC procedures for permanently installed AMS specified in national or international standards shall be observed. NOTE General QA/QC procedures for permanently installed AMS are specified, for example, in EN 14181[5]. The results of the QA/QC procedures shall be documente
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