BS EN 1911:2010 BSI Standards Publication Stationary source emissions — Determination of mass concentration of gaseous chlorides expressed as HCl — Standard reference method BS EN 1911:2010 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 1911:2010 It supersedes BS EN 1911-1:1998 and BS EN 1911-2:1998 and BS EN 1911-3:1998 which are withdrawn The UK participation in its preparation was entrusted to Technical Committee EH/2/1, Stationary source emission A list of organizations represented on this committee can be obtained on request to its secretary This publication does not purport to include all the necessary provisions of a contract Users are responsible for its correct application © BSI 2010 ISBN 978 580 64333 ICS 13.040.40 Compliance with a British Standard cannot confer immunity from legal obligations This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 August 2010 Amendments issued since publication Date Text affected BS EN 1911:2010 EN 1911 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM August 2010 ICS 13.040.40 Supersedes EN 1911-1:1998, EN 1911-2:1998, EN 19113:1998 English Version Stationary source emissions - Determination of mass concentration of gaseous chlorides expressed as HCl - Standard reference method Emissions de sources fixes - Détermination de la concentration massique en chlorures gazeux, exprimée en HCl - Méthode de référence normalisée Emissionen aus stationären Quellen - Bestimmung der Massenkonzentration von gasförmigen Chloriden, angegeben als HCl - Standardreferenzverfahren This European Standard was approved by CEN on 26 June 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 EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels © 2010 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 1911:2010: E BS EN 1911:2010 EN 1911:2010 (E) Contents Page Foreword 4 Introduction 5 1 Scope 6 2 Normative references 6 3 3.1 3.2 Terms, definitions and abbreviations 6 Terms and definitions 6 Abbreviations 9 4 Principle 11 5 5.1 5.1.1 5.1.2 5.1.3 5.1.4 5.2 5.3 5.3.1 5.3.2 5.3.3 Sampling 11 Sampling strategy 11 General 11 Non isokinetic sampling 12 Isokinetic sampling 13 Losses of gaseous chlorides and side reactions during sampling 14 Sampling equipment 14 Sampling procedure 18 Preparation and installation of equipment 18 Sampling procedure 19 Validation of results 20 6 6.1 6.2 6.2.1 6.2.2 6.3 6.3.1 6.3.2 6.3.3 6.3.4 6.3.5 6.4 6.4.1 6.4.2 6.4.3 6.4.4 6.4.5 6.4.6 6.5 Analysis 21 Introduction 21 Reagents and samples to be analysed 22 Reagents for analysis 22 Samples to be analysed 22 Silver titration: potentiometric method 22 Apparatus 22 Reagents and solutions 23 Procedure 23 Interferences 23 Calculations 24 Mercuric-thiocyanate spectrophotometry 24 Warning 24 Apparatus 24 Reagents 24 Procedure 25 Interferences 25 Calculations 26 Ion-exchange chromatography 26 7 Expression of results 27 8 8.1 8.2 8.2.1 8.2.2 8.2.3 8.3 Determination of the characteristics of the method: sampling and analysis 28 General 28 Relevant performance characteristics of the method and performance criteria 28 General 28 Sampling procedure 28 Analyse procedure 29 Establishment of the uncertainty budget 30 9 Measurement report 31 BS EN 1911:2010 EN 1911:2010 (E) Annex A (informative) Examples of absorbers 32 Annex B (informative) Comparison between mercuric-thiocyanate spectrophotometry and ion exchange chromatography method (methods B and C) 34 Annex C (informative) Example of assessment of compliance of the reference method for chlorides 35 C.1 General 35 C.2 Process of uncertainty estimation 35 C.3 Specific conditions in the field 36 C.4 Performance characteristics of the method .37 C.5 Calculation of standard uncertainty of concentration measured 38 C.6 Calculation of the overall (or expanded) uncertainty 41 C.7 Uncertainty associated to the mass concentration of gaseous chlorides at O2 reference concentration 41 Annex D (informative) Performance characteristics of the whole measurement method 43 D.1 Analytical detection limit of the method 43 D.2 Repeatability and reproducibility of the method in the field 43 Annex E (informative) Significant technical changes 45 Bibliography 46 BS EN 1911:2010 EN 1911:2010 (E) Foreword This document (EN 1911:2010) has been prepared by Technical Committee CEN/TC 264 “Air quality”, the secretariat of which is held by DIN This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2011, and conflicting national standards shall be withdrawn at the latest by February 2011 Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights This document supersedes EN 1911-1:1998, EN 1911-2:1998 and EN 1911-3:1998 Annex E provides details of significant technical changes between this European Standard and the previous edition According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: 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 the United Kingdom BS EN 1911:2010 EN 1911:2010 (E) Introduction This European Standard describes the Standard Reference Method (SRM) with three alternative analytical techniques for determining gaseous chlorides content emitting to atmosphere from ducts and stacks The specific components and the requirements for the measuring system are described A number of performance characteristics with associated minimum performance criteria are specified for the measuring system (see Tables and in 8.2) This European Standard can be used as an SRM provided the overall uncertainty of the method is less than 30,0 % relative at the daily Emission Limit Value (ELV) for incineration and large combustion plants or at the ELV prescribed by the specific regulations for other plants An Alternative Method to this SRM may be used provided that the user can demonstrate equivalence according to CEN/TS 14793 BS EN 1911:2010 EN 1911:2010 (E) Scope The method described in this European Standard determines the concentration of chlorinated compounds in a flue gas that – after passage of the sampling system including a particle filter – give Cl ions in the absorption solution This Standard Reference Method has been evaluated during field tests on waste incineration The method applies to waste gases in which chlorides concentration expressed as HCl may vary between -3 -3 mg⋅m and 000 mg⋅m under normal pressure and temperature conditions (see Note 1), and according to emission limit values laid down, for example, in the Council Directive 2000/76/EC on waste incineration plants NOTE The limit values of this European Standard are expressed in mg HCl/m , on dry basis, at the reference conditions of 273 K and 101,3 kPa and at the reference O2 concentration NOTE The required uncertainty results from the capacity of the method tested in the field (Annex D) and in the laboratory (see performance characteristics in Tables and and Annex C) 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 EN 13284-1:2001, Stationary source emissions — Determination of low range mass concentration of dust — Part 1: Manual gravimetric method ENV 13005, Guide to the expression of uncertainly in measurement EN 15259:2007, Air quality — Measurement of stationary source emissions — Requirements for measurement sections and sites and for the measurement objective, plan and report EN ISO 3696:1995, Water for analytical laboratory use — Specification and test methods (ISO 3696:1987) EN ISO 10304-1, Water quality — Determination of dissolved anions by liquid chromatography of ions — Part 1: Determination of bromide, chloride, fluoride, nitrate, nitrite, phosphate and sulfate (ISO 10304-1:2007) EN ISO 14956, Air quality — Evaluation of the suitability of a measurement procedure by comparison with a required measurement uncertainty (ISO 14956:2002) 3.1 Terms, definitions and abbreviations Terms and definitions For the purposes of this document, the following terms and definitions apply 3.1.1 absorber device in which gaseous chloride is absorbed into an absorption solution 3.1.2 chemical blank chloride ion content of an unexposed sample of the absorption solution, plus reagents that are added to the solution before analysis if necessary BS EN 1911:2010 EN 1911:2010 (E) 3.1.3 analytical detection limit DL concentration value of the measurand below which there is at least 95 % level of confidence that the measured value corresponds to a sample free of that measurand 3.1.4 field blank value determined by a specific procedure used to ensure that no significant contamination has occurred during all steps of the measurement and to check that the operator can achieve a quantification level adapted to the task 3.1.5 isokinetic sampling sampling at a rate such that the velocity and direction of the gas entering the sampling nozzle is the same as that of the gas in the duct at the sampling point [EN 13284-1:2001] 3.1.6 measurand particular quantity subject to measurement [ISO/IEC Guide 99:2007, 2.6] 3.1.7 measurement series several successive measurements carried out on the same sampling plane and at the same process operating conditions [EN 13284-1:2001] 3.1.8 performance characteristic one of the quantities (described by values, tolerances, range, etc.) assigned to equipment in order to define its performance 3.1.9 analytical repeatability closeness of the agreement between the results of successive measurements of the same measurand carried out under the same conditions of measurement NOTE Analytical repeatability conditions include: the same measurement procedure; the same laboratory; the same sampling equipment, used under the same conditions and at the same location; repetition over a short period of time NOTE results Analytical repeatability may be expressed quantitatively in terms of the dispersion characteristics of the [ISO/IEC Guide 99:2007, 3.6] NOTE of 95 % In this European Standard the analytical repeatability is expressed as a value with a level of confidence BS EN 1911:2010 EN 1911:2010 (E) 3.1.10 repeatability in the field closeness of the agreement between the results of simultaneous measurements of the same measurand carried out with two sets of equipment under the same conditions of measurement NOTE These conditions include: the same measurement procedure; two sets of equipment, the performances of which are fulfilling the requirements of the reference method, used under the same conditions; the same location; implemented by the same laboratory; typically calculated over short periods of time in order to avoid the effect of changes of influence parameters (e.g 30 min) NOTE Repeatability may be expressed quantitatively in terms of the dispersion characteristics of the results NOTE In this European Standard the repeatability under field conditions is expressed as a value with a level of confidence of 95 % 3.1.11 reproducibility in the field closeness of the agreement between the results of simultaneous measurements of the same measurand carried out with several sets of equipment under the same conditions of measurement NOTE These conditions are called field reproducibility conditions and include: the same measurement procedure; several sets of equipment, the performance of which fulfils the requirements of the reference method, used under the same conditions; the same location; implemented by several laboratories NOTE Reproducibility may be expressed quantitatively in terms of the dispersion characteristics of the results NOTE In this European Standard the reproducibility under field conditions is expressed as a value with a level of confidence of 95 % 3.1.12 sampling location specific area close to the sampling plane where the measurement devices are set up 3.1.13 sampling plane plane normal to the centreline of the duct at the sampling position [EN 13284-1:2001] 3.1.14 sampling point specific position on a sampling plane at which a sample is extracted BS EN 1911:2010 EN 1911:2010 (E) Annex B (informative) Comparison between mercuric-thiocyanate spectrophotometry and ion exchange chromatography method (methods B and C) -3 After sampling of gases emitted by a municipal refuse incinerator (range of HCI concentration mg⋅m -3 to 15 mg⋅m ), 26 absorption solution samples were analysed by two different laboratories, the first one by method B, the second by method C, without comparing reference chloride solutions used by both laboratories -1 -1 In the tested range of chlorides concentrations in the absorption solutions (0,2 mg⋅l to 25 mg⋅l ), Student and Wilcoxon tests were applied concluding that both methods may be considered as giving equivalent results 34 BS EN 1911:2010 EN 1911:2010 (E) Annex C (informative) Example of assessment of compliance of the reference method for chlorides C.1 General This informative annex gives an example of calculation of the overall uncertainty C.2 Process of uncertainty estimation C.2.1 General The procedure for calculating measurement uncertainty as follows is based on the law on propagation of uncertainty laid down in EN ISO 14956 or ENV 13005 The calculation procedure presents different steps: C.2.2 Determination of the model equation Define the measurand and all the parameters that influence the result of the measurement These parameters, called "input quantities" shall be clearly defined Identify all sources of uncertainty contributing to any of the input quantities or to the measurand directly Then the model equation, that is to say the relationship between the measurand and the influence quantities, shall be established, if possible in mathematical equation form C.2.3 Quantification of uncertainty components Each uncertainty source is estimated to obtain its contribution to the overall uncertainty Use available performance characteristics of the measurement system, data from the dispersion of repeated measurements, data provided in calibration certificates Convert all uncertainty components (e.g performance characteristics) to standard uncertainties of input and influence quantities C.2.4 Calculation of the combined uncertainty Then the combined uncertainty u c is calculated by combining standard uncertainties, by applying the "law of propagation of uncertainty" In general, the uncertainty associated to a concentration is expressed in overall uncertainty form The overall uncertainty U c corresponds to the expanded combined uncertainty, obtained by multiplying by a coverage factor k: U c = k × u c The value of the coverage factor k is chosen on the basis of the level of confidence required In most cases, k is taken equal to 2, for a level of confidence of approximately 95 % The following tables give one example of: 35 BS EN 1911:2010 EN 1911:2010 (E) the specific conditions of the site (Table C.1); the performance characteristics of the method (Table C.2) related to the parameters which can have an influence on the results C.3 Specific conditions in the field Table C.1 — Example of measurement conditions Specific conditions Value/range 3a Studied concentration of gaseous chlorides (limit value of 10 mg/m at standard conditions of temperature HCl for the site, at O2,ref) and pressure, and at 11 % O2 concentration - corresponding to: mchlorides=1,02 mg Cl trapped in absorption solution O2 reference concentration for the site: O2,ref 11 % volume O2 measured concentration: O2,mes 12,3 % volume ± % relative (k = 2) Volume of gas sampled 0,132 m Mean temperature (in Kelvins (K)) at the gas meter b 296,2 K Mean absolute pressure at the gas meter c 100 281 Pa Analyse Ion chromatography a m3: cubic meter at standard conditions of temperature (273 K) and pressure (101,325 kPa) b Mean temperature is calculated from data recording of continuous temperature measurement (1 measurement / 30 s = 60 measurements in 30 min) The standard deviation of the mean σmean,T of measurements calculated is equal to 0,854 K c Mean absolute pressure is calculated from five measurements of relative pressure at the gas meter and one measurement of atmospheric pressure during the sampling period (100,212 kPa) Table C.2 — Example of measured values of relative pressure Full scale of the pressure device: 0-200 Pa Measurement Mean Standard deviation of the mean σmean,Prel of measured values Pa Relative pressure at the gas meter (Pa) 70,0 68,7 Mean absolute pressure: P = 100,281 kPa 36 69,0 68,6 69,8 69,2 0,287 BS EN 1911:2010 EN 1911:2010 (E) C.4 Performance characteristics of the method Table C.3 — Example of performance characteristics Performance characteristics for the reference method Performance criteria Laboratory or field tests results Gas volume sampled Vstd : Expanded uncertainty of calibration ≤ 2,0 % of the measured value 1,4 % of the measured value Overall uncertainty of calibration Standard deviation measurement of repeatability Drift between two adjustments Reading of Temperature at the gas volume meter Overall uncertainty of calibration Drift between two adjustments Resolution Absolute pressure at gas volume meter Relative pressure at the gas volume meter; scale of the manometer: 0-200Pa 0,3 % of the measured value 1,0 % of the measured value 0,000 m Expanded uncertainty of calibration ≤ 2,5 K 1,0 K 1,0 K 0,1 K Expanded uncertainty of calibration ≤ 1,0 % of the meas value Overall uncertainty of calibration Resolution Lack of fit Drift between two adjustments ± 300 Pa Atmospheric pressure 20 Pa Maximum permissible error Reading ± 0,6 Pa 0,01 Pa 1,4 % FS (full scale) 1,0 % FS Absorption efficiency of the first absorber > 95,0 % 98 % Gaseous chlorides quantity in the absorption solution mchlorides(Cl) ≤ 2,5 % of the measured value 2,1 % of the measured value Standard deviation of analytical repeatability 37 BS EN 1911:2010 EN 1911:2010 (E) C.5 Calculation of standard uncertainty of concentration measured C.5.1 Model equation and application of rule of uncertainty propagation Cchlorides ( HCl ) = Cchlorides (Cl ) × with Vstd = VT , P M HCl mchlorides M HCl = × M Cl Vstd M Cl (C.1) Tstd P × T Pstd (C.2) where is the mass concentration of gaseous chlorides at standard conditions of temperature C chlorides (HCl ) and pressure, expressed as HCl (in mg HCl/m ); is the mass concentration of gaseous chlorides at standard conditions of temperature C chlorides (Cl ) and pressure, expressed as chlorides (in mg Cl/m ); mchlorides is the mass concentration of gaseous chlorides (in milligrams (mg)) collected in the sample absorption solution; Vstd is the gas volume sampled from the gas meter, dry and at standard conditions, in cubic metres (m³); T is the mean temperature (in Kelvins (K)) of the sampled gas at the gas-meter; Tstd is the standard temperature, 273 K; P = Prel + Patm is the absolute pressure (in kilopascals (kPa)) at the gas volume meter; P is equal to P the sum of relative pressure measured at the gas volume meter rel plus atmospheric pressure Pstd VT ,P Patm ; is the standard pressure, 101,325 kPa; is the gas volume sampled (in cubic metres (m³)) achieved by difference between values given by the gas volume meter at the end and at the beginning of the sampling period The value at the beginning of the sampling period corresponds to a reading of an indicator; the value at the end of the sampling period corresponds to a reading of a measured value Calculation of the concentration: Vstd = 0,132 × 273 100,281 × = 0,120 m 296,2 101,325 The mass concentration at standard conditions of temperature and pressure, and at O2 concentration measure, is equal to: 38 BS EN 1911:2010 EN 1911:2010 (E) Cchlorides ( HCl ) = mchlorides M HCl 1,020 36,5 × = × = 8,71 mg HCl/m 0,120 35,5 Vstd M Cl Expression for the calculation of the combined uncertainty of Cchlorides ( HCl ) : ( u ² Cchlorides ( HCl ) (Cchlorides( HCl ) )² ) = u ²(mchlorides ) + u ²(Vstd ) + u ²(M HCl ) + u ²(M Cl ) (mchlorides )² (Vstd )² (M HCl )² (C.3) (M Cl )² Uncertainty associated to the molar mass can be neglected: ( u ² Cchlorides ( HCl ) (Cchlorides( HCl ) )² ) = u ²(mchlorides ) + u ²(Vstd ) (mchlorides )² (C.4) (Vstd )² Calculation of the combined uncertainty of Vstd : Vstd = VT ,P Tstd T P + P atm P × = VT ,P std × rel T Pstd T Pstd (C.5) Hypothesis: we consider that uncertainties of Tstd and Pstd are negligible ∂V u ²(Vstd ) = std ∂VT , P 2 × u ²(VT , P ) + ∂Vstd × u ²(T ) + ∂Vstd ∂P ∂T rel ∂V × u ²( Prel ) + std ∂P atm × u ²( P atm ) (C.6) Calculation of sensitivity coefficients: ∂V std Tstd Prel + Patm Vstd = × = T Pstd VT , p ∂VT , p (C.7) P + Patm V ∂Vstd = −VT , p × Tstd × rel × = − std Pstd T ∂T T (C.8) T Vstd V ∂Vstd = VT , p × std × = = std T Pstd Prel + Patm P ∂Prel (C.9) T Vstd V ∂Vstd = VT , p × std × = = std T Pstd Prel + Patm P ∂Patm (C.10) Equation (C.6) is equivalent to: V u ²(Vstd ) = std VT , p 2 2 × u ²(VT , P ) + − Vstd × u ²(T ) + Vstd × u ²( Prel ) + Vstd × u ²( P atm ) T P P (C.11) Equation (C.4) is equivalent to: ( ) = u ²(mchlorides ) + u ²(VT ,P ) + u ²(T ) + u ²( Prel ) + u ²(Patm ) (Cchlorides( HCl ) )² (mchlorides )² (VT ,P )2 (T )² ( Prel ) ( Patm ) u ² C chlorides ( HCl ) (C.12) 39 BS EN 1911:2010 EN 1911:2010 (E) C.5.2 Results of the standard uncertainties calculations Table C.4 — Results of the standard uncertainty calculations Performance characteristic Determination quantity of Value of standard uncertainty at limit value of the gaseous m chlorides chlorides absorption solution in the u (m chlorides ) = 2,10 × 1,02 = 0,0214 100 mg Cl + u²( drift ,VT ,P ) + u²( resol ,VT ,P ) u(VT ,P ) = the u (m chlorides ) = 0,021 (m chlorides ) u²(VT ,P ) = u²( cal ,VT ,P ) + u²( rep,VT ,P ) Volume of sampled gas Temperature at volume meter Relative standard uncertainty gas 1,4 × 0,132 0,3 × 0,132 + × 100 100 2 0,0002 / 100 × 0,132 + 2 + = 0,0013 m3 u (VT ,P ) (VT ,P ) = 0,0096 u²(T ) = u²( cal ,T ) + u²( resol ,T ) + u²( drift ,T ) + (σmean ,T )2 2 0,1 + + 0,854 = 1,146 K u(T ) = + 2 2 ) = u²( cal , P u²( P ) + u²( resol , P ) u (T ) = 0,0039 (T ) rel rel rel Relative pressure at the gas meter + u²( lfit , Prel ) + u²( drift , Prel ) + σmean ,Prel 2 u( Prel ) = Atmospheric pressure ( ) 0,01 1,4 / 100 × 200 0,6 + + 3 2 / 100 × 200 + 0,287 + = 2,030 Pa u( Prel ) = 2,1.10 −5 P u²( Patm ) = u²( MPE , Patm ) + u²( resol , Patm ) u( Patm ) = 0,00173 P 20 300 = 173,3 Pa + u( Patm ) = 2 C.5.3 Estimation of the combined uncertainty Uncertainty associated to Cchlorides ( HCl ) The result of the calculation of the combined uncertainty according to Equation (C.12) is: Standard uncertainty: 40 ( ) u Cchlorides ( HCl ) = 0,21 mg HCl/m BS EN 1911:2010 EN 1911:2010 (E) C.6 Calculation of the overall (or expanded) uncertainty Overall uncertainty: ( ) U C chlorides ( HCl ) = ± 0,41 mg HCl/m (k = 2); ( ) U rel Cchlorides ( HCl ) = ± 4,7 % (k = 2) C.7 Uncertainty associated to the mass concentration of gaseous chlorides at O2 reference concentration The mass concentration of gaseous chloride at O2 reference concentration is calculated as follows: Cchlorides ( HCl ),O2, ref = Cchlorides ( HCl ) × 21 − O2,ref (C.13) 21 − O2,meas where C chlorides ( HCl ),O2 , ref is the mass concentration at O2 reference concentration (mg/m ); Cchlorides ( HCl ) is the mass concentration at O2 measured concentration in the duct (mg/m ); O2,ref is O2 reference concentration (in % volume); O2,meas is O2 measured concentration in the duct (in % volume) 3 The uncertainty associated to this concentration is calculated by applying Equation (C.14): ( u (C chlorides( HCl )O2,ref ) = Cchlorides( HCl )O2,ref ) × u(C(C chlorides( HCl ) ) chlorides( HCl ) ) + u ((O2,meas ) dry ) (21 − (O2,meas ) dry ) (C.14) where u (C chlorides ( HCl ) O2 , ref ) is the uncertainty associated the mass concentration at O2 reference concentration; u ((O2,rmeas ) dry ) is the uncertainty associated to the measured O2 concentration The mass concentration at standard conditions of temperature and pressure, and at O2 reference concentration, is equal to: C chlorides ( HCl ) O2 , ref = 8,71 × 21 − 11 = 10 ,01 mg HCl/m3 21 − 12 ,3 The combined standard uncertainty is equal to: 41 BS EN 1911:2010 EN 1911:2010 (E) u (C chlorides( HCl )O2, ref Overall uncertainty: × 12,3 × 100 0,204² ) = 10,01 × + (21 − 12,3) 8,71² ( U C chlorides ( HCl )O2 ,ref ( U rel Cchlorides( HCl )O2,ref 42 ) ) = 0,485 mg HCl/m3 = ± 0,97 mg HCl/m (k = 2); = ± 9,7 % (k = 2) BS EN 1911:2010 EN 1911:2010 (E) Annex D (informative) Performance characteristics of the whole measurement method D.1 Analytical detection limit of the method -3 Based on measurements achieved at very low HCI concentration (less than 0,2 mg⋅m ), the standard -3 deviation of results is 0,07 mg⋅m This leads to an estimation of the analytical detection limit (three times the -3 standard deviation) which is about 0,2 mg⋅m However, it has to be noted that these results were achieved by sampling during h (sampled gas volumes 400 l to 500 l); by sampling only 30 min, the analytical detection limit would be higher D.2 Repeatability and reproducibility of the method in the field Repeatability standard deviation s r and reproducibility standard deviation s R are determined by performing inter-laboratory tests Repeatability standard deviation s r , repeatability confidence interval ( CI r ) are calculated according to ISO 5725-2 and ISO 5725-6, from the results of the double measurements implemented by the same laboratory CIr = t 0,95;n −1 × sr and r = × t 0,95;n−1 × s r where CI r is the repeatability confidence interval; sr is the repeatability standard deviation; t0,95;n-1 is the Student factor for a level of confidence of 95 % and a degree of freedom of n-1 (n: number of double measurements) Available data concerning the repeatability confidence interval are listed in Table D.1, which distinguishes between wet gases (water saturated) and dry gases (temperature in the duct much higher than the dew point) -3 -3 In the range of mg⋅m to 230 mg⋅m , Table D.1 gives values of repeatability confidence interval Reproducibility standard deviation s R , reproducibility confidence interval ( CI r ) are calculated according to ISO 5725-2, from the results of parallel measurements performed simultaneously by several laboratories CIR = t 0,95;np −1 × s R where CI r is the reproducibility confidence interval; sR is the reproducibility standard deviation; 43 BS EN 1911:2010 EN 1911:2010 (E) t0,95;np-1 is the Student factor for a level of confidence of 95 % and a degree of freedom of np-1 (n: number of measurements; p: number of laboratories) Because most of the tests were performed in order to compare different sampling protocol results, only few data are available in order to estimate the reproducibility confidence interval Table D.1 Plant Concentration mean Number of double value (extreme values) determinations mg⋅m Wet gases Dry gases Reproducibility Standard deviation s R -3 mg⋅m Reproducibility confidence interval CI R -3 % 0,08 (0,02 to 0,2) 0,07 200 (3 to 8) 15 0,7 30 40 (35 to 45) 10 0,8 5 (1 to 15) 18 0,4 17 (less than 10) 19 1,05 26 14 (10 to 20) 14 0,8 27 (20 to 40) 0,7 215 (190 to 230) Plant A: Industrial waste incinerator, equipped with an electrostatic precipitator (ESP) and wet scrubber Plants B and C: Municipal refuse incinerator equipped with an ESP and wet scrubber Plants D and E: Municipal refuse incinerator equipped with and ESP and semi dry process (gas temperature: 140 °C) Plant F: Coal boiler equipped with an ESP (gas temperature: 130 °C) 44 BS EN 1911:2010 EN 1911:2010 (E) Annex E (informative) Significant technical changes Details of significant technical changes between this European Standard and the previous edition are: This European Standard, EN 1911, is now a single document (instead of three) for the sampling and analysis dealing with chloride concentration determination expressed as HCl Requirements of EN 15259 are integrated A procedure for carrying out isokinetic sampling without a side stream is included The temperature of filtration has undergone lengthy discussions and divergent opinions that have ultimately led to not set any value, but to establish the requirement that the filtration temperature shall be at least 20 °C above the dew point Performance criteria and a maximum uncertainty are fixed (Clause 8) An example of uncertainty calculation is given in Annex C 45 BS EN 1911:2010 EN 1911:2010 (E) Bibliography [1] CEN/TS 14793, Stationary source emission — Intralaboratory validation procedure for an alternative method compared to a reference method [2] ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method [3] ISO 5725-6, Accuracy (trueness and precision) of measurement methods and results — Part 6: Use in practice of accuracy values [4] ISO/IEC Guide 99:2007, International vocabulary of metrology — Basic and general concepts and associated terms (VIM) [5] Directive 2000/76/EC of the European Parliament and of the Council of December 2000 on the incineration of waste 46 This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION 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