CEN TS 16490-2013 Fertilizers - Comparison of the CEN TC 260 WG 7 ring test results with tolerances given in the Regulation (EC) Nr 2003 2003 Annex II and conclusions《肥料 CEN TC 260.pdf

1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationFertilizers Comparison of the CEN/TC 260/WG 7 ring test results with tolerancesgiven in the Regulation (EC) Nr 2003/2003 Annex II and conclusionsPD CEN/TS 16490:2013National fore

2、wordThis Published Document is the UK implementation of CEN/TS 16490:2013.The UK participation in its preparation was entrusted to Technical CommitteeCII/37, Fertilisers and related chemicals.A list of organizations represented on this committee can be obtained onrequest to its secretary.This public

3、ation does not purport to include all the necessary provisions of acontract. Users are responsible for its correct application. The British Standards Institution 2013Published by BSI Standards Limited 2013ISBN 978 0 580 80142 6ICS 65.080Compliance with a British Standard cannot confer immunity froml

4、egal obligations.This Published Document was published under the authority of theStandards Policy and Strategy Committee on 30 April 2013.Amendments issued since publicationAmd. No. Date Text affectedPUBLISHED DOCUMENTPD CEN/TS 16490:2013TECHNICAL SPECIFICATION SPCIFICATION TECHNIQUE TECHNISCHE SPEZ

5、IFIKATION CEN/TS 16490 April 2013 ICS 65.080 English Version Fertilizers - Comparison of the CEN/TC 260/WG 7 ring test results with tolerances given in the Regulation (EC) Nr 2003/2003 Annex II and conclusions Engrais - Comparaison des rsultats des essais interlaboratoires mens par le CEN/TC 260/WG

6、7 avec les tolrances donnes dans le rglement (CE) n2003/2003 Annexe II et conclusions Dngemittel - Vergleich der Ringversuchsergebnisse der CEN/TC 260/WG 7 mit den in der Verordnung (EG) Nr. 2003/2003 Anhang II angegebenen Toleranzen und Schlussfolgerungen This Technical Specification (CEN/TS) was a

7、pproved by CEN on 12 February 2013 for provisional application. The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to submit their comments, particularly on the question whether the CEN/TS can be converted into a European S

8、tandard. CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in parallel to the CEN/TS) until the final de

9、cision about the possible conversion of the CEN/TS into an EN is reached. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland

10、, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Mar

11、nix 17, B-1000 Brussels 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. CEN/TS 16490:2013: EPD CEN/TS 16490:2013CEN/TS 16490:2013 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and defin

12、itions .5 4 Statistical method validation 6 4.1 General 6 4.2 Approach taken by CEN/TC 260/WG 7 .6 4.3 Statistical data: results versus tolerances 6 4.4 Refined statistical analysis .7 4.5 Field data 7 5 Conclusions .8 Annex A (informative) Statistical data of the inter-laboratory tests and findings

13、 . 10 A.1 General . 10 A.2 Nitrogen . 10 A.3 Phosphate 13 A.4 Potassium 15 A.5 Sulfur 15 A.6 Chloride . 18 A.7 Secondary nutrients . 18 Annex B (informative) Refined statistical evaluation . 26 B.1 General . 26 B.2 Meaning of symbols . 26 B.3 Tolerances for SO3. 27 B.4 Tolerances for CaO, MgO. Na2O

14、and Cl . 28 B.5 Refinement of results . 32 B.6 Comments . 32 Bibliography . 33 PD CEN/TS 16490:2013CEN/TS 16490:2013 (E) 3 Foreword This document (CEN/TS 16490:2013) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials”, the secretariat of which is held by DIN. Atten

15、tion 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 has been prepared under a mandate given to CEN by the European Commission and

16、 the European Free Trade Association. According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former

17、Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. PD CEN/TS 16490:2013CEN/TS 16490:2013 (E) 4

18、Introduction Following a request from the European Commission (Mandate M/418), an evaluation was done of the existing tolerances as per Regulation (EC) No. 2003/2003. Input for this evaluation was derived from the precision data obtained via the several ring tests that have been made according to Ma

19、ndate M/335. As to exclude eventual interference from effects due to inhomogeneity of physically blended grades, no blends have been included in the ring tests; test samples have been limited and chosen as to be representing some main product grades sold within the EU. The statistical evaluation has

20、 been done in line with ISO 5725-2 and whenever deemed necessary for appropriate evaluation and interpretation of the test results, some extra statistical evaluation was made on the test data. As to judge to what extent problems arise in case of enforcement controls, some field data have been analys

21、ed as to verify to what extent actual conflicts exist in between test results from official controls and applied tolerances. The evaluation revealed no real need for adjustments to tolerances as they relate to analytical variability. However, it should be emphasised that the tolerances given in Regu

22、lation 2003/2003 relate not only to analytical variability but to the total variability including allowances for sampling error and product variability. Finally if the European Commission sees the necessity of further method improvements, then one could consider a project entitled to develop an alte

23、rnative method. Only following a full evaluation including ring testing, a final judgment can be made if the newly developed method could be a candidate for replacement of the existing one(s) assuming better accuracy data. PD CEN/TS 16490:2013CEN/TS 16490:2013 (E) 5 1 Scope In Regulation (EC) No. 20

24、03/2003 2 tolerance limits are mentioned for nutrient contents in mineral fertilizers (Annex II of Regulation (EC) No. 2003/2003) as well as prescribed methods for control purposes (Annex IV of Regulation (EC) No. 2003/2003). Prior to the work done by CEN/TC 260 following Mandate M/335, no statistic

25、al data were available for the official analytical methods to be applied. Due to the standardization work done for this mandate, statistical data have been generated as ring testing was a major topic in this mandate. This Technical Specification describes to what extent the presently applied toleran

26、ces are in line with the obtained precision data from the analytical methods studied. The purpose of this document is to give feedback on the applied tolerances within Regulation (EC) No. 2003/2003 based on the method evaluation done as an outcome of the work executed by CEN/TC 260/WG 7 according to

27、 Mandate M/335. This evaluation of the tolerances was part of Mandate M/418. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated r

28、eferences, the latest edition of the referenced document (including any amendments) applies. ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions 3 Terms and definitions For the purposes of this document, the following terms

29、 and definitions apply. 3.1 tolerance (T) variation including manufacturing, raw materials, sampling and analytical methods 3.2 repeatability limit (r) the value less than or equal to which the absolute difference between two test results obtained under repeatability conditions may be expected to be

30、 with a probability of 95 % SOURCE: ISO 5725-1:1994 Note 1 to entry: In other words, r is the minimum difference between two results in order to be statistically different, under repeatability conditions, at a 95 % probability level. 3.3 reproducibility limit (R) the value less than or equal to whic

31、h the absolute difference between two test results obtained under reproducibility conditions may be expected to be with a probability of 95 % SOURCE: ISO 5725-1:1994 Note 1 to entry: In other words, R is the minimum difference between two results in order to be statistically different, under reprodu

32、cibility conditions, at a 95 % probability level. PD CEN/TS 16490:2013CEN/TS 16490:2013 (E) 6 4 Statistical method validation 4.1 General European laboratories were involved, including as well private, industry, official as commercial laboratories. ISO 5725-2 was applied as standard for ring testing

33、 and statistical evaluation of its results. In general, legislative tolerances are given to accommodate variability in raw materials, manufacturing, sampling and analytical routines. 4.2 Approach taken by CEN/TC 260/WG 7 4.2.1 Product selection The European market is characterised by a broad portfol

34、io of different types of fertilizer grades, Hence there was a need for selection of a limited number of products to be tested for the ring-test(s). Aim during the selection process was to get fertilizer samples tested reflecting some main grades sold in the EEC. 4.2.2 Samples and their preparation I

35、n order to be able to evaluate the precision data of the method as such, samples have been taken to the utmost extent as a spot (not agglomerated) sample out of a bulk production. This was done on purpose as to reduce the possible variation originating from raw materials, manufacturing and sampling

36、procedure. Furthermore, all samples have been ground before distribution to the participating labs. Only solid, homogeneous samples and liquid samples have been used; no blends. The aim was to work with a limited number of samples, representing the main fertilizer grades applied. 4.2.3 Laboratories

37、involved The participation of the laboratories was on a voluntary basis, enabling as well private and industry, official and commercial laboratories to contribute. As far as the lab proficiency concerns, the ring test set-up did not require a familiarisation step for each of the individual participa

38、ting laboratories nor for the methods evaluated. The chosen approach does not imply any assurance on the degree of experience and routine of the labs involved with the method under investigation and reflects the day-to-day situation as is. 4.2.4 Data evaluation As already stated, ISO 5725-2 has been

39、 applied as the standard for the statistical data evaluation. However, for some methods a more in depth approach has been made, with the support of an expert statistician, due to the fact that the reproducibility parameters seemed to be in conflict with the existing tolerances. Based on this refined

40、 statistical analysis, it has been the intention to come up with adequate tolerances. As stated in 1, R should be 0,7 T. In case this condition is not fulfilled, one should from a theoretical perspective considering the following alternative options: improve the method of analysis; propose an altern

41、ative method with better performance; increase the tolerances. 4.3 Statistical data: results versus tolerances The ring test data and findings are given in the informative Annex A. PD CEN/TS 16490:2013CEN/TS 16490:2013 (E) 7 4.4 Refined statistical analysis Despite the method refinements to the dete

42、rmination of water soluble sulfur and water soluble calcium, reproducibility figures could not be improved substantially. Therefore, a more in-depth statistical analysis has been performed by an expert statistician. The main principles are described below; the detailed information can be consulted i

43、n Annex B. In a first step, after applying the classical criteria for removing outliers of a population of data (see ISO 5725-2), it could be concluded that the reproducibility data were in conflict with the existing tolerances. A substantial number of test results show high R values which implies t

44、hat the methods only comply with tolerance substantially higher than the existing ones. In order to improve these reproducibility data, data sets outside the 99,9 % confidence interval (after removal of outliers according to Grubbs and Cochrans tests) have been removed. The sRcalculated from the rem

45、aining data is used to find a more adequate tolerance value and at the same time comply with the performance of the method. The same exercise has been performed for the total sulfur content. Further, the remaining data population has been crosschecked with the official tolerances. However, still con

46、flicts were observed. In a final step, it has been attempted to derive, based on statistical principles, reasonable tolerances for the concerned nutrients. 4.5 Field data In order to cross-check the outcome of the statistical evaluation of official methods versus tolerances in place and verify the n

47、ecessity for eventual adjustment of the existing tolerance limits, a population of obtained anonymised test results have been evaluated. The test results submitted were data derived from official controls (enforcement) and covering data from nutrient analysis on various fertilizer types such as: cal

48、cium ammonium nitrate (CAN), CAN+MgO and NPK. In total about 450 analyses were presented, covering analysis of Nitrogen, Sulfur, Magnesium and Phosphorus. Sampling as well as analyses has been conducted according to EC methods. These data have only been used to check whether problems arise in case o

49、f enforcement controls or not. The enforcement data have not been evaluated statistically on repeatability or reproducibility. Neither have they been used to evaluate the precision or correctness of the data obtained with CEN methods. Tables 1 to 3 summarise data for fertilizer types that were numerously represented. Table 1 Product type: CAN27 Component Declared value % Number of analyses Deviation from declaration % Out of tolerance N total 27 30 -0,4 to +0,6 No N NH413,5 30 -0,4 to +0,5 No Table 2 Product type: CAN27 + MgO Compon