1、January 2010DEUTSCHE NORM English price group 13No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 67.060!$Tq“1564978www.
2、din.deDDIN EN ISO 7971-2Cereals Determination of bulk density, called mass per hectolitre Part 2: Method of traceability for measuring instruments throughreference to the international standard instrument (ISO 7971-2:2009)English version of DIN EN ISO 7971-2:2010-01Getreide Bestimmung der Schttdicht
3、e, sogenannte Masse je Hektoliter Teil 2: Verfahren zur Rckverfolgbarkeit von Messgerten mittels Referenz aufinternationale Normalgerte (ISO 7971-2:2009)Englische Fassung DIN EN ISO 7971-2:2010-01www.beuth.deDocument comprises pages24DIN EN ISO 7971-2:2010-01 National foreword This standard has been
4、 prepared by Technical Committee CEN/TC 338 “Cereal and cereal products” (Secretariat: AFNOR, France) in collaboration with Technical Committee ISO/TC 34 “Food products” (Secretariat: AFNOR, France), Subcommittee SC 4 “Cereals and pulses” (Secretariat: SAC, China) and has been published in accordanc
5、e with the result of the parallel voting procedure within the scope of the Agreement on technical cooperation between ISO and CEN (Vienna Agreement) to adopt, without alteration, International Standard ISO 7971-2:2009 as a European Standard. The responsible German body involved in its preparation wa
6、s the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee), Working Committee NA 057-05-06 AA Getreide und Getreideerzeugnisse. DIN EN ISO 7971 consists of the following parts, under the general title Cereals Determination of bulk density
7、, called mass per hectolitre: Part 1: Reference method Part 2: Method of traceability for measuring instruments through reference to the international standard instrument Part 3: Routine method The DIN Standards corresponding to the International Standards referred to in this document are as follows
8、: ISO 712 DIN EN ISO 712 ISO 7971-1 DIN EN ISO 7971-1 National Annex NA (informative) Bibliography DIN EN ISO 712, Cereals and cereal products Determination of moisture content Routine reference method DIN EN ISO 7971-1, Cereals Determination of bulk density, called mass per hectolitre Part 1: Refer
9、ence method 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 7971-2 August 2009 ICS 67.060 English Version Cereals - Determination of bulk density, called mass per hectolitre - Part 2: Method of traceability for measuring instruments through reference to the international standard instrume
10、nt (ISO 7971-2:2009) Crales - Dtermination de la masse volumique, dite masse lhectolitre - Partie 2: Mthode de raccordement des instruments de mesure ltalon international (ISO 7971-2:2009) Getreide - Bestimmung der Schttdichte, sogenannte Masse je Hektoliter - Teil 2: Verfahren zur Rckverfolgbarkeit
11、 von Messgerten mittels Referenz auf internationale Normalgerte (ISO 7971-2:2009) This European Standard was approved by CEN on 8 August 2009. 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 na
12、tional 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 i
13、n 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, Cyprus, Czech Republic, Denmark
14、, 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 COMIT EUROPEN DE NORMALISATIO
15、N EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2009 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 7971-2:2009: EContents Page Foreword. Scope . 4 2 Normative references . 4 3 Terms and d
16、efinitions. 4 4 Requirements 5 4.1 Certified international or national standard instrument . 5 4.2 National standard instrument 5 4.3 Secondary or internal standard instrument.5 4.4 Routine measuring instrument 5 5 Principle. 6 6 Apparatus 6 7 Procedure 7 7.1 Traceability of national standard instru
17、ments through reference to the certified international or national standard instrument.7 7.2 Traceability of the secondary standard instruments through reference to the national standard instrument . 9 7.3 Verification of instruments in operation. 10 8 Monitoring of instrument performance 12 9 Test
18、reports . 12 9.1 Analysis certificate . 12 9.2 Conformity certificate. 13 10 Identification of traced measuring instruments 13 Annex A (normative) Method for calculation of performance parameters of standard instruments and of measurement instruments. 14 Annex B (informative) Some owners of certifie
19、d standard measurement instruments 21 Bibliography . 22 EN ISO 7971-2:2009 (E) DIN EN ISO 7971-2:2010-01 2.3Foreword This document (EN ISO 7971-2:2009) has been prepared by Technical Committee CEN/TC 338 “Cereal and cereal products”, the secretariat of which is held by AFNOR, in collaboration with T
20、echnical Committee ISO/TC 34 “Food products“. 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 2010, and conflicting national standards shall be withdrawn at the latest by February 2010. A
21、ttention 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. According to the CEN/CENELEC Internal Regulations, the national standards organizations
22、 of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, S
23、lovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. EN ISO 7971-2:2009 (E) DIN EN ISO 7971-2:2010-01 31 Scope This part of ISO 7971 specifies a test method for ensuring the traceability of mass per hectolitre measuring instruments through reference to standard measurement instrumen
24、ts. The mass per hectolitre or bulk density is of commercial importance for grain cereals. Several types of instruments with varying performances exist for measuring it. This part of ISO 7971 also specifies the performances required of national standards instruments, secondary standards instruments,
25、 and measuring instruments used in laboratories or in collection or storage silos. 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
26、 referenced document (including any amendments) applies. ISO 712, Cereals and cereal products Determination of moisture content Reference method ISO 7971-1, Cereals Determination of bulk density, called “mass per hectolitre” Part 1: Reference method 3 Terms and definitions For the purposes of this d
27、ocument, the following terms and definitions apply. 3.1 bulk density “mass per hectolitre” cereals ratio of the mass of a cereal to the volume it occupies after being poured into a container under well-defined conditions NOTE Bulk density is expressed in kilograms per hectolitre of grains as receive
28、d. ISO 7971-1:2009 3.2 traceability cereals establishment of a relationship between the usual measuring instrument and the international standard instrument via a chain EN ISO 7971-2:2009 (E) DIN EN ISO 7971-2:2010-01 43.3 analysis certificate document supplied by the international standard instrume
29、nt holder body or national standard instrument holder body containing the individual values of measurements, the mass per hectolitre average value and its uncertainty for the test sample being analysed 3.4 conformity certificate document, issued by the body in charge of verifying the performances of
30、 the instrument, specifying the conformity decision for the requested use 3.5 control chart chart on which some statistical measure of a series of samples is plotted in a particular order to steer the process with respect to that measure and to control and reduce variation ISO 3534-2:20061, 2.3.1 NO
31、TE The analysis values are plotted on the ordinate against the date (day or hour) of carrying out the measurement on the abscissa. 4 Requirements 4.1 Certified international or national standard instrument A standard measurement instrument for mass per hectolitre has a 20 l hopper and is certified b
32、y a national or international authority. An informative list of such instruments is given in Annex B. 4.2 National standard instrument Each country defines, on the basis of the specifications given in 6.2, the instrument designated as a national standard instrument within the respective country. Thi
33、s national standard instrument should be an instrument designated by its name (model, manufacturer, serial number). Any other instrument of the same model as that adopted as the national standard instrument shall not be referred to as a “national standard instrument”. Each country defines the public
34、 or private organization responsible for the safe keeping, use, and maintenance of this national standard instrument. This same organization ensures its traceability through reference to a certified international or national standard instrument (4.1), according to the provisions specified in 7.1, ev
35、ery 10 years. Each country shall ensure that no natural or legal person is refused access to the results of this national standard instrument so that any manufacturer, holder, repairer, controller or user can ensure the traceability of his own instruments through reference to the national standard i
36、nstrument. 4.3 Secondary or internal standard instrument For the purposes of inspection of instruments in operation, a body may possess an appliance specific to this activity. This instrument shall have the required qualities, established using the national standard instrument. It shall then constit
37、ute the reference which ensures the traceability of the instruments in operation. Verify and adjust these secondary standard instruments every 2 years in accordance with 7.2. 4.4 Routine measuring instrument This term designates any mass per hectolitre measuring instrument used in commercial transac
38、tions. EN ISO 7971-2:2009 (E) DIN EN ISO 7971-2:2010-01 5The traceability of instruments in operation and of new instruments (prior to commissioning) shall be ensured through reference to a secondary standard instrument (4.3) according to the provisions specified in 7.3. The frequency of this tracea
39、bility operation is 1 year. 5 Principle This part of ISO 7971 specifies a procedure for ensuring the traceability of mass per hectolitre measuring instruments through reference to standard instruments. The traceability principle is illustrated by Figure 1. Figure 1 Principle of traceability of instr
40、uments through reference to standard instruments 6 Apparatus 6.1 International standard instrument for mass per hectolitre as specified in ISO 7971-1. 6.2 National standard instrument for mass per hectolitre. Manual or automatic, mechanical, electric or electronic mass per hectolitre measuring instr
41、ument, of which the capacity of the measuring container is at least 1 l, accepting a bias correction or a bias and slope correction. This instrument is used according to the requirements given in 4.2 and traceability is ensured through reference to the international standard instrument according to
42、the procedure specified in 7.1. EN ISO 7971-2:2009 (E) DIN EN ISO 7971-2:2010-01 6The correction made to the instrument ensures a slope and an intercept which are not significantly different from 1 and 0 at the 5 % threshold see Equations (A.8), (A.9), and (A.10), A.7.3 and A.8.2. If the national st
43、andard instrument is a 20 l apparatus, for any correction refer to ISO 7971-1. 6.3 Secondary standard instrument for the mass per hectolitre. Manual or automatic, mechanical, electric or electronic mass per hectolitre measuring instrument, of which the capacity of the measuring container is at least
44、 750 ml, accepting a bias and/or slope correction. This instrument is used according to the requirements given in 4.3 and traceability is ensured through reference to the national standard instrument according to the procedure specified in 7.2. The correction made to the instrument ensures a slope a
45、nd an intercept which are not significantly different from 1 and 0 at the 5 % threshold see Equations (A.8), (A.9), and (A.10), A.7.3 and A.8.2. 6.4 Mass per hectolitre measuring instrument. Manual or automatic, mechanical, electric or electronic, adjustable or fixed mass per hectolitre measuring in
46、strument, associated if necessary with an equivalence or correction table and used according to the requirements given in 4.4. The verification of these instruments specified in 7.3 concerns both new instruments and instruments in operation. The amplitude between the highest and the lowest value, i,
47、 measured on each control sample (see 7.3.4), shall not exceed 0,3 kg/hl. For each control sample, the difference between the value given by the national standard instrument or the secondary standard instrument and the mean of the measurements carried out on the instrument, i,2m, (see 7.3.4), shall
48、not exceed 0,3 kg/hl for mass per hectolitre under 70 kg/hl and 0,4 kg/hl for mass per hectolitre greater than or equal to 70 kg/hl. 6.5 Divider. Manual or mechanical cone-shaped divider that can representatively reduce a 25 l volume of grains to a volume suited to the instruments to undergo traceab
49、ility. 7 Procedure 7.1 Traceability of national standard instruments through reference to the certified international or national standard instrument 7.1.1 General description The traceability of national standard instruments is conducted using a series of test samples referenced with their mass per hectolitre and accompanied by their analysis certificate (3.3). The use of wheat and barley test samples is recommended because of the regular shape of the grain and the good availability of these species of grains. O
