EN ISO 7971-3:2009

SLOVENSKI STANDARD
01-december-2009
äLWR'RORþDQMHSURVWRUQLQVNHPDVHLPHQRYDQHKHNWROLWUVNDPDVDGHO
5XWLQVNDPHWRGD,62
Cereals - Determination of bulk density, called mass per hectolitre - Part 3: Routine
method (ISO 7971-3:2009)
Getreide - Bestimmung der Schüttdichte, sogenannte Masse je Hektoliter - Teil 3:
Routineverfahren (ISO 7971-3:2009)
Céréales - Détermination de la masse volumique, dite masse à l'hectolitre - Partie 3:
Méthode pratique (ISO 7971-3:2009)
Ta slovenski standard je istoveten z: EN ISO 7971-3:2009
ICS:
67.060 äLWDVWURþQLFHLQSURL]YRGLL] Cereals, pulses and derived
QMLK products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 7971-3
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2009
ICS 67.060
English Version
Cereals - Determination of bulk density, called mass per
hectolitre - Part 3: Routine method (ISO 7971-3:2009)
Céréales - Détermination de la masse volumique, dite Getreide - Bestimmung der Schüttdichte, sogenannte
masse à l'hectolitre - Partie 3: Méthode pratique (ISO 7971- Masse je Hektoliter - Teil 3: Routineverfahren (ISO 7971-
3:2009) 3:2009)
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 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, 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
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7971-3:2009: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 7971-3:2009) has been prepared by Technical Committee CEN/TC 338 “Cereal and
cereal products”, the secretariat of which is held by AFNOR, in collaboration with Technical 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.
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.
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, 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.

INTERNATIONAL ISO
STANDARD 7971-3
First edition
2009-08-15
Cereals — Determination of bulk density,
called mass per hectolitre —
Part 3:
Routine method
Céréales — Détermination de la masse volumique, dite masse
à l'hectolitre —
Partie 3: Méthode pratique
Reference number
ISO 7971-3:2009(E)
©
ISO 2009
ISO 7971-3:2009(E)
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ii © ISO 2009 – All rights reserved

ISO 7971-3:2009(E)
Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle. 1
5 Apparatus . 2
6 Procedure . 2
6.1 General. 2
6.2 Hand-operated instruments. 2
6.3 Automatic instruments. 3
6.4 Expression of results . 3
7 Precision. 3
7.1 Interlaboratory test . 3
7.2 Repeatability. 3
7.3 Reproducibility. 3
7.4 Comparison of two groups of measurements in one laboratory. 4
7.5 Comparison of two groups of measurements in two laboratories. 4
7.6 Uncertainty . 4
8 Test report . 5
Annex A (informative) Description of dimensions and use of KERN apparatus . 6
Annex B (informative) Description of dimensions and use of NILEMA LITRE apparatus . 10
Annex C (informative) Results of interlaboratory tests. 12
Bibliography . 14

ISO 7971-3:2009(E)
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 7971 (all parts) was prepared by the European Committee for Standardization (CEN) Technical
Committee CEN/TC 338, Cereal and cereal products, in collaboration with Technical Committee ISO/TC 34,
Food products, Subcommittee SC 4, Cereals and pulses, in accordance with the Agreement on technical
cooperation between ISO and CEN (Vienna Agreement).
The first edition of ISO 7971-3 cancels and replaces the first edition of ISO 7971-2:1995, which has been
technically revised.
ISO 7971 consists of the following parts, under the general title Cereals — Determination of bulk density,
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
iv © ISO 2009 – All rights reserved

INTERNATIONAL STANDARD ISO 7971-3:2009(E)

Cereals — Determination of bulk density, called mass
per hectolitre —
Part 3:
Routine method
1 Scope
This part of ISO 7971 specifies a routine method for the determination of bulk density, called “mass per
hectolitre” of cereals as grain using manual or automatic, mechanical, electric or electronic mass per hectolitre
measuring instruments.
NOTE Further details of the measuring instruments are specified in ISO 7971-2:2009, 6.4.
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 7971-2, Cereals — Determination of bulk density, called mass per hectolitre — Part 2: Method of
traceability for measuring instruments through reference to the international standard instrument
3 Terms and definitions
For the purposes of this document, 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 1 Bulk density is expressed in kilograms per hectolitre of grains as received.
NOTE 2 The bulk density, as defined in this part of ISO 7971, is different from “packing density” or “intrinsic density” of
cereals.
[ISO 7971-1:2009]
4 Principle
The mass per hectolitre of a cereal is obtained from the mass of a volume of cereal determined under
controlled sample filling and flow conditions.
ISO 7971-3:2009(E)
The mass per hectolitre can be affected by:
a) space between the grains, which depends on the grain size and shape;
b) density of the grains.
5 Apparatus
5.1 General requirement for bulk density apparatus. Any apparatus (5.2 and 5.3) shall be verified
according to ISO 7971-2 and shall fulfil the performance demands specified therein.
5.2 Hand-operated measuring instrument. Apparatus consisting of a filling hopper, a measuring
container and the accessories necessary for their use.
The manner in which the grain is poured into the measuring container and the way in which it packs into the
container can cause the measurements taken by the various instruments to vary and lead to measurement
errors.
To minimize such variations, special attention should be given to ensuring that the design of the instruments
and their size, material and shape are appropriate.
NOTE Annexes A and B of this part of ISO 7971 contain examples of technical specifications of two hand-operated
instruments with a capacity of 1 l.
5.3 Automatic measuring instrument. This category includes various types of devices, some of which can
be used on their own or combined with an infrared analyser.
The measurement is based on the application of equations to allow the correcting of the bias and/or the drifts
monitored. It does not include manual weighing. The numeric value of the hectolitre mass is directly displayed.
5.4 Analytical balance, capable of being read to the nearest 0,1 g or 0,01 g depending on the volume of
the container (see 6.2).
6 Procedure
6.1 General
The measurements shall be taken using grain from which large impurities (straw, stones, husks, etc.) have
been discarded, taking environmental conditions into consideration to ensure that there is no difference in
temperature between the grain and the room in which the test is performed.
Determine the bulk density in duplicate. For all the devices and for every sample, it is advisable to perform the
two measurements on two different grain test portions.
NOTE Repeating the measurement on the same grain test portion changes the friction coefficient which therefore
makes it easier for the grains to slide; they are then more tightly packed, which increases the value of the bulk density.
6.2 Hand-operated instruments
Check that the various components of the instrument are clean and that they are working properly.
Make sure that equipment is placed on a firm, flat base, after using a spirit level to check that the base is
horizontal.
Take great care to avoid any impact during filling. If the apparatus is jolted, cancel the test and start again.
2 © ISO 2009 – All rights reserved

ISO 7971-3:2009(E)
Each type of apparatus is different; use each according to the manufacturer’s instructions.
When using the analytical balance (5.4), weigh to the nearest 1 g for a 1 l container or the nearest 0,1 g for
apparatus with a container of smaller volume.
6.3 Automatic instruments
As the operations to be performed prior to the actual measurement differ according to the type of equipment
used, reference to the manufacturer's instructions is recommended.
Ensure that the instrument is placed on a horizontal surface in a room protected from extreme temperatures,
humidity, dust and vibrations.
Take particular care to:
a) select the correct cereal to be measured to ensure that the right calibration is used;
b) use the volume of cereals recommended for the device in question;
c) empty the collector drawer between samples.
6.4 Expression of results
Take the arithmetic mean of the two determinations as the result if the repeatability conditions are met.
Express the result to the nearest 0,1 kg/hl.
7 Precision
7.1 Interlaboratory test
Details of an interlaboratory test on the precision of the method are summarized in Annex C. The values
derived from this interlaboratory test cannot be applied to other bulk density ranges and matrices than those
given.
7.2 Repeatability
The absolute difference between two independent single test results, obtained using the same method on
ide
...