EN ISO 7971-3:2019

Cereals - Determination of bulk density, called mass per hectolitre - Part 3: Routine method (ISO 7971-3:2019)

This document 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 7971‑2:2019, 6.4.

Getreide - Bestimmung der Schüttdichte, sogenannte Masse je Hektoliter - Teil 3: Routineverfahren (ISO 7971-3:2019)

Dieses Dokument legt ein Routineverfahren zur Bestimmung der Schüttdichte, der sogenannten „Masse je Hektoliter“ von Getreide in Körnerform mit manuellen oder automatischen, mechanischen, elektrischen oder elektronischen „Masse je Hektoliter“-Messgeräten fest.
ANMERKUNG Weitere Details von Messgeräten werden in ISO 7971-2:2019, 6.4, festgelegt.

Céréales - Détermination de la masse volumique, dite masse à l'hectolitre - Partie 3: Méthode pratique (ISO 7971-3:2019)

Le présent document spécifie une méthode pratique pour la détermination de la masse volumique, dite «masse à l'hectolitre», des céréales en grains à l'aide d'un instrument de mesure de la masse à l'hectolitre à fonctionnement manuel ou automatique, mécanique, électrique ou électronique.
NOTE       Des détails relatifs aux instruments de mesure sont spécifiés dans l'ISO 7971‑2:2019, 6.4.

Žito - Določanje prostorninske mase, imenovane hektolitrska masa - 3. del: Rutinska metoda (ISO 7971-3:2019)

Ta dokument določa rutinsko metodo za določevanje prostorninske mase, imenovane »hektolitrska masa«, žita v zrnu z uporabo instrumentov za ročno ali samodejno, mehansko, električno ali elektronsko merjenje hektolitrske mase.
OPOMBA: Dodatne podrobnosti o merilnih instrumentih so podane v standardu ISO 7971-2:2019, 6.4.

General Information

• Status: Published
• Publication Date: 05-Mar-2019
• Withdrawal Date: 29-Sep-2019
• ICS: 67.060 - Cereals, pulses and derived products
• Technical Committee: CEN/TC 338 - Cereal and cereal products
• Drafting Committee: CEN/TC 338/WG 7 - Mass per hectolitre
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 06-Mar-2019
• Completion Date: 06-Mar-2019
• Ref Project: SIST EN ISO 7971-3:2019 - Cereals - Determination of bulk density, called mass per hectolitre - Part 3: Routine method (ISO 7971-3:2019)

Relations

• Replaces: EN ISO 7971-3:2009 - Cereals - Determination of bulk density, called mass per hectolitre - Part 3: Routine method (ISO 7971-3:2009)
• Effective Date: 05-Nov-2014

Overview

EN ISO 7971-3:2019 - "Cereals - Determination of bulk density, called mass per hectolitre - Part 3: Routine method" specifies a practical, repeatable procedure for measuring the bulk density (mass per hectolitre / hectolitre mass) of cereals as grain. It covers routine use of manual or automatic mass per hectolitre measuring instruments (mechanical, electric or electronic) and sets out how results should be recorded and reported for quality control and trade.

Key topics and technical requirements

• Scope and principle: Defines mass per hectolitre as the mass of cereal occupying a known volume under specified filling/flow conditions; result expressed in kg/hl.
• Instruments: Differentiates hand-operated and automatic measuring instruments. Instruments must be verified for performance and traceability in accordance with ISO 7971-2:2019.
• Analytical balance: The standard requires an analytical balance with appropriate readability depending on container volume (examples given in the standard: weighing to nearest 1 g for a 1 L container or 0.1 g for smaller containers).
• Measurement procedure:
  • Prepare samples by removing large impurities and equilibrating temperature.
  • Perform measurements in duplicate (two determinations); when repeatability criteria are not met, increase to four measurements and use the mean.
  • Use separate test portions when sample size allows (repeating on the same portion may change packing).
  • Ensure equipment is level, avoid jolting during filling, and follow manufacturer instructions for each device.
• Expression of results: Take the arithmetic mean of determinations when repeatability conditions are satisfied and express result to the nearest 0.1 kg/hl.
• Precision and uncertainty: The standard includes precision data from interlaboratory trials and guidance on repeatability, reproducibility and uncertainty evaluation.
• Annexes: Informative annexes describe example hand instruments (e.g., KERN and NILEMA litre) and interlaboratory test results; a formula for NILEMA litre results (wheat & barley) was introduced in the 2019 revision.

Applications and users

This routine method is directly applicable to:

• Grain laboratories and quality control teams in milling, feed and seed industries
• Grain traders and inspectors performing commodity grading and acceptance testing
• Storage and logistics operators monitoring bulk density for silo/transport planning
• Manufacturers of hectolitre mass measuring instruments and calibrations services
• Regulatory bodies and standardization organizations ensuring consistent test methods

Practical uses include commodity valuation, lot grading, calibrating automatic analyzers, and verifying equipment traceability.

Related standards

• ISO 7971-2:2019 - Method of traceability for measuring instruments (referenced for instrument verification)
• Other parts of the ISO 7971 series (list available on ISO website) and national adoptions (EN ISO 7971-3:2019) apply where CEN members have implemented the standard.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2019
1DGRPHãþD
SIST EN ISO 7971-3:2009
äLWR'RORþDQMHSURVWRUQLQVNHPDVHLPHQRYDQHKHNWROLWUVNDPDVDGHO
5XWLQVNDPHWRGD,62
Cereals - Determination of bulk density, called mass per hectolitre - Part 3: Routine
method (ISO 7971-3:2019)
Getreide - Bestimmung der Schüttdichte, sogenannte Masse je Hektoliter - Teil 3:
Routineverfahren (ISO 7971-3:2019)
Céréales - Détermination de la masse volumique, dite masse à l'hectolitre - Partie 3:
Méthode pratique (ISO 7971-3:2019)
Ta slovenski standard je istoveten z: EN ISO 7971-3:2019
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.

EN ISO 7971-3
EUROPEAN STANDARD
NORME EUROPÉENNE
March 2019
EUROPÄISCHE NORM
ICS 67.060 Supersedes EN ISO 7971-3:2009
English Version
Cereals - Determination of bulk density, called mass per
hectolitre - Part 3: Routine method (ISO 7971-3:2019)
Céréales - Détermination de la masse volumique, dite Getreide - Bestimmung der Schüttdichte, sogenannte
masse à l'hectolitre - Partie 3: Méthode pratique (ISO Masse je Hektoliter - Teil 3: Routineverfahren (ISO
7971-3:2019) 7971-3:2019)
This European Standard was approved by CEN on 8 February 2019.

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-CENELEC 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-CENELEC 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 7971-3:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 7971-3:2019) has been prepared by Technical Committee ISO/TC 34 "Food
products" in collaboration with Technical Committee CEN/TC 338 “Cereal and cereal products” the
secretariat of which is held by AFNOR.
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 September 2019, and conflicting national standards
shall be withdrawn at the latest by September 2019.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 7971-3:2009.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 7971-3:2019 has been approved by CEN as EN ISO 7971-3:2019 without any
modification.
INTERNATIONAL ISO
STANDARD 7971-3
Second edition
2019-02
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 7971-3:2019(E)
©
ISO 2019
ISO 7971-3:2019(E)
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 7971-3:2019(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 trial . 3
7.2 Repeatability . 3
7.3 Reproducibility . 4
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 . 6
Annex B (informative) Description of dimensions and use of Nilema litre .11
Annex C (informative) Results of interlaboratory tests .14
Bibliography .16
ISO 7971-3:2019(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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 34, Food products, Subcommittee SC 4,
Cereals and pulses.
The second edition cancels and replaces the first edition (ISO 7971-3:2009), which has been technically
revised. The main changes compared with the previous edition are as follows:
— a formulae has been introduced to express the results obtained with NILEMA LITRE for wheat
and barley.
A list of all parts in the ISO 7971 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 7971-3:2019(E)
Cereals — Determination of bulk density, called mass per
hectolitre —
Part 3:
Routine method
1 Scope
This document 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 7971-2:2019, 6.4.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 7971-2:2019, 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.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
mass per hectolitre
bulk density
test weight
ratio of the mass of a cereal to the volume it occupies after being poured into a container
under defined manufacturer’s conditions
Note 1 to entry: Mass per hectolitre is expressed in kilograms per hectolitre of grains as received.
Note 2 to entry: Mass per hectolitre, as defined in this document, is different from “packing density” or “intrinsic
density” of cereals.
[SOURCE: ISO 7971-1:2009, 2.1, modified — In the definition, “defined manufacturer’s conditions” has
replaced “well-defined conditions”.]
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 7971-3:2019(E)
The mass per hectolitre can be affected by
a) space between the grains, which depends on the grain size and shape, and
b) density of the grains.
5 Apparatus
5.1 General requirement for mass per hectolitre apparatus. Any apparatus (5.2 and 5.3) shall be
verified in accordance with 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 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 formulae 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).
5.5 Spirit level.
6 Procedure
6.1 General
The measurements shall be taken using grain from which large impurities (straw, stones, large
amounts of loose 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 mass per hectolitre in duplicate. For all the devices and for every sample, it is advisable
to perform the two measurements on two different grain test portions, when the sample size enables it.
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 mass per hectolitre.
6.2 Hand-operated instruments
Check that the various components of the instrument are clean and that they are working properly.
2 © ISO 2019 – All rights reserved

ISO 7971-3:2019(E)
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.
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, and
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.
If they are not met, take as a final result the mean of the four measurement
...