ISO 2403:2021

Textiles — Cotton fibres — Determination of micronaire value

This document specifies a method of determining the micronaire value of loose disorientated cotton fibres taken from bales, laps and slivers, or other sources of lint cotton.

Textiles — Fibres de coton — Détermination de l'indice micronaire

Le présent document spécifie une méthode de détermination de l’indice micronaire des fibres de coton ouvertes et sans orientation spécifique, prélevées sur balles, nappes ou rubans ou toute autre source de coton en bourre.

Tekstilije - Bombažna vlakna - Določanje mikronerske vrednosti

Ta dokument določa metodo določanja mikronerske vrednosti prostih neurejenih bombažnih vlaken, ki se odvzamejo iz bal, zank, prej ali drugih virov bombaža, ki ne pušča vlaken.

General Information

• Status: Published
• Publication Date: 26-Aug-2021
• ICS: 59.060.10 - Natural fibres
• Technical Committee: ISO/TC 38/SC 23 - Fibres and yarns
• Drafting Committee: ISO/TC 38/SC 23/WG 2 - Fibres - Natural cellulosic
• Current Stage: 6060 - International Standard published
• Start Date: 27-Aug-2021
• Due Date: 22-Oct-2021
• Completion Date: 27-Aug-2021
• Ref Project: SIST ISO 2403:2022 - Textiles - Cotton fibres - Determination of micronaire value

Relations

• Revises: ISO 2403:2014 - Textiles — Cotton fibres — Determination of micronaire value
• Effective Date: 23-Apr-2020

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ISO 2403:2022
01-marec-2022
Tekstilije - Bombažna vlakna - Določanje mikronerske vrednosti
Textiles - Cotton fibres - Determination of micronaire value
Textiles - Fibres de coton - Détermination de l'indice micronaire
Ta slovenski standard je istoveten z: ISO 2403:2021
ICS:
59.060.10 Naravna vlakna Natural fibres
SIST ISO 2403:2022 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 2403:2022

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SIST ISO 2403:2022
INTERNATIONAL ISO
STANDARD 2403
Third edition
2021-08
Textiles — Cotton fibres —
Determination of micronaire value
Textiles — Fibres de coton — Détermination de l'indice micronaire
Reference number
ISO 2403:2021(E)
©
ISO 2021

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SIST ISO 2403:2022
ISO 2403:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 4 ----------------------
SIST ISO 2403:2022
ISO 2403:2021(E)

Contents Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Principle . 1
5  Apparatus and materials. 1
6  Conditioning . 2
7  Preparation of test specimen . 2
8  Procedure. 2
9  Calculation and expression of results . 3
10  Test report . 3
Annex A (informative) Method of calibration of instruments . 5
Annex B (informative) Precision experiment. 6
Annex C (informative) Comparison experiment . 7
Bibliography . 9
© ISO 2021 – All rights reserved iii

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SIST ISO 2403:2022
ISO 2403:2021(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 38, Textiles, Subcommittee SC 23, Fibres
and yarns.
This third edition cancels and replaces the second edition (ISO 2403:2014), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— an introduction clause has been added;
— a short description of the available apparatus, operation details and reference to calibration method
in 5.2, Notes 1 and 2, respectively, has been added ;
— permission of the use of two different sample preparation methods have been added in 7.2;
— the specification of applied sample preparation method, the date of the test, any deviations from the
procedure, and any unusual features observed have been added in the test report in Clause 10;
— former Annexes B and C (operation of different instruments) have been removed;
— a new informative Annex B with precision data for micronaire measurements has been added;
— a new informative Annex C with precision data for comparison of the both test specimen preparation
methods has been added;
— a bibliography has been added;
— grammar and linguistic consistency have been reviewed.
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 2021 – All rights reserved

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SIST ISO 2403:2022
ISO 2403:2021(E)

Introduction
The micronaire value, one of the most important cotton fibre quality parameters, is measured on a
plug of cotton fibres, it hence represents an average value. Due to a simple test specimen preparation, a
measurement is carried out in relatively short time and thereby leads to fast testing results.
Based on the air permeability of a compressed cotton fibre test specimen, early manual micronaire
testers used a mechanical air-flow meter, where a float sensor indicates the amount of air flowing
through the test specimen, and a mechanical manometer showing the air pressure difference across the
test specimen. Modern micronaire testers generally use electronic sensors for both, the air flow and the
pressure difference.
In any case, the dimensionless micronaire value is calculated from the air flow through the test
specimen and the pressure difference along the test specimen. Micronaire values are within a scale of 2
and 8, where a value of 2 represents a low air permeability (high packing density of the test specimen,
caused by very fine and/or immature fibres) and a value of 8 represents a high air permeability (low
packing density of the test specimen, caused by very coarse and/or mature fibres).
© ISO 2021 – All rights reserved v

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SIST ISO 2403:2022

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SIST ISO 2403:2022
INTERNATIONAL STANDARD ISO 2403:2021(E)
Textiles — Cotton fibres — Determination of micronaire
value
1  Scope
This document specifies a method of determining the micronaire value of loose disorientated cotton
fibres taken from bales, laps and slivers, or other sources of lint cotton.
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 139, Textiles — Standard atmospheres for conditioning and testing
ISO 1130, Textile fibres — Some methods of sampling for testing
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 https:// www .electropedia .org/
3.1
micronaire value
measure for the air permeability of a mass of cotton under specified conditions
Note 1 to entry: The micronaire scale is based on a range of cottons to which micronaire values have been
assigned by international agreement.
Note 2 to entry: It is expressed in terms of an arbitrary scale, the so-called micronaire scale.
4  Principle
Air is passed through a test specimen consisting of a plug of fibres. The permeability is indicated on a
scale for recording variations in either the rate of flow through, or the pressure difference across, the
plug. The mass and volume of the test specimen are either a constant for a given type of instrument or
varied appropriately in relation to each other. The scale indicating variations in permeability can be
calibrated in arbitrary units of micronaire value or marked in the appropriate absolute units of rate of
flow or of pressure difference and a table or graph provided for conversion of the observed readings
into micronaire values.
5  Apparatus and materials
5.1  Balance, of sufficient capacity to weigh the test specimen required for the airflow instrument used,
with an accuracy of ±0,2 %.
© ISO 2021 – All rights reserved 1

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SIST ISO 2403:2022
ISO 2403:2021(E)

5.2  Airflow instrument, whose principal parts are as follows.
5.2.1  Compression cylinder with perforated ends of such dimensions that with the prescribed
mass of test specimen each cubic centimetre shall contain between 0,16 g and 0,30 g of cotton when
compressed.
5.2.2 Means for measuring the air permeability of the test specimen, comprising, for example:
a) a suitable air pump;
b) one or more valves or other means for controlling the flow of air through, or the pressure difference
across, the test specimen in the compression cylinder;
c) a manometer for measuring the required air pressure difference across the test specimen and a
flowmeter for indicating the rate of airflow through it.
NOTE 1 There are several models of airflow instruments, which vary only in details of construction and
operation. Any details of the operation are described in the manufacturer's instructions included with the
instrument.
NOTE 2 For information on the method of calibration of airflow instruments, see Annex A.
5.3  International calibration cotton standards (see A.1).
6  Conditioning
6.1 Condition samples
...

INTERNATIONAL ISO
STANDARD 2403
Third edition
2021-08
Textiles — Cotton fibres —
Determination of micronaire value
Textiles — Fibres de coton — Détermination de l'indice micronaire
Reference number
ISO 2403:2021(E)
©
ISO 2021

---------------------- Page: 1 ----------------------
ISO 2403:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 2403:2021(E)

Contents Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Principle . 1
5  Apparatus and materials. 1
6  Conditioning . 2
7  Preparation of test specimen . 2
8  Procedure. 2
9  Calculation and expression of results . 3
10  Test report . 3
Annex A (informative) Method of calibration of instruments . 5
Annex B (informative) Precision experiment. 6
Annex C (informative) Comparison experiment . 7
Bibliography . 9
© ISO 2021 – All rights reserved iii

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ISO 2403:2021(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 38, Textiles, Subcommittee SC 23, Fibres
and yarns.
This third edition cancels and replaces the second edition (ISO 2403:2014), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— an introduction clause has been added;
— a short description of the available apparatus, operation details and reference to calibration method
in 5.2, Notes 1 and 2, respectively, has been added ;
— permission of the use of two different sample preparation methods have been added in 7.2;
— the specification of applied sample preparation method, the date of the test, any deviations from the
procedure, and any unusual features observed have been added in the test report in Clause 10;
— former Annexes B and C (operation of different instruments) have been removed;
— a new informative Annex B with precision data for micronaire measurements has been added;
— a new informative Annex C with precision data for comparison of the both test specimen preparation
methods has been added;
— a bibliography has been added;
— grammar and linguistic consistency have been reviewed.
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 2021 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 2403:2021(E)

Introduction
The micronaire value, one of the most important cotton fibre quality parameters, is measured on a
plug of cotton fibres, it hence represents an average value. Due to a simple test specimen preparation, a
measurement is carried out in relatively short time and thereby leads to fast testing results.
Based on the air permeability of a compressed cotton fibre test specimen, early manual micronaire
testers used a mechanical air-flow meter, where a float sensor indicates the amount of air flowing
through the test specimen, and a mechanical manometer showing the air pressure difference across the
test specimen. Modern micronaire testers generally use electronic sensors for both, the air flow and the
pressure difference.
In any case, the dimensionless micronaire value is calculated from the air flow through the test
specimen and the pressure difference along the test specimen. Micronaire values are within a scale of 2
and 8, where a value of 2 represents a low air permeability (high packing density of the test specimen,
caused by very fine and/or immature fibres) and a value of 8 represents a high air permeability (low
packing density of the test specimen, caused by very coarse and/or mature fibres).
© ISO 2021 – All rights reserved v

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INTERNATIONAL STANDARD ISO 2403:2021(E)
Textiles — Cotton fibres — Determination of micronaire
value
1  Scope
This document specifies a method of determining the micronaire value of loose disorientated cotton
fibres taken from bales, laps and slivers, or other sources of lint cotton.
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 139, Textiles — Standard atmospheres for conditioning and testing
ISO 1130, Textile fibres — Some methods of sampling for testing
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 https:// www .electropedia .org/
3.1
micronaire value
measure for the air permeability of a mass of cotton under specified conditions
Note 1 to entry: The micronaire scale is based on a range of cottons to which micronaire values have been
assigned by international agreement.
Note 2 to entry: It is expressed in terms of an arbitrary scale, the so-called micronaire scale.
4  Principle
Air is passed through a test specimen consisting of a plug of fibres. The permeability is indicated on a
scale for recording variations in either the rate of flow through, or the pressure difference across, the
plug. The mass and volume of the test specimen are either a constant for a given type of instrument or
varied appropriately in relation to each other. The scale indicating variations in permeability can be
calibrated in arbitrary units of micronaire value or marked in the appropriate absolute units of rate of
flow or of pressure difference and a table or graph provided for conversion of the observed readings
into micronaire values.
5  Apparatus and materials
5.1  Balance, of sufficient capacity to weigh the test specimen required for the airflow instrument used,
with an accuracy of ±0,2 %.
© ISO 2021 – All rights reserved 1

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ISO 2403:2021(E)

5.2  Airflow instrument, whose principal parts are as follows.
5.2.1  Compression cylinder with perforated ends of such dimensions that with the prescribed
mass of test specimen each cubic centimetre shall contain between 0,16 g and 0,30 g of cotton when
compressed.
5.2.2 Means for measuring the air permeability of the test specimen, comprising, for example:
a) a suitable air pump;
b) one or more valves or other means for controlling the flow of air through, or the pressure difference
across, the test specimen in the compression cylinder;
c) a manometer for measuring the required air pressure difference across the test specimen and a
flowmeter for indicating the rate of airflow through it.
NOTE 1 There are several models of airflow instruments, which vary only in details of construction and
operation. Any details of the operation are described in the manufacturer's instructions included with the
instrument.
NOTE 2 For information on the method of calibration of airflow instruments, see Annex A.
5.3  International calibration cotton standards (see A.1).
6  Conditioning
6.1 Condition samples in the standard atmosphere for 4 h in moving air (or alternatively for 12 h in
still air) or for a shorter time if the change in mass in a 2 h period does not exceed 0,25 % before weighing
and testing the test specimen. Preconditioning is not required.
6.2 Weigh and test the test specimen in the standard atmosphere for conditioning in accordance with
ISO 139.
7  Preparation of test specimen
7.1 Take test specim
...

NORME ISO
INTERNATIONALE 2403
Troisième édition
2021-08
Textiles — Fibres de coton —
Détermination de l'indice micronaire
Textiles — Cotton fibres — Determination of micronaire value
Numéro de référence
ISO 2403:2021(F)
©
ISO 2021

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ISO 2403:2021(F)

DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2021
Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette
publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,
y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut
être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.
ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse
ii © ISO 2021 – Tous droits réservés

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ISO 2403:2021(F)

Sommaire Page
Avant-propos .iv
Introduction .vi
1 Domaine d’application . 1
2 Références normatives . 1
3 Termes et définitions . 1
4 Principe . 1
5 Appareillage et matériaux . 2
6 Conditionnement . 2
7 Préparation de l’éprouvette . 2
8 Mode opératoire. 3
9 Calculs et expression des résultats . 3
10 Rapport d’essai . 4
Annexe A (informative) Méthode d’étalonnage des appareils . 5
Annexe B (informative) Expérience relative à la fidélité . 6
Annexe C (informative) Expérience de comparaison . 7
Bibliographie . 9
© ISO 2021 – Tous droits réservés iii

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ISO 2403:2021(F)

Avant-propos
L’ISO (Organisation internationale de normalisation) est une fédération mondiale d’organismes
nationaux de normalisation (comités membres de l’ISO). L’élaboration des Normes internationales est
en général confiée aux comités techniques de l’ISO. Chaque comité membre intéressé par une étude
a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,
gouvernementales et non gouvernementales, en liaison avec l’ISO participent également aux travaux.
L’ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui
concerne la normalisation électrotechnique.
Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont
décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier, de prendre note des différents
critères d’approbation requis pour les différents types de documents ISO. Le présent document a été
rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2 (voir www
.iso .org/ directives).
L’attention est attirée sur le fait que certains des éléments du présent document peuvent faire l’objet de
droits de propriété intellectuelle ou de droits analogues. L’ISO ne saurait être tenue pour responsable
de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant
les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de
l’élaboration du document sont indiqués dans l’Introduction et/ou dans la liste des déclarations de
brevets reçues par l’ISO (voir www .iso .org/ brevets).
Les appellations commerciales éventuellement mentionnées dans le présent document sont données
pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un
engagement.
Pour une explication de la nature volontaire des normes, la signification des termes et expressions
spécifiques de l’ISO liés à l’évaluation de la conformité, ou pour toute information au sujet de l’adhésion
de l’ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles
techniques au commerce (OTC), voir le lien suivant: www .iso .org/ iso/ fr/ avant -propos .html.
Le présent document a été élaboré par le comité technique ISO/TC 38, Textiles, sous-comité SC 23, Fibres
et fils.
Cette troisième édition annule et remplace la deuxième édition (ISO 2403:2014), qui a fait l’objet d’une
révision technique.
Les principales modifications par rapport à l’édition précédente sont les suivantes:
— une introduction a été ajoutée;
— une courte description de l’appareillage disponible, de ses caractéristiques de fonctionnement et
une référence à la méthode d’étalonnage ont été ajoutés en 5.2, respectivement dans les Notes 1 et 2;
— l’autorisation d’utiliser deux méthodes différentes de préparation de l’échantillon a été ajoutée
en 7.2 ;
— des mentions concernant la spécification de la méthode de préparation de l’échantillon utilisée, la
date de l’essai, tout écart par rapport au mode opératoire et tout phénomène inhabituel observé ont
été ajoutées dans le rapport d’essai à l’Article 10;
— les anciennes Annexes B et C (utilisation des différents appareils) ont été supprimées;
— une nouvelle Annexe B informative concernant les données de fidélité des mesurages de l’indice
micronaire a été ajoutée;
— une nouvelle Annexe C informative concernant les données de fidélité pour la comparaison des deux
méthodes de préparation des éprouvettes a été ajoutée;
— une bibliographie a été ajoutée;
iv © ISO 2021 – Tous droits réservés

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ISO 2403:2021(F)

— la grammaire et la cohérence linguistique ont été vérifiées.
Il convient que l’utilisateur adresse tout retour d’information ou toute question concernant le présent
document à l’organisme national de normalisation de son pays. Une liste exhaustive desdits organismes
se trouve à l’adresse www .iso .org/ fr/ members .html.
© ISO 2021 – Tous droits réservés v

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ISO 2403:2021(F)

Introduction
L’indice micronaire, l’un des paramètres les plus importants des fibres de coton, est mesuré sur un
tampon de fibres de coton et représente donc une valeur moyenne. Comme la méthode de préparation
des éprouvettes est simple, le mesurage est effectué en un temps relativement court et permet donc
d’obtenir rapidement des résultats d’essai.
Fondés sur la perméabilité à l’air d’une éprouvette en fibres de coton comprimée, les premiers appareils
d’essai micronaire manuels utilisaient un débitmètre mécanique dans lequel un flotteur indiquait la
quantité d’air circulant dans l’éprouvette, et un manomètre mécanique indiquant la différence de
pression de l’air à travers l’éprouvette. Les appareils d’essai micronaire modernes utilisent généralement
des capteurs électroniques pour mesurer à la fois le débit d’air et la différence de pression.
Dans les deux cas, l’indice micronaire sans dimension est calculé à partir du débit d’air à travers
l’éprouvette et de la différence de pression le long de l’éprouvette. Les indices micronaires sont compris
sur une échelle allant de 2 à 8, où une valeur de 2 représente une perméabilité à l’air peu élevée (haute
densité de tassement de l’éprouvette causée par des fibres très fines et/ou immatures) et une valeur
de 8 représente une perméabilité à l’air élevée (faible densité de tassement de l’éprouvette causée par
des fibres très grossières et/ou matures).
vi © ISO 2021 – Tous droits réservés

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NORME INTERNATIONALE ISO 2403:2021(F)
Textiles — Fibres de coton — Détermination de l'indice
micronaire
1 Domaine d’application
Le présent document spécifie une méthode de détermination de l’indice micronaire des fibres de coton
ouvertes et sans orientation spécifique, prélevées sur balles, nappes ou rubans ou toute autre source de
coton en bourre.
2 Références normatives
Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur
contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.
Pour les références non datées, la dernière édition du document de référence s'applique (y compris les
éventuels amendements).
ISO 139, Textiles — Atmosphères normales de conditionnement et d'essai
ISO 1130, Fibres textiles — Diverses méthodes d'échantillonnage en vue des essais
3 Termes et définitions
Pour les besoins du présent document, les termes et définitions suivants s’appliquent.
L’ISO et l’IEC tiennent à jour des bases de données terminologiques destinées à être utilisées en
normalisation, consultables aux adresses suivantes:
— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp
— IEC Electropedia: disponible à l’adresse http:// www .electropedia .org/
3.1
indice micronaire
mesure de la perméabilité à l’air d’une masse de coton dans des conditions spécifiées
Note 1 à l'article: L’échelle micronaire est fondée sur une série de cotons auxquels des indices micronaires ont été
attribués par accord international.
Note 2 à l'article: Il est exprimé selon une échelle arbitraire appelée échelle micronaire.
4 Principe
De l’air circule à travers une éprouvette composée d’un tampon de fibres. La perméabilité est indiquée
sur une échelle permettant d’enregistrer les variations de débit ou les différences de pression à travers
le plongeur. La masse et le volume de l’éprouvette sont soit constants pour un type donné d’appareil,
soit variables l’un par rapport à l’autre. L’échelle indiquant les variations de la perméabilité peut être
étalonnée en unités arbitraires de l’indice micronaire ou être marquée en unités absolues appropriées
pour le débit ou la différence de pression, et un tableau ou un graphique peut être fourni pour convertir
les lectures observées en indices micronaires.
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ISO 2403:2021(F)

5 Appareillage et matériaux
5.1 Balance, d’une capacité suffisante pour peser l’éprouvette requise pour le type d’appareil à flux
d’air utilisé, à ± 0,2 % près.
5.2 Appareil à flux d’air, constitué essentiellement des éléments suivants:
5.2.1 Cylindre de compression perforé aux deux extrémités, ayant des dimensions choisies de
manière à contenir entre 0,16 g et 0,30 g par centimètre cube de coton comprimé constituant la masse
prescrite d’éprouvette.
5.2.2 Dispositifs permettant de mesurer la perméabilité à l’air de l’éprouvette, comprenant par
exemple:
a) une pompe à air appropriée;
b) une ou plusieurs soupapes ou autres moyens de réglage du flux d’air ou de la différence de pression
à travers l’éprouvette dans le cylindre de compression;
c) un manomètre pour mesurer la différence de pression requise et un débitmètre pour indiquer le
débit d’air à travers l’éprouvette.
NOTE 1 Il existe plusieurs modèles d’appareils à flux d’air, qui se distinguent uniquement par leurs
caractéristiques de construction et de fonctionnement. Toutes les caractéristiques de fonctionnement sont
décrites dans les instructions du fabricant fournies avec l’appareil.
NOTE 2 Pour des informations sur la méthode d’étalonnage des appareils à flux d’air, voir l’Annexe A.
5.3 Gamme d’étalons de cotons de référence internationaux (voir A.1).
6 Conditionnement
6.1 Avant de peser et de soumettre à l’essai l’éprouvette, conditionner les échantillons dans
l’atmosphère normale pendant 4 h dans de l’air en mouvement (ou pendant 12 h dans de l’air statique) ou
pendant une durée plus courte si la variation de la masse sur une période de 2 h ne dépasse pas 0,25 %.
Un conditionnement préalable n’est pas nécessaire.
6.2 Peser et soumettre à l’essai l’éprouvette dans l’atmosphère normale de conditionnement
conformément à l’ISO 139.
7 Préparation de l’éprouvette
7.1 Prélever les éprouvettes en su
...

INTERNATIONAL ISO
STANDARD 2403
Third edition
Textiles — Cotton fibres —
Determination of micronaire value
Textiles — Fibres de coton — Détermination de l'indice micronaire
PROOF/ÉPREUVE
Reference number
ISO 2403:2021(E)
©
ISO 2021

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ISO 2403:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
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]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
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ISO 2403:2021(E)

Contents Page
Foreword .iv
Introduction .v
1  Scope . 1
2  Normative references . 1
3  Terms and definitions . 1
4  Principle . 1
5  Apparatus and materials. 1
6  Conditioning . 2
7  Preparation of test specimen . 2
8  Procedure. 2
9  Calculation and expression of results . 3
10  Test report . 3
Annex A (informative) Method of calibration of instruments . 5
Annex B (informative) Precision experiment. 6
Annex C (informative) Comparison experiment . 7
Bibliography . 9
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ISO 2403:2021(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 38, Textiles, Subcommittee SC 23, Fibres
and yarns.
This third edition cancels and replaces the second edition (ISO 2403:2014), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— an introduction clause has been added;
— a short description of the available apparatus, operation details and reference to calibration method
in 5.2, Notes 1 and 2, respectively, has been added ;
— permission of the use of two different sample preparation methods have been added in 7.2;
— the specification of applied sample preparation method, the date of the test, any deviations from the
procedure, and any unusual features observed have been added in the test report in Clause 10;
— former Annexes B and C (operation of different instruments) have been removed;
— a new informative Annex B with precision data for micronaire measurements has been added;
— a new informative Annex C with precision data for comparison of the both test specimen preparation
methods has been added;
— a bibliography has been added;
— grammar and linguistic consistency have been reviewed.
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.
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ISO 2403:2021(E)

Introduction
The micronaire value, one of the most important cotton fibre quality parameters, is measured on a
plug of cotton fibres, it hence represents an average value. Due to a simple test specimen preparation, a
measurement is carried out in relatively short time and thereby leads to fast testing results.
Based on the air permeability of a compressed cotton fibre test specimen, early manual micronaire
testers used a mechanical air-flow meter, where a float sensor indicates the amount of air flowing
through the test specimen, and a mechanical manometer showing the air pressure difference across the
test specimen. Modern micronaire testers generally use electronic sensors for both, the air flow and the
pressure difference.
In any case, the dimensionless micronaire value is calculated from the air flow through the test
specimen and the pressure difference along the test specimen. Micronaire values are within a scale of 2
and 8, where a value of 2 represents a low air permeability (high packing density of the test specimen,
caused by very fine and/or immature fibres) and a value of 8 represents a high air permeability (low
packing density of the test specimen, caused by very coarse and/or mature fibres).
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INTERNATIONAL STANDARD ISO 2403:2021(E)
Textiles — Cotton fibres — Determination of micronaire
value
1  Scope
This document specifies a method of determining the micronaire value of loose disorientated cotton
fibres taken from bales, laps and slivers, or other sources of lint cotton.
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 139, Textiles — Standard atmospheres for conditioning and testing
ISO 1130, Textile fibres — Some methods of sampling for testing
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 https:// www .electropedia .org/
3.1
micronaire value
measure for the air permeability of a mass of cotton under specified conditions
Note 1 to entry: The micronaire scale is based on a range of cottons to which micronaire values have been
assigned by international agreement.
Note 2 to entry: It is expressed in terms of an arbitrary scale, the so-called micronaire scale.
4  Principle
Air is passed through a test specimen consisting of a plug of fibres. The permeability is indicated on a
scale for recording variations in either the rate of flow through, or the pressure difference across, the
plug. The mass and volume of the test specimen are either a constant for a given type of instrument or
varied appropriately in relation to each other. The scale indicating variations in permeability can be
calibrated in arbitrary units of micronaire value or marked in the appropriate absolute units of rate of
flow or of pressure difference and a table or graph provided for conversion of the observed readings
into micronaire values.
5  Apparatus and materials
5.1  Balance, of sufficient capacity to weigh the test specimen required for the airflow instrument used,
with an accuracy of ±0,2 %.
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ISO 2403:2021(E)

5.2  Airflow instrument, whose principal parts are as follows.
5.2.1  Compression cylinder with perforated ends of such dimensions that with the prescribed
mass of test specimen each cubic centimetre shall contain between 0,16 g and 0,30 g of cotton when
compressed.
5.2.2 Means for measuring the air permeability of the test specimen, comprising, for example:
a) a suitable air pump;
b) one or more valves or other means for controlling the flow of air through, or the pressure difference
across, the test specimen in the compression cylinder;
c) a manometer for measuring the required air pressure difference across the test specimen and a
flowmeter for indicating the rate of airflow through it.
NOTE 1 There are several models of airflow instruments, which vary only in details of construction and
operation. Any details of the operation are described in the manufacturer's instructions included with the
instrument.
NOTE 2 For information on the method of calibration of airflow instruments, see Annex A.
5.3  International calibration cotton standards (see A.1).
6  Conditioning
6.1 Condition samples in the standard atmosphere for 4 h in moving air (or alternatively for 12 h in
still air) or for a shorter time if the change in mass in a 2 h period does not exceed 0,25 % before weighing
and testing the test specimen. Preconditioning is not required.
6.2 Weigh and test the test specimen in the standard atmosphere for conditioning in accordance with
ISO 139.
7  Preparation of test specimen
7.1 Take test specimens in accordance with
...