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UDC 677
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IS0
FOR STAND AR D IZAT I O N
I N T E RN AT I O N A L ORGAN I Z AT 1 ON
IS0 RECOMMENDATION
R 271
TEXT I LES
IMPLEMENTATION OF THE TEX SYSTEM
FOR DESIGNATING THE SIZE OF TEXTILE FIBRES,
YARNS AND SIMILAR STRUCTURES
1st EDITION
September 1962
COPYRIGHT RESERVED
The copyright of IS0 Recommendations and IS0 Standards
belongs to IS0 Member Bodies. Reproduction of these
documents, in any country, may be authorized therefore only
by the national standards organization of that country, being
a member of EO. 1
For each individual country the only valid standard is the national standard of that country.
Printed in Switzerland
Also issued in French and Russian. Copies to be obtained through the national standards organizations.
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BRIEF HISTORY
The IS0 Recommendation R 271, Implementation of the Tex System for Designating
the Size of Textile Fibres, Yarns and Similar. Structures, was drawn up by Technical Com-
mittee ISO/TC 38, Textiles, the Secretariat of which is held by the British Standards Insti-
tution (B.S.I.).
Work on this question by the Technical Committee began in 1948 and led, in 1957, to
the adoption of a Draft IS0 Recornmendation.
In August 1958, this Draft IS0 Recommendation (No. 391) was circulated to all the
few modifications of an
IS0 Member Bodies for enquiry. It was approved, subject to a
editorial nature, by the following Member Bodies :
Australia India Portugal
Austria Iran Republic of South Africa
Bel gi urn Ireland Romania
Canada Israel Spain
Chile Italy Sweden
Czechoslovakia Japan Turkey
Denmark Netherlands U.S.A.
New Zealand U.S.S.R.
France
Germany Norway
Greece Poland
One Member Body opposed the approval of the Draft : United Kingdom.
The Draft IS0 Recommendation was then submitted by correspondence to the IS0
Coiincil, which decided, in September 1962, to accept it as an IS0 RECOMMENDATION.
FOREWORD
It has long been customary to designate the size (coarseness or fineness) of textiIe yarns by
numbering or counting systems. Many branches of the textile industry employ systems of
their own for this purpose, and those in current use may be classified in two groups:
(a) Direct syslems, in which the size of the yarn is expressed in terms of the mass of
yarn per unit Iength (linear density, often called yarn number);
(b) Indirect systems, in which the size of the yarn is expressed in terms of the length
of yarn per unit mass (usually called yarn count).
With the growing use of yarns containing more than one kind of fibre, and of fabrics
containing these yarns, it has become increasingly evident that the general adoption of a
single system of numbering or counting would avoid confusion and save time.
In 1956, after detailed studies, Technical Committee ISO/TC 38, Textiles, agreed unani-
mously to recommend the Tex System for international adoption in place of the various
traditional methods of numbering or counting. That system is direct and based on metric
units. This decision has since been embodied in IS0 Recommendation R 138, Universal
Yarn Count System.
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iSO/ R 271 - 1962 (E)
E
IS0 Recommendation R 271 September 1962
TEXTILES
IMPLEMENTATION OF THE TEX SYSTEM
FOR DESIGNATING THE SIZE OF TEXTILE FIBRES,
YARNS AND SIMILAR STRUCTURES
1. SCOPE
This IS0 Recommendation reaffirms the principlzs, given iii IS0 Recommendation R 138,
Universal Yarn Count System, of the Tex System of numbering textile fibres, intermediate products
(e.g. tops, rovings, etc.), yarns and similar structures. It provides for the conversion of counts or
numbers expressed in other systems into tex values, both exact and rounded, and includes
guidance on the gradual implementation of the Tex System in trade and industry.
2. UNIVERSAL YARN COUNT SYSTEM OR TEX SYSTEM
2.1 Definition and units
The recommended system for designating the count or number of textile fibres, yarns,
intermediate and similar products is a direct, metric system in which the basic unit is the tex.
The linear density (number) of a yarn in tex expresses the mass in grammes of yarn having
a length of one thousand metres. Thus a yarn designated 1 tex has a mass of one gramme
per thousand metres of its length.
in preference to other
The multiple and sub-multiple of the tex unit recommended for use
possible combinations are the following:
kilogramme per thousand metres, designated kilotex;
milligramme per thousand metres, designated millitex;
The unit tex is recommended for application to single and plied yarns and to monofilaments.
TABLE 1. .- Tex units
I Name of unit 1 Abbreviation Size of unit (1) 1
value
millitex
tex tex
kilotex
(1) The unit of length has been written as 1000 m instead of as 1 km, to avoid all confusion with kilotcx (ktex).
2.2 Notation *
The linear density (number) in the Tex System is indicated by the appropriate numerical
value followed by the name of the unit used.
Examples : Fibres . 170 mtex
.... 20 ktex
Tops and similar products
Rovings . 500 tex
Single yarns . 30 tex
if a symbol is needed to represent a linear density in the Tex System (e.g. in formulae), the
abbreviation Tt is used.**
* Proposals for the notation of plied and cabled yarns are being developed by Technical Committee ISO/TC 38, Textiles.
** The abbreviation Tt is not used immediately before or after the value of linear density, as it does not indicate a unit,
but the concept of linear density itself, as expressed in the Tex System.
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ISO/ R 271 - 1962 (E)
3. C'ONVRHSION
3.1 Conversion to exact tex values
Counts and linear densities (numbers), as expressed in other counting or numbering systems,
are converted into tex values, or vice versa, as set out below.
The result is expressed to four significant figures, where necessary, to give an accuracy
of 0.05 per cent.
If the other systems are
mass of yam
(a) dircci >ywtrms, where size of yarn? =
unit of length
Table 2 gives the conversion factors for multiplying the known linear density (number) :
length of yarn
(h) indirect systems, where size of yarn =
unit of miss
Table 3 gives the constant which is to be used as follows:
For conversion from an indirect system to the Tex System, the constant is divided by
the count of the indirect system.
Example: The equivalent of yarn count N,20 in the Tex System is
tex = 44.29 tex (rounded: 44 tex; see clause 3.2).
20
For conversion from the Tex System to an indirect system, the constant is divided by
the number of the Tex System.
Example: The equivalent of 44 tex in the worsted system is
885.8
-- N, 20.13, to three significant figures: Ne 20.1.
44
TAULE 2. -- Conversion factors for direct systems
Conversion factors *
Unit
of mas
to yarn number I to tex number
system abbre
used
from tex number 1 from yarn number
I viatio
I
- -
Tex Tt gramme 1000 metres g11000 m
~
gramme 9000 metres g/9000 m Td=9 Tt Tt-0.1 I Il Td
Denier Td
~~ ~ ~~
1 pound 14 400 yards lb/14 400 yd TI -=0.029 03 Tt Tt -34.45 TJ
Linen dry spun
TJ
Hemp, Jute (spindle unit)
~
~ ~~-
1 /4 onza 500 canas 0.25 onzal To -0.0933 Tt 'Tt= 10.71 To
Numero en
500 canas
cuartos de onza
~ ~~ ~ __ ._- ~
~
Ta-0.029 03 Tt Tt- 34.45 Ta
1 pound 14 400 yards lb/ 14 400 yd
Woollen
(Aberdeen)
-
~
1 grain 20 yards grain120 yd Tga-0.2822 Tt Tt=3.543 Tga
Woollen
(American
grain)
~~ --
-~
1 grammt 504 metres g/504 m Tcw=0.504 Tt 1 Tt= 1.984 TcW
Woollen
(Catalonian)
I
* See ciausc 3.1 (a).
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[SO/ R 271 - 1962 (E) E
ïa~r I. 3. -- Constants for conversion of indirect systems
I
;ym-
iolic i Unit of length 1 Unit of mass ~ Unit of yarn Coiirtants *
Yarn count system
count
bbre- 1
ation 1
used - ~ used
Vah 100 yards (cut) i 1 pound 100 yd/lb 4961 =Tt.iV,,
4sbestos (American)
I
Vck 50 yards 1 p
...