KENYA STANDARD                                            DKS 1113: PART 5:2022  
© KEBS 2022  — All rights reserved    1                                                                                            
 
 
 
 
 
 
 
 
 
 
 
 
 
 
               Specification for staple spun yarns  
                Part 5.  Polyester  Yarns  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
   © KEBS 202 2                                                                                     First Edition  2022  
 DKS 1113 : PART 5:2022  
 
2  © KEBS 202 2 — All rights reserved   
TECHNICAL COMMITTEE REPRESENTATION  
 
The following organizations were represented on the Technical Committee:  
 
Kenya Industrial Rese arch and Development Institute  (KIRDI)  
State Department for Industrialization Directorate of Agro -Industries  
Spin Knit Ltd  
Kenya Association of Manufacturers (KAM)  
Kenya Agricultural & Livestock Research Organization (KALRO)  
Agriculture and Food Authority - Fibre Crops Directorate (AFA -FCD)  
Rivatex East Africa Limited  
Moi University  
Technical University of Kenya - Department of Fashion, Clothing and Textiles  
Texfab B.S  
Ministry of State Defence -R&D Department  
Spinners & Spinners Ltd  
Intertek  
Kenya Bureau of Standards — Secretariat  
 
 
 
 
 
 
REVISION  OF KENYA STANDARDS  
 
In order to keep abreast of progress in industry, Kenya Standards shall be regularly reviewed. Suggestions 
for improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, 
are welcome . 
 
 
 
© Kenya Bureau of Standards, 2022 
 
Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 12 of 2001 of  the Laws of Kenya, copyright 
subsists in all Kenya Standards and except as provided under Section 26 of this Act, no Kenya Standa rd produced by Kenya Bureau of 
Standards may be reproduced, stored in a retrieval system in any form or transmitted by any means without prior permission in  writing 
from the Managing Director . 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                       DKS 1113: PART 5:2022  
© KEBS 2022  — All rights reserved  3  
 
 
 
 
 
 
 
Specification for staple spun yarns  
                Part 5 . Polyester Yarns  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Kenya Bureau of Standards, Popo Road, Off Mombasa Road,  
P.O. Box 54974 - 00200,  Nairobi, Kenya  
 +254 020 6948000, + 254 722202137, + 254 734600471  
 info@kebs.org  
 @KEBS_ke  
 kenya bureau of  standards (kebs)  
 
 
 
 
 
 
 DKS 1113 : PART 5:2022  
 
4  © KEBS 202 2 — All rights reserved   
 
Foreword  
 
This Kenya Standard has been prepared by the Technical Committee on Yarns and Fibers  under guidance 
of the Standards Projects Committee, and it is in accordance with the procedures of the Kenya Bureau of 
Standards.  
 
Yarn quality affects not only the efficiency of fabric production but also the fabric quality. Yarn quality  
specification will therefore be of utmost importance and interest to the spinner, weaver, knitter and yarn  
merchant. Yarns are produced in a wide ra nge of counts (linear densities) or varying fibre blend 
compositions and proportions for various end -users. This Kenya Standard takes into consideration all the 
variations and specifies only the minimum requirements for essential quality characteristics of  yarns.  
 
During the development of this standard reference was made to the following:  
 
KS 1113 -1:1993 Specification  for Spun Yarns - Part 1: Cotton Y arns.  
KS 1113 -3:1993 Specifications for Spun Yarns - Part 3: Polyester/Cellulose Blended Yarns  
 
Acknowledgme nt is hereby made for assistance received from this source.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                       DKS 1113: PART 5:2022  
© KEBS 2022  — All rights reserved  5  
 
 
 
1 SCOPE  
 
This Part of this Kenya Standard specifies the requirements for 100 per cent polyester spun yarns.  
 
2 NORMATIVE REFERENCES  
 
The following refere nced documents 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 (i ncluding any amendments) applies.  
KS ISO 6741 -1, Textiles — Fibres and yarns — Determination of commercial mass of consignments — Part 
1: Mass determination and calculations . 
 
KS EAS 257,  Methods for estimation of moisture , total size for finish, ash, fat ty matter and determination 
of water -soluble matter in textiles.   
 
KS ISO 2062, Textiles — Yarns from packages — Determination of single -end breaking force and elongation 
at break using constant rate of extension (CRE) tester.  
 
KS ISO 2060, Textiles — Yarn  from packages — Determination of linear density (mass per unit length) by 
the skein method.  
 
KS ISO 2061, Textiles — Determination of twist in yarns — Direct counting method.  
 
KS ISO 16549, Textiles — Unevenness of textile strands — Capacitance method.  
 
KS ISO 1139, Textiles — Designation of yarns.  
 
KS ISO 1144, Textiles — Universal system for designating linear density (Tex System).  
 
 
 
 
 
 
 
 
 
 
 
 
 DKS 1113 : PART 5:2022  
 
6  © KEBS 202 2 — All rights reserved   
 
3 DEFINITIONS  
 
For the purpose of this Part XXX  of this Kenya Standard, the following definitions together wi th those  
given in KS ISO 1139 and KS ISO 1144  shall apply:  
 
3.1 linear density  — The mass per unit length of a yarn. It is expressed in tex, or  multiples or submultiples  
thereof.  
 
3.2 tex  — Number of grams per kilometer  of yarn.  
 
3.3 breaking force  — The m aximum force applied to a specimen in a tensile test carried to rupture. It is  
expressed in Newtons, centiNewtons or milliNewtons.  
 
3.4 tenacity  — The ratio of the tension to the linear density of an unstrained specimen. It is expressed in  
Newtons per tex or centiNewtons per tex.  
 
3.5 breaking tenacity  — The tenacity corresponding to the breaking force.  
 
NOTE: The breaking tenacity is calculated from the breaking force and the linear density of the  unstrained specimen, or, for specimens 
of known linear dens ity, obtained directly from tensile  testing machines, which can be suitably adjusted to indicate tenacity instead of 
breaking force.  
 
3.6 twist  — The number of turns about the axis of a length of specimen equal to the nominal gauge length  
before untwisting . Twist shall preferably be expressed in turns per metre (t.p.m.) but may also be  
expressed in turns per centimetre (t.p.cm.).  
 
3.7 elongation per cent  — The increase in length of a specimen expressed as a percentage of the  original 
length; extension per c ent. 
 
NOTE: In a tensile test, the elongation per cent, or extension per cent, is calculated on the basis of  the nominal gauge length of a pre -
tensioned specimen.  
 
3.8 elongation at the breaking force  — The elongation produced by the breaking force, i.e. t he maximum 
force.  
 
3.9 yarn packages — A length or lengths of yarn in a form suitable for use, handling, storing or shipping.  
Packages may be unsupported, such as balls, skeins or cakes or supported, such as bobbins, cops,  
cones, pirns, spools, tubes, or b eams.  
 
3.10 moisture regain — The mass of moisture present in a textile material expressed as a percentage of  
the oven -dry mass.  
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                       DKS 1113: PART 5:2022  
© KEBS 2022  — All rights reserved  7  
 
 
4. REQUIREMENTS  
 
4.1 Linear Density — The nominal linear density of the yarn shall be as declared, subject to  a tolerance of  
± 3 per cent . This shall be determi ned in accordance with KS ISO 2060 . 
 
 
4.2 Coefficient of Variation of Linear Density — The coefficient of variation of the linear density of the  
yarn shall not excee d 2.5 per cent . The coefficient  of varia tion (C.V.) of the yarns shall be determined from 
the following formula:  
 
C.V. =
%100 X 
x  
 
 
where,   

nx2x

  
 
 where,   
 
   
 x = the linear density in tex of any yarn sample;  
 
  
x  = the mean linear density in tex of all the yarn samples;  
 
   
n  = the total number of samples; and  
 
   
  = the standard deviation in tex.  
 
4.3 Yarn Twist — The tu rns per metre (or centimetre) of the yarn shall be as declared subject to a tolerance 
of ± 5 per cent . This shall be determi ned in accordance with KS ISO 2061 . 
 
4.4 Elongation at the Breaking Force — The minimum elongation at the breaking force of the yarn shall  
be 5 per cent.  
 
4.5 Bre aking Tenacity — The minimum breaking tenacity of the yarn shall be as specified in Table 1. The  
breaking tenacity of the yarn shall be determined in accordance with KS ISO 2062 . 
 
4.6 Yarn Unevenness (Irregularity) — The yarn unevenness in terms of coeffic ient variation (% C.V.)  
shall be determined in accordance with KS ISO 16549 . 
 
4.6.1 Ring Spun Yarns — The coefficient of variation (irregularity) of the carded ring  spun yarns shall not 
exceed those specified in Table 2.  
 
4.6.2 Rotor Spun Yarns — The coeff icient of variations (irregularity) of the carded rotor  spun yarns shall not 
exceed those specified in Table 3.  
 
4.7 Moisture Regain — The moisture regain of the yarn shall not exceed 0.4 per cent . This shall be  
determin ed in accordance with KS EAS 257  
 
4.8 Package Mass — The mass of the package shall be as declared su bject to a tolerance of ±2 per cent . 
This shall be determin ed in accordance with KS ISO 6741 -1 
 
 
 
 DKS 1113 : PART 5:2022  
 
8  © KEBS 202 2 — All rights reserved   
 
 
TABLE 1 — REQUIREMENT FOR BREAKING TENACITY  
 
SN YARN TYPE  MINIMUM BREAKING  
TENACITY: CN/Te x 
1.  Ring spun  24 
2.  Rotor spun  22 
 
TABLE 2 — REQU IREMENTS FOR EVENNESS FOR RING  SPUN YARNS  
 
 
SN No.   
LINEAR DENSITY, t ex  
C.V. % Max.  
1.  45-25 10.0 
2.  24-20 11.0 
3.  19-16 11.5 
4.  15-13 12.5 
5.  12-11 13.0 
6.  10-9 13.5 
7.  8-7.2 14.0 
8.  7-6.4 14.5 
9.  6.3-5.9 15.0 
10.  Finer than 5.9  15.5 
 
 
 
TABLE 3 — REQU IREMENTS FOR EVENNESS FOR ROTOR  SPUN YARNS  
 
SN No.   
LINEAR DENSITY, t ex  
C.V. % Max.  
1.  Courser than 60  12.0 
2.  60-35 12.5 
3.  34-25 13.0 
4.  24-20 13.5 
5.  19-16 14.0 
6.  15-12 15.0 
 
 
5 WRAPPING AND PACKING  
 
Yarn package(s) shall  be wrapped in suitable wrappers or packed in suitable containers to protect  them from 
damage while being handled or while on transit or in storage.  
 
6.  MARKING                                                                                                        DKS 1113: PART 5:2022  
© KEBS 2022  — All rights reserved  9  
6.1 Unit Packages — Each unit package shall have a label bearing the following information:  
 
a) Manufacturer’s name and address  or registered trade mark.  
b) Linear density in tex.  
c) Spinning method used, e.g. ring spun or rotor spun.  
d) Name of ma terial, i.e. 100 per cent polyester  yarn.  
e) Package mass.  
f) Yarn twist in t.p.m or t.p.cm  
g) Country of origin  
h) Lot/batch  number  
 
6.2 Bulk Containers — Each bulk container shall have a label bearing the following information:  
 
a) Manufacture’s name  and address  or registered trade mark.  
b) Name of ma terial, i.e. 100 per cent polyester  yarn.  
c) Linear density in tex.  
d) Quantity of pieces . 
e) Spinning method used, e.g. ring spun or rotor spun.  
f) Gross mass of the container.  
g) Lot/batch  number.  
h) Country of origin