KENYA STANDARD  KS 1113 -3:2022  
ICS 59.080.20  
Second Edition  
 
 © KEBS 2022   
 Specification  for spun yarns  
Part 3 : Polyester/cellulosic blended  yarns  
 
 KENYA STANDARD  KS 1113 -3:2022  
ICS 59.080.20  
Second Edition  
 
© KEBS 2022 – All rights reserved  ii 
 TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
Agriculture and Food Authority — Fibre Crops Directorate (AFA -FCD)  
Intertek International Ltd.  
Kenya Agricultura l & Livestock Research Organization (KALRO)  
Kenya Association of Manufacturers (KAM)  
Ministry of State Defence — Research and Development Department  
Moi University  
Spin Knit Ltd.  
Ministry of Industrialization, Trade and Enterprise Development — State Depar tment for Industrialization — 
Directorate of Agro -Industries  
Technical University of Kenya — Department of Fashion, Clothing and Textiles  
Texfab B.S  
East Africa Fine Spinners Ltd.  
Synthetic Fibres (K) Ltd.  
Spinners & Spinners Ltd.  
Kenya Threads Industry Ltd. 
Kenya Taitex Mills Ltd.  
Ministry of Public Works — Materials Department  
Nakuru Industries Ltd.  
Rift Valley Textiles Ltd.  
Blanket Industries Ltd.  
Raymond Woollen Mills (K) Ltd.  
Kicomi (1983) Ltd.  
Cotton Board of Kenya  
Ken-Knit (K) Ltd.  
Kenya Prisons — Tailoring Division  
Bonar (E.A.) Ltd.  
Kenya Industrial Research and Development Institute (KIRDI)  
Kenya Bureau of Standards — Secretariat  
REVISION OF KENYA STANDARDS  
In order to keep abreast of progress in industry, Kenya Standards shall be regularly revie wed.  Suggestions for 
improvements to published standards, addressed to the Managing Director, Kenya Bureau of Standards, are 
welcome.  
© Kenya Bureau of Standards 2022  KENYA STANDARD  KS 1113 -3:2022  
ICS 59.080.20  
Second Edition  
 
© KEBS 2022 – All rights reserved  iii 
 Copyright. Users are reminded that by virtue of Section 25 of the Copyright Act, Cap. 13 0 of 2001 of the Laws of Kenya, copyright subsists 
in all Kenya Standards and except as provided under Section 25 of this Act, no Kenya Standard produced by Kenya Bureau of Sta ndards 
may be reproduced, stored in a retrieval system in any form or transmitte d by any means without prior permission in writing from the 
Managing Director.  
  KENYA STANDARD  KS 1113 -3:2022  
ICS 59.080.20  
Second Edition  
 
© KEBS 2022 – All rights reserved  iv 
 Specification  for spun yarns  
Part 3 : Polyester/cellulosic blended 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)  
KENYA STANDARD  KS 1113 -3:2022  
ICS 59.080.20  
Second Edition  
 
© KEBS 2022 – All rights reserved  v 
 Foreword  
This Kenya Standard has been prepared by the Technical Committee on Yarns and Fibres 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 effi ciency 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. This Part 3 of this Kenya Standard has been developed with these int erests in mind.  
  
Yarns are produced in a wide range of counts (linear densities) of varying fibre blend compositions and 
proportions for various end -uses.  This Kenya Standard takes into consideration all these variations and 
specifies only the minimum r equirements for essential quality characteristics of yarns.  
 This Second edition cancels and replaces the First edition (KS 1113 -3:1993) which has been technically 
revised. The changes are as follows.  
               -Test methods in clauses 5.1, 5.4, 5.6,  5.7 and 5.9  have been updated  
               -Formular for coefficient of variation of linear density has been added  
               -Clause 7 on sampling have been added  
               -Method of determination of moisture regain  have been added in annex A  
 
 
During the preparation of this standard, reference was made to the following document:  
KS 1113 -3:1993 Specification for staple spun yarns Part 3. Polyester/cellulosic blended yarns  
Acknowledgment is hereby made for assistance received from these source s. 
 KS 1113 -3:2022   
 
© KEBS 2022 – All rights reserved   
 Specification  for spun yarns  — Part 3. Polyester/cellulosic blended yarns  
1 Scope  
This Part 3 of this Kenya Standard specifies the requirements , test methods and sampling methods  for 
polyester/cellulosic blended yarns.  
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.  
KS ISO 139,  Textiles — Standard atmospheres for conditioning and testing  
ISO 1833 -11, Textiles — Quantitative chemi cal analysis — Part 11: Mixtures of certain cellulose fibres with 
certain other fibres (method using sulfuric acid)  
KS ISO 2060, Textiles — Yarn from packages — Determination of linear density (mass per unit length) by the 
skein method  
KS ISO 2061, Textile s — Determination of twist in yarns — Direct counting method  
KS ISO 6741 -1, Textiles — Fibres and yarns — Determination of commercial mass of consignments — Part 1: 
Mass determination and calculations.  
 
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 16549, Textiles — Unevenness of textile strands — Capacitance method  
 
3  Application  
This Part 3 of this Kenya Standard applies to sing les-spun grey polyester/cellulosic blended yarns, except 
singles -spun slub yarns.  
 
4 Terms and definitions  
For the purposes of this Part 3 of KS 1113, the following definitions together with those given in KS 1113: Part 1, 
shall apply:  
 
4.1 cellulosic fibre  — Cellulosic fibre shall refer to cotton fibre or viscose fibre or polynosic fibre or any other 
regenerated fibre derived from cellulose.  
   
© KEBS 2022 – All rights reserved  iii 
 4.2 regenerated fibre  — A fibre formed from a solution of natural polymer or a chemical derivative of a natural 
polymer and having the same chemical constitution as the natural polymer from which the solution or 
derivative was made.  
 4.3 blend   
An intimately and thoroughly in termixed fibres in predetermined proportions.  
5 Requirements  
5.1 Fibre Composition and Proportion  
The fibre composition and proportion of the yarn shall be as declared subject to a tolerance of ± 5 per cent.  
This shall be determined in accordance with KS  ISO 1833 -11. 
5.2 Linear density  
The nominal linear density of the yearn shall be as declared subject to a tolerance of ± 3 per cent.  This shall 
be determined in accordance with K S ISO 2060  
5.3 Coefficient of variation of linear density  
The coefficient of  variation of the linear density of the yarn shall not exceed 2 %. The coefficient of variation 
(C.V.) of the yarns shall be determined using the following formula:  
C.V. =
%100 X 
x  
where  
 
 
where  
x is the linear density in tex of any yarn sample;  
x
 is the mean linear density in tex of all the yarn samples;  
n
 is the total number of samples; and  

 is the standard deviation in tex.  
5.4 Yarn twist  
The turns per metre (or centimetre) in the yarn shall be as declared subject to a tolerance of ± 5 per cent.  This 
shall be determined in accordance with KS ISO 2061.  
5.5 Elongation at the breaking force  
The minimum elongation at breaking force shall be 5 per cent.  This shall be determined in accordance with KS 
ISO 2062.  

12


nxx
 
© KEBS 2022 – All rights reserved  iv 
 5.6 Breaking tenacity  
The minimum breaking tenacity of the yarn shall be as specified in Table 1.  The breaking tenac ity of the yarn 
shall be determined in accordance with KS  ISO 2062.  
5.7 Yarn unevenness (irregularity)  
The yarn unevenness in terms of coefficient of variation (per cent c.v.) shall be determined in accordance with 
KS ISO 16549.  
5.7.1  Unevenness of Ring Sp un Yarns  — The coefficient of variation (irregularity) of the ring spun yarns shall 
not exceed those specified in Table 2.  
  
5.7.2  Unevenness of Rotor Spun Yarns -The coefficient of variation (irregularity) of the rotor spun yarns shall 
not exceed those sp ecified in Table 3.  
5.8 Moisture regain  
The moisture regain of the yarn shall not exceed 5 per cent.  This shall be determined in accordance with Annex 
A 
5.9 Package mass  
The mass of the package, conditioned as per KS ISO 139 , shall be as declared subject to a tolerance of – 2 per 
cent.   
 
 
Table 1. Requirements for Breaking Tenacity  
  
  
S/N   
YARN BLEND AND USE    
MINIMUM BREAKING 
TENACITY, CN/tex  
   
Test Met hod 
  
(i)    
Ring spun polyester/cotton yarn for 
weaving    
18  KS ISO 2062  
  
(ii)    
Ring spun polyester/viscose/polynosic 
yarn for weaving    
24  
  
(iii)    
Ring spun polyester/cotton yarn for 
knitting    
16  
 
(iv)    
Ring spun polyester/viscose/polynosic 
yarn for knitting    
20  
 
(v)    
Rotor spun polyester/cotton yarn for 
weaving     
15  
 
(vi)    
Rotor spun polyester/viscose/polynosic 
yarn for weaving    
18   
© KEBS 2022 – All rights reserved  v 
  
(vii)    
Rotor spun polyester/cotton yarn for 
knitting    
13  
  
(viii)    
Rotor spun polyester/viscose/polynosic 
yarn for knitting    
15  
  
  
  
  
   
Table 2. Requirements for Unevenness of Ring Spun Yarns  
  
 
S/N   
LINEAR DENSITY, tex    
% C.V. max.   
Test Method  
i.    
45-25    
10  KS ISO 
16549  
ii.    
24-20    
11  
iii.    
19-16    
11.5  
iv.    
15-13    
12.5  
v.    
12-11    
13  
vi.    
10-9    
13.5  
vii.    
8-7.2    
14.0  
viii.    
7-6.4    
14.5  
ix.    
6.3-5.9    
15.0  
x.    
Finer than 5.9    
15.5  
  
  
 
 
 
 
 
 
 
  
© KEBS 2022 – All rights reserved  vi 
 Table 3. Requirements for Unevenness of Rotor Spun Yarns  
  
 
S/N   
LINEAR DENSITY, 
tex    
% C.V. max.   
Test Method  
i.    
Coarser than 60    
12.0  KS IS0 16549  
ii.    
60-35    
12.5  
iii.    
35-25    
13.0  
iv.    
24-20    
13.5  
v.    
19-16    
14.0  
vi.    
15-12    
15.0  
 
 
6 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 in transit or in storage.  
 
7 Marking  
7.1  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 material, i.e. 100 % polyester /cellulose  yarn;  
e) package  net mass  in kilograms ; 
f) yarn twist in t.p.m or t.p.cm;  
g) lot/batch number.  
h) Fibre composition and proportion;  
i) Whether waxed or not waxed (rotor spun yarns);  
j) Country of origin  
k) Recommended end -use.  
 
7.2 Bulk containers  
Each unit package shall have a label bearing the following information   
© KEBS 2022 – All rights reserved  vii 
 a) manufa cture’s name and address or registered trade mark;  
b) name of material, i.e. 100 % polyester/cellulose 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; and  
h) The counry of origin  
 
8 Sampling  
8.1 Lot  
 
8.1.1 The quantity of polyester /cellulose  spun yarns of the same variety delivered to a buyer against a d ispatch 
note shall constitute the lot.  
8.1.2 The conformity of the lot to the requirements of this standard shall  be determined based on the tests 
carried out on the samples selected from the lot.  
8.1.3 Unless otherwise agreed to between the buyer and the seller, the number of packs to be selected at 
random from a lot shall be as follows:  
SN Number of Packs in the Lo t Number of Packs to be Selected  
i.  Upto 15  5 
ii.  16-30 7 
iii.  31-50 10 
iv.  51-100 15 
v.  101-300 25 
vi.  301 and above  30 
 
8.1.4 Acceptance criteria - Acceptance shall be based on conformity of the lot to the requirements of this 
standard.  
 
 
 
 
 
  
© KEBS 2022 – All rights reserved  viii 
 ANNEX A  
(Normative)  
Determination of Moisture Regain  
A.1 Principe  
A known mass of yarns is dried and then the loss in mass expressed as a ratio of the dry mass.  
 
A.2 Apparatus  
 A.2.1 Weighing balance , Capable of weighing to an accuracy of 0.001 g.  
A.2.2 Drying Oven , well vent ilated with a temperature of 102 °C to 105 °C  
A.2.3 Desiccator , waterproof when sealed, will be used for transfer of analysed material and during weighing.  
 
 A.3 Procedure  
A.3.1  From the sample under test draw at least three test specimens each weighing ap proximately 5 g.  
A.3.2 Take a test specimen drawn as in A.3.1 and weigh it accurately  (M1) 
A.3.3 Dry it at a temperature of 102°C to 105°C until constant mass is obtained (see note)  
A.3.4 Cool the test specimen in a desiccator and determine the oven -dry mass (M2).  
NOTE The mass is usually regarded as constant if the loss between two successive weighing, taken at an interval of 30 min does not 
exceed  0.1 per cent of the first of the two v alues.  
 
A.3.5  Similarly test the other test specimen(s).  
 
A.4 Calculation  
Moisture regain = 
%100 
22 1X 
MM M  
A.5 Report  
 Report the average of the value calculated in A.4 as the moisture regain in %.