KENYA STANDARD   DKS 479-2:2022 
ICS 59.080.020 
Third  Edition  
 
 © KEBS 2022   
 Specification  for Sewing threads  
Part 2: Sewing threads made wholly or partly from  
  synthetic fibres  
 
 
 DKS 479-2:2022 
 © KEBS 2022 – All rights reserved  
 TECHNICAL COMMITTEE REPRESENTATION  
The following organizations were represented on the Technical Committee:  
East African Fine Spinners Ltd.  
Synthetic Fibres (K) Ltd.  
Kenya Industrial Research and Development Inst itute (KIRDI)  
Kenya Prisons — Tailoring Division  
Kenya Taitex Mills Ltd.  
Kenya Threads Industries Ltd.  
Ken-Knit (K) Ltd.  
Ministry of Public Works – Materials Department  
Raymond Woollen Mills Ltd.  
Nakuru Industries Ltd.  
Rift Valley Textiles Ltd.  
Blanket Industries Ltd.  
Kicomi (1983) Ltd.  
Cotton Board of Kenya  
Bonar (E.A.) Ltd.  
Agriculture and Food Authority - Fibre Crops Directorate (AFA -FCD)  
Intertek International Ltd  
Kenya Agricultural & Livestock Research Organization (KALRO)  
Kenya Association of Manufa cturers (KAM)  
Ministry of State Defence -R&D Department  
Moi University  
Rivatex East Africa Limited  
State Department for Industrialization Directorate of Agro -Industries  
Technical University of Kenya - Department of Fashion, Clothing and Textiles  
Texfab B.S  
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, Ke nya 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. 130 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 transmitted by any mea ns without prior permission in writing from the 
Managing Director.  
  KENYA STANDARD  DKS 479-2:2022  
ICS 59.08 0.20 
Third  Edition  
 
© KEBS 2022 – All rights reserved  iii 
 Specification for Sewing threads  
Part 2: Sewing threads made wholly or partly from   
 synthetic fibres  
 
 
  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 479-2:2022 
 © KEBS 2022 – All rights reserved  
 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.  
Sewing threads made wholly or partly from synthetic fibres are used for industrial and domestic stitching of the 
correspondin g fabrics. It is important that sewing thread meets minimum requirements of the end -use. This Part 
2 of KS 479 specifies these minimum requirements.  
This Third  edition cancels and replaces the Second  edition (KS 479-2:1992 ) which has been technically 
revised. The changes are as follows;  
               -Test methods in clauses 4.2.1, 4.2.2, 4.2.7  and 4.2.8 have been updated  
               -Clause 7 on sampling have been added  
               -Method of determination of length  have been added in annex A  
               -Breaking tenacity requirement for polypropylene  threads has been added  
 
During the preparation of this standard, reference was made to the following document:   
KS 479-2:1992 , Specification for Sewing threads Part 2: Sewing threads made wholly or partly from   
 synthetic fibres  
BS 6157: 19 90 Specification for industrial sewing threads made wholly or partly from synthetic    
 fibres.  
Acknowledgment is hereby made for assistance r eceived from these sources.  DKS 479-2:2022   
 
© KEBS 2022 – All rights reserved   
 Specification for Sewing threads Part 2: Sewing threads made wholly or 
partly from synthetic fibres  
1 Scope  
This Part 2 of KS 479 specifies requirements , test methods and sampling method  of sewing threads made 
wholly or partly from synthetic fibres.  
 
2 Normative Reference s 
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  
KS ISO 1144, Textiles — Universa l system for designating linear density (Tex System).  
KS ISO 1833 , Textiles — Quantitative chemical analysis  
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 2076 , Textiles — Man-made fibres — Generic names  
KS ISO 105 -B01, Textiles — Tests for colour fastness — Part B01: Colour fastness to light: Daylight  
KS ISO 105 -B02, Textiles — Tests for colour fastness — Part B02: Colour fastness to artificial light: Xenon arc 
fading lamp test  
KS ISO 105 -B03, Textiles — Tests for colour fastness — Part B03: Colour fastness to weatheri ng: Outdoor 
exposure  
KS ISO 105 -B04, Textiles — Tests for colour fastness — Part B04: Colour fastness to artificial weathering: 
Xenon arc fading lamp test  
KS ISO 105 -C10, Textiles — Tests for colour fastness — Part C10: Colour fastness to washing with soap  or 
soap and soda  
KS ISO 105 -E04, Textiles — Tests for colour fastness — Part E04: Colour fastness to perspiration  
KS ISO 2061, Textiles — 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 545 , Method for determination of colour fastness of textiles to peroxide washing (sodium perborate).  
  
© KEBS 2022 – All rights reserved  iii 
  
3 Terms and definitions  
For the purpose of this Part 2 of KS 479, the following definitions, together with those given in K S 209, KS ISO 
2076 , and KS ISO 1144 , shall apply:  
 
3.1 loop textured   
threads made from continuous filament yarns which have  been subjected to a  texturing process by overfeeding 
in a turbulent air stream.  
3.2 crimp textured   
threads made from continuous filament yarns which have been subjected to a texturing process by highly 
twisting, heat setting in the twisted state and then untwisting.  
3.3 polyester and cotton core spun  
threads made from two or  more single core yarns (i.e. yarns produced at the spinning frame by feeding a filament 
yarn through the delivery rollers simultaneously with the spinning of the staple material).  
3.4 polyester and cotton component plied  
threads made from combination yarns in which a  continuous filament polyester yarn is folded with a cotton 
yarn.  
3.5 tenacity   
the ratio of the tension to the linear density of unstrained specimen. It is expressed in,  for example, 
centinewtons per tex  
3.6 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 density, obtained directly from tens ile testing machines which can be suitably adjusted to 
indicate tenacity instead of breaking force.  
4 Requirements   
4.1 General requirements  
4.1.1 Application  
 
This Part 2 of KS 479 applies to sewing threads made from the following fibres and combinations 
thereof:  
 
i. continuous filament polyester;  
 
ii. staple fibre polyester;  
 
iii. loop textured polyester;   
 © KEBS 2022 – All rights reserved  
  
iv. crimp textured polyester;  
 
v. continuous filament nylon 6.6;  
 
vi. staple fibre nylon 6.6;  
 
vii. staple fibre aramid nylon;  
 
viii. crimp textured nylon 6.6;  
 
ix. polyester and cotton core spun (continuous filament polyester core, cotton sheath);  
 
x. polyester and cotton component plied ; 
 
xi. polypropylene  thread . 
 
 
4.1.2 Appearance  
 When visually examined, sewing thread shall have a uniform shade or whiteness  and shall be devoid of 
singeing  defects and stains.  
4.1.3 Finishing  
Sewing threads shall be well lubricated to ensure efficient working on the appropriate  types of sewing 
machines.  
4.2 Specific requirements  
4.2.1 Resultant Linear Density   
The resultant linear density of the thread in tex shall be as declared subject to a tolerance of  2 per cent for 
continuous filament threads and  4 per cent for spun and plied threads.  This shall be determined in accordance 
with KS ISO 2060 . 
4.2.2 Type o f Sewing Thread  
The type of sewing thread shall be as declared. In the case of blends, the blend composition shall be as declared 
subject to a tolerance of  5 per cent . The thread type shall be determined by microscopic observation and the 
relevant part o f KS ISO 1833 . 
4.2.3 Coefficient of Variation of Linear Density  
The coefficient of variation of the resultant linear density shall not exceed 2 per cent for continuous filament 
threads and 5 per cent for spun plied threads.  
The coefficient of variation 
CV  shall be calculated from the following formula:  

CV
 x 100 %  

12


nxx

  
© KEBS 2022 – All rights reserved  v 
 where,  
 
                          x   –   the resultant linear density in tex of any thread sample;  
              
                  
x  =  the mean resultant linear density of all the samples;  
                            
                           n   =  the total number of all samples; and  
                           
                              =  the standard de viation in tex.  
 
 
4.2.4 Knots  
 
The number of knots permissible in a package of sewing thread shall be as specified in Table 1.  
 
Table 1 -Number of Permissible Knots in A Package of Sewing Thread  
SN Package Length, Metres  Permissible Knots  
i.  Up to 1 000  Not more than 1  
ii.  1001 -2500  Not more than 2  
iii.  2501 -4000  Not more than 3  
iv.  4001 -5500  Not more than 4  
v.  5501-7000  Not more than 5  
vi.  7001 -8500  Not more than 6  
vii.  More than 8 500  Not more than 7  
 
4.2.5 Length   
The length of the sewing thread contained in a package shall be as declared subject to a tolerance of 0.2 % 
when tested in accordance with annex A  
4.2.6 Net Mass  
The mass of the package, conditioned as per KS ISO 139 shall be as declared subject to a tolera nce of – 0.2 
per  cent  
4.2.7 Breaking Tenacity   
The minimum breaking tenacity for each type of sewing thread shall be as specified in Table 2.  This shall be 
determined in accordance with KS ISO 2062 . 
 
 
  
 © KEBS 2022 – All rights reserved  
 Table 2.  Specification for Breaking Tenacity  
SN Type of Sewing Thread  Breaking Tenacity 
cN per tex (min.) 
i.  Continuous filament polyester thread  40 
ii.  Spun staple fibre polyester thread  30 
iii.  Textured polyester thread  30 
iv.  Continuous filament nylon 6.6 thread  45 
v.  Spun staple nylon 6.6 thread  30 
vi.  Crimp textured nylon 6.6 thread  30 
vii.  Aramid nylon thread  22 
viii.  Polyester and cotton core spun thread  30 
ix.  Polyester and cotton component plied 
thread  30 
x.  Polypropylene  thread 40 
 
 
4.2.8 Colour Fastness  
The colour fastness of the dyed threads shall be as specified in Table 3 when tested with the methods specified 
therein.  
Table 3 - Colour Fastness Requirements  
SN  
AGENCY  NUMERICAL RATING   
METHOD OF TEST  Colour Change, (m in.) Staining, ( min.) 
i.  Light  6 - KS ISO 105 -B01  
KS ISO 105 -B02  
ii.  Washing  4 4 KS ISO 105 -C10 
iii.  Dry cleaning  4 4 KS ISO 105 -D01 
iv.  Perspiration  4 4 KS ISO 105 -E04 
 
v.  Peroxide washing  4 4 KS 08 -545 
 
vi.  Weathering  6 - KS ISO 105 -B03 
KS ISO 105 -B04 
 
  
© KEBS 2022 – All rights reserved  vii 
 5 Package Formation, Wrapping and Packing  
5.1 Package Formation  
 
Sewing threads shall be compactly and uniformly wound into cones or cheeses (spools). The free end of the 
thread shall be securely fastened to prevent unravelling  
 
5.2 Wrapping  
 
Each package (cone or cheese) shall be neatly and securely wrapped in celloph ane wrappers to prevent it 
from damage or contamination with dust, moisture, or fumes.  
 
5.3 Packing  
 
The neatly and securely wrapped packages shall be packed in boxes (cartons) in the agreed  quantities 
(preferably in dozens or grosses).  
 
6 Marking  
6.1 Unit packages  
 
Each unit package (cone or cheese) shall have a label bearing the following information:  
 
i. manufacturer’s name or registered trade mark;  
 
ii. type of sewing thread (refer to Clause 4.2.2); 
 
iii. nominal resultant linear density;  
 
iv. length of the sewing thread in metres;  
 
v. net mass of the sewing thread in grams;  
 
vi. ticket number in accordance with KS 08 -1141;  
 
vii. country of origin  
 
 
7.2 Bulk Containers  
 
Each bulk container (box) shall bear the following information:  
 
a) manufacturer’s name or registered trade mark;  
 
b) type of sewing thread;  
 
c) nominal resultant linear density;  
 
d) quantity of pieces;  
 
e) gross mass of the container;  
 
f) ticket number in accordance with KS 08 -1141;  
 
g) country of origin  
 
  
 © KEBS 2022 – All rights reserved  
 7 Sampling  
7.1 Lot  
 
7.1.1 The quantity of sewing  thread of the same variety delivered to a buyer against a despatch note shall 
constitute the lot.  
7.1.2 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.  
7.1.3 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 Lot  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 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  
© KEBS 2022 – All rights reserved  ix 
 ANNEX  A 
DETERMINATION OF  LENGTH  
A.1 Atmospheric Conditions for Testing  
The atmospheres for preconditioning, conditioning,  and testing shall be as specified in ISO 139.  
A.2 Conditioning of Test Specimens  
Prior to test, the test specimens  shall be conditioned in the standard atmosphere for at least 24 hours.  
A.3 Apparatus  
A.3.1 Warp Reel - with a perimeter of 100 0 ± 4 mm. Determine the actual perimeter of the reel with a strip of 
gummed paper passed tightly around the reel and secured by adhesion at the overlap . Cut the paper  strip and 
measure its length to an accuracy of 0 .1 percent.   
A.3.2 - Adjust able Yarn Tensioni ng Device -It shall be capable of giving a reeling tension that will result in 
skeins of the specified length when measured under a load of 0.5 gf/tex.  
A.3.3  Weighing Balance -It shall be capable of weighing skeins in  grams and with an accuracy of 0.2 percent.  
 
A.4 Procedure  
A.4.1 Determine linear density in tex as per KS ISO 2060  
A.4.2 Determine the net weight of the yarn in the package in grams  
 
A.5 Calculation  
Calculate the length per kilogram by the following formula:   
𝐿𝑒𝑛𝑔𝑡 ℎ 𝑖𝑛 𝑚𝑒𝑡𝑒𝑟  =1000  𝑋 𝑁𝑒𝑡 𝑤𝑒𝑖𝑔 ℎ𝑡
𝑙𝑖𝑛𝑒𝑎𝑟  𝑑𝑒𝑛𝑠𝑖𝑡𝑦  𝑖𝑛 𝑡𝑒𝑥 
 
A.6- Similarly determine the length in m eters of other test specimens.