ICS 59.060.20  
 
Reference number
DRS 443: 2020
© RSB 2020
  
 RWANDA 
STANDARD  DRS 443 
 
First edition  
2020 -mm-dd 
Silk yarn  — Specification  
 
   
DRS 443: 2020  
©RSB 2020 - All rights reserved                  ii 
 In order to match with technological development and to keep continuous progress in industries, 
standards are subject to periodic review. Users shall ascertain that they are in possession of the latest 
edition  
 
 
 
 
 
 
 
 
© RSB2020  
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or ut ilized 
in any form or by any means, electronic or mechanical, including photocopying and microfilm, without 
prior written permission from R SB. 
Requests for permission to reproduce this document should be addressed to : 
Rwanda Standards  Board  
P.O Box 7099 Kigali -Rwanda  
KK 15 Rd, 49  
Tel. +250 788303492  
Toll Free: 3250  
E-mail: info@rsb.gov.rw  
Website: www.rsb.gov.rw  
ePortal: www.portal.rsb.gov.rw  DRS 443 : 2020  
iii                ©RSB 2020 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................... iv 
1 Scope  ................................ ................................ ................................ ................................ ................ 1 
2 Normative references  ................................ ................................ ................................ ....................... 1 
3 Terms and definitions  ................................ ................................ ................................ ...................... 2 
4 Classification  ................................ ................................ ................................ ................................ ....4 
4.1 Raw silk categories  ................................ ................................ ................................ .......................... 4 
4.2 Grading in accordance with the major tests  ................................ ................................ ................... 4 
4.3 Degrading in accordance with the auxiliary tests  ................................ ................................ ........... 4 
5 Expression of raw silk size  ................................ ................................ ................................ .............. 5 
6 Requirements  ................................ ................................ ................................ ................................ ...5 
6.1 General requirements ................................ ................................ ................................ ....................... 5 
6.2 Specific r equirements  ................................ ................................ ................................ ...................... 5 
6.2.1  Yarn linear density  ................................ ................................ ................................ ........................... 9 
6.2.2  Evenness, cleanness and neatness  ................................ ................................ ................................ 9 
6.2.3  Yarn size, size deviation and maximum deviation  ................................ ................................ .......... 9 
6.2.4  Breaking load, tenacity and elongation at break ................................ ................................ ............. 9 
6.2.5  Skein breaking strength  ................................ ................................ ................................ .................  10 
6.2.6  Yarn twist  ................................ ................................ ................................ ................................ ........  10 
6.2.7  Moisture regain  ................................ ................................ ................................ ...............................  10 
7 Packing and marking ................................ ................................ ................................ ......................  10 
7.1 Packing  ................................ ................................ ................................ ................................ ...........  10 
7.2 Marking  ................................ ................................ ................................ ................................ ...........  10 
8 Sampling  ................................ ................................ ................................ ................................ .........  11 
Annex A (normative)  Windi ng test  ................................ ................................ ................................ ............  12 
A.1 Test sample  ................................ ................................ ................................ ................................ .... 12 
A.2 Atmospheric conditions for conducting the test  ................................ ................................ ..........  12 
A.3 Conditioning of the test sample ................................ ................................ ................................ ..... 12 
A.4 Apparatus  ................................ ................................ ................................ ................................ ....... 12 
A.5 PROCEDURE  ................................ ................................ ................................ ................................ .. 13 
A.6 Records ................................ ................................ ................................ ................................ ...........  13 
 DRS 443: 2020  
©RSB 2020 - All rights reserved                  iv 
 Foreword  
Rwanda Standard sareprepared by Technical Committees and approved by R wanda Standards Board (RSB) 
Board  of Directors in  accordance with the procedures of RSB, in compliance with Annex 3 of the WTO/TBT 
agreement on the preparation, adoption and application of standards.  
The main task of technical committees is to prepare national standards.  Final Draft Rwanda S tandards 
adopted by Technical committ ees are ratified  by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 443 was prepared by Technical Committee RSB/TC 029, Textile and leather technology . 
In the preparation of this standar d, reference was made to the following standard:  
1) IS 15090 (Parts 1 to 11), Raw silk — Grading and methods of tests  
The assistance de rived from the above source is hereby acknowledged with thanks.  
Committee membership  
The following organizations were represented on the Technical Committee on Textile and Lather 
Technology (RSB/TC 029) in the preparation of this standard.  
Ministry of Trade and Industry (MINICOM)  
University of Rwanda -College of Science and Technology (UR -CST) 
National Agricultural Export Development Board (NAEB)  
 Rwanda Inspectorate, Competition and Consumer P rotection  Authority  (RICA)  
HeWorks Silk Rwanda Ltd  
Rene Pharmacy  
UTEXRWA Ltd  
OXALIS Ltd  
LIXIL/SATO  
Rwanda Standards Board (RSB) – Secretariat  
 DRS 443 : 2020  
v                ©RSB 2020 - All rights reserved  
 Rwand a Standards Board (RSB) – Secretariat  
 
 
 
 
 DRS 443 : 2020  
1                ©RSB 2020 - All rights reserved  
 Silk yarn — Specification  
1 Scope  
This Draft Rwanda Standard  specifies the requirements, sampling and test methods for raw silk in skein or on 
cone  or bobbin .  
2 Normative references  
The following documents are referred to in the text in such a way that some or all of their content constitutes 
requirem ents 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.  
ASTM D2255, Standard test method for grading spun yarns for appearance  
ASTM D5647, Standard Guide for Measuring Hairiness of Yarns by the Photo -Electric Apparatus  
RS ISO 139, Textiles Standard atmospheres for conditioning and testing  
ISO 2060, Textiles — Yarn from packages — Determination of linear density (mass per unit length ) — Skein 
method.  
ISO 2061, Textiles — Determination of twist in yarns — Direct counting method  
ISO 2062, Textiles — Yarn from packages — Method for determination of breaking toad and elongation at the 
breaking toad of single strand  
ISO 3951 -4, Sampling procedures for inspection by variables — Part 4: Procedures for assessment of 
declared quality levels  
ISO 6741 -1, Textiles — Fibres and yarns — Determination of commercial mass of consignments — Part 1: 
Mass determination and calculations  
ISO 6939, Textiles — Yarns from packages — Method of test for breaking strength of yarn by the skein 
method  
ISO 15625, Silk — Electronic test method for defects and evenness of raw silk  
ISO 16549 , Textiles — Unevenness of textile strands — Capacitance method  
ISO 172 02, Textiles — Determination of twist in single spun yarns — Untwist/retwist method  
ISO 21046, Silk — Test method for determining the size of silk yarns   
©RSB 2020 - All rights reserved                  2 
 ISO 21046, Silk — Test method for determining the size of silk yarns  
ISO 17202, Textiles — Determinatio n of twist in single spun yarns — Untwist/retwist method  
3 Terms and definitions  
For the purposes of this standard, the follow ing terms and definitions apply  
3.1 
silk 
animal fibre produced by certain insects to build their cocoons and webs . They are several  silkworm, but the 
silk produced by mulberry s ilkworm is t he main source of manufactured silk, name mulberry s ilk 
3.2 
silk yarn  
yarn made of nature silk fibres, including raw silk, tussah silk, dupion silk, thrown silk  
3.3 
thrown silk  
silk that has been twisted or doubled and twisted  
3.4 
raw silk  
silk filament formed by conglutinating a number of Bombyx mori cocoon baves by reeling machine accord ing 
to a certain reeling technique and quality requirements  
3.5 
Skein  
silk reeled and removed from a re -reeling  machine in the form of an open band  
3.6 
mulberry silk  
silk mainly of yellow, white or greenish yellow colour obtained from  domesticated silkworm Bombyx m ori of 
the family bombycida e which feed on mulberry leaves  DRS 443 : 2020  
3                ©RSB 2020 - All rights reserved  
 3.7 
linear density  
mass per unit length of a yarn  
3.8 
breaking load  
maximum load (or force) applied to a specimen in a tensile test carried to rupture  
3.9 
elongation at break  
increase in length of a specimen produced by the breaking load  
3.10 
tenacity  
tensile force per unit of linear density of  the unstrained specimen  
3.11 
twist  
number of turns about the axis of a length equal to the nominal gauge length before untwisting  
3.12 
twist factor  
measure of the spiralling orientation of the fibres in a spun yarn or of the filaments in a filament  yarn  
3.13 
tex 
 mass in grams of 1000 m of the yarn. It is expressed as a number  
3.14 
denier  
mass in grams of 9000 meters of he ya rn. It is expressed as a number   
©RSB 2020 - All rights reserved                  4 
 3.15 
evenness  
uniformity of a yarn with respect to its linear density  
3.16 
evenness  variation  
variation in mass per unit length along the length of the yarn, expressed as coefficient of variatio n 
4 Classification  
4.1 Raw silk categories  
For grading purposes, raw silk shall be divided into three categories according to their sizes:  
4.1.1 Category I : 2.0 t ex (or 18 d enier ) or below  
4.1.2  Category II : 2.1 to 3.7  tex (or 19 to 33 denier)  
4.1.3 Category III : 3.8tex (or 34 denier) or above  
The grades shall be expressed in the following order in all categories of raw silk where 4A is of th e highest 
and E is of the lowest  merit: 4A, 3A, 2A, A, B, C, D, E. 
4.2 Grading in accordance with the major tests  
4.2.1  The grade of a lot of size 2.6 tex (or 33 denier) and finer ( catego ries 1 and 2) shall be determined 
according to the lowest respective grade of its size deviation, evenness variation I, evenness variation II, 
cleanness, average neatness and low neatness  in accordance with table 2 and 3.  
4.2.2  The grade of a lot size 3.7 tex (or 34 denier) and coa rser (category 3) shall be determined according 
to the lower respective grade of its size deviation, maximum deviation, evenness variation I, evenness 
variation II, average neatness and low neatness as given in table 4.  
4.2.3  In case any one or more of results fall below the limits prescribed for a grade, the lot sh all be 
degraded to the lowest grade wherein such value is given in the classification tables.  
4.3 Degrading in accordance with the auxiliary tests  
In case of lot size 2.6 tex (or 33 denier) and finer if observed value for maximum deviation, evenne ss III, 
windi ng, tenacity, elongation or cohesion, and observed value for evenness variation III, winding, tenaci ty or 
elongation in case of a lot of size 3.7 tex (or 34 denier) and coarser, is found to be lower than th e 
corresponding value specified in the class of au xiliary test, then the grade provisionally established in 
accordance with the preceding  paragraph shall be lowered by as many grades as the numerical differe nce 
that exists between the required auxiliary test class and the class actually found, provided t hat any difference 
of more than one class shall be deemed as on class difference with respect to the maximum deviation and DRS 443 : 2020  
5                ©RSB 2020 - All rights reserved  
 evenness variation III of a lot of size 33 denier and finer and evenness variation  III of a lot of size 34 denier 
and coarser . 
5 Expre ssion of raw silk size  
Raw silk value is marked with lower and upper size limit. Thus its central value is nominal size.  
Example  
a) 20/22 denier: indicates that the nominal size is 21 denier. The lower size limit is 20 denier and th e upper 
size limit is 22 de nier 
b) 40/44 denier: indicates that the nominal size is 42 denier, the lower size limit is 40 denier and th e upper 
size limit is 44.  
6 Requirements  
6.1 General requirements  
6.1.1  The yarn shall be reasonably free from snarls, slubs, thin and thick places, fuzz, bunches , loose 
ends, odd, knots, knots with long tails, stains, burrs, etc. However, one knot per kg of shoddy yarn  shall be 
permissible.  
6.1.2  White silk yarn shall have a uniform bleached finish. The dyed yarn shall have the required shade 
and free from all dyeing defects.  
6.1.3  When coloured, raw silk yarn shall be of uniform colour, luster and feel.  
6.2 Specific requirements  
6.2.1  Raw silk shall comply with the requirements of tables 2 -4 when tested in accordance with 6.3. 
Table 2 - Specific requirements for raw silk of c ategory I and grading  2.0 tex (or 18 denier)  and below  
Items  Nominal size  4A 3A 2A A B C D E 
Size Deviation  
Tex or denier  1.3 tex (or 12 
denier) and below  0.089  
(0.80)  0.106  
(0.95)  0.122  
(1.10)  0.150  
(1.35)  0.189  
(1.70)  0.256  
(2.30)  0.322  
(2.90)  Above 0.322  
(Above 2.90)  
1.4 to 1.7 tex (13 to 
15 denier)  0.100  
(0.90)  0.117  
(1.05)  0.139  
(1.25)  0.167  
(1.50)  0.200  
(1.80)  0.272  
(2.45)  0.339  
(3.05)  Above 0.339  
(Above 3.05)  
1.8 to 2.0 tex (16 to 
18 denier )  0.111  
(1.00)  0.133  
(1.20)  0.156  
(1.40)  0.189  
(1.70)  0.211  
(2.00)  0.289  
(2.60)  0.356  
(3.20)  Above 0.356  
(Above 3.20)  
Evenness 
variation I  (Count )  30 34 38 42 46 48 50 Above 50   
©RSB 2020 - All rights reserved                  6 
 Evenness 
variation II  (Count )  2 3 5 7 11 15 20 Above 20  
Cleanness,%  97 95 93 88 83 79 75 Below  75  
Average neatness, %  94 92 90 87 82 78 74 Below 74  
Low neatness, %  90 87 83 77 74 72 70 Below 70  
Auxiliary tests  
Items  class  (1) (2) (3) (4) (5) (6) (7) 
Maximum 
deviation  
 
Tex or denier  1.3 tex (or 12 
denier) and below  0.23 
(2.1) 0.29 
(2.6) 0.33 
(3.0) 0.40 
(3.6) 0.52 
(4.7) 0.67 
(6.0) Above o.67  
(Above 6.0)  
1.4 to 1.7 tex (13 to 
15 denier)  0.27 
(2.4) 0.31 
(2.8) 0.37 
(3.3) 
 0.46 
(4.1) 0.64 
(5.8) 0.72 
(6.5) Above 0.72  
(Above 6.5)  
1.8 to 2.0 tex (16 to 
18 denier )  0.30 
(2.7) 0.36 
(3.2) 0.42 
(3.8) 0.51 
(4.6) 0.67 
(6.0) 0.81 
(7.3) Above 0.81  
(Above 7.3)  
Items  class  (1) (2) (3) (4) (5) (6) 
Evenness 
variation III  (Count)  0 1 2 3 4 Above 4  
Items  Class  (1) (2) (3) (4) (5) (6) (7) 
Winding  
(Breaks)a 1.3 tex (or 12 
denier)  2 4 6 9 12 25 Above 25 
1.4 to 2.0 tex (or  
13 to 18 denier)  1 3 5 8 11 14 Above 14  
Items  Class  (1) (2) 
Tenacity g/tex (or g/denier)  
 33 and above  
(3.7) Below 33  
(below 3.7)  
Elongation  20 19 18 Below 18  
Items  Class  (1) (2) (3) 
Cohesion (strokes)  40 30 Below 30  
Moisture regain, %, max.  11 
a Not applicable for silk on cone  
6.2.2  In case two or more auxiliarytest classes are found to be lower than the corresponding values listed  
in the classes of the auxiliary tests, then the lot shall be declassed by a number eq ual to the highest of the 
numerical differences as determined above.  DRS 443 : 2020  
7                ©RSB 2020 - All rights reserved  
 6.2.3  In case the result of visual inspection of a lot is found to be poor in the general finish and /or t he 
result of the skein finish in the winding test of a lot is found to be poor, t he grade of the lot shall be one below 
that as determined in accordance with 4.2.1 . 
6.2.4  In case the result of the visual inspection of a lot is found to be inferior in its general finish, or in case 
the number of breaks in the winding test exceeds the li mits mentioned below, the lot shall be classified as E 
grade:  
S/No. Class  Breaks  
i.  2.1 to 3.7  tex (or 19 t 33 denier)       26 
ii.  3.8 to 7.7 tex (or 34 to 69 denier)      24 
iii.  7.8 tex (or 70 denier) or above         22 
Table 3 Specific requirements for raw silk of c ategory II and  grading 2.1 to 3.7 tex (or 19 to 33 denier)  
Items  Nominal size  4A 3A 2A A B C D E 
Size Deviation  
Tex or denier  2.1 to 2.4 tex (or 19 
to 22 denier)  0.128  
(1.15)  0.150  
(1.35)  0.178  
(1.60)  0.217  
(1.95)  0.261  
(2.35)  0.317  
(2.85)  0.383  
(3.45)  Above 0.383  
(Above 3.45)  
2.6 to 2.8 tex (23 to 
25 denier)  0.144  
(1.30)  0.167  
(1.50)  0.200  
(1.80)  0.244  
(2.20)  0.289  
(2.60)  0.333  
(3.00)  0.389  
(3.50)  Above 0.389  
(Above 3.50)  
2.9 to 3.2 tex (26 to 
29 denier)  0.156  
(1.40)  0.183  
(1.65)  0.217  
(1.95)  0.261  
(2.35)  0.306  
(2.75)  0.344  
(3.10)  0.394  
(3.55)  Above 0.390  
(Above 3.55)  
3.3 to 3.7 tex (or 30 
to 33 denier)  0.167  
(1.50)  0.194  
(1.75)  0.228  
(2.05)  0.278  
(2.50)  0.328  
(2.95)  0.378  
(3.40)  0.428  
(3.85)  Above 0.428  
(Above 3.20)  
Evenness 
variation I  (Count )  30 34 38 42 46 48 50 Above 50  
Evenness 
variation II  (Count )  2 3 5 7 11 15 20 Above 20  
Cleanness,%  97 95 93 88 83 79 75 Below  75  
Average neatness, %  94 92 90 87 82 78 74 Below 74  
Low neatness, %  90 87 83 77 74 72 70 Below 70  
 
Items  class  (1) (2) (3) (4) (5) (6) (7) 
Maximum 
deviation  
 
Tex or denier  2.1 to 2.4 tex (or 19 
to 22 denier)  0.38 
(3.4) 0.40 
(3.6) 0.48 
(4.3) 0.59 
(5.3) 0.70 
(6.3) 0.78 
(7.0) Above 0.78  
(Above 7.0)  
2.6 to 2.8 tex (23 to 
25 denier)  0.39 
(3.5) 0.46 
(4.1) 0.54 
(4.9) 
 0.66 
(5.9) 0.73 
(6.6) 0.79 
(7.0) Above 0.79  
(Above 7.1 ) 
2.9 to 3.2 tex (26 to 
29 denier)  0.42 
(3.8) 0.50 
(4.5) 0.59 
(5.3) 0.70 
(6.3) 0.76 
(6.8) 0.80 
(7.2) Above 0.81  
(Above 7.2)   
©RSB 2020 - All rights reserved                  8 
  3.3 to 3.7 tex (or 30 
to 33 denier)  0.44 
(4.0) 0.52 
(4.7) 0.61 
(5.5) 0.73 
(6.6) 0.80 
(7.2) 0.84 
(7.6) Above 0.84  
(Above 7.6)  
Items  class  (1) (2) (3) (4) (5) (6) 
Evenness 
variation III  (Count)  0 1 2 3 4 Above 4  
Items  Class  (1) (2) (3) (4) (5) (6) (7) 
Winding (breaks)  1 3 5 7 11 13 Above 13  
Items  Class  (1) (2) 
Tenacity g/tex (or g/denier)  
 33 
(3.7) Below 33  
(below 3.7)  
Elongation  18 Below 18  
Items  Class  (1) (2) (3) 
Cohesion (strokes)  60 20 Below 40  
Moisture regain, %, max  11 
 
Table 4 -Specific requireme nts for raw silk ofc ategory III and classification [3.8 tex (or 34 denier) and 
above  
Items  Nominal size  4A 3A 2A A B C D E 
Size Deviation  
Tex or denier  3.8 to 5.4 tex (or 
34 to 49 denier)  0.289  
(2.60)  0.344  
(3.10)  0.406  
(3.65)  0.494  
(4.45)  0.589  
(5.30)  0.689  
(6.20)  0.794  
(7.15)  Above 0.794  
(Above 7.15)  
5.6 to 7.7 tex (50 
to 69 denier)  0.417  
(3.75)  0.489  
(4.40)  0.578  
(5.20)  0.706  
(6.35)  0.833  
(5.50)  0.978  
(8.80)  1.128  
(10.15)  Above 1.128  
(Above 10.15)  
7.8 tex ( 70 denier) 
and above  0.494  
(4.45)  0.583  
(5.25)  0.689  
(6.20)  0.844  
(7.60)  0.944  
(8.50)  1.144  
(10.30)  1.350  
(12.15)  Above 1.350  
(Above 12.15)  
Maximum 
deviation  
 
Tex or denier  3.8 to 5.4 tex (or 
34 to 49 denier)  0.81 
(7.3) 0.88 
(7.9) 0.94 
(8.5) 1.03 
(9.3) 1.11 
(10.0)  1.18 
(10.6)  1.29 
(11.6)  Above 1.29  
(Above 11.6)  
5.6 to 7.7 tex (50 
to 69 denier)  0.94 
(8.5) 1.02 
(9.2) 1.10 
(9.9) 
 1.19 
(10.7)  1.26 
(11.3)  1.30 
(11.7)  1.34 
(12.1)  Above1.34  
(Above 12.1)  
7.8 tex ( 70 denier) 
and above  1.03 
(9.3) 1.11 
(10.0)  1.18 
(10.6)  1.28 
(11.5)  1.33 
(12.0)  1.38 
(12.4)  1.44 
(13.0)  Above 1.44  
(Above 13.0)  
Evenness 
variation I  (Count )  30 34 38 42 46 48 50 Above 50  DRS 443 : 2020  
9                ©RSB 2020 - All rights reserved  
 Evenness 
variation II  (Count )  2 3 5 7 11 20 28 Above 28  
Cleanness,%  97 95 93 88 83 79 75 Below  75  
Average neatness, %  94 92 90 87 82 78 74 Below 74  
Low neatness, %  90 87 83 77 74 72 70 Below 70  
 
Items  class  (1) (2) (3) (4) (5) (6) 
Evenness 
variation III  (Count)  0 1 2 3 4 Above 4  
Items  Class  (1) (2) (3) (4) (5) (6) (7) 
Winding 
(breaks)  3.8 to 7.7 tex (or 
34 to 69 denier)  0 2 3 6 9 12 Above 12  
7.8 tex (or 70 
denier ) and above  0 1 2 5 8 11 Above 11  
Items  Class  (1) (2) 
Tenacity g/tex (or g/denier)  
 33 
(3.7) Below 33  
(below 3.7)  
Elongation  18 Below 18  
Moisture regain, %, max  11 
 
6.2.1  Yarn linear density  
The linear density of the yarn shall be determi ned in accordance with ISO 2060 . 
6.2.2  Evenness , cleanness and neatness  
The evenness of the yarn and yarn faults shall be determined in accordance with ISO 15625 . 
6.2.3  Yarn size, size deviation and maximum deviation  
Yarn size, size deviation and maximum deviation, conditioned size and CV size shall be determi ned in 
accordance with ISO 21046.  
6.2.4  Breaking load, tenacity and elongation at break  
The breaking load of single strands and elongation at break shall be determined in accordance with I SO 2062.   
©RSB 2020 - All rights reserved                  10 
 6.2.5  Skein breaking strength  
The skein breaking strength of the yarn s hall be determined in accordance with ISO 6939.  
6.2.6  Yarn twist  
The number of turns per unit length shall be determined in accordance with ISO 17202. The direction for twist 
shall be indicated by the capital letter “S” or “Z”  
6.2.7  Moisture regain  
Moisture regain sh all be determined in accordance with ISO 6741 -1. 
7 Packing and marking  
7.1 Packing  
7.1.1  Suitable number of skeins prepared shall be made into neat books, each weighing approximately 
5kgs of equal dimensions on a long skein book making machine. Each such book shall be neatly tied with 
separate cotton bands at three or five different places and wrapped in light packaging paper. Twelve  such 
books of 5kgs shall be carefully wrapped in a cotton shirt and jute cloth and packed intoa bale.  Skeins shall be 
uniform in ci rcumference, width and mass; free from reel arm gums; the beginning of raw silk thread shall be 
capable of being unwound from skein with the least possible amount of waste.  
7.1.2  The net mass of silk in a bale shall be 30kgs.  
7.2 Marking  
Individual units shall  be identified and marked with the following information  
a)  name of material;  
b) manufacturer’s name, trademark or other means of identification ; 
c) linear density;  
d) batch number;  
e) mass of consignment, in accordance with ISO 6741 -1; 
f) end use of yarn, e.g. weaving or knitting;  and 
g) storage condition s. DRS 443 : 2020  
11                ©RSB 2020 - All rights reserved  
 8 Sampling  
The sampling shall be done in accordance with ISO 3951 -4. 
 
   
©RSB 2020 - All rights reserved                  12 
 Annex A  
(normative ) 
 
Winding test  
A.1 Test sample  
The sample for the test shall be 10 skeins in the case of a lot consisting of skeins of approximatel y 70 g  each 
and 5 skeins in the case ofa lot consisting of skeins of approximately 140 g each.  
A.2 Atmospheric conditions for conducting the test  
The test shall be carried out in a standard atmosphere at 65 ± 2 % relative humidity and 27 ± 20C temperature.  
A.3 Conditionin g of the test sample  
Prior to test, the test sample shall be conditioned to moisture equilibrium in a standard atmosphere at 65± 2 % 
relative humidity and 27± 20C temperature for 24 hours.  
A.4 Apparatus  
A.4.1   Winding Frame : the winding frame shall be equipped to drive the bobbins from both ends and shall 
be capable of being adjusted to run at uniform winding speed of 110, 140 or 165 m/min depending on y arn  
size.  
A.4.1.1    Swifts : the swifts used in the shall be automatic,  self centering, pin -hub swifts, and each swift 
shall weigh about 530 g.  
A.4.1.2   Bobbins : the bobbins used for the test shall be smooth and well balanced so as to give regular 
tension and uniform angular speed. The dimensions shall be as per table A.2  
Table A.2 -Bobbins dimensions  
S/N Characteristics  Size 
i. Diameter of head  60 mm  
ii. Diameter of barrel  38 mm  
iii. Length between heads  85 mm  
iv. Weight  105 g  
 
 
 DRS 443 : 2020  
13                ©RSB 2020 - All rights reserved  
 A.4.2   Stop w atch 
A.5 PROCEDURE  
One half of the sample skeins shall be wound from t he outer surface of the skeins and the other half from the 
inner surface of the skeins.in case of 140 g skeins, 3 skeins shall be wound from t he outer surface and the 
other 2 skeins from the inner surface or vice -versathe sample skeins shall be put on the swifts with care to 
ensure that each skein is in good condition.  
The average winding speed, the breaks counting period and the time of the preliminary winding operation for 
winding test shall be determined according to the size under test as per table A.1  
 Table  A.1 Average speed and winding period for winding test  
Size under test  Preliminary 
winding  Average speed 
(metre/min.)  Winding period(minutes)  
70 g skeins  140 g skeins  
1.3 tex (or 12 denier ) or finer  10 110 60 120 
1.4 to 1.9 tex ( 13-18 denier)  10 140 60 120 
2.0 to 3.7 tex ( 19-33 denier)  10 165 60 120 
3.8 to 7.7 tex ( 34-69 denier)  5 165 30 60 
7.8 tex ( 70 denier)  or coarser  5 165 20 40 
The preliminary winding operation is applicabe onlyfor the winding from the inner surface, and the  breaks 
occurring duirng a specific period shall be counted and recorded.  
In the case of winding skeins of approximately 140 g each, the winding for the first half of the win ding period 
shall be done on a set of 5 bobbins and the second half of the winding  period shall be done on anther set of 5 
bobbins so as to prepare 10 bobbins in total.  
A.6 Records  
The r ecord shall show the number of breaks in respect of each skein by a frequency distribution chart and the 
total number of breaks occurring in 10 sample skeins in the case of skeins of approximately 70 g each and in 
5 sample skeins in the case of skeins of approximately 140 g each during the specific period.  The results of 
the winding test shall be recorded as per table A.3.  
Table A.3 -Record and report of winding test of raw silk  
S/N Characteristics  Value recorded  
i.  Mark of the lot :   
ii.  Serial No. of bales in the lot:   
iii.  Starting time:   
iv.  Ending time:   
v.  Total time :    
©RSB 2020 - All rights reserved                  14 
 vi.  Nominal denier of the lot:   
vii.  Speed of the machine (m/min):   
Skein No.  Breaks  Winding period  
Preliminary winding  
1.   
2.    
3.    
4.    
5.   
6.    
7.    
8.    
9.    
10.   
Breaks for 10 skeins per hour of 
winding:    
Remarks :    
Date:    
 
  DRS 443 : 2020  
15                ©RSB 2020 - All rights reserved  
 Bibliography  
[1] ISO 10290 Textiles — Cotton yarns — Basis for specification  DRS 443 : 2020  
 
Price based on nnn pages  
©RSB 2020 - All rights reserved