ICS 59.080.30  
 
Reference number
DRS444 : 2020
© RSB 2020
  
 RWANDA 
STANDARD  DRS
444
First edition
2020 -mm-dd
 
Spun silk woven fabric and silk sheet — 
Specification  
 
   
DRS 444 : 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 utilized 
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 thi s 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 444 : 2020  
iii                ©RSB 2020 - All rights reserved  
 Contents  Page 
Foreword  ................................ ................................ ................................ ................................ ...................... iv 
1 Scope  ................................ ................................ ................................ ................................ ................ 1 
2 Normative references  ................................ ................................ ................................ ....................... 1 
3 Terms and defi nitions  ................................ ................................ ................................ ...................... 2 
4 Requirements  ................................ ................................ ................................ ................................ ...3 
4.1 General requirements ................................ ................................ ................................ ....................... 3 
4.2 Specific requirements  ................................ ................................ ................................ ...................... 3 
5 Packing and labelling  ................................ ................................ ................................ ....................... 5 
5.1 Packing  ................................ ................................ ................................ ................................ ............. 5 
5.2 Labelling  ................................ ................................ ................................ ................................ ........... 5 
6 SAMPLING  ................................ ................................ ................................ ................................ ........ 5 
 DRS 444 : 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 ratifie d by me mbers of RSB Board of Director s for publication and 
gazettment as Rwanda Standards.  
DRS 444 was prepared by Technical Committee RSB/TC 029, Textile and leather technology . 
Committee membership  
The following organizations were represented on the Tech nical Committee on Textile and leather 
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 Protection Authority (RICA)  
HeWorks Silk Rwanda Ltd  
Rene Pharmacy  
UTEXRWA Ltd  
OXALIS Ltd  
LIXIL/SATO  
Rwanda Standards Board (RSB) – Secretariat  DRS 444 : 2020  
v                ©RSB 2020 - All rights reserved  
 Introduction  
Spun silk woven fabric  issolely made from silk fibre that is recovered from silk waste and cut cocoons (from 
silk breeding facilities)  while silk sheet is derived from un -reelable silk cocoons and silk waste. The fabric is 
The fabric is woven by a weaving machine into a grey fabr ic with the original shiny cream colour . The yarn 
and fabric can by dyed to any colour  or shade.  
Spun silk can be used for shantung, pile fabrics, dress trimmings and linings, elastic webbing, sewi ng silk, 
summer weight silks, velvets, umbrella fabrics and  insulation. Short lengths of inferior silk filaments taken from 
waste material are combed and spun together as silk thread. Spun silk threads are soft but less lust rous, 
strong and elastic than reeled silks.  
Spun silk woven fabrics a pplications include cl othing, home textiles and accessories.  
There are several sources to fabricate spun silk:  
a) pierced cocoons,  
b) double cocoons;  
c) floss, brushed from cocoons before reeling;  
d) friese, the coarse and uneven silk fibre at the beginning and end of each cocoon;  
e) waste d erived fro m the processing of spun silk y arn is also used. Such fibre is labelled as waste silk, silk 
waste or most frequently noil silk. Silk noil may be reprocessed into spun yarn ad woven into textur ed 
fabrics for draperies, upholstery and sportswear. T hese fabrics are dull, rough, with a cotton -like 
appearance and more resilience.  
 
 DRS 444 : 2020  
1                ©RSB 2020 - All rights reserved  
 Spun silk woven fabric and silk  sheet  — Specification  
1 Scope  
This Draft Rwanda Standard specifies the requirements, sampling and test methods for spun silk woven fabric  
and silk sheet.  
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.  
RS ISO 105 -B01, Textiles — Tests fo r colour fastness — Part B01: Colour fastness to light: Daylight  
RS ISO 105 -C10, Textiles — Tests for colour fastness — Part C10: Colour fastness to washing with soap or 
soap and soda  
RS ISO 105 -E04, Textiles — Tests for colour fastness — Part E04: Colour fastness to perspiration  
RS ISO 105 -X11, Textiles — Tests for colour fastness — Part X11: Colour fastness to hot pressing  
ASTM D1388 , Standard Test Method for Stiffness of Fabrics  
RS ISO 139, Textiles — Standard atmospheres for conditioning and testing  
RS ISO 1833 -18, Textiles — Quantitative chemical analysis — Part 18: Mixtures of silk with other protein 
fibres (method using sulfuric acid)  
ISO 2313 , Textiles — Determination of the recovery from creasing of a horizontally folded specimen of fabric 
by measur ing the angle of recovery  
RS ISO 3071 , Textile materials — Method for determination of pH value of aqueous extracts  
RS ISO 3758, Textiles — Care labelling code using symbols  
RS ISO 3801, Textiles — Woven fabrics — Determination of mass per unit length and mass per unit area  
RS ISO 5077 , Textiles — Determination of dimensional change in washing and drying  
ISO 5084, Textiles — Determination of thickness of textiles and textile products  
ISO 7211 -5, Textiles — Woven fabrics — Construction — Methods of analysis — Part 5: Determination of 
linear density of yarn removed from fabric   
©RSB 2020 - All rights reserved                  2 
 RS ISO 7211 -2, Textiles — Woven fabrics — Construction — Methods of analysis — Part 2: Determination of 
number of threads per unit length  
ISO 9073 -9, Textiles — Test methods for nonwovens — Part 9: Determination of drapability including drape 
coefficient  
RS ISO 13934 -1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and 
elongation at maximum force using the strip method  
RS ISO 22198, Textiles — Fabrics — Determination of width and length  
ISO 24153, Random sampling and randomization procedures  
ISO 13937 -2, Textiles — Tear properties of fabrics — Part 2: Determination of tear force of trouser -shaped 
test specimens (Single tear method)  
ISO 13934 – 1, Textiles — Tensile properties of fabrics — Part 1: Determination of maximum force and 
elongation at maximum force using the strip method  
RS EAS 96 -1, Sanitary towels — Specification — Part 1: Disposable  
ISO 9073 -2, Textiles — Test methods for nonwovens — Part 2: Determination of thickness  
ISO 9073 -18, Textiles — Test methods for nonwovens — Part 18: Determination of breaking strength and 
elongation of nonwoven materials using the grab tensile test  
3 Terms and definitions  
For the purposes of this standard, the  follow ing terms and definitions apply . 
3.1 
spun silk  
yarn produced by spinning , un-reelable silk cocoons,silk waste, short and broken filaments from which the 
sericin has been removed  
3.2  
spun silk fabric  
fabric woven from spun silk  yarn DRS 444 : 2020  
3                ©RSB 2020 - All rights reserved  
 4 Requirements  
4.1 General requirements  
a) The spun silk woven fabric shall be woven from 100 % silk yarns when tested in accordance with RS ISO 
1833 -18. 
b) The spun silk woven fabric shall be generally free from defects which effect the performance such as 
holes, cuts, tears, spots, stains, gap stitches, loose ends and frayed ends  
c) The selvedge shall be straight and firm  
d) When coloured, the spun silk woven fabric  shade shall be uniform throughout when visually examined in 
ordinary daylight  
4.2 Specific requirements  
4.2.1  The spun sil k woven fabric  properties shall be as specified in Table 1 when  tested  in accordance with 
the test methods given  therein.  
Table 1 – Mechanical and comfort properties of spun silk woven fabric  
S/No.  Characteristic  Requirement  Test method  
i.  pH value  6.0-8.0 RS ISO 3071  
ii.  Pilling resistance  3-4 ISO 12945 -1 
iii.  Drape coefficient , %, min  75 ISO 9073 -9 
iv.  Thickness, mm, min  0.44 ISO 5084  
v.  Mass per unit area, g/m2, min  180 RS ISO 3801  
vi.  Tensile strength,  N, min  Warp  380 RS ISO 13934 -1 
Weft  550 
vii.  Elongation at  break , %  Warp  30 
weft  20 
viii.  Flexural rigidity, mg -cm Warp  1.41 ASTM D1388  
Weft  22.17  
Overall  5.60 
ix.  Threads density  Ends/cm  50 RS ISO 7211 -2 
Picks/cm  20 
x.  Yarn count, denier   Weft  378 ISO 7211 -5 
Warp (2 ply)  64 
xi.  Crease recovery angle, degree  
(weft + warp)  Initial  120.5  ISO 2313  
Final  131.0   
©RSB 2020 - All rights reserved                  4 
 4.2.2  The silk sheet properties shall be as specified in Table 2  when tested in accordance with the test 
methods given therein . 
Table 2 —silksheets  
S/No.  Characteristic  Requirement  Test method  
i.  Fibre composition, %  100 ISO 1833 -18: 2019  
ii.  pH value  6.0-8.5 RS ISO 3071  
iii.  Moisture  content, % m/m , max.  8 RS EAS 96 -1 
iv.  Mass per unit area (Specificweight), g/m2 590 ISO 3081  
v.  Tear strength, N ,min Warp  25 ISO 13937 -2 
Weft 10 
vi.  Tensile strength, N , min  Warp  2900 ISO 13934 – 1 
Weft  20 
vii.  Thickness, mm, min.  
 1.1 ISO 9073 -2 
4.2.3  The width of the spun silk woven fabric  shall be as declared subject to a tolerance of ± 2 % when 
measur ed in accordance with ISO 22198.  
4.2.4  The spun silk woven fabric length shall be as declared subject to a tolerance of ±1  %when determined 
in accordance with ISO 22198.  
4.2.5 Dimensional change  of spun silk woven fabric shall not exceed ±2 % when determined in accordance 
with RS ISO 5077.  
4.2.6  Colour fastness –The colour fastness of the coloured  spun silk woven fabric shall comply with the 
requirements given in Table 3  when tested in accordance with test methods specified  therein.  
Table 3  –Colour fastness requirements for dyed spun silk wove n fabrics  
S/No.  Fastness to:  Numerical Rating (min)  Method of test  
i. Change in colour  Staining adjacent 
fabric  
ii. Light  5 - RS ISO 105 -B01 
iii. Washing  4 4 RS ISO 105 -C10 
iv. Perspiration  4 4 RS ISO 105 -E04 
v. Hot pressing  4 4 RS ISO 105 -X11 
vi. Rubbing  Dry - 4 RS ISO 105 -C10 
Wet - 4 DRS 444 : 2020  
5                ©RSB 2020 - All rights reserved  
  
5 Packing and labelling  
5.1 Packing  
The spun silk woven fabric shall be rolled and packed in suitable and environmental friendly packaging 
material that protects it from any damage during handling, storage and transportation.  
5.2 Labelling  
The following information shall be legibly and indelibly marked on each roll or bale:  
a) name of the material ; 
b) fibre content ; 
c) length in metres (m);  
d) width in centimetres ( cm); 
e) mass of roll or bale in kilograms (kg);  
f)  manufacturer's name or registered trademark;  
g) country of origin ;  
h) intended use; and  
i) care labelling symbolsas per RSISO 3758 d epending upon the end use . 
6 SAMPLING  
Spun silk woven fabrics shall be sampled randomly  in accordance with ISO 24153  and the samples  shall be 
conditioned as per  RS ISO 139 . 
   
©RSB 2020 - All rights reserved                  6 
 Bibliography  
[1] Indian Journal of Fibre & Textile Research, Vol.19, December 1994, pp.247 -250 
 DRS 444 : 2020  
 
Price based on nnn pages  
©RSB 2020 - All rights reserved