ICS 83.140.99; 67.250  
 
Reference number
DRS 558: 2023
© RSB 2023
  
 RWANDA 
STANDARD  DRS 
558 
 
First edition  
2023-mm-dd 
 
Compostable drinking straws — 
Specification 
 
   
DRS 558: 2023 
©RSB 2023- 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 
 
 
 
 
 
 
 
 
© RSB2023 
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 RSB. 
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  Formatted:  French (France)
Field Code Changed
Formatted:  English (United Kingdom)
Formatted:  French (France)DRS 558: 2023 
iii                ©RSB2023- All rights reserved 
 Contents Page 
Foreword ............................................................................................................................................................ iv  
1 Scope ...................................................................................................................................................... 1  
2 Normative references ............................................................................................................................ 1  
3 Terms and definitions ........................................................................................................................... 1  
4 Requirements ......................................................................................................................................... 3  
4.1 Raw materials ........................................................................................................................................ 3  
4.2 Appearance ............................................................................................................................................ 3  
4.3 Standard size ......................................................................................................................................... 3  
4.4 Industrial compostability ...................................................................................................................... 4  
4.5 Water content ......................................................................................................................................... 4  
4.6 Solubility resistance.............................................................................................................................. 4  
4.7 Concentration of heavy metals and other elements .......................................................................... 4  
5 Packaging ............................................................................................................................................... 4  
6 Labelling ................................................................................................................................................. 5  
7 Sampling ................................................................................................................................................ 5  
Annex A (normative)  Test methods ................................................................................................................. 6  
A.1 Conditioning and testing atmosphere ................................................................................................. 6  
A.2 Standard sizes ....................................................................................................................................... 6  
A.2.1 Length deviation .................................................................................................................................... 6  
A.2.2 Calculation of average deviation of thickness ................................................................................... 6  
A.2.3 Outer diameter deviation ...................................................................................................................... 7  
A.2.4 Wall thickness uniformity ..................................................................................................................... 7  
A.2.5 Spoon type end development rate ....................................................................................................... 7  
A.2.6 Damage rate after straightening the corrugated pipe ....................................................................... 7  
A.2.7 Mass deviation ....................................................................................................................................... 8  
 DRS 558: 2023 
©RSB 2023- All rights reserved                  iv 
 Foreword 
Rwanda Standardsarepreparedby Technical Committees and approved by Rwanda 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 Standards 
adopted by Technical committees are ratified by members of RSB Board of Directors for publication and 
gazettment as Rwanda Standards. 
DRS 558 was prepared by Technical Committee RSB/TC  067, Consumer Products  
In the preparation of this standard, reference was made to the following standard: 
ISO/DIS 5424:Industrial compostable drinking straws  
The assistance derived from the above source is hereby acknowledged with thanks. 
Committee membership  
The following organizations were represented on the Technical Committee on Consumer Products (RSB/TC 
067) in the preparation of this standard. 
University of Rwanda/College of Sciences and Technology (UR/CST) 
AGROPY 
Standards for Sustainability (SfS) 
University of Rwanda/College of Education (UR/CE) 
Rwanda Inspectorate, Competition and Consumer Protection Authority (RICA) 
SULFO Rwanda Industries 
JEENA TRADE Co. Ltd 
Rwanda Standards Board(RSB) – Secretariat DRS 558: 2023 
v                ©RSB2023- All rights reserved 
 Introduction 
Plastic drinking straws are used worldwide for many years, which caused several environmental problems, 
such as terrestrial pollution and contamination of soil, water and marine environment pollution. These pose a 
severe risk to ecosystems, biodiversity and human health. Recently, many countries, regions, and cities have 
enacted legislation to ban or severely reduce the use of plastic drinking straws to help tackle these issues. 
 
 DRS 558: 2023 
1                ©RSB2023- All rights reserved 
 Compostable drinking straws— Specification 
1 Scope 
This Draft Rwanda Standard specifies the requirements, sampling and test methods for compostable drinking 
straws. 
It covers drinking straws made from natural plant material, such a plant fibers or Corn PLA. It will also cover 
drinking straws made from papers. 
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 editioncited applies. For undated references, 
the latest edition of the referenced document (including any amendments) applies. 
ISO 17088, Plastics – Organic recycling – Specifications for compostable plastics 
ISO 291, Plastics – Standard atmospheres for conditioning and testing 
ISO 638-1, Paper, board, pulps and cellulosic nanomaterials – Determination of dry matter content by oven-
drying method – Part 1: Materials in solid form  
ISO 18188, Specification of polypropylene drinking straws  
ISO 2859-1/Amid. 1, Sampling procedures for inspection by attributes – Part 1: Sampling scheme indexed by 
acceptance quality limit (AQL) for lot-by-lot inspection – Amendment 1  
ISO 17294-2, Water quality – application of inductively coupled plasma mass spectrometry (ICP-MS) – Part 2: 
Determination of selected elements including uranium isotopes. 
EN 14582, Characterization of waste – Halogen and sulphur content – Oxygen combustion in closed systems 
and determination methods  
3 Terms and definitions 
For the purposes of this standard, the following terms and definitions apply. 
3.1 
compost 
organic soil conditioner obtained by biodegradation of a mixture consisting principally of vegetable residues, 
occasionally with other organic material and having a limited mineral content  
©RSB 2023- All rights reserved                  2 
 3.2 
compostable plastic 
plastic that undergoes degradation by biological processes during composting to yield CO 2, water, inorganic 
compounds and biomass at a rate consistent with other known compostable materials and leave no visible, 
distinguishable or toxic residue 
Note 1 to entry: “Hazardous” is used synonymously to toxic. 
3.3 
composting 
aerobic process designed to produce compost starting from biodegradable waste 
Note 1 to entry: Composting is classified into industrial composting, home composting and worm composting. 
3.4 
corn Polylactic acid (corn PLA) 
made from fermented corn starch instead of petroleum, but it can also be made from cassava or sugarcane 
starch. 
3.5 
industrial composting 
composting process performed under controlled conditions on industrial scale with the aim of producing 
compost for the market 
Note 1 to entry: In some regions industrial composting is referred to as professional composting. 
3.6 
drinking straw 
hollow tubes for drinking water, beverages and liquid foods 
3.7 
straight straw 
straight-type straws with ends that are perpendicular to the axis 
3.8 
flexible straw 
straw that has a curved corrugation and can be bent at will DRS 558: 2023 
3                ©RSB2023- All rights reserved 
 3.9 
pointed straw 
straw that is machined into a bevel at one end 
3.10 
spoon straw 
straw that is processed into a spoon at one end 
3.11 
telescopic straw 
retractable straw formed by connecting two or more straws 
4 Requirements 
4.1 Raw materials 
Raw materials used shall be conforming to the food or food contact requirements. Additives, e.g. colorants, 
shall also be food grade.Printing shall not be done on the drinking straws. 
4.2 Appearance 
Compostable drinking straws shall be free of visible contaminants and structural defects such as visible cracks 
or splits. 
4.3 Standard size 
Specification and size requirements shall meet the requirements as specified in table 1. 
Table 1 – Specifications and size requirements 
S/N Parameters  Requirements  Test method  
1. Length deviation, %, max. 2 
Annex A 2. Outer diameter deviation, %, max. 3 
3. Maximal wall thickness to minimum 
wall thickness ratio, max. 1.2 
4. End spreading rate of spoon type 
straw, %, min. 65 
5. Damage rate after straightening the 
corrugated pipe, %, max. 2 
6. Total mass deviation of 100 straws, %, 
max. 5  
©RSB 2023- All rights reserved                  4 
 4.4 Industrial compostability 
The industrial compostability shall be in accordance with the requirements of ISO 17088. 
4.5 Water content 
For paper straws and straws made of other natural polymer materials, the water content shall not be less 
more than 10% (m/m) when tested in accordance with ISO 638-1 Straws made of other biodegradable 
polymer materials are not required. 
4.6 Solubility resistance 
For paper straws and other straws made of natural polymer materials, after immersion in liquid, there shall be 
no warping, bending, cracking, etc. of more than 5 mm, which may cause the straw to not be used normally. 
Straws made of other biodegradable polymer materials are not required. 
4.7 Concentration of heavy metals and other elements 
The concentration of heavy metals and other toxic substances shall comply with the requirements prescribed 
in table 2. 
Table 2 – Specifications and size requirements 
S/N Elements  Limits  Test methods  
1.  Zinc (Zn), mg/kg, max. 150 
ISO 17294-2 2.  Copper (Cu), mg/kg, max. 50 
3.  Nickel (Ni), mg/kg, max. 25 
4.  Cadmium (Cd), mg/kg, max. 0.5 
5.  Lead (Pb), mg/kg, max. 10 
6.  Mercure (Hg), mg/kg, max. 0.2 
7.  Chromium (Cr), mg/kg, max. 50 
8.  Molybdenum (Mo), mg/kg, max. 1 
9.  Selenium (Se), mg/kg, max. 0.75 
10.  Arsenic (As), mg/kg, max. 5 
11.  Cobalt (Co), mg/kg, max. 30 
12.  Fluor (F), mg/kg, max. 100 EN 14582 
5 Packaging 
5.1 In counting the number of boxes from randomly extracted 2 boxes of straws, no inadequate number of 
boxes shall be found. 
5.2 The number of straws in each bag (boxes) of the 2 bags (boxes) randomly drawn shall not be less than 
98% of the nominal number. 
5.3 In the same batch, if less than adequate number of packages (boxes) is found, the batch shall be judged 
as unqualified; In case of an unqualified number of straws in the package (box), double number of samples 
shall be taken for re-examination. If the results of the re-examinations are qualified, this item (packing 
quantity) is judged as qualified, otherwise the item will be rejected. Formatted:  French (France)DRS 558: 2023 
5                ©RSB2023- All rights reserved 
 6 Labelling 
The package of straws shall be marked with the following information: 
a) Name and address of the manufacturer; 
b) Name of the product, as “compostable drinking straws”; 
c) Material used; 
d) Number of straws in a package; 
e) Production date; 
f) Best before date;  
g) Country of origin;and 
h) Any information regarding health and safety for the users. 
7 Sampling 
Sampling shall be done in accordance with ISO 2859-1  
©RSB 2023- All rights reserved                  6 
 Annex A 
(normative)  
 
Test methods 
A.1 Conditioning and testing atmosphere 
The standard environment for sample conditioning ant testing shall be performed in accordance with 
procedures as specified in ISO 291. 
A.2 Standard sizes 
A.2.1 Length deviation 
The length of straw shall be measured using a graduated ruler or other suitable means, capable of reading to 
0.5 mm or less. 
The value of the length deviation of the straw is calculated by using the following formula: 
   Δl=௟ି௟˳
௟˳𝑥 100 
Where, 
 Δl is the length deviation of the straw, expressed as a percentage (%); 
 L is the measured length, in millimetres (mm); and 
 l˳ is the nominal length, in millimetres (mm). 
A.2.2 Calculation of average deviation of thickness 
    Δē =௘ି௘˳
௘˳𝑥 100 
Where, 
 Δē is the average thickness deviation, expressed as a percentage (%); 
 e is the average thickness, in millimetres (mm); and 
 e˳ is the nominal thickness, in millimetres (mm). DRS 558: 2023 
7                ©RSB2023- All rights reserved 
 A.2.3 Outer diameter deviation 
Measure the outer diameter of straw at one end, using a Vernier calipers or other suitable means capable of 
reading to 0.02 mm or less. 
The value of the outer diameter deviation of the straw is calculated by using the following formula: 
    Δd =ௗିௗ˳
ௗ˳𝑥 100 
Where, 
 Δd is the outer diameter deviation of the straw, expressed as a percentage (%); 
 d is the measured diameter, in millimetres (mm); and 
 d˳ is the nominal diameter, in millimetres (mm). 
A.2.4 Wall thickness uniformity 
The straw wall thickness uniformity shall be tested in accordance with the method specified in ISO 18188, 
paragraph 6.3.4. 
A.2.5 Spoon type end development rate 
Unfold the spoon-shaped straw section of spoon type straw. Measure the maximum width using a graduated 
ruler orother suitable means, capable of reading to 1 mm or less. 
The value of the spoon type end development rate of the straw is calculated by using the following formula: 
    Δk =௞
గௗ˳𝑥 100 
Where, 
 Δk is the outer diameter deviation of the straw, expressed as a percentage (%); 
 k is the measured maximum width, in millimetres (mm); and 
 d˳ is the nominal diameter, in millimetres (mm). 
A.2.6 Damage rate after straightening the corrugated pipe 
Randomly select 100 straws from the same batch of products and perform damage rate by visual inspection 
after straightening the corrugated pipe.  
©RSB 2023- All rights reserved                  8 
 Fracture, breakage and cracking properties shall be evaluated by straightening the corrugated pipe. 
A.2.7 Mass deviation 
Randomly choose 300 straws from the same batch of products, and divide them into 3 groups, with 100 
straws in each group. 
Measure the mass of each group (100 straws), using a balance or other suitable means, capable of reading to 
0,1 g or less. 
The value of mass deviation of the straw is calculated by using the following formula: 
    Δg =௚ି௚˳
௚˳𝑥 100 
Where, 
 Δg is the mass deviation of the straw, expressed as a percentage (%); 
 d is the measured mass, in gram (mm); and 
 d˳ is the nominal mass, in gram (mm). 
 
  DRS 558: 2023 
9                ©RSB2023- All rights reserved 
 Bibliography 
[1] ISO/IEC Directives, Part 2, Rules for the structure and drafting of International Standards , 2016 
[2] ISO/IEC TR 10000-1, Information technology— Framework and taxonomy of International 
Standardized Profiles— Part 1: General principles and documentation framework 
 
 DRS 558: 2023 
 
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