Plastics - Determination of the degree of disintegration of plastic materials under defined composting conditions in a pilot-scale test (ISO 16929:2021)

This document defines a test method used to determine the degree of disintegration of plastic materials
in a pilot-scale aerobic composting test under defined conditions. It forms part of an overall scheme for
the evaluation of the industrial compostability of plastics as outlined in ISO 17088.
The test method laid down in this document is also used to determine the influence of the test material
on the composting process and the quality of the compost obtained. This test method cannot be used to
determine the aerobic biodegradability of a test material.
NOTE Other methods are available for this test (for example, see ISO 14851, ISO 14852 or ISO 14855-1 and
ISO 14855-2).

Kunststoffe - Bestimmung des Zersetzungsgrades von Kunststoffmaterialien unter festgelegten Bedingungen der Kompostierung mittels einer Technikumsmaßstab-Prüfung (ISO 16929:2021)

Dieses Dokument wird zur Bestimmung des Zersetzungsgrades von Kunststoffmaterialien unter festgelegten Bedingungen in einer aeroben Kompostierprüfung im Technikumsmaßstab angewendet. Es ist Teil eines Gesamtschemas zur Bewertung der Kompostierbarkeit von Kunststoffen, wie in ISO 17088 dargelegt.
Das in diesem Dokument festgelegte Prüfverfahren kann auch zur Bestimmung des Einflusses der Prüfsubstanz auf den Kompostierungsprozess und die Qualität des erhaltenen Komposts eingesetzt werden. Es kann nicht zur Bestimmung der aeroben Bioabbaubarkeit einer Prüfsubstanz angewendet werden. Dafür stehen andere Verfahren zur Verfügung (siehe z. B. ISO 14851, ISO 14852 oder ISO 14855-1 und ISO 14855-2).

Plastiques - Détermination du degré de désintégration des matériaux plastiques dans des conditions de compostage définies lors d'un essai à échelle pilote (ISO 16929:2021)

Le présent document définie une méthode d'essai utilisée pour déterminer le degré de désintégration des matériaux plastiques lors d'un essai de compostage aérobie à échelle pilote dans des conditions définies. Elle fait partie d'un programme global pour l'évaluation de l'aptitude des plastiques au compostage, comme indiqué dans l'ISO 17088.
La méthode d'essai exposée dans le présent document peut également être utilisée pour déterminer l'influence du matériau d'essai sur le processus de compostage et la qualité du compost obtenu. Cette méthode d'essai ne peut être utilisée pour déterminer la biodégradabilité aérobie d'un matériau d'essai.
NOTE       Il existe d'autres méthodes pour cet essai (voir par exemple l'ISO 14851, l'ISO 14852 ou l'ISO 14855-1 et l'ISO 14855-2).

Polimerni materiali - Ugotavljanje stopnje razpada polimernih materialov pri določenih pogojih kompostiranja v pilotnem merilu (ISO 16929:2021)

General Information

Status
Published
Public Enquiry End Date
31-Jul-2020
Publication Date
28-Apr-2021
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
08-Apr-2021
Due Date
13-Jun-2021
Completion Date
29-Apr-2021

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SLOVENSKI STANDARD
SIST EN ISO 16929:2021
01-junij-2021
Nadomešča:
SIST EN ISO 16929:2020
Polimerni materiali - Ugotavljanje stopnje razpada polimernih materialov pri
določenih pogojih kompostiranja v pilotnem merilu (ISO 16929:2021)
Plastics - Determination of the degree of disintegration of plastic materials under defined
composting conditions in a pilot-scale test (ISO 16929:2021)
Kunststoffe - Bestimmung des Zersetzungsgrades von Kunststoffmaterialien unter
festgelegten Bedingungen der Kompostierung mittels einer Technikumsmaßstab-Prüfung
(ISO 16929:2021)
Plastiques - Détermination du degré de désintégration des matériaux plastiques dans
des conditions de compostage définies lors d'un essai à échelle pilote (ISO 16929:2021)
Ta slovenski standard je istoveten z: EN ISO 16929:2021
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
SIST EN ISO 16929:2021 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN ISO 16929:2021

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SIST EN ISO 16929:2021


EN ISO 16929
EUROPEAN STANDARD

NORME EUROPÉENNE

March 2021
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 16929:2019
English Version

Plastics - Determination of the degree of disintegration of
plastic materials under defined composting conditions in a
pilot-scale test (ISO 16929:2021)
Plastiques - Détermination du degré de désintégration Kunststoffe - Bestimmung des Zersetzungsgrades von
des matériaux plastiques dans des conditions de Kunststoffmaterialien unter festgelegten Bedingungen
compostage définies lors d'un essai à échelle pilote der Kompostierung mittels einer Technikumsmaßstab-
(ISO 16929:2021) Prüfung (ISO 16929:2021)
This European Standard was approved by CEN on 13 March 2021.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 16929:2021 E
worldwide for CEN national Members.

---------------------- Page: 3 ----------------------
SIST EN ISO 16929:2021
EN ISO 16929:2021 (E)
Contents Page
European foreword . 3

2

---------------------- Page: 4 ----------------------
SIST EN ISO 16929:2021
EN ISO 16929:2021 (E)
European foreword
This document (EN ISO 16929:2021) has been prepared by Technical Committee ISO/TC 61 "Plastics"
in collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by
NBN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by September 2021, and conflicting national standards
shall be withdrawn at the latest by September 2021.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 16929:2019.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 16929:2021 has been approved by CEN as EN ISO 16929:2021 without any modification.

3

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SIST EN ISO 16929:2021

---------------------- Page: 6 ----------------------
SIST EN ISO 16929:2021
INTERNATIONAL ISO
STANDARD 16929
Fourth edition
2021-03
Plastics — Determination of the
degree of disintegration of plastic
materials under defined composting
conditions in a pilot-scale test
Plastiques — Détermination du degré de désintégration des
matériaux plastiques dans des conditions de compostage définies lors
d'un essai à échelle pilote
Reference number
ISO 16929:2021(E)
©
ISO 2021

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SIST EN ISO 16929:2021
ISO 16929:2021(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved

---------------------- Page: 8 ----------------------
SIST EN ISO 16929:2021
ISO 16929:2021(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 2
6 Test procedure . 3
6.1 Actions before and during incubation . 4
6.1.1 Start-up of the test . 4
6.1.2 Turning . 5
6.1.3 Termination of the test . 5
6.2 Analysis and process control . 6
6.2.1 Start-up of the test . 6
6.2.2 During the test . 7
6.2.3 Termination of the test . 8
7 Calculation . 9
8 Validity of the test . 9
9 Test report . 9
Bibliography .11
© ISO 2021 – All rights reserved iii

---------------------- Page: 9 ----------------------
SIST EN ISO 16929:2021
ISO 16929:2021(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 14,
Environmental aspects, in collaboration with the European Committee for Standardization (CEN)
Technical Committee CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation
between ISO and CEN (Vienna Agreement).
This fourth edition cancels and replaces the third edition (ISO 16929:2019), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— in 6.1.1, the minimum amount of biowaste has been changed to 15 kg from 30 kg due to the smaller
size of composting bins;
— in 6.2.2.3, a separate temperature profile has been added to cover tests including also production of
compost for ecotoxicity tests.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2021 – All rights reserved

---------------------- Page: 10 ----------------------
SIST EN ISO 16929:2021
ISO 16929:2021(E)

Introduction
The biological treatment of biodegradable plastic materials includes aerobic composting in well-
operated, municipal or industrial biological waste treatment facilities. Determining the degree of
disintegration of plastic materials in a pilot-scale plant is an important step within a test scheme to
evaluate the industrial compostability of such materials.
To claim industrial compostability, a material not only has to disintegrate in a composting system, it
also has to biodegrade in a composting system (as can be shown by standard test methods) and has to
complete its biodegradation during the end-use of the compost. Furthermore, the compost has to meet
the relevant quality criteria, including low content of regulated metals, no ecotoxicity, and no obviously
distinguishable residues.
© ISO 2021 – All rights reserved v

---------------------- Page: 11 ----------------------
SIST EN ISO 16929:2021

---------------------- Page: 12 ----------------------
SIST EN ISO 16929:2021
INTERNATIONAL STANDARD ISO 16929:2021(E)
Plastics — Determination of the degree of disintegration of
plastic materials under defined composting conditions in a
pilot-scale test
1 Scope
This document defines a test method used to determine the degree of disintegration of plastic materials
in a pilot-scale aerobic composting test under defined conditions. It forms part of an overall scheme for
the evaluation of the industrial compostability of plastics as outlined in ISO 17088.
The test method laid down in this document is also used to determine the influence of the test material
on the composting process and the quality of the compost obtained. This test method cannot be used to
determine the aerobic biodegradability of a test material.
NOTE Other methods are available for this test (for example, see ISO 14851, ISO 14852 or ISO 14855-1 and
ISO 14855-2).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
degradation
irreversible process leading to a significant change in the structure of a material, typically characterized
by a loss of properties (e.g. integrity, molecular mass or structure, mechanical strength) and/or by
fragmentation, affected by environmental conditions, proceeding over a period of time and comprising
one or more steps
3.2
biodegradation
degradation (3.1) caused by biological activity especially by enzymatic action leading to a significant
change in the chemical structure of a material
3.3
disintegration
physical breakdown of a material into very small fragments
3.4
compost
organic soil conditioner obtained by biodegradation (3.2) of a mixture principally consisting of various
vegetable residues, occasionally with other organic material, and having a limited mineral content
© ISO 2021 – All rights reserved 1

---------------------- Page: 13 ----------------------
SIST EN ISO 16929:2021
ISO 16929:2021(E)

3.5
composting
aerobic process designed to produce compost (3.4)
3.6
compostability
property of a material to be biodegraded in a composting (3.5) process
3.7
maturity of compost
assignment of the maturity of a compost (3.4) based on the measurement of the maximum temperature
in a self-heating test using Dewar vessels
Note 1 to entry: It is expressed in terms of the so-called “Rottegrad” (see 6.2.3.1).
3.8
total dry solids
amount of solids obtained by taking a known volume of test material or compost (3.4) and drying at
about 105 °C to constant mass
3.9
volatile solids
amount of solids obtained by subtracting the residues of a known volume of test material or compost
(3.4) after incineration at about 550 °C from the total dry solids (3.8) content of the same sample
Note 1 to entry: The volatile solids content is an indication of the amount of organic matter present.
4 Principle
The disintegration test is performed under defined and standardized composting conditions on a pilot-
scale level.
The test material is mixed with fresh biowaste in a precise concentration and introduced into a
defined composting environment. A natural ubiquitous microbial population starts the composting
process spontaneously and the temperature increases. The composting mass is regularly turned over
and mixed. Temperature, pH-value, moisture content and gas composition are regularly monitored.
They should fulfil certain requirements to ensure sufficient and appropriate microbial activity. The
composting process is continued until a fully stabilized compost is obtained. This is usually the case
after 12 weeks.
The compost is visually observed at regular time intervals to detect any adverse effect of the test
material on the composting process. At the end of the test, the maturity of compost is determined, and the
mixture of compost and test material is sieved through 2 mm and 10 mm mesh sieves. The disintegration
of the test material is evaluated based on the total dry solids by comparing the fraction of test material
retained by the 2 mm sieve and the amount tested. The compost obtained at the end of the composting
process may be used for further measurements, such as chemical analyses and ecotoxicity tests.
5 Apparatus
5.1 Composting environment.
5.1.1 General
The composting environment may be either a pilot-scale composting bin or nets buried in a pilot-scale
composting bin. The volume of each bin shall be high enough for natural self-heating to occur. Sufficient
and even aeration shall be provided by an appropriate air supply system. To standardize conditions for
the test, the composting trials can be run in bins which are placed in a climatic chamber with a constant
chamber temperature or in insulated bins.
2 © ISO 2021 – All rights reserved

---------------------- Page: 14 ----------------------
SIST EN ISO 16929:2021
ISO 16929:2021(E)

If during the spontaneous thermophilic phase the compost reaches temperatures higher than 65 °C,
the diversity of microbial species can be reduced. To restore a full array of thermophilic bacteria, the
compost can be re-inoculated with mature compost (about 10 g/kg initial biowaste mass) of recent
origin (maximum
...

SLOVENSKI STANDARD
oSIST prEN ISO 16929:2020
01-julij-2020
Polimerni materiali - Ugotavljanje stopnje razpada polimernih materialov pri
določenih pogojih kompostiranja v pilotnem merilu (ISO/DIS 16929:2020)
Plastics - Determination of the degree of disintegration of plastic materials under defined
composting conditions in a pilot-scale test (ISO/DIS 16929:2020)
Kunststoffe - Bestimmung des Zersetzungsgrades von Kunststoffmaterialien unter
festgelegten Bedingungen der Kompostierung mittels einer Technikumsmaßstab-Prüfung
(ISO/DIS 16929:2020)
Plastiques - Détermination du degré de désintégration des matériaux plastiques dans
des conditions de compostage définies lors d'un essai à échelle pilote (ISO/DIS
16929:2020)
Ta slovenski standard je istoveten z: prEN ISO 16929
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
oSIST prEN ISO 16929:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
oSIST prEN ISO 16929:2020

---------------------- Page: 2 ----------------------
oSIST prEN ISO 16929:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 16929
ISO/TC 61/SC 14 Secretariat: DIN
Voting begins on: Voting terminates on:
2020-05-12 2020-08-04
Plastics — Determination of the degree of disintegration of
plastic materials under defined composting conditions in a
pilot-scale test
Plastiques — Détermination du degré de désintégration des matériaux plastiques dans des conditions de
compostage définies lors d'un essai à échelle pilote
ICS: 83.080.01
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 16929:2020(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2020

---------------------- Page: 3 ----------------------
oSIST prEN ISO 16929:2020
ISO/DIS 16929:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

---------------------- Page: 4 ----------------------
oSIST prEN ISO 16929:2020
ISO/DIS 16929:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Apparatus . 3
6 Test procedure . 4
6.1 Actions before and during incubation . 4
6.1.1 Start-up of the test . 4
6.1.2 Turning . 5
6.1.3 Termination of the test . 5
6.2 Analysis and process control . 6
6.2.1 Start-up of the test . 6
6.2.2 During the test . 7
6.2.3 Termination of the test . 8
7 Calculation . 8
8 Validity of the test . 9
9 Test report . 9
Bibliography .10
© ISO 2020 – All rights reserved iii

---------------------- Page: 5 ----------------------
oSIST prEN ISO 16929:2020
ISO/DIS 16929:2020(E)

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/ patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/
iso/ foreword .html.
This document was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 14,
Environmental aspects.
This fourth edition cancels and replaces the third edition (ISO 16929:2019), which has been technically
revised.
The main changes compared to the previous edition are as follows:
— in 6.1.1, the minimum amount of biowaste has been changed to 15 kg from 30 kg due to the smaller
size of composting bins;
— in 6.2.2.3, a separate temperature profile has been added to cover tests including also production of
compost for ecotoxicity tests .
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

---------------------- Page: 6 ----------------------
oSIST prEN ISO 16929:2020
ISO/DIS 16929:2020(E)

Introduction
The biological treatment of biodegradable plastic materials includes aerobic composting in well-
operated, municipal or industrial biological waste treatment facilities. Determining the degree of
disintegration of plastic materials in a pilot-scale plant is an important step within a test scheme to
evaluate the compostability of such materials.
© ISO 2020 – All rights reserved v

---------------------- Page: 7 ----------------------
oSIST prEN ISO 16929:2020

---------------------- Page: 8 ----------------------
oSIST prEN ISO 16929:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 16929:2020(E)
Plastics — Determination of the degree of disintegration of
plastic materials under defined composting conditions in a
pilot-scale test
WARNING — Compost can contain potentially pathogenic organisms. Therefore, appropriate
precautions should be taken when handling it.
1 Scope
This document is used to determine the degree of disintegration of plastic materials in a pilot-scale
aerobic composting test under defined conditions. It forms part of an overall scheme for the evaluation
of the compostability of plastics as outlined in ISO 17088.
The test method laid down in this document is also used to determine the influence of the test material
on the composting process and the quality of the compost obtained. It cannot be used to determine
the aerobic biodegradability of a test material. Other methods are available for this (for example, see
ISO 14851, ISO 14852 or ISO 14855-1 and ISO 14855-2).
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
degradation
irreversible process leading to a significant change in the structure of a material, typically characterized
by a loss of properties (e.g. integrity, molecular mass or structure, mechanical strength) and/or by
fragmentation, affected by environmental conditions, proceeding over a period of time and comprising
one or more steps
3.2
biodegradation
degradation (3.1) caused by biological activity especially by enzymatic action leading to a significant
change in the chemical structure of a material
3.3
disintegration
physical breakdown of a material into very small fragments
3.4
compost
organic soil conditioner obtained by biodegradation (3.3) of a mixture principally consisting of various
vegetable residues, occasionally with other organic material, and having a limited mineral content
© ISO 2020 – All rights reserved 1

---------------------- Page: 9 ----------------------
oSIST prEN ISO 16929:2020
ISO/DIS 16929:2020(E)

3.5
composting
aerobic process designed to produce compost (3.4)
3.6
compostability
property of a material to be biodegraded in a composting (3.5) process
Note 1 to entry: To claim compostability, it shall have been demonstrated that a material can be biodegraded
and disintegrated in a composting system (as can be shown by standard test methods) and completes its
biodegradation (3.3) during the end-use of the compost. The compost shall meet the relevant quality criteria.
Quality criteria include low content of regulated metals, no ecotoxicity, no obviously distinguishable residues.
3.7
maturity of compost
assignment of the maturity of a compost (3.4) based on the measurement of the maximum temperature
in a self-heating test using Dewar vessels
Note 1 to entry: It is expressed in terms of the so-called “Rottegrad” (see 6.2.3.1).
3.8
total dry solids
amount of solids obtained by taking a known volume of test material or compost (3.4) and drying at
about 105 °C to constant mass
3.9
volatile solids
amount of solids obtained by subtracting the residues of a known volume of test material or compost
(3.4) after incineration at about 550 °C from the total dry solids (3.8) content of the same sample
Note 1 to entry: The volatile solids content is an indication of the amount of organic matter present.
4 Principle
The disintegration test is performed under defined and standardized composting conditions on a pilot-
scale level.
The test material is mixed with fresh biowaste in a precise concentration and introduced into a
defined composting environment. A natural ubiquitous microbial population starts the composting
process spontaneously and the temperature increases. The composting mass is regularly turned over
and mixed. Temperature, pH-value, moisture content and gas composition are regularly monitored.
They should fulfil certain requirements to ensure sufficient and appropriate microbial activity. The
composting process is continued until a fully stabilized compost is obtained. This is usually the case
after 12 weeks.
The compost is visually observed at regular time intervals to detect any adverse effect of the test
material on the composting process. At the end of the test, the maturity of compost is determined, and the
mixture of compost and test material is sieved through 2 mm and 10 mm mesh sieves. The disintegration
of the test material is evaluated based on the total dry solids by comparing the fraction of test material
retained by the 2 mm sieve and the amount tested. The compost obtained at the end of the composting
process may be used for further measurements, such as chemical analyses and ecotoxicity tests.
2 © ISO 2020 – All rights reserved

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oSIST prEN ISO 16929:2020
ISO/DIS 16929:2020(E)

5 Apparatus
5.1 Composting environment.
5.1.1 General
The composting environment may be either a pilot-scale composting bin or nets buried in a pilot-scale
composting bin. The volume of each bin shall be high enough for natural self-heating to occur. Sufficient
and even aeration shall be provided by an appropriate air supply system.
NOTE To standardize conditions for the test, the composting trials can be run in bins which are placed in a
climatic chamber with a constant chamber temperature or in insulated bins.
If during the spontaneous thermophilic phase the compost reaches temperatures higher than 65 °C,
the diversity of microbial species can be reduced. To restore a full array of thermophilic bacteria, the
compost can be re-inoculated with mature compost (about 1 % of the total initial biowaste mass) of
recent origin (maximum 3 months old).
5.1.2 Composting bins
5.1.2.1 Volume and material
The bins shall:
— have a minimum volume of 35 l;
— consist of a sturdy, heat-resistant and non-biodegradable material;
— not affect the composting process or the quality of the compost.
5.1.2.2 Drainage
The drainage shall consist of a layer of drains with a thickness of at least 5 cm at the bottom of the bins.
5.1.3 Sample nets, if used, shall consist of mesh-like material with a mesh size of 1 mm made of non-
degradable plastic which is resistant to temperatures up to 120 °C. The minimum volume shall be 20 l.
5.2 Apparatus for temperature measurement.
5.3 pH-meter.
5.4 Apparatus for oxygen measurement.
5.5 Sieves, of suitable shape with screens of 2 mm and 10 mm mesh (as specified, for i
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