ISO/TR 21916:2021

TECHNICAL ISO/TR
REPORT 21916
First edition
2021-07
Solid recovered fuels — Guidance for
the specification of solid recovered
fuels (SRF) for selected uses
Reference number
©
ISO 2021
© 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

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviations . 1
3.1 Terms and definitions . 1
3.2 Symbols and abbreviated terms. 5
4 Compilation, structure and use of data . 6
5 SRF and other waste derived fuels . 7
5.1 General . 7
5.2 Terms used for secondary fuels from waste .10
5.3 Rules for the classification and specification of SRF .14
5.4 Market for SRF and other waste-derived fuels .18
6 Coal co-combustion in the cement manufacturing industry .20
6.1 General .20
6.2 End use requirements of SRF and other waste derived fuels .21
6.2.1 Technical limitation of the technologies .21
6.2.2 Quality requirements in plant permits .25
6.2.3 Quality requirements in general guidelines .25
6.2.4 Quality requirements in voluntary end user specifications .26
6.3 Typical values for SRF .27
7 Coal co-combustion in power plants .29
7.1 General .29
7.2 End use requirements for SRF and other waste derived fuels .30
7.2.1 Technical limitations of the technologies .30
7.2.2 Quality requirements in plant permits .34
7.2.3 Quality requirements in general guidelines .34
7.2.4 Quality requirements in voluntary end user specifications .35
7.3 Typical values for SRF .36
8 Gasification .37
8.1 General .37
8.2 End use requirements for SRF and other waste derived fuels .37
8.2.1 Technical limitations of the technologies .37
8.2.2 Quality requirements in plant permits .42
8.2.3 Quality requirements in general guidelines .42
8.2.4 Quality requirements in voluntary end user specifications .43
8.3 Typical values for SRF .44
9 Conclusions and guidance .45
Annex A (informative) Background references on the production of SRF and other waste
derived fuels .48
Annex B (informative) Fuel specification: Provisions in national standards, legislation,
plant permits. General and national guidelines. Voluntary specification by the end user .56
Annex C (informative) Background reference on technologies .77
Annex D (informative) Typical values for SRF: background data and outcomes of a
statistical assessment of measured values .98
Bibliography .121
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 300, Solid recovered materials, including
solid recovered fuels.
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

Introduction
Waste-to-energy is a broad term that covers much more than waste incineration. It includes various
treatment processes that have different environmental impacts but also offer potential for the progress
desired towards a low-carbon and circular economy. Processes that convert waste into solid fuels and
generate electricity and/or thermal energy from it can play an increasing role in achieving such goals.
Traditionally, solid fuels recovered from waste have been used as an integrative fuel in incineration or
co-incineration plants treating a mix of wastes, so as to improve the energy performance of the plant.
There are also some dedicated SRF-EfW plants (e.g. incineration plants and industrial combustion
plants recovering thermal and/or electrical energy from the solid recovered fuel alone).
An increasing role as substitutive fuel has occurred over time to allow a reduction of fossil fuel
consumption and the impact on climate change and greenhouse gas emission of industrial activities
with a high energy consumption. In recent years, the use of solid recovered fuels has expanded to other
interesting and promising fields, such as gasification or combined gasification and pyrolysis. Waste
gasification and co-incineration of the resulting syngas in a combustion plant, co-processing to power
and material recovery in cement kilns and waste incineration in dedicated facilities can be highlighted
as best proven techniques to increase the energy efficiency of waste-to-energy processes and optimize
their contribution to national and global climate and energy goals.
All the above-mentioned waste-to-energy processes rank differently in the waste hierarchy and
have different needs for fuel quality to ensure better plant management as well as compliance with
requirements set by national and supranational legislation.
Quite an extensive family of solid fuels can be recovered from waste, with different physico-chemical
properties and a quality that is not always well defined. Those produced from non-hazardous waste,
classified as SRF (Solid Recovered Fuel), are specifically of interest in this document. The term SRF
itself identifies a family of fuels that can differ in origin (input waste streams), composition and quality.
Many barriers still hamper the extensive development of SRFs. As discussed later, a continuing confusion
in terminology can be highlighted. Solid fuels recovered from non-hazardous waste are identified in
different countries by different terms (e.g. CSS, CDR, CDR-Q, RPF, SBS, CSR,), shipped with different
waste codes, and an ambiguous use of the terms RDF and SRF still occurs. SRF is largely produced
and traded as waste, different countries labelling it with different waste codes based on local waste
legislation. An end-of-waste of SRF is allowed in some countries (e.g. Austria, Italy) if the fuels produced
comply with specific and mandatory requirements legally set.
Solid recovered fuels are intended to be classified and specified according to ISO/TC 300 standards.
Fuel specification is also the subject of national guidelines, in places addressed to specific end uses
of the fuel (e.g. in cement kilns), and of local voluntary commitments on fuel properties between the
producer and the end user aimed at ensuring that the latter meets its own technological, economic and
environmental needs.
Generic (all solid waste) or specific (SRF) quality requirements are set by national or local regulators
(e.g. administrative bodies authorized to issue plant permits), mainly to ensure that waste-to-energy
plants at least meet the requirements for environmental and human protection and to regulate the role
of waste-to energy plants within the national/regional waste management systems as a
...