ISO 22241-1:2019

INTERNATIONAL ISO
STANDARD 22241-1
Second edition
2019-02
Diesel engines — NOx reduction agent
AUS 32 —
Part 1:
Quality requirements
Moteurs diesel — Agent AUS 32 de réduction des NOx —
Partie 1: Exigences de qualité
Reference number
©
ISO 2019
© ISO 2019
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 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Designation . 2
5 Requirements and testing . 2
6 Handling, transportation and storage. 2
7 Marking . 2
Annex A (informative) Chemical characteristics. 4
Annex B (informative) Precision of test methods . 5
Bibliography . 6
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 on 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 22, Road vehicles, Subcommittee SC 34,
Propulsion, powertrain and powertrain fluids.
This second edition cancels and replaces the first edition (ISO 22241-1:2006), which has been technically
revised. The main changes compared to the previous edition are as follows:
— the test method for measuring urea content by refractive index was revised;
— an alternate test method for measuring trace amounts of phosphorous by ICP-OES was added (a
referee method is indicated); and
— the refractive index, nD20, limit values were revised.
A list of all parts in the ISO 22241 series can be found on the ISO website.
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 2019 – All rights reserved

Introduction
In order to protect the environment, keeping the air quality as clean as possible, exhaust emissions
regulations around the world have been strengthened considerably. In motor vehicles with diesel
engines, particulate matters (PM) and nitrogen oxide (NOx) emissions are the main concern, and
efforts have been focused on the development of technology which can reduce them effectively with
minimum fuel economy penalty. Selective catalytic reduction (SCR) converters using urea solution as
the reduction agent are considered to be a key technology for reducing NOx emissions. The quality of the
urea solution used for that technology needs to be specified to ensure reliable and stable operation of
the SCR converter systems. The ISO 22241 series provides the specifications for quality characteristics,
for handling, transportation and storage and for the refilling interface as well as the test methods,
needed by the manufacturers of motor vehicles and their engines, by converter manufacturers, by
producers and distributors of the urea solution and by fleet operators.
The urea solution (AUS 32) as specified in this document is commercially available and may exist under
1)
various trade names .
1) Trade names of products AdBlue®, ARLA 32®, DEF, etc. are examples of suitable products available commercially.
This information is given for the convenience of users of this document and does not constitute an endorsement by
ISO of the products named.
INTERNATIONAL STANDARD ISO 22241-1:2019(E)
Diesel engines — NOx reduction agent AUS 32 —
Part 1:
Quality requirements
1 Scope
This document specifies the quality characteristics of the NOx reduction agent AUS 32 (aqueous urea
solution) which is needed to operate selective catalytic reduction (SCR) converter systems in motor
vehicles with diesel engines. SCR co
...