ISO 21018-1:2024
(Main)Hydraulic fluid power — Monitoring the level of particulate contamination of the fluid — Part 1: General principles
Hydraulic fluid power — Monitoring the level of particulate contamination of the fluid — Part 1: General principles
This document specifies methods and techniques that are applicable to the monitoring of particulate contamination levels in hydraulic systems that cannot be calibrated in accordance with ISO 11171. It also describes the relative merits of various techniques, so that the correct monitor for a given application can be selected. The techniques described in this document are suitable for monitoring: a) the general cleanliness level in hydraulic systems; b) the progress in flushing operations; c) support equipment and test rigs. This document can also be applicable for other liquids (e.g. lubricants, fuels and process liquids). NOTE Instruments used to monitor particulate contamination that cannot be calibrated according to ISO 11171 are not considered as or claimed to be particle counters, even if they use the same physical principles as particle counters
Transmissions hydrauliques — Surveillance du niveau de pollution particulaire des fluides — Partie 1: Principes généraux
L'ISO 21018-1:2008 spécifie les méthodes et les techniques applicables à la surveillance des niveaux de pollution particulaire des systèmes hydrauliques. Elle décrit aussi le bien-fondé des différentes techniques afin de pouvoir choisir le détecteur qui convient à une application donnée. Les techniques décrites dans l'ISO 21018-1:2008 permettent de surveiller le niveau de propreté général des systèmes hydrauliques, l'évolution des opérations de rinçage, les matériels auxiliaires et les montages d'essai. L'ISO 21018-1:2008 peut aussi être appliquée à d'autres fluides (par exemple les lubrifiants, les carburants et les fluides de procédé).
General Information
Relations
Standards Content (Sample)
International
Standard
ISO 21018-1
Second edition
Hydraulic fluid power —
2024-10
Monitoring the level of particulate
contamination of the fluid —
Part 1:
General principles
Transmissions hydrauliques — Surveillance du niveau de
pollution particulaire des fluides —
Partie 1: Principes généraux
Reference number
© ISO 2024
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
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Health and safety . 4
4.1 General .4
4.2 Electric power .4
4.3 Mechanical fluid power.4
4.4 Process liquids .4
4.4.1 Flammable or combustible liquids .4
4.4.2 Chemical compatibility .4
4.5 Electrical earthing/grounding .4
4.6 Environmental .4
5 Selection of monitoring technique. 5
5.1 General .5
5.2 Selection .5
6 Procedures and precautions . 5
6.1 General .5
6.2 Sampling .5
6.2.1 Obtaining representative samples .5
6.2.2 Off-line sampling .6
6.2.3 Off-line analysis .6
6.3 Analysis .6
6.3.1 On-line analysis .6
6.3.2 In-line analysis .6
6.3.3 Off-line analysis .7
6.4 Calibration procedures .7
6.5 Checking data repeatability .7
6.6 Training .8
6.7 Controlling the precision of the technique .8
7 Test report . 8
Annex A (informative) Summary of various technique attributes . 9
Annex B (informative) Description and relative merits of different contaminant monitoring
techniques .15
Bibliography .23
iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 131, Fluid power systems, Subcommittee SC 6,
Contamination control.
This second edition cancels and replaces the first edition (ISO 21018-1:2008), which has been technically
revised. The main changes are as follows:
— 3.1 contains an updated definition for automated particle counter;
— 3.2 contains an updated definition for particle contamination model;
— 3.10 contains an updated definition for mesh;
— 3.11 now contains a note for the particle size definition;
— B.8.1 has been updated to accurately describe the capabilities of image analysis.
A list of all parts in the ISO 21018 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
Introduction
In hydraulic fluid power systems, power is transmitted through a liquid under pressure within a closed
circuit. The liquid is both a lubricant and a power-transmitting medium. The presence of solid particulate
contamination in the liquid interferes with the ability of the hydraulic liquid to lubricate and causes wear
to the components. The extent of this form of contamination in the liquid has a direct bearing on the
performance and reliability of the system and it is necessary to control this to levels that are considered
appropriate for the system concerned. Hydraulic oil filters are used to control the amount of particulate
contamination to a level that is suitable for both the contaminant sensitivity of the system and the level of
reliability required by the user.
Operators of hydraulic equipment are gradually defining maximum particle concentration levels for
components, systems and processes. These are often referred to as the required cleanliness level (RCL). This
cleanliness level is obtained by sampling the hydraulic liquid and measuring the particulate contamination
level. If the contamination level is above the RCL, then corrective actions are necessary to reduce the
contamination level. To avoid taking unnecessary actions, which can often prove costly, precision in sampling
and measuring the particulate contamination level is required.
A comprehensive range of measurement equipment is available, but the instruments used are usually
laboratory-based. This often requires that the equipment is operated in a special environment by specialist
laboratories and this delays delivery of the test result to the user. To overcome this disadvantage, instruments
are being continuously developed to determine the particulate contamination level, either using equipment
that can be operated in or near the workplace or directly using on-line or in-line techniques. For equipment
operated in the workplace, direct traceability to national measurement standards can be inappropriate, or
irrelevant, as the instruments are used to monitor the general level of particulate contamination or to inform
the user of a significant change in the level. When a significant change in the particulate contamination level
is detected, the actual level is then usually qualified by using an approved particle-counting method. Also,
these monitors can have simplified circuitry compared to similar laboratory units and this means that they
can be less accurate and precise.
In addition, some instruments are designed to work on the “go/no-go” principle and their ability to rapidly
evaluate the cleanliness level has resulted in an increase in their usage both in the fluid power industry and
other markets. Unfortunately, the lack of a standardized method for their use, recalibration (if applicable)
and means of checking the output validity means that the variability in the measurement data is at a level
higher than is desirable.
This document h
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.