ISO 12131-3:2020

Plain bearings - Hydrodynamic plain thrust pad bearings under steady-state conditions - Part 3: Guide values for the calculation of thrust pad bearings

This document specifies guide values for avoiding damage to thrust-pad bearings in service. The explanation of the symbols as well as examples for calculation are given in ISO 12131-1.

Paliers lisses — Butées hydrodynamiques à patins géométrie fixe fonctionnant en régime stationnaire — Partie 3: Paramètres opérationnels admissibles pour le calcul des butées à segments

General Information

• Status: Published
• Publication Date: 07-Jul-2020
• ICS: 21.100.10 - Plain bearings
• Technical Committee: ISO/TC 123/SC 8 - Calculation methods for plain bearings and their applications
• Drafting Committee: ISO/TC 123/SC 8 - Calculation methods for plain bearings and their applications
• Current Stage: 9060 - Close of review
• Completion Date: 04-Mar-2031

Relations

• Consolidated By: ISO 4064-4:2024 - Water meters for cold potable water and hot water - Part 4: Non-metrological requirements not covered in ISO 4064-1
• Effective Date: 24-Dec-2022
• Revises: ISO 12131-3:2001 - Plain bearings - Hydrodynamic plain thrust pad bearings under steady-state conditions - Part 3: Guide values for the calculation of thrust pad bearings
• Effective Date: 23-Apr-2020

Overview

ISO 12131-3:2020 is an international standard published by the International Organization for Standardization (ISO) that provides guide values for the calculation of hydrodynamic plain thrust pad bearings under steady-state conditions. This part of the ISO 12131 series focuses specifically on operational limits essential to avoid damage such as wear, mechanical overloading, and thermal overloading during the service life of thrust-pad bearings.

The document complements ISO 12131-1, which contains detailed explanations of symbols and calculation examples. ISO 12131-3 offers practical empirical guide values grounded in tribological expertise to ensure reliability and extend the operational life of plain thrust bearings used in diverse industrial applications.

Key Topics

• Minimum Lubricant Film Thickness
  To prevent bearing wear and failure, maintaining an adequate lubricant film thickness is critical. The standard defines minimum permissible lubricant film thickness values based on sliding velocity, bearing diameter, and lubrication conditions. Clean, filtered lubricants and properly manufactured components are emphasized to reduce friction, scoring, and overheating.

• Mechanical Overload Limits
  The standard specifies maximum permissible specific bearing loads to prevent irreversible deformation or cracking of bearing surfaces. It advises checking load conditions during machine start-up, recommending hydrostatic arrangements if the starting load is too high, to avoid premature wear.

• Thermal Overload Criteria
  Operating temperatures must be controlled within specified guide values to maintain bearing material strength and lubricant effectiveness. The standard provides maximum allowable bearing temperatures depending on lubrication method (pressure or self-lubrication) and lubricant flow rates, highlighting risks such as material softening and lubricant degradation above these thresholds.

• Operational Reliability
  These guide values serve as empirical thresholds that offer sufficient reliability even when minor disturbances are present in bearing operation. Adjustments may be necessary for specific applications, especially at high loads or rotational speeds where thermal and hydrodynamic complexities increase.

Applications

ISO 12131-3:2020 is essential for engineers and maintenance professionals involved in:

• Designing hydrodynamic thrust pad bearings in heavy machinery, turbines, compressors, and electric motors
• Establishing preventive maintenance schedules to avoid bearing failures through appropriate lubrication and load monitoring
• Developing bearing calculation models aligned with international best practices to enhance performance and service life
• Assessing and improving machine reliability by limiting mechanical and thermal stresses within safe empirical values
• Optimizing the selection of bearing materials and lubricants suited for application-specific operating conditions

By applying this standard, industries can reduce unplanned downtime, improve equipment lifespan, and ensure efficient operation of critical rotating machinery components.

Related Standards

For comprehensive understanding and application, ISO 12131-3:2020 should be used together with:

• ISO 12131-1:2020 – Calculation methods for hydrodynamic plain thrust pad bearings, including symbol definitions and calculation examples
• ISO 4381, ISO 4382-1, ISO 4382-2, ISO 4383 – Standards covering tin and copper alloy materials commonly used in plain bearing manufacturing
• Other tribology references that explain tolerance effects, lubrication regimes, and material properties relevant to plain bearing design

These interconnected standards provide a robust framework for plain bearing design, manufacture, and maintenance aligned with international best practices.

---

Keywords: hydrodynamic plain thrust pad bearings, ISO 12131-3:2020, thrust bearing calculation, lubricant film thickness, bearing load limits, thermal overloading, plain bearing reliability, bearing maintenance, bearing wear prevention, industrial bearing standards, hydrodynamic lubrication, ISO standards for bearings.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 12131-3
Second edition
2020-07
Plain bearings — Hydrodynamic plain
thrust pad bearings under steady-
state conditions —
Part 3:
Guide values for the calculation of
thrust pad bearings
Paliers lisses — Butées hydrodynamiques à patins géométrie fixe
fonctionnant en régime stationnaire —
Partie 3: Paramètres opérationnels admissibles pour le calcul des
butées à segments
Reference number
©
ISO 2020
© 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: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Guide values for avoiding damage caused by wear . 1
5 Guide values to avoid mechanical overloading . 2
6 Guide values to avoid thermal overloading . 3
Bibliography . 5
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 123, Plain bearings, Subcommittee SC 8,
Calculation methods for plain bearings and their applications.
This second edition cancels and replaces the first edition (ISO 12131-3:2001), of which it constitutes a
minor revision. The changes compared to the previous edition are as follows:
— adjustments have been made to ISO/IEC Directives, Part 2:2018;
— typographical errors have been corrected.
A list of all parts in the ISO 12131 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 2020 – All rights reserved

Introduction
In order to achieve that pad thrust, bearings calculated in accordance with ISO 12131-1 are sufficiently
reliable in operation, it is necessary that the calculated operational parameters h , T or T and p do
min B 2
not fall below or exceed the guide values h , T and p .
lim lim
lim
For limiting cases at high specific loads and/or high rotational frequencies, more accurate calculations
are necessary taking into consideration thermal, elastic, hydrodynamic and/or turbulence effects.
The guide values represent limiting values in the tribological system plain bearing unit which are
dependent on geometry and technology. These are empirical values which still give sufficient reliability
in operation even when subjected to slight disturbing influences (see ISO 12131-1:2020, Clause 5).
The empirical values given can be modified for specific fields of application.
INTERNATIONAL STANDARD ISO 12131-3:2020(E)
Plain bearings — Hydrodynamic plain thrust pad bearings
under steady-state conditions —
Part 3:
Guide values for the calculation of thrust pad bearings
1 Scope
This document specifies guide values for avoiding damage to thrust-pad bearings in service.
The explanation of the symbols as well as examples for calculation are given in ISO 12131-1.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
No terms and definitions are listed in this document.
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/
4 Guide values for avoiding damage caused by wear
To achieve minimum wear and low susceptibility to failure, full lubrication of the plain bearing un
...