ISO 7919-3:2009

INTERNATIONAL ISO
STANDARD 7919-3
Second edition
2009-02-01
Mechanical vibration — Evaluation of
machine vibration by measurements on
rotating shafts —
Part 3:
Coupled industrial machines
Vibrations mécaniques — Évaluation des vibrations des machines par
mesurages sur les arbres tournants —
Partie 3: Machines industrielles couplées

Reference number
©
ISO 2009
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

©  ISO 2009
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2009 – All rights reserved

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 7919-3 was prepared by Technical Committee ISO/TC 108, Mechanical vibration, shock and condition
monitoring, Subcommittee SC 2, Measurement and evaluation of mechanical vibration and shock as applied
to machines, vehicles and structures.
This second edition cancels and replaces the first edition (ISO 7919-3:1996), of which it constitutes a minor
revision. It also incorporates the Technical Corrigendum ISO 7919-3:1996/Cor.1:2007.
ISO 7919 consists of the following parts, under the general title Mechanical vibration — Evaluation of machine
vibration by measurements on rotating shafts:
⎯ Part 1: General guidelines
⎯ Part 2: Land-based steam turbines and generators in excess of 50 MW with normal operating speeds of
1 500 r/min, 1 800 r/min, 3 000 r/min and 3 600 r/min
⎯ Part 3: Coupled industrial machines
⎯ Part 4: Gas turbine sets with fluid-film bearings
⎯ Part 5: Machine sets in hydraulic power generating and pumping plants
Introduction
This part of ISO 7919 specifies guidelines for measuring transverse shaft vibration on coupled industrial
machines. Evaluation criteria, based on previous experience, are given for use as guidelines for assessing the
vibratory conditions of such machines.
A general description of the principles that are generally applicable for the measurement and evaluation of
shaft vibration of non-reciprocating machines is outlined in ISO 7919-1.

iv © ISO 2009 – All rights reserved

INTERNATIONAL STANDARD ISO 7919-3:2009(E)

Mechanical vibration — Evaluation of machine vibration by
measurements on rotating shafts —
Part 3:
Coupled industrial machines
1 Scope
This part of ISO 7919 gives guidelines for applying evaluation criteria of shaft vibration under normal operating
conditions, measured at or close to the bearings of coupled industrial machines. These guidelines are
presented in terms of both steady running vibration and any amplitude changes which can occur in these
steady values. The numerical values specified are not intended to serve as the only basis for vibration
evaluation since, in general, the vibratory condition of a machine is assessed by consideration of both the
shaft vibration and the associated structural vibration.
This part of ISO 7919 applies to coupled industrial machines with fluid-film bearings, having maximum
continuous rated speeds in the range 1 000 r/min to 30 000 r/min and not limited by size and power,
comprising
⎯ steam turbines,
⎯ turbocompressors,
⎯ turbogenerators,
⎯ turbofans,
⎯ electric drives and associated gears, where relevant, and
⎯ rotodynamic pumps (turbo pumps).
The information relating to pumps provided in this part of ISO 7919 complements that given in
ISO 10816-7. In particular, the conditions for in-situ operation, performing acceptance tests and the
influence of bearing clearance given in ISO 10816-7 shall be taken into account when evaluating the
shaft vibration of pumps
This part of ISO 7919 is neither applicable to land-based steam turbine-generator sets for power stations with
outputs greater than 50 MW (see ISO 7919-2), nor machine sets in hydraulic power generating and pumping
plants with outputs of 1 MW or greater (see ISO 7919-5).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 7919-1, Mechanical vibration of non-reciprocating machines — Measurements on rotating shafts and
evaluation criteria — Part 1: General guidelines
3 Measurement procedures
The measurement procedures to be followed and the instrumentation which shall be used are specified in
ISO 7919-1.
In industrial machines, shaft vibration relative to the bearing is normally measured. Therefore, unless stated
otherwise, this part of ISO 7919 always refers to relative vibration displacement. In view of the relatively high
rotational speeds involved with industrial machines, measuring methods using non-contacting transducers are
most common and are generally preferred on rotor elements with operating speeds of 3 000 r/min and above.
For monitoring purposes the measuring system shall be capable of covering overall vibration up to a
frequency equivalent to 2,5 times the maximum service speed. However, it should be noted that for diagnostic
purposes it might be desirable to cover a wider frequency range.
4 Evaluation criteria
The criteria for vibration magnitude, changes in vibration magnitude and operational limits are given in
Annex A.
The vibration magnitude is the higher value of the peak-to-peak displacement measured in two selected
orthogonal measurement directions. The values presented are the result of experience with machinery of this
type and, if due regard is paid to them, acceptable operation can be expected. If only one measuring direction
is used, care should be taken to ensure that it provides adequate information (see ISO 7919-1).
The criteria are presented for the specified steady-state operating conditions at the rated speed and load
ranges. They apply for normal slow changes in load but do not apply when different conditions exist or during
transient changes, for example during start-up and shut-down and when passing through resonance ranges.
In these cases alternative criteria are necessary.
It should be noted that overall judgement of the vibratory state of a machine is often made on the basis of both
shaft relative vibration as defined above and of measurements made on non-rotating parts (see
[2]
ISO 10816-3) .
2 © ISO 2009 – All rights reserved

Annex A
(normative)
Evaluation criteria for relative shaft vibration of coupled industrial
machines under specified operating conditions
A.1 General
Two evaluation criteria are used to assess the relative shaft vibration of coupled industrial machines,
measured at or close to the bearings. One criterion considers the magnitude of the observed broad-band
relative shaft vibration; the second considers changes in magnitude, irrespective of whether they are increases
or decreases.
Caution should be exercised when using the criteria presented in Annex A to ensure that no contact occurs
between the rotating shaft and stationary parts. Therefore, in certain cases the shaft displacement limits given
in this part of ISO 7919 may exceed the available clearance. In such cases the evaluation zone limits should
be adjusted accordingly.
A.2 Criterion I: Vibration magnitude at rated speed under steady operating
conditions
This criterion is concerned with defining limits for shaft vibration magnitude consistent with acceptable
dynam
...