ISO 24999:2008

INTERNATIONAL ISO
STANDARD 24999
First edition
2008-07-01
Corrected version
2008-09-15
Flexible cellular polymeric materials —
Determination of fatigue by a
constant-strain procedure
Matériaux polymères alvéolaires souples — Détermination de la fatigue
par un procédé de déformation constante

Reference number
©
ISO 2008
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ii © ISO 2008 – All rights reserved

Contents Page
Foreword. iv
1 Scope . 1
2 Normative references . 1
3 Principle. 1
4 Apparatus . 1
5 Test pieces . 2
6 Procedure . 3
7 Expression of results . 3
8 Precision. 4
9 Test report . 4
Annex A (informative) Precision . 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
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The main task of technical committees is to prepare International Standards. Draft International Standards
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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 24999 was prepared by Technical Committee ISO/TC 45, Rubber and rubber products, Subcommittee
SC 4, Products (other than hoses).
This corrected version of ISO 24999:2008 incorporates the following correction: in Subclause 5.4, second
paragraph, the reference to “ISO 23549” has been replaced by a reference to “ISO 23529”.

iv © ISO 2008 – All rights reserved

INTERNATIONAL STANDARD ISO 24999:2008(E)

Flexible cellular polymeric materials — Determination of fatigue
by a constant-strain procedure
WARNING — Persons using this International Standard should be familiar with normal laboratory
practice. This standard does not purport to address all of the safety problems, if any, associated with
its use. It is the responsibility of the user to establish appropriate safety and health practices and to
ensure compliance with any national regulatory conditions.
1 Scope
This International Standard specifies a method for determining the loss in thickness of flexible cellular
materials when compressed repetitively to a fixed level of strain. It is particularly useful for quality control in
the manufacture of flexible polymeric cellular materials.
Another procedure already exists as ISO 3385: this measures the fatigue characteristics of flexible polymeric
cellular materials by constant-stress loading of the specimen rather than constant strain. It forms the basis of a
material classification system in ISO 5999.
These two fatigue procedures are complementary to each other and can both be useful in the prediction of
end-use performance.
The procedure and equipment used in this International Standard allow testing of a large number of test
pieces at any one time, whereas ISO 3385 only allows testing of one test piece at a time under the
compression device.
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 1923, Cellular plastics and rubbers — Determination of linear dimensions
3 Principle
Constant strain is repetitively applied to the whole surface of the test piece, then the final thickness of the test
piece is measured.
4 Apparatus
The test machine to be used shall be a compression type having the following structure and functions.
The machine shall have two
...