ISO 27996:2024

International
Standard
ISO 27996
Second edition
Aerospace fluid systems —
2024-02
Elastomer seals — Storage and shelf
life
Systèmes de fluides pour l'aéronautique et l'espace — Joints
élastomères — Stockage et durée de conservation
Reference number
© ISO 2024
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General . 2
5 Packaging. 2
5.1 General .2
5.2 Packaging materials.3
5.3 Labelling .3
6 Storage . 3
6.1 Temperature .3
6.2 Humidity .3
6.3 Light .4
6.4 Radiation .4
6.5 Ozone .4
6.6 Deformation .4
6.7 Contact with liquid and semi-solid materials .4
6.8 Contact with metals .4
6.9 Contact with dusting powder .4
6.10 Contact between different elastomers .4
6.11 Elastomeric seals with metal parts bonded to them .5
6.12 Stock rotation .5
7 Recording of data during storage . 5
8 Discarding of seals . 5
8.1 After limited storage life has been exceeded and negative test results .5
8.2 After storage life limit has been exceeded.5
9 Storage period . 5
9.1 Duration of storage .5
9.2 Extension of storage life for class III materials .6
9.2.1 General .6
9.2.2 Visual inspection .6
9.2.3 Testing .7
9.2.4 Extended storage life .7
10 Identification statement . 7
Bibliography . 8

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
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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)
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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 20, Aircraft and space vehicles, Subcommittee
SC 10, Aerospace fluid systems and components.
This second edition cancels and replaces the first edition (ISO 27996:2009), which has been technically
revised.
The main changes are as follows:
— change of the term 3.1 “date of vulcanization” to “cure date”;
— extension of shelf life for EPDM (Table 2) based upon practical experience.
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 fluid power systems, power is transmitted and controlled through a fluid (liquid or gas) under pressure
within an enclosed circuit. Testing of components to meet performance requirement provides users a basis
of assurance for determining design application and for checking component compliance with their stated
requirements.
The requirement for packaging is an integral part of the controlled storage procedure and provides a means
of positive product identity from the time of manufacture to the time of assembly into a component.
This information is intended to be utilized by those organizations who do not have specific requirements or
recommendations already in place for the control of elastomeric seals and seal assemblies. This standard
can be specified in control, storage, and procurement documents. However, when the requirements of
this document are in conflict with the customer's requirements or specifications, the requirements of the
customer's detailed specification govern.

v
International Standard ISO 27996:2024(en)
Aerospace fluid systems — Elastomer seals — Storage and
shelf life
1 Scope
This document specifies the general requirements for data recording procedures, packaging, and storing of
elastomeric seals and seal assemblies which include an elastomeric element prior to the seal being assembled
into hardware components.
This document does not establish limitations or storage times for assembled components, or the operating
life of the said components.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements 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 1629, Rubber and latices — Nomenclature
ISO 5598, Fluid power systems and components — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 5598 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
cure date
the date on which the elastomer (3.2) product was vulcanized, expressed in quarters (Q) of a year
EXAMPLE 4Q04 (October to December, 2004).
3.2
elastomer
material that possesses elastic properties and has undergone vulcanization and/or conversion into a
finished product
Note 1 to entry: The basic building block of the elastomer is the rubber (3.6) polymer it contains.
3.3
extended storage life
period for which an elastomer (3.2) seal (3.7) element moulded from class III material and properly packaged
may be stored after the initial storage period and the successful reinspection and testing of representative
samples
3.4
hardware component
unit in which the elastomeric seal (3.7) element is installed

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