EN ISO 23936-2:2011

SLOVENSKI STANDARD
01-marec-2012
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Petroleum, petrochemical and natural gas industries - Non-metallic materials in contact
with media related to oil and gas production - Part 2: Elastomers (ISO 23936-2:2011)
Erdöl-, petrochemische und Erdgasindustrie - Nichtmetallische Werkstoffe mit
Medienkontakt bei der Öl- und Gasproduktion - Teil 2: Elastomere (ISO 23936-2:2011)
Industries du pétrole, de la pétrochimie et du gaz naturel - Matériaux non métalliques en
contact avec les fluides relatifs à la production de pétrole et de gaz - Partie 2:
Élastomères (ISO 23936-2:2011)
Ta slovenski standard je istoveten z: EN ISO 23936-2:2011
ICS:
75.180.01 Oprema za industrijo nafte in Equipment for petroleum and
zemeljskega plina na splošno natural gas industries in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 23936-2
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2011
ICS 75.180.01
English Version
Petroleum, petrochemical and natural gas industries - Non-
metallic materials in contact with media related to oil and gas
production - Part 2: Elastomers (ISO 23936-2:2011)
Industries du pétrole, de la pétrochimie et du gaz naturel - Erdöl-, petrochemische und Erdgasindustrie -
Matériaux non métalliques en contact avec les fluides Nichtmetallische Werkstoffe mit Medienkontakt bei der Öl-
relatifs à la production de pétrole et de gaz - Partie 2: und Gasproduktion - Teil 2: Elastomere (ISO 23936-
Élastomères (ISO 23936-2:2011) 2:2011)
This European Standard was approved by CEN on 14 December 2011.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same
status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 23936-2:2011: E
worldwide for CEN national Members.

Contents Page
Foreword .3
Foreword
This document (EN ISO 23936-2:2011) has been prepared by Technical Committee ISO/TC 67 "Materials,
equipment and offshore structures for petroleum, petrochemical and natural gas industries" in collaboration
with Technical Committee CEN/TC 12 “Materials, equipment and offshore structures for petroleum,
petrochemical and natural gas industries” the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by June 2012, and conflicting national standards shall be withdrawn at
the latest by June 2012.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 23936-2:2011 has been approved by CEN as a EN ISO 23936-2:2011 without any
modification.
INTERNATIONAL ISO
STANDARD 23936-2
First edition
2011-12-15
Petroleum, petrochemical and natural gas
industries — Non-metallic materials in
contact with media related to oil and gas
production —
Part 2:
Elastomers
Industries du pétrole, de la pétrochimie et du gaz naturel — Matériaux
non métalliques en contact avec les fluides relatifs à la production de
pétrole et de gaz —
Partie 2: Élastomères
Reference number
ISO 23936-2:2011(E)
©
ISO 2011
ISO 23936-2:2011(E)
©  ISO 2011
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 2011 – All rights reserved

ISO 23936-2:2011(E)
Contents Page
Foreword . iv
Introduction . v
1  Scope . 1
2  Normative references . 1
3  Terms, definitions and abbreviated terms . 2
3.1  Terms and definitions . 2
3.2  Abbreviated terms . 4
4  Technical requirements . 4
5  Documentation requirements . 5
6  Requirements for manufacturers . 6
6.1  General requirements . 6
6.2  Validation of compliance . 7
7  Qualification of elastomer materials (ageing and RGD) . 8
7.1  General . 8
7.2  Requirements for ageing tests . 8
7.3  Requirements for rapid gas decompression testing . 9
8  Qualification of elastomeric materials in bonded flexible hose . 9
8.1  General . 9
8.2  Qualification of bonded flexible hose liner material . 10
8.3  Qualification of bonded flexible hose – Layers outside the liner . 14
9  Qualification of elastomeric materials in other large components . 15
9.1  General . 15
9.2  Qualification of elastomeric materials in flexible joints . 15
9.3  Qualification of elastomeric materials in blow-out preventers . 15
9.4  Qualification of elastomeric materials for packers . 16
Annex A (normative) Test media, conditions, equipment and procedures for ageing of
elastomeric materials . 17
Annex B (normative) Test media, conditions, equipment and procedures for rapid gas
decompression testing of elastomeric materials . 26
Annex C (informative) Most commonly used elastomeric materials . 40
Annex D (normative) Procedure for estimation of material service life using the Arrhenius
relationship . 42
Annex E (informative) Physical and chemical ageing . 47
Annex F (informative) Rapid gas decompression (RGD) . 62
Bibliography . 66

ISO 23936-2:2011(E)
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 23936-2 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical and natural gas industries.
ISO 23936 consists of the following parts, under the general title Petroleum, petrochemical and natural gas
industries — Non-metallic materials in contact with media related to oil and gas production:
 Part 1: Thermoplastics
 Part 2: Elastomers
The following parts are planned:
 Part 3: Thermosets
 Part 4: Fibre-reinforced composite
 Part 5: Other non-metallic materials

iv © ISO 2011 – All rights reserved

ISO 23936-2:2011(E)
Introduction
ISO 23936 is intended to be of benefit to a broad industry group, ranging from operators and suppliers to
engineering companies and authorities. ISO 23936 covers relevant generic types of non-metallic material
(thermoplastics, elastomers, thermosetting plastics, fibre-reinforced plastics, etc.) and draws upon a wide
range of existing technical experience, which has never before been summarized in a technical standard.
ISO 23936 does not cover polymeric coatings such as thermal insulation and paint that are applied to the
outside of components but that are not in contact with oilfield fluids.
The evaluation and qualification process described in this part of ISO 23936 is intended to ensure that the
user of non-metallic materials has sufficient understanding and knowledge of the applicable materials to
obtain acceptable performance in the specified environment, and that the user can rely on stable quality to
meet given specifications. A quality system is useful to ensure compliance with the requirements of this part of
ISO 23936.
Successful qualification of a manufacturer and a specific material is intended to be valid for other projects and
different operators. The consideration of qualification of a manufacturer is at the discretion and determination
of the purchaser, normally on the basis of documentation provided by the manufacturer, as required in this
part of ISO 23936 or any specific additional documentation.
The purchaser is responsible for ensuring (if necessary, with external competence) that the manufacturers
selected are qualified.
This part of ISO 23936 is based on NORSOK standard M-710.
INTERNATIONAL STANDARD ISO 23936-2:2011(E)

Petroleum, petrochemical and natural gas industries — Non-
metallic materials in contact with media related to oil and gas
production —
Part 2:
Elastomers
1 Scope
ISO 23936 describes general principles and gives requirements and recommendations for the selection and
qualification of non-metallic materials for service in equipment used in oil and gas production environments,
where the failure of such equipment could pose a risk to the health and safety of the public and personnel, or
to the environment. It can be applied to help avoid failures of the equipment itself. It supplements, but does
not replace, the material requirements given in the appropriate design codes, standards or regulations.
This part of ISO 23936 describes the requirements and procedures for qualification of elastomeric material
used in equipment for oil and gas production.
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 34-1:2010, Rubber, vulcanized or thermoplastic — Determination of tear strength — Part 1: Trouser,
angle and crescent test pieces
ISO 37, Rubber, vulcanized or thermoplastic — Determination of tensile stress-strain properties
ISO 48, Rubber, vulcanized or thermoplastic — Determination of hardness (hardness between 10 IRHD and
100 IRHD)
ISO 815-1, Rubber, vulcanized or thermoplastic — Determination of compression set — Part 1: At ambient or
elevated temperatures
ISO 2781, Rubber, vulcanized or thermoplastic — Determination of density
ISO 2921, Rubber, vulcanized — Determination of low-temperature retraction (TR test)
ISO 3601-3:2005, Fluid power systems — O-rings — Part 3: Quality acceptance criteria
ISO 7619-1, Rubber, vulcanized or thermoplastic — Determination of indentation hardness — Part 1:
Durometer method (Shore hardness)
ISO 13628-10:2005, Petroleum and natural gas industries — Design and operation of subsea production
systems — Part 10: Specification for bonded flexible pipe
ISO 23936-2:2011(E)
ASTM D297, Standard Test Methods for Rubber Products — Chemical Analysis
ASTM D395, Standard Test Methods for Rubber Property — Compression Set
ASTM D412, Standard Test Methods for Vulcanized Rubber and Thermoplastic Elastomers — Tension
ASTM D624, Standard Test Method for Tear Strength of Conventional Vulcanized Rubber and Thermoplastic
Elastomers
ASTM D1414, Standard Test Methods for Rubber O-Rings
ASTM D1415, Standard Test Method for Rubber Property — International Hardness
ASTM D2240, Standard Test Method for Rubber Property — Durometer Hardness
API 17K, Specification for Bonded Flexible Pipe
3 Terms, definitions and abbreviated terms
For the purposes of this document, the following terms, definitions and abbreviated terms apply.
3.1 Terms and definitions
3.1.1
accelerated test
test undertaken under conditions designed to speed material deterioration
NOTE This is usually accomplished by increasing temperature, in order to raise chemical reaction rates, but fluid
concentration and stress are variables which can also be manipulated.
3.1.2
asset operator
person who operates an asset, who has knowledge of well parameters and who transmits this information to
the user (3.1.15)
NOTE 1 An asset can be a well, a production train, a plant, etc.
NOTE 2 Well parameters can be fluid exposure, temperatures, pressures, duration, etc.
3.1.3
compression set
difference between the original sample height and the post-test height, divided by the interference, expressed
as a percentage
3.1.4
elastomer
rubber
amorphous material mechanically mixed with other constituents to form a rubber compound, which is then
shaped by flow into articles by means of the manufacturing processes of moulding or extrusion, and then
(invariably) chemically cured at elevated temperature to form an elastic insoluble material
3.1.5
fluid
medium such as a gas, liquid, supercritical gas, or a mixture of these
2 © ISO 2011 – All rights reserved

ISO 23936-2:2011(E)
3.1.6
interference
difference between the original sample height and the height of spacer bar, each measured in the same
direction as the direction of compression
3.1.7
compound manufacturer
manufacturer
producer of the elastomer material or of semi-finished products made from elastomer materials
3.1.8
modulus
tensile stress at a given elongation
NOTE In the rubber industry, the modulus at 50 % elongation is often chosen.
3.1.9
polymer
high molecular weight molecule, natural or synthetic, whose chemical structure can be represented by
repeated small units which collectively form molecular chains
NOTE This material class has three main sub-groups: elastomers, thermoplastics and thermosets.
3.1.10
rapid gas decompression
RGD
depressurization
explosive decompression
rapid pressure-drop in a high pressure gas-containing system which disrupts the equilibrium between external
gas pressure and the concentration of gas dissolved inside any polymer, with the result that excess gas tries
to escape from the solution at points throughout the material, causing expansion
NOTE If large enough, and if the pressure-drop rate is faster than the natural gas diffusion rate, blistering or rupturing
can occur.
3.1.11
room temperature
temperature of (23  2) °C
3.1.12
seal cross-section
cross-section diameter
CSD
free height of a seal at room temperature, measured normal to seal diameter in the direction of compression in
the test
NOTE The measurement is taken at three circumferentially equidistributed positions.
3.1.13
seal type
seal design of specified geometry, size and orientation
EXAMPLE An O-ring.
3.1.14
thermoplastic
material capable of being repeatedly softened by heating and hardened by cooling through a temperature
range characteristic of the plastic and, in the softened state, of being repeatedly shaped by flow into articles
by moulding, extrusion or forming
ISO 23936-2:2011(E)
3.1.15
user
person responsible for the selection of suitable materials for a service operation based on information
received from the asset operator (3.1.2)
3.1.16
purchaser
party responsible for procuring the elastomer material or component
3.2 Abbreviated terms
BOP blow-out preventer
BRE base resistant elastomers
COC certificate of conformance
CSD cross-section diameter
DMA dynamic mechanical analysis
DMTA dynamic mechanical thermal analysis
DSC differential scanning calorimetry
GMPHOM Guide to Manufacturing and Purchasing Hoses for Offshore Moorings
HNBR hydrogenated nitrile butadiene rubber
HP high pressure
LNG liquefied natural gas
NBR nitrile butadiene rubber
OCIMF Oil Companies International Marine Forum
PBR polished bore receptacle
RGD rapid gas decompression (rapid gas depressurization)
SPS solubility parameter spectroscopy
TMA thermo mechanical analysis
4 Technical requirements
Technical requirements depend on material property characteristics and specific functional tests for an
application.
Elastomer selection shall be based on evaluation of compatibility with service environment, functionality under
service and the design lifetime. This part of ISO 23936 covers materials tests and not functional tests. The
following should be considered as appropriate to the component requirements and evaluated when selecting
the material:
4 © ISO 2011 – All rights reserved

ISO 23936-2:2011(E)
a) adequate physical and mechanical properties (density, hardness, tensile strength, elongation at break,
modulus of elasticity, compression set, tear strength, etc.); standard properties from which design
specifications are selected and for quality assurance and control aspects;
b) resistance against RGD events; a property of importance in high pressure gas sealing applications,
covered in depth in this part of ISO 23936;
c) long-term behaviour; resistance to chemical/physical change of the material; an important characteristic
regarding sealing generally in the oil and gas sector, covered in this part of ISO 23936;
d) low temperature flexibility; a property highly relevant to low temperature sealing applications;
e) for large components exposed to gaseous production fluid, high pressure gas permeation; a property
highly relevant to possible gas pressure build-up within the component structure, e.g. for hoses;
f) resistance to high pressure extrusion or creep (functional tests not covered by this part of ISO 23936);
g) resistance to thermal cycling and dynamic movement (functional tests not covered by this part of
ISO 23936).
Clause 2 gives references to relevant standards for elastomeric materials. The standards describe the test
methodology for performing particular materials tests. The test conditions and durations shall be as described
in this part of ISO 23936 and shall take precedence in those cases where this part of ISO 23936 deviates from
the referenced standards.
Long term (ageing) test objectives are described in Clause 7; procedural details are given in Annex A.
RGD test objectives and procedures for elastomer O-ring seals are described in Clause 7 and Annex B.
It is the responsibility of the asset operator to provide all necessary information about service conditions and
environment.
Information on elastomer characteristics is provided in Annex C.
5 Documentation requirements
NOTE The required documentation of material properties of thermoplastic materials is described in ISO 23936-1.
Required documentation of material properties is given in Table 1. Requirements pertaining both to
documentation of properties and quality control are given. Each elastomer material used shall be traceable to
the compound manufacturer and their quality control documentation as required in Table 1. Each batch of
material shall be supplied with, as a minimum, a certificate of conformance (COC) and traceability information.
Table 1 also defines the minimum amount of production and quality control testing required during
manufacturing of the elastomer materials. The final procedures, with respect to key parameters and
tolerances, shall be defined based on results from testing performed according to this part of ISO 23936.
The user shall define the necessary requirements with tolerances in the purchase specification.
Guidelines on selection of standards are given in parentheses. Characteristics, which are not relevant for
expected service conditions and/or material type, may be omitted.
ISO 23936-2:2011(E)
Table 1 — Required documentation for elastomer material properties
Properties Documentation Quality control tests
a c
Density (ISO 2781 or ASTM D297)
D B
Hardness (IRHD/Shore A) (ISO 48/ISO 7619-1, ASTM D2240/
D B
ASTM D1415)
Tensile and elongation properties (ISO 37, ASTM D1414, D B
ASTM D412)
Compression set (ISO 815-1, ASTM D395/ASTM D1414) D
Low temperature characteristics by DSC, DMA or TMA D
Tear strength (ISO 34-1:2010, Method A, ASTM D624) D
Temperature of retraction (ISO 2921) D
Ageing/RGD characteristics (Annexes A/B) D
b
High pressure gas permeation
DH
a
D: Properties to be documented for each supplier for each type of material. Nominal values with tolerances shall be
given (Data Sheet).
b
DH: As for D, but specifically when using all large components exposed to high pressure gas.
c
B: Properties to be documented on a batch-wise basis, minimum 5 samples per test per batch with all results presented.
The acceptance criteria shall be established prior to the test and based on qualification test results.

Material property tests may also be omitted if users have documented performance-based functional tests that
they use to approve rubber materials.
6 Requirements for manufacturers
6.1 General requirements
It is the requirement of the manufacturer to provide documents attesting that the material has been
manufactured and tested appropriately and that the material has met the relevant quality control requirements
in this part of ISO 23936.
The testing shall be performed on specimens produced from specific rubber formulations and, where possible,
production procedures. The COC should include as a minimum density, batch hardness, tensile properties
(moduli, strength, elongation at break), date of manufacture and (where referenced) the sample curing
process. The COC should be signed by a quality representative. For large rubber components, tests on small
components shall be suitable for the properties of the large component unless otherwise agreed between the
interested parties.
This part of ISO 23936 specifies the required types of tests that shall be performed in order to document the
material suitability and compatibility with test fluids specified in this part of ISO 23936 which are applicable to
the intended application.
The testing shall apply for the elastomer materials and the results shall be valid as long as the requirements
stated in 6.2 are satisfied. For later supplies of identical material from the same manufacturer, a quality control
of each batch of material shall be sufficient. Table 2 lists typical quality assurance and quality control
document templates showing imaginary data.
6 © ISO 2011 – All rights reserved

ISO 23936-2:2011(E)
Table 2 — Typical quality assurance and quality control information
Material
Manufacturer Acme Seals, Inc.
Compound grade FabFluoro
Elastomer type ASTM D1418-05 FKM Type 3
Lot/batch no. FF2344rw4r/07
Cure date Q4 2010
Typical Properties Applicable standard Unit Value
Density ISO 2781 g/cm 1,8
Hardness ISO 48 IRHD 85
Tensile strength ISO 37 MPa 21
Modulus at 50% elongation ISO 37 MPa 10,1
Modulus at 100% elongation ISO 37 MPa 18,5
Elongation at break ISO 37 % 125

It may not be necessary to perform qualification testing for a particular material, if relevant successful well-
documented in-service experience with traceable production records and quality control documentation is
available to all relevant parties. This shall be agreed between interested parties.
Such documentation shall contain detailed information about service conditions such as time, temperature,
pressure, fluid composition and chemicals added. An asset operator can, for example, provide the
documentation of flawless service. The existing service temperature recorded therein shall be in the same
range as for the new application (it shall be a maximum of 10 °C below), the existing service pressure shall
not be more than 10 % below that for the new application, and the existing service life shall be a minimum of
50 % of design life.
The manufacturer who has tested and qualified his compound(s) can make a statement making this known.
Such a statement shall define which parts of ISO 23936 are complied with. Further, the statement shall
include whether the testing was done according to Annex A and/or Annex B, and define the fluid composition,
conditions and overall duration for the testing.
6.2 Validation of compliance
The elastomer properties shall apply to each specific elastomer compound produced by each specific
manufacturer. The existing elastomer data used by one purchaser may also be accepted by subsequent
purchasers, provided the requirements in this part of ISO 23936 are still complied with.
A compound shall be re-tested if changes are made to the compound or the process. If compound mixing
and/or moulding is carried out at different plants/locations, a separate qualification shall be performed for each
plant.
NOTE All materials previously approved in accordance with NORSOK M-710 are approved in accordance with this
part of ISO 23936.
ISO 23936-2:2011(E)
7 Qualification of elastomer materials (ageing and RGD)
7.1 General
The technical necessities for the testing of elastomeric materials are divided into two parts:
 7.2 defines the chemical ageing test requirements (see Annex A);
 7.3 defines the requirements for RGD testing (see Annex B).
The test regimes shall be selected based on an analysis of the service conditions applying to the material in
question, if these are known. Such an assessment shall include the nature and type of all fluids which contact
the elastomer. The service life of the seal material in the relevant service environment shall be evaluated
using appropriate techniques.
7.2 Requirements for ageing tests
7.2.1 General
This part of ISO 23936 defines test procedures for the prediction of the progressive degradation of elastomeric
materials exposed to fluids at elevated temperatures over extended periods of time. It is applicable where it is
necessary to forecast material life in a specific application and for directly comparing the performance of
candidate elastomer materials. Other standards, such as API TR6J1, also provide methods to assess life of
elastomer materials.
The objective is to assess the physical effects of the fluid on the elastomer and to thermally accelerate
chemical reaction (if this occurs) between the fluid and the elastomer, causing tensile and related property
levels to shift systematically towards a pre-defined limit of acceptability. The material is considered to have
“failed” (i.e. reached the end of its useful life) when this limit is attained. These data are then used to quantify
service life and suitability for service.
By running exposure tests with test fluids at three different elevated temperatures above the operating
temperature, three different times to reach the acceptance boundary will result, with the highest test
temperature producing the shortest “time to failure”. Plotting the log of failure times against the reciprocal of
the test temperature should result in a linear trend, enabling an estimate of service life at the operating
temperature.
For accelerated testing, the upper test temperature should be limited to give some confidence that only
service-relevant chemical and/or physical processes will occur.
The preferred test piece geometry is the tensile dumbbell; various standards apply (see Table 1). The ageing
of moulded sheet, for subsequent stamping-out of tensile test pieces, is not allowed. The elastomer shall be
tested in unconstrained mode; that is, free-standing, with fluid able to freely access all surfaces.
When extrapolating data from the present procedures, appropriate statistical techniques shall be applied. For
example, if progressive degradation is apparently dependent on a single chemical ageing process, a method
based on the Arrhenius relationship shall be used as described in Annex D. It is recommended that results
always first be assessed on an Arrhenius basis. If an Arrhenius relationship does not exist or ageing does not
occur, see Annex E for further guidance.
Test media, conditions, equipment, procedures and test report requirements are described in detail in
Annex A.
7.2.2 Acceptance criteria for elastomers
The acceptance criteria shall be established prior to commencing the ageing test. The following criteria have
been established as the maximum acceptable ranges for three particular properties; any relaxation of these
8 © ISO 2011 – All rights reserved

ISO 23936-2:2011(E)
requirements shall be agreed upon by the user. A narrower acceptance range can be applied to any of these if
required by circumstances.
 Hardness: 10/20 units (5/20 units when initial nominal hardness is 90); applies to Shore A and IRHD
scales
 Volume: 25 % /5 %
 Tensile: 50 % [modulus (at 50 % or 100 % elongation), tensile strength, elongation at break]
Tensile test results shall be used to extrapolate the service life according to Arrhenius equation (see
Annexes A and E). Other properties may be used by agreement between all parties.
7.3 Requirements for rapid gas decompression testing
7.3.1 General
This part of ISO 23936 gives test procedures for measuring the effect on elastomeric O-ring seals of rapid
depressurization after periods at elevated temperature and high pressure in gaseous environments. In
addition, guidance notes for interpretation of the results are provided. The supplier shall discuss with the user
those applications for which this failure mode is relevant.
The test fluids, conditions, procedure, equipment, inspection procedure and test reporting requirements are
described in Annex B.
7.3.2 Acceptance criterion
No seal cross-section shall have a rating of more than 3 (see Clause B.4).
8 Qualification of elastomeric materials in bonded flexible hose
8.1 General
Bonded flexible hose is the general class of flexible hose constructed from layers of elastomer and wire, wire
fabric or textile fabric reinforcement that are bonded together by vulcanization during manufacture. The hose
section from the internal to external diameter generally consists of the following:
 liner: inner layer of elastomer providing resistance to the fluids being transported;
 body layers: layers of reinforcement typically including textile fabric or parallel cords impregnated with
elastomer, parallel steel wire cords impregnated with elastomer, and embedded helical wire. Infill
elastomer layers may also be present;
 cover: outer layer of elastomer providing resistance to the external environment;
 insulation or buoyancy: an additional outer layer for hoses where either insulation or buoyancy is required.
The hose structure is integrated into suitable end fittings according to the specific design, usually by bonding
of the elastomer to the metal end fitting with a suitable curable adhesive system during the vulcanization of the
hose.
Bonded flexible hose usage can be generally classified into:
a) lower pressure applications that are typically used for loading and discharge of liquids and LNG in
offshore mooring situations;
ISO 23936-2:2011(E)
b) higher pressure applications used in oil and gas production.
For a), guidance is provided in GMPHOM/OCIMF [Guide to Manufacturing and Purchasing Hoses for Offshore
Moorings (Oil Companies International Marine Forum)], including materials tests for the liner and cover
materials for materials acceptance and prototype hose approval.
For b), ISO 13628-10 specifies material property requirements and test procedures for the qualification of liner,
breaker and reinforcing layers in terms of mechanical/physical properties, thermal properties, permeation
characteristics and compatibility/ageing properties covering all pressures.
In the context of this part of ISO 23936, the main consideration is the qualification of the liner material that is in
contact with the fluids being transported. For the longer term, the effects of the permeation of fluids through
the liner to other elastomer layers should also be considered as well as ageing effects on mechanical/physical
properties. Because of the multi-layer construction of bonded hoses, not only should the properties of the
individual elastomer layers be considered, but also the adhesion between layers including the bonding with
the end fittings.
8.2 Qualification of bonded flexible hose liner material
8.2.1 General
Qualification should be according to the subclauses below, which are based on the existing guidelines
mentioned in 8.1.
8.2.2 Guide to manufacturing and purchasing hoses for offshore moorings
The procedure of GMPHOM/OCIMF should be applied or adapted as appropriate with regard to materials test
procedures. It possesses two clauses entitled Materials Tests, one under “Acceptance Tests” and one for
“Prototype Hose Approval”; the most relevant should be agreed between supplier and purchaser and
employed. Particular points are:
a) Within both clauses termed Material Tests, for resistance to liquids, GMPHOM/OCIMF specifies the use
of ISO 1817 using the conditions 48 h at 40 C in the test liquid as a volume swell test, with a requirement
of swell being no greater than 60 %.
NOTE GMPHOM/OCIMF specifies use of (ASTM) liquid C, which can still conform to this part of ISO 23936 if
liquid C is stated to be the bespoke liquid agreed between participants (see Annex A).
This part of ISO 23936 allows the same procedure for use with a standard liquid selected to be
reasonably representative of the composition of the service fluid to be transported or contained, in
accordance with Annex A. Bespoke acceptance properties will be required if alternative low temperature
requirements and/or products and/or service fluids are relevant.
b) GMPHOM/OCIMF specifies for temperature resistance “no significant deterioration” at –20 °C using the
Gehman test to ISO 1432.
c) Under “Acceptance Tests”, GMPHOM/OCIMF also specifies adhesion testing between bonded layers of
body and end-fitting elastomer using a standard peel test as described in ISO 36:2005, which specifies a
test method for measuring the force required to separate two plies of fabric bonded with rubber, or a
rubber layer and a fabric ply bonded together. The ply surfaces should be plane or nearly so, with no
gross irregularities. Supplier and user should agree a threshold force for acceptance, based on
experience.
d) If the service temperature is higher than ambient, the material test temperature should be increased
accordingly. The test conditions, test duration and acceptance criteria should be agreed between supplier
and purchaser. Consideration to the temperatures and fluids chosen should be made with consultation to
ISO 1817.
10 © ISO 2011 – All rights reserved

ISO 23936-2:2011(E)
8.2.3 ISO 13628-10 and API 17K
ISO 13628-10 and API 17K specify property tests for liner and reinforcing layers (see Tables 9 and 11 in
API 17K:2005) and describe test procedures and acceptance criterion for fluid permeability (liquid and gas),
blistering, fluid compatibility, ageing and void formation (the last being a component test), concerning
interlayer failures. Much of ISO 13628-10 and API 17K is useful for incorporation in this part of ISO 23936, but
some variations are required.
8.2.4 Requirements for gas permeation
Gas permeation testing should be made at appropriate high pressure on a specimen from liner or other layer
material, and procedures shall vary depending on conditions and fluid type. Test gases shall be in accordance
with Tables A.2 and A.3, using the bespoke category for testing single gases.
For high pressure (HP) gas permeation testing of an elastomer material, a test assembly pressure cell with the
following features is required.
a) A chamber which can be pressurized to high pressure by a gas supply. This will be separated from a low
pressure chamber by a suitably sealed elastomer test piece. Facilities for continuous monitoring of the
pressures in the high and low pressure chambers are required.
b) Heating (insulated band heater) facilities and temperature monitoring and control of the permeation cell to
within 2 °C.
Test times are governed by diffusion characteristics of candidate elastomers (see Annex E). In one test
arrangement, test pieces of test elastomer of diameter 10 mm are bonded during vulcanization into a suitable
holder. Moulding pressure shall be high to minimize porosity and microporosity. The test specimen holder is
installed and sealed in the HP permeation cell. A porous steel sinter necessary for supporting the specimen is
inserted appropriately. The cell is then heated to test temperature and allowed to equilibrate before applying
test gas to the specimen and pressurizing. As a minimum, the following test conditions shall apply:
 high pressure (P ): hose design pressure, may be used if pipe design pressure is not known;
 temperature (T): service, or three higher temperatures for three accelerated tests followed by Arrhenius-
extrapolation of the three resulting data points to service (see Annex D).
The pressure increase due to permeation in the low pressure chamber with time may be converted to the rate
of gas permeation (cm /s at standard temperature and pressure), assuming the gas to be ideal, by
Equation (1):

273V
dq P
 lp
 (1)



dtt T

lp

where
V is the volume of the low pressure chamber;
...