ISO 13628-2:2000

Petroleum and natural gas industries - Design and operation of subsea production systems - Part 2: Flexible pipe systems for subsea and marine applications

La présente partie de l'ISO 13628 définit les exigences minimales applicables à la conception, la sélection des matériaux, la fabrication, le test, le marquage et l'emballage des liaisons flexibles, ainsi que les exigences techniques applicables aux liaisons flexibles interchangeables en matière de sécurité, de dimensions et de fonctionnalités. La présente partie de l'ISO 13628 s'applique aux liaisons flexibles sans armure, composées de longueurs unitaires de flexibles avec éléments de raccordement à chaque extrémité. La présente partie de l'ISO 13628 couvre les applications de production avec et sans H2S , y compris les lignes d'expédition ou d'injection. Les fluides peuvent être du pétrole brut, du gaz, de l'eau ou des additifs chimiques. La présente partie de l'ISO 13628 s'applique aux liaisons statiques et dynamiques utilisées comme lignes de production, de remontées sur plate-forme et de liaisons entre supports (flowlines, risers andjumpers). La présente partie de l'ISO 13628 ne couvre pas les pipes flexibles armés et ne s'applique pas aux accessoires des liaisons flexibles. La présente partie de l'ISO 13628 ne s'applique pas aux liaisons flexibles utilisées pour les applications de bouchage de puit (choke and kilt line applications). NOTE Des recommandations concernant les raidisseurs (bend stiffeners) ou limiteurs de rayon (bend restrictors) sont données en annexe B. Des lignes directrices pour les autres composants sont données dans l'API RP 17B.

Industries du pétrole et du gaz naturel — Conception et exploitation des systèmes de production immergés — Partie 2: Systèmes de canalisations flexibles pour applications sous-marines et en milieu marin

General Information

• Status: Withdrawn
• Publication Date: 20-Dec-2000
• Withdrawal Date: 20-Dec-2000
• ICS: 75.180.10 - Exploratory, drilling and extraction equipment
• Technical Committee: ISO/TC 67/SC 4 - Drilling and production equipment
• Drafting Committee: ISO/TC 67/SC 4/WG 6 - Subsea equipment
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 12-Jul-2006
• Completion Date: 13-Dec-2025

Relations

• Consolidates: ISO/R 390:1964 - Title missing - Legacy paper document
• Effective Date: 28-Feb-2023
• Revised: ISO 13628-2:2006 - Petroleum and natural gas industries - Design and operation of subsea production systems - Part 2: Unbonded flexible pipe systems for subsea and marine applications
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 13628-2
First edition
2000-12-01
Petroleum and natural gas industries —
Design and operation of subsea production
systems —
Part 2:
Flexible pipe systems for subsea and
marine applications
Industries du pétrole et du gaz naturel — Conception et exploitation
des systèmes de production immergés —
Partie 2: Systèmes de canalisations flexibles pour applications
sous-marines et en milieu marin
Reference number
©
ISO 2000
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ii © ISO 2000 – All rights reserved

Contents Page
Foreword.v
Introduction.vi
1 Scope .1
2 Normative references .1
3 Terms, definitions, symbols and abbreviated terms.3
3.1 Terms and definitions .3
3.2 Symbols and abbreviated terms .7
4 Functional requirements and recommendations .8
4.1 General.8
4.2 Overall requirements.8
4.3 General design parameters .9
4.4 Internal fluid parameters.9
4.5 External environment .10
4.6 System requirements and recommendations.11
5 Design requirements and recommendations .14
5.1 Loads and load effects.14
5.2 Pipe design methodology.17
5.3 Pipe structure design .18
5.4 System design requirements.22
6 Materials .25
6.1 Material requirements .25
6.2 Qualification requirements and recommendations.29
6.3 Quality assurance requirements.36
7 Manufacturing requirements .38
7.1 Quality assurance.38
7.2 Carcass .39
7.3 Polymer extrusions.40
7.4 Pressure and tensile armour layers.41
7.5 Anti-wear and insulation layers.41
7.6 End fittings .42
7.7 Special processes.43
7.8 Manufacturing tolerances .45
7.9 Repairs.45
8 Documentation.46
8.1 General.46
8.2 Design premise .46
8.3 Design load report .47
8.4 Design report.47
8.5 Manufacturing quality plan .48
8.6 Fabrication specification .48
8.7 As-built documentation.48
8.8 Operation manual .48
9 Factory acceptance tests (FATs) .49
9.1 General.49
9.2 Gauge test.49
9.3 Hydrostatic pressure test.50
9.4 Electrical continuity and resistance tests.50
9.5 Gas venting system test.51
10 Marking and packaging.51
10.1 Marking .51
10.2 Packaging .51
Annex A (informative) Purchasing guidelines.53
Annex B (informative) Bend stiffeners and bend restrictors .62
Bibliography .67
iv © ISO 2000 – 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 3.
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 part of ISO 13628 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 13628-2 was prepared by Technical Committee ISO/TC 67, Materials, equipment and
offshore structures for petroleum and natural gas industries, Subcommittee SC 4, Drilling and production
equipment.
ISO 13628 consists of the following parts, under the general title Petroleum and natural gas industries — Design
and operation of subsea production systems:
� Part 1: General requirements and recommendations
� Part 2: Flexible pipe systems for subsea and marine applications
�
Part 3: Through flowline (TFL) systems
�
Part 4: Subsea wellhead and tree equipment
�
Part 5: Subsea control umbilicals
�
Part 6: Subsea production control systems
�
Part 7: Workover/completion riser systems
�
Part 8: Remotely Operated Vehicle (ROV) interfaces on subsea production systems
�
Part 9: Remotely Operated Tool (ROT) intervention systems
Annexes A and B of this part of ISO 13628 are for information only.
Introduction
This part of ISO 13628 is based on API Spec 17J, Unbonded Flexible Pipe, first edition, December 1996.
This part of ISO 13628 is complementary to ISO 10420 [29]. API Spec 17J was the result of a Joint Industry Project
to develop a worldwide industry standard specification for the design, material selection, manufacture, testing,
marking and packaging of flexible pipes.
Users of this part of ISO 13628 should be aware that further or differing requirements may be needed for individual
applications. This part of ISO 13628 is not intended to inhibit a vendor from offering, or the purchaser from
accepting, alternative equipment or engineering solutions for the individual application. This may be particularly
applicable where there is innovative or developing technology. Where an alternative is offered, the vendor should
identify any variations from this part of ISO 13628 and provide details.
vi © ISO 2000 – All rights reserved

INTERNATIONAL STANDARD ISO 13628-2:2000(E)
Petroleum and natural gas industries — Design and operation
of subsea production systems —
Part 2:
Flexible pipe systems for subsea and marine applications
1 Scope
This part of ISO 13628 specifies the minimum requirements and recommendations for the design, material
selection, manufacture, testing, marking and packaging of flexible pipes, and defines the technical requirements
and recommendations for safe, dimensionally and functionally interchangeable flexible pipes.
This part of ISO 13628 applies to unbonded flexible pipe assemblies, consisting of segments of flexible pipe body
with end fittings attached to both ends.
This part of ISO 13628 covers applications in both sweet and sour service production, including export and injection
applications. Production fluids include oil, gas, water and injection chemicals. This part of ISO 13628 applies to
both static and dynamic flexible pipes used as flowlines, risers and jumpers.
This part of ISO 13628 does not cover flexible pipes of bonded structure, and does not apply to flexible pipe
ancillary components.
This part of ISO 13628 does not apply to flexible pipes for use in choke and kill line applications.
NOTE Guidelines for bend stiffeners and bend restrictors are given in annex B and guidelines for other components are
given in API RP 17B [1].
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 13628. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 13628 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 10423, Petroleum and natural gas industries — Drilling and production equipment — Wellhead and christmas
tree equipment.
ISO 10474, Steel and steel products — Inspection documents.
ISO 13628-4, Petroleum and natural gas industries — Design and operation of subsea production systems —
Part 4: Subsea wellhead and tree equipment.
ANSI/NACE MR0175, Sulfide Stress Cracking Resistant Metallic Materials for Oilfield Equipment.
ANSI/NACE TM0177, Laboratory Testing of Metals for Resistance to Specific Forms of Environment.
API Spec 16C, Choke and Kill Systems.
API Std 1104, Welding of Pipelines and Related Facilities.
ASME Section IX, Boiler and Pressure Vessel Code, Section IX, Welding and Brazing Qualifications.
ASTM A 29, Standard Specification for Steel Bars, Carbon and Alloy, Hot-Wrought and Cold-Finished — General
Requirements.
ASTM A 182, Standard Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings and Valves and
Parts for High-Temperature Service.
ASTM A 370, Standard Test Methods and Definitions for Mechanical Testing of Steel Products.
ASTM A 388, Standard Practice for Ultrasonic Examination of Heavy Steel Forgings.
ASTM A 480, Standard Specification for General Requirements for Flat-Rolled Stainless and Heat-Resisting Steel
Plate, Sheet and Strip.
ASTM A 668, Standard Specification for Steel Forgings, Carbon and Alloy for General Industrial Use.
ASTM A 751, Standard Test Methods, Practices and Terminology for Chemical Analysis of Steel Products.
ASTM D 695, Standard Test Methods for Compressive Properties of Rigid Plastics.
ASTM D 789, Standard Test Methods for Determination of Relative Viscosity, Standard and Moisture Content of
Polyamide (PA).
ASTM D 1238, Standard Test Method for Flow Rates of Thermoplastics by Extrusion Plastometer.
ASTM D 1418, Standard Practice for Rubber and Rubber Latices — Nomenclature.
ASTM D 4019, Standard Test Method for Moisture in Plastics by Coulometric Regeneration of Phosphorus
Pentoxide.
ASTM D 5028, Standard Test Method for Curing Properties of Pultrusion Resins by Thermal Analysis.
ASTM E 10, Standard Test Method for Brinell Hardness of Metallic Materials.
ASTM E 18, Standard Test Methods for Rockwell Hardness and Rockwell Superficial Hardness of Metallic
Materials.
ASTM E 92, Standard Test Method for Vickers Hardness of Metallic Materials.
ASTM E 94, Standard Guide for Radiographic Testing.
ASTM E 165, Standard Test Method for Liquid Penetrant Examination.
ASTM E 384, Standard Test Method for Microindentation Hardness of Materials.
ASTM E 428, Standard Practice for Fabrication and Control of Steel Reference Blocks Used in Ultrasonic
Inspection.
ASTM E 709, Standard Guide for Magnetic Particle Examination.
ASTM E 1356, Standard Test Method for Assignment of the Glass Transition Temperatures by Differential
Scanning Calorimetry or Differential Thermal Analysis.
DNV Fire Test, DNV Classification Note 6.1 Test (Fire Test).
2 © ISO 2000 – All rights reserved

EN 287-1, Approval testing of welders — Fusion welding — Part 1: Steels.
EN 288-3, Specification and approval of welding procedures for metallic materials — Part 3: Welding procedure
tests for the arc welding of steels.
Lloyds Fire Test, Lloyds Register of Shipping, Fire Testing Memorandum ICE/Fire OSG 1000/499.
3 Terms, definitions, symbols and abbreviated terms
For the purposes of this part of ISO 13628, the following terms, definitions, symbols and abbreviated terms apply.
3.1 Terms and definitions
3.1.1
ancillary component
component used to control the flexible pipe behaviour
EXAMPLES Bend stiffeners and buoyancy modules.
3.1.2
annulus
space between the internal pressure sheath and outer sheath
NOTE Permeated gas and liquid is generally free to move and mix in the annulus.
3.1.3
anti-wear layer
non-metallic layer, either extruded thermoplastic sheath or tape wrapping, used to minimize wear between
structural layers
3.1.4
bellmouth
part of a guide tube, formed in the shape of a bellmouth and designed to prevent overbending of the flexible pipe
3.1.5
bend limiter
device used to restrict bending of the flexible pipe
NOTE Bend limiters include bend restrictors, bend stiffeners and bellmouths.
3.1.6
bend radius
radius of curvature of the flexible pipe measured to the pipe centreline
NOTE Storage and operating MBRs are defined in 5.3.1.6 and 5.3.1.7.
3.1.7
bend restrictor
mechanical device that functions as a mechanical stop and limits the local radius of curvature of the flexible pipe to
a minimum value
3.1.8
bend stiffener
ancillary conically shaped component which locally supports the pipe to limit bending stresses and curvature of the
pipe to acceptable levels
NOTE Bend stiffeners can be attached to either an end fitting or a support structure if the flexible pipe passes through the
bend stiffener.
3.1.9
bending stiffness
property analogous to the structural stiffness of a rigid beam or pipe (modulus of elasticity times the second area
moment of inertia), except that it can vary to a large extent with temperature and pressure
NOTE It is often quantified as the product of an applied bending moment and the resultant bend radius of the pipe.
3.1.10
burst-disk
weak point in the outer sheath designed to burst when the gas pressure in the annulus exceeds a specified value
NOTE The weak point is induced by reducing the thickness of the sheath over a localised area.
3.1.11
carcass
interlocked metallic construction that can be used as the innermost layer to prevent total or partial collapse of the
internal pressure sheath or pipe due to pipe decompression, external pressure, tensile armour pressure and
mechanical crushing loads
NOTE It may be used externally to protect the external surface of the pipe.
3.1.12
choke and kill line
flexible pipe jumper located between a choke manifold and a blow-out preventer
3.1.13
connector
device used to provide a leak-tight structural connection between an end fitting and adjacent piping
NOTE Connectors include bolted flanges, clamped hubs and proprietary connectors. They may be designed for diver-
assisted makeup or for diverless operation using either mechanical or hydraulic apparatus.
3.1.14
design methodology verification report
evaluation report prepared by an independent verification agent at the time of an initial review, for a specific
manufacturer, confirming the suitability and appropriate limits of the manufacturer’s design methodologies
NOTE The design methodology verification report may include occasional amendments or revisions to address the
exceeding of previous limits or changes in methodologies.
3.1.15
design pressure
minimum or maximum pressure, inclusive of operating pressure, surge pressure including shut-in pressure and, if
applicable, vacuum conditions and static pressure head
3.1.16
dynamic application
application in which the flexible pipe is exposed to cyclically varying loads and deflections during normal operation
NOTE The pipe is specially constructed to withstand a large number of bending, tensile and torsional cycles.
3.1.17
end fitting
mechanical device which forms the transition between the flexible pipe body and the connector
NOTE The different pipe layers are terminated in the end fittings in such a way as to transfer the load between the flexible
pipe and the connectors.
4 © ISO 2000 – All rights reserved

3.1.18
flexible pipe
assembly of a pipe body and end fittings
NOTE The pipe body comprises a composite of layered materials that form a pressure-containing conduit. The pipe
structure allows large deflections without a significant increase in bending stresses. Normally the pipe body is built up as a
composite structure comprising metallic and polymer layers. The term “pipe” is used in this part of ISO 13628 as a generic term
for flexible pipe.
3.1.19
fish-scaling
tendency of one tensile armour wire edge to become detached from the underlying layer either because of
deflection or because of incorrect twist deformation during armour winding
3.1.20
independent verification agent
independent party or group, selected by the manufacturer, that can verify the indicated methodologies or
performance in the light of the technical literature, analyses, test results and other information provided by the
manufacturer
NOTE The agent is also called upon to witness some measurements and tests related to material qualification.
3.1.21
insulation layer
additional layer added to the flexible pipe to increase its thermal insulation properties
NOTE The layer is usually located between the outer tensile armour layer and the outer sheath.
3.1.22
intermediate sheath
extruded polymer layer located between internal pressure and outer sheaths
NOTE This layer may be used either as a barrier to external fluids in smooth bore pipes or as an anti-wear layer.
3.1.23
internal pressure sheath
polymer layer that ensures internal fluid integrity
NOTE This layer may consist of a number of sub-layers.
3.1.24
jumper
short flexible pipe used in subsea and topside, static or dynamic applications
3.1.25
lay angle
angle between the axis of a spiral wound element (e.g. armour wires) and a line parallel to the flexible pipe
longitudinal axis
3.1.26
outer sheath
polymer layer used to protect the pipe against penetration by sea water and other external environments, corrosion,
abrasion and mechanical damage, and to keep the tensile armours in position after forming
3.1.27
piggyback
two pipes attached at regular intervals with clamps
NOTE Either or both of the pipes may be flexible.
3.1.28
pressure armour layer
structural layer, with a lay angle close to 90°, that increases the resistance of the flexible pipe to internal and
external pressure and to mechanical crushing loads
NOTE The layer also structurally supports the internal pressure sheath and typically consists of an interlocked metallic
construction, which may be backed up by a flat metallic spiral layer.
3.1.29
quality
conformance to specified requirements
3.1.30
quality assurance
planned, systematic and preventive actions which are required to ensure that materials, products or services will
meet specified requirements
3.1.31
quality control
inspection, test or examination to ensure that materials, products or services conform to specified requirements
3.1.32
rough bore
flexible pipe with a carcass as the innermost layer
3.1.33
service life
period of time during which the flexible pipe fulfils all performance requirements
3.1.34
smooth bore
flexible pipe with an internal pressure sheath as the innermost layer
3.1.35
S-N curves
curves showing stress range versus number of cycles
3.1.36
sour service
serviceconditions withanH S content exceeding the minimum specified by ANSI/NACE MR0175 at the design
pressure
3.1.37
static application
application in which the flexible pipes are not exposed to significant cyclically varying loads or deflections during
normal operations
3.1.38
sweet service
service conditions with an H S content not exceeding the minimum specified by ANSI/NACE MR0175 at the design
pressure
3.1.39
tensile armour layer
structural layer consisting of helically wound metallic wires, typically with a lay angle of between 20° and 55°
NOTE Tensile armour layers are typically counter-wound in pairs, and are used to sustain, totally or partially, tensile loads
and internal pressure.
6 © ISO 2000 – All rights reserved

3.1.40
third party
independent party qualified to witness, confirm or approve the referenced data, result, procedure, test or
qualification
3.1.41
torsional balance
pipe characteristic that is achieved by designing the structural layers in the pipe so that axial and pressure loads do
not induce significant twist or torsional loads in the pipe
3.1.42
tensile strength
maximum tensile stress which a material is capable of sustaining; calculated from the maximum load during a
tension test carried to rupture and the original cross-sectional area of the specimen
3.1.43
unbonded pipe
construction consisting of separate unbonded polymeric and metallic layers, which allows relative movement
between layers
3.1.44
visual examination
examination of parts and equipment for visible defects in material and workmanship
3.1.45
yield strength
engineering stress at which, by convention, it is considered that plastic elongation has commenced
NOTE It is specified in terms of either a specified deviation from a linear stress-strain relationship, or a specified total
extension attained, or maximum or minimum engineering stresses measured during discontinuous yielding.
3.2 Symbols and abbreviated terms
ASNT American Society of Nondestructive Testing
DNV Det Norske Veritas
DSC differential scanning calorimetry
FAT factory acceptance test
HAZ heat-affected zone
HIC hydrogen-induced cracking
ID internal diameter
MBR minimum bend radius
NDE non-destructive examination
PA polyamide
PE polyethylene
PVC polyvinylchloride
PVDF polyvinylidene fluoride
RAO response amplitude operator
S-N stress range — number of cycles
SSC sulfide stress cracking
TAN titrated acid number
TFL through flowline
UV ultraviolet
WPS welding procedure specification
WPQR welding procedure qualification record
� material yield strength
y
� material tensile strength
u
� tensile hoop stress
t
� equivalent stress (Von Mises or Tresca)
e
n permissible utilization factor as specified in Table 7
P combined probability of occurrence (yearly)
c
4 Functional requirements and recommendations
4.1 General
4.1.1 The purchaser shall specify his functional requirements for the flexible pipe. The purchasing guidelines in
annex A give a sample format for the specification of the functional requirements.
4.1.2 Functional requirements not specifically required by the purchaser which may affect the design, materials,
manufacturing and testing of the pipe shall be specified by the manufacturer.
4.1.3 If the purchaser does not specify a requirement, and 4.1.2 does not apply, manufacturer may assume that
there is no requirement.
4.2 Overall requirements
4.2.1 Flexible pipe
The minimum overall functional requirements of the flexible pipe that shall be demonstrated by the manufacturer
are as follows:
a) the pipe shall provide a leak-tight conduit;
b) the pipe shall be capable of withstanding all design loads and load combinations defined herein;
c) the pipe shall perform its function throughout the specified service life;
d) the flexible pipe materials shall be compatible with the environment to which the material is exposed;
e) the flexible pipe materials shall conform to the corrosion control requirements specified in this part of
ISO 13628.
8 © ISO 2000 – All rights reserved

4.2.2 End fittings
The manufacturer shall demonstrate that the end fittings, as a minimum, meet the same functional requirements as
the flexible pipe. If relevant, the following shall be demonstrated:
a) the end fittings shall provide a structural interface between the flexible pipe and the support structure;
b) the end fittings shall provide a structural interface between the flexible pipe and bend-limiting devices,
including bend stiffeners, bend restrictors and bellmouths, such that the bend-limiting devices meet their
functional requirements.
4.3 General design parameters
The purchaser shall specify any project-specific design requirements, including the requirements given in 4.4, 4.5,
4.6 and the following:
a) nominal ID;
b) length and tolerances of flexible pipe, including end fittings;
c) service life.
4.4 Internal fluid parameters
4.4.1 General
The purchaser shall specify the internal fluid parameters for the application. The parameters listed in Table 1
should be specified. When known the minimum, normal and maximum conditions should be specified for the
internal fluid parameters of Table 1. Expected variations in the internal fluid parameters over the service life should
be specified.
Table 1 — Internal fluid parameters
Parameter Comment
Internal pressure See 4.4.2
Temperature See 4.4.3
Fluid composition See 4.4.4
Service definition Sweet or sour in accordance with 4.4.4 a)
Fluid/flow description Fluid type and flow regime
Flow rate parameters Flow rates, fluid density, viscosity, minimum inlet pressure and
required outlet pressure
Thermal parameters Fluid heat capacity
4.4.2 Internal pressure
The following internal pressures shall be specified:
a) maximum design pressure;
b) minimum design pressure.
The following internal pressures should be specified:
� operating pressure or pressure profile throughout service life;
� factory and field-test pressure requirements of governing and/or certifying authorities.
4.4.3 Temperature
4.4.3.1 The following temperatures shall be specified:
a) design minimum temperature;
b) design maximum temperature.
The operating temperature or temperature profile throughout the service life should also be specified.
4.4.3.2 The design minimum and maximum temperatures are the minimum and maximum temperatures to
which the flexible pipe may be exposed during its service life. These design temperatures may be specified on the
basis of the following minimum set of considerations:
a) operating temperatures;
b) upset temperatures (number and range of cycles);
c) gas cooling effects (time/temperature curve);
d) fluid thermal characteristics;
e) flow characteristics;
f) storage, transport and installation conditions.
4.4.4 Fluid composition
The purchaser should specify the produced fluids (composition of individual phases), injected fluids, and continual
and occasional chemical treatments (dosages, exposure times, concentrations and frequency). In the specification
of the internal fluid composition the following should be defined:
a) all parameters which define service conditions, including partial pressure of H S and CO , pH of aqueous
2 2
phase, TAN (in accordance with ASTM D 664 [9] or ASTM D 974 [14]) and water content (produced water, sea
water and free water);
b) gases, including oxygen, hydrogen, methane and nitrogen;
c) liquids, including oil composition and alcohols;
d) aromatic components;
e) corrosive agents, including bacteria, chlorides, organic acids and sulfur-bearing compounds;
f) injected chemical products including alcohols, and inhibitors for corrosion, hydrate, paraffin, scale and wax;
g) solids, including sand, precipitates, scale, hydrates, wax and biofilm.
4.5 External environment
The purchaser should specify the external environment to which the pipe system will be exposed. The parameters
listed in Table 2 should be considered. The design water depth shall be the maximum water depth to which the
pipe section may be lowered.
10 © ISO 2000 – All rights reserved

Table 2 — External environment parameters
Parameter Comment
Location Geographical data for the installation location
Water depth Design water depth, variations along pipe route and tidal variations
Sea water data Density, pH value, and minimum and maximum temperatures
Air temperature Minimum and maximum during storage, installation and operation
Soil data Description, shear strength or angle of internal friction, friction coefficients,
seabed scour, sand waves and variations along pipe route
Marine growth Maximum values and variations along pipe route
Ice Maximum ice accumulation, or drifting icebergs and ice floes
Sunlight exposure Length of pipe exposed during operation and storage conditions
Current data As a function of water depth, direction and return period, and including the
known effects of local currents
Wave data In terms of significant and maximum waves, associated periods, wave spectra,
spreading functions and scatter diagrams, as a function of direction and return
period
Wind data As a function of direction, height above water level and return period
4.6 System requirements and recommendations
4.6.1 Minimum system requirements and recommendations
4.6.1.1 General
4.6.1.1.1 The purchaser shall specify the functional requirements of the system. The requirements given in
4.6.1.2, 4.6.1.9 and 4.6.1.10 shall be specified by the purchaser. Specification of the other system requirements
defined in this subclause should be considered. Annex A may be referred to for guidance.
4.6.1.1.2 The purchaser should specify the documentation, as listed in 8.1.2, to be delivered by the
manufacturer.
4.6.1.2 Application definition
The flexible pipe system shall be specified as either flowline, riser or jumper. The flexible pipe application shall be
specified as either static or dynamic and in the latter case the expected number of load cycles and their magnitudes
should be specified.
4.6.1.3 Corrosion protection
The corrosion protection requirements for the flexible pipe should be specified, with attention paid to the following:
a) internal and external corrosion protection of the end fittings;
b) cathodic protection system for the pipe;
c) protection voltage, current source and current density.
4.6.1.4 Thermal insulation
The purchaser should specify any heat loss or retention requirements that the flexible pipe shall satisfy. Overall
heat transfer coefficients shall be based on the pipe's nominal ID, and shall differentiate between the pipe itself and
any external effects such as soil cover of buried pipe.
4.6.1.5 Gas venting
A gas venting system shall be provided to prevent excessive pressure build-up in the annulus of the pipe. The
purchaser should specify the requirements for the gas venting system, considering the following:
a) gas venting system components;
b) allowable gas permeation rates;
c) restrictions on gas venting locations;
d) interface requirements;
e) gas monitoring system.
4.6.1.6 Pigging and TFL requirements
Any tool-related requirements, including ID, bend radius, and end fitting transitions, for pigging, TFL, workover or
other operations through the flexible pipe should be specified by the purchaser.
4.6.1.7 Fire resistance
Fire resistance design requirements for the pipe should be specified with reference to the Lloyds Fire Test or the
DNV Fire Test. See 5.4.6.1 for specific requirements.
4.6.1.8 Piggyback lines
Any piggyback requirements for the flexible pipe should be specified, including details of the piggyback pipe(s) and
pipe operating conditions.
4.6.1.9 Connectors
The connector requirements for both end fittings in the flexible pipe shall be specified. This shall include, as a
minimum, connector type, welding specification, seal type and sizes.
4.6.1.10 Interface definitions
Interface details, including at least the following, shall be specified:
a) regulations, codes and standards including definition of code breaks;
b) geometric, dimensional and imposed loading data;
c) purchaser supplied installation aids and equipment;
d) purchaser supplied pull-in and connection tools and terminations;
e) manufacturer's scope of supply.
4.6.1.11 Inspection and condition monitoring
The requirements for the manufacturer's design to cater for flexible pipe inspection, monitoring and condition
assessment systems and procedures should be specified.
12 © ISO 2000 – All rights reserved

4.6.1.12 Installation requirements
4.6.1.12.1 The purchaser should specify performance requirements for the installation services to be provided,
considering the following as a minimum:
a) for installation by the purchaser, the purchaser should specify any load restrictions, clamping/tensioner loads,
overboarding chute requirements, installation tolerances and port facility limitations;
b) for installation by the manufacturer, the purchaser should specify any seasonal or environmental constraints,
vessel limitations, installation tolerances, restrictions due to conflicting activities, length of time wet parked, and
installation scope (including trenching, burial, testing, inspection, surveying and documentation).
4.6.1.12.2 The purchaser should specify any requirements for the recoverability and reusability of the flexible pipe
throughout its service life.
4.6.1.13 Exothermal chemical reaction cleaning
The purchaser should specify the relevant parameters for pipe cleaning operations by means of exothermal
chemical reaction, considering the following as a minimum:
a) flow rate;
b) pressure variation;
c) maximum heat output;
d) chemical composition.
4.6.2 Flowline parameters
The purchaser should specify to the manufacturer any requirements for the design and analysis of the flowline (or
static jumper) system additional to the requirements given in clause 5. The parameters listed in Table 3 should be
considered.
Table 3 — Flowline parameters
Parameter Details
Flowline routing Route drawings, topography, seabed/soil conditions, obstacles, installed equipment
and pipelines
Guides and supports Proposed geometry of guides, I-tubes, J-tubes and bellmouths through which flowline
is to be installed
Protection requirements Trenching, rock dumping, mattresses and extent of protection requirements along the
pipe route (e.g. protection against impact loads from trawl boards, dropped objects and
anchors)
On-bottom stability Allowable displacements
Upheaval buckling Specification of design cases to be considered by manufacturer
Crossover requirements Crossing of pipes (flexible and rigid), including already installed pipes and gas lines
Pipe attachments Bend restrictors, clamps, etc., and attachment methods
Load cases Definition of yearly probability for installation, normal operation and abnormal
operation. Specification of accidental load cases and yearly probabilities
4.6.3 Riser parameters
The purchaser shall specify to the manufacturer any requirements for the design and analysis of the riser (or
dynamic jumper) system additional to the requirements given in clause 5. The parameters listed in Table 4 should
be considered.
Table 4 — Riser parameters
Parameter Details
Riser configuration Specification of any configuration requirements, including description (lazy-S, steep
wave, etc.), layout and components
Selection of configuration or confirmation of suitability of specified configuration
Connection systems Descriptions of upper and lower connection systems, including quick disconnection
systems and buoy disconnection systems, connection angles and location tolerances
Pipe attachments Bend stiffeners, buoys, etc., and attachment methods
Attached vessel data Data for attached floating vessels, including the following:
a) vessel data, dimensions, drafts, etc.;
b) static offsets;
c) first (RAOs) and second order motions;
d) vessel motion phase data;
e) vessel motion reference point;
f) mooring system interface data;
g) position tolerances.
Interference requirements Specification of possible interference areas, including other risers, mooring lines,
platform columns, vessel pontoons, tanker keel, etc., and definition of allowable
interference/collision
Load cases Definition of yearly probability for installation, normal operation and abnormal operation
Specification of accidental load cases and yearly probabilities
5 Design requirements and recommendations
5.1 Loads and load effects
5.1.1 General
The pipe design is based on the information supplied by the purchaser (see annex A), with reference to the
requirements and recommendations of clause 4. All relevant information shall be defined in the design premise
(see 8.2) including design load cases. Results of the design load case analyses shall be included in the design load
report (see 8.3).
5.1.2 Load classes
5.1.2.1 As listed in Table 5, loads are classified as functional, environmental (external) or accidental, as follows:
a) functional loads are all loads on the pipe in operation, including all loads which act on the pipe in still water
except wind, wave or current loads;
b) environmental loads are loads induced by external environmental parameters;
c) accidental loads are loads caused by accidental occurrences.
Load classes and subclasses are listed in the left column of Table
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