EN ISO 13628-8:2006

Petroleum and natural gas industries - Design and operation of subsea production systems - Part 8: Remotely Operated Vehicle (ROV) interfaces on subsea production systems (ISO 13628-8:2002)

ISO 13628:2002 gives functional requirements and guidelines for ROV interfaces on subsea production systems for the petroleum and natural gas industries. It is applicable to both the selection and use of ROV interfaces on subsea production equipment, and provides guidance on design as well as the operational requirements for maximising the potential of standard equipment and design principles. The auditable information for subsea systems it offers will allow interfacing and actuation by ROV-operated systems, while the issues it identifies are those that have to be considered when designing interfaces on subsea production systems. The framework and detailed specifications set out will enable the user to select the correct interface for a specific application.

Erdöl- und Erdgasindustrie - Auslegung und Betrieb von Unterwasser-Produktionssystemen - Teil 8: Schnittstellen mit ferngelenkten Transporteinheiten (ROV) auf Unterwasser-Produktionssystemen (ISO 13628-8:2002)

Industries du pétrole et du gaz naturel - Conception et exploitation des systèmes de production immergés - Partie 8: Véhicules commandés à distance pour l'interface avec les matériels immergés (ISO 13628-8:2002)

L'ISO 13628-8:2002 fournit les exigences fonctionnelles et les recommandations applicables aux interfaces des véhicules commandés à distance avec les systèmes de production immergés dans les industries du pétrole et du gaz naturel. Elle s'applique à la sélection et à l'utilisation des interfaces des véhicules commandés à distance avec le matériel de production immergé et elle fournit des lignes directrices sur la conception ainsi que sur les exigences opérationnelles permettant d'accroître le plus possible le potentiel des équipements normalisés et des principes de conception. Les informations auditables relatives aux systèmes immergés, contenues dans l'ISO 13628-8:2002, permettront l'interface et la mise en œuvre par des systèmes utilisant des véhicules commandés à distance. Les problèmes identifiés, quant à eux, devront être pris en compte lors de la conception des interfaces avec les systèmes de production immergés. Le cadre et les spécifications détaillées établis permettront à l'utilisateur de choisir l'interface adaptée à une application spécifique.

Industrija za predelavo nafte in zemeljskega plina - Načrtovanje in delovanje podvodnih proizvodnih sistemov - 8. del: Vmesniki daljinsko vodenih vozil (ROV) za uporabo v podvodnih proizvodnih sistemih (ISO 13628-8:2002)

General Information

• Status: Published
• Publication Date: 05-Dec-2006
• Withdrawal Date: 29-Jun-2007
• ICS: 75.180.10 - Exploratory, drilling and extraction equipment
• Technical Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Drafting Committee: CEN/TC 12 - Materials, equipment and offshore structures for petroleum and natural gas industries
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 06-Dec-2006
• Due Date: 23-Jan-2008
• Completion Date: 06-Dec-2006
• Ref Project: SIST EN ISO 13628-8:2007 - Petroleum and natural gas industries - Design and operation of subsea production systems - Part 8: Remotely Operated Vehicle (ROV) interfaces on subsea production systems (ISO 13628-8:2002)

Relations

• Revised: prEN ISO 13628-8 - Petroleum and natural gas industries - Design and operation of subsea production systems - Part 8: Remotely operated tools and interfaces on subsea production systems (ISO/DIS 13628-8:2010)
• Effective Date: 18-Jan-2023

Overview

EN ISO 13628-8:2006 (ISO 13628-8:2002) provides functional requirements and practical guidance for Remotely Operated Vehicle (ROV) interfaces on subsea production systems used in the petroleum and natural gas industries. The standard helps users select and use ROV interfaces for installation, inspection, maintenance and actuation of subsea equipment, and defines an intervention philosophy, design guidance and operational requirements to maximize reuse of standard equipment and reduce life‑cycle cost.

Key topics and technical requirements

The standard addresses a broad set of technical topics essential to reliable subsea ROV intervention, including:

• Intervention philosophy and ROV task configurations - guidance on planning and typical intervention scenarios.
• Design performance and materials - criteria for load capability, operating forces/torques, lifting devices, temperature ratings, quality control and material selection.
• Detailed design considerations - conceptual and detailed design guidance, desirable and undesirable design features.
• ROV interfaces - standardized interface types such as stabilisation, handles (manipulator and TDU), rotary (low and high torque), linear (push) interfaces, rotary docking, hot‑stab hydraulic connections (Type A - 69.0 MPa / 10 000 psi noted), rotary fluid couplings, CCO interfaces, lifting mandrels, and jumper handling.
• Operational considerations and indicator systems - requirements that support safe and auditable ROV actuation and system feedback.
• Documentation, testing and information feedback - what manufacturers and operators should record for auditable subsea systems.

Practical applications and who uses it

EN ISO 13628-8 is intended for professionals responsible for the design, procurement, operation and maintenance of subsea production equipment:

• Subsea and completion engineers designing trees, manifolds, flowline tie‑ins and control systems
• ROV system designers and manufacturers of end‑effectors and intervention tooling
• Offshore operators, asset integrity and maintenance teams planning intervention and life‑cycle strategies
• Procurement and quality assurance teams specifying auditable interface requirements Using this standard helps ensure interfaces are compatible with work‑class ROVs, simplify intervention tasks, reduce risk during subsea operations and support regulatory/compliance needs.

Related standards

EN ISO 13628-8 is part of the ISO 13628 series for subsea production systems, which includes:

• Part 1: General requirements
• Part 2: Flexible pipe systems
• Part 3: Through flowline systems
• Part 4: Subsea wellhead and tree equipment
• Part 5: Subsea umbilicals
• Part 6: Subsea production control systems
• Part 7: Completion/workover riser systems
• Part 9: Remotely Operated Tool (ROT) intervention systems

By applying EN ISO 13628-8, stakeholders standardize ROV interfaces, improve interoperability, and reduce operational cost and risk in subsea oil & gas activities.

Standards Content (Sample)

SLOVENSKI STANDARD
01-maj-2007
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]DXSRUDERYSRGYRGQLKSURL]YRGQLKVLVWHPLK,62
Petroleum and natural gas industries - Design and operation of subsea production
systems - Part 8: Remotely Operated Vehicle (ROV) interfaces on subsea production
systems (ISO 13628-8:2002)
Erdöl- und Erdgasindustrie - Konstruktion und Betrieb von Unterwasser-
Produktionssystemen - Teil 8: Schnittstellen ferngelenkter Fahrzeuge (ROV) mit
Unterwasser-Produktionssystemen (ISO 13628-8:2002)
Industries du pétrole et du gaz naturel - Conception et exploitation des systemes de
production immergés - Partie 8: Véhicules commandés a distance pour l'interface avec

les matériels immergés (ISO 13628-8:2002)
Ta slovenski standard je istoveten z: EN ISO 13628-8:2006
ICS:
75.180.10 Oprema za raziskovanje in Exploratory and extraction
odkopavanje equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 13628-8
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2006
ICS 75.180.10
English Version
Petroleum and natural gas industries - Design and operation of
subsea production systems - Part 8: Remotely Operated Vehicle
(ROV) interfaces on subsea production systems (ISO 13628-
8:2002)
Industries du pétrole et du gaz naturel - Conception et Erdöl- und Erdgasindustrie - Konstruktion und Betrieb von
exploitation des systèmes de production immergés - Partie Unterwasser-Produktionssystemen - Teil 8: Schnittstellen
8: Véhicules commandés à distance pour l'interface avec ferngelenkter Fahrzeuge (ROV) mit Unterwasser-
les matériels immergés (ISO 13628-8:2002) Produktionssystemen (ISO 13628-8:2002)
This European Standard was approved by CEN on 13 November 2006.
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 Central Secretariat 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 Central Secretariat has the same status as the official
versions.
CEN members are the national standards bodies of Austria, Belgium, 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: rue de Stassart, 36  B-1050 Brussels
© 2006 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 13628-8:2006: E
worldwide for CEN national Members.

Foreword
The text of ISO 13628-8:2002 has been prepared by Technical Committee ISO/TC 67
"Materials, equipment and offshore structures for petroleum and natural gas industries” of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 13628-
8:2006 by 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 2007, and conflicting national
standards shall be withdrawn at the latest by June 2007.

According to the CEN/CENELEC Internal Regulations, the national standards organizations of
the following countries are bound to implement this European Standard: Austria, Belgium,
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.

Endorsement notice
The text of ISO 13628-8:2002 has been approved by CEN as EN ISO 13628-8:2006 without any
modifications.
INTERNATIONAL ISO
STANDARD 13628-8
First edition
2002-12-15
Petroleum and natural gas industries —
Design and operation of subsea
production systems —
Part 8:
Remotely Operated Vehicle (ROV)
interfaces on subsea production systems
Industries du pétrole et du gaz naturel — Conception et exploitation
des systèmes de production immergés —
Partie 8: Véhicules commandés à distance pour l'interface avec
les matériels immergés
Reference number
ISO 13628-8:2002(E)
©
ISO 2002
ISO 13628-8:2002(E)
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ii © ISO 2002 — All rights reserved

ISO 13628-8:2002(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope. 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions. 1
3.2 Abbreviated terms. 2
4 Intervention philosophy and functional requirements. 2
4.1 General. 2
4.2 Intervention by ROV. 3
4.3 ROV intervention task configurations . 4
4.4 Subsea facilities system design. 10
5 Design performance . 13
5.1 General. 13
5.2 Materials. 13
5.3 Load capability. 13
5.4 Operating force or torque. 13
5.5 Lifting devices . 13
5.6 Quality control. 13
5.7 Temperature ratings . 14
5.8 Colours and marking . 14
6 Design considerations. 14
6.1 General. 14
6.2 Conceptual design. 14
6.3 Detailed design. 16
6.4 Desired design features . 18
6.5 Undesirable design features. 20
7 ROV interfaces and subsea systems . 21
8 Operational considerations . 24
9 Indicator systems. 24
10 Material selection. 25
10.1 General. 25
10.2 Selection criteria . 25
11 Documentation . 25
11.1 General. 25
11.2 Equipment design. 26
11.3 Testing. 26
11.4 Information feedback. 26
12 ROV interfaces . 26
12.1 General. 26
12.2 Stabilization . 26
12.3 Handles for use with manipulators . 32
12.4 Handles for use with TDUs. 34
12.5 Rotary (low torque) interface . 35
12.6 Rotary (high-torque) interface . 37
12.7 Linear (push) interface — Types A and C.38
ISO 13628-8:2002(E)
12.8 Linear (push) interface type B.41
12.9 Rotary docking .42
12.10 Hot stab hydraulic connection type A — 69,0 MPa (10 000 psi) working pressure.45
12.11 Hot stab hydraulic connection type B.46
12.12 Rotary fluid coupling.49
12.13 CCO interface.51
12.14 Lifting mandrels.56
12.15 Electrical and hydraulic jumper handling.57
Annex A (informative) Summary of work class ROV specifications .63
Annex B (informative) Access .64
Annex C (informative) Manipulator operating envelopes .65
Annex D (informative) Alternative designs for end-effectors.66
Annex E (informative) Flowline tie-in systems .68
Bibliography.69

iv © ISO 2002 — All rights reserved

ISO 13628-8:2002(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 13628-8 was prepared by Technical Committee ISO/TC 67, Materials, equipment and offshore structures
for petroleum, petrochemical 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 umbilicals
 Part 6: Subsea production control systems
 Part 7: Completion/workover riser systems
 Part 8: Remotely Operated Vehicle (ROV) interfaces on subsea production systems
 Part 9: Remotely Operated Tool (ROT) intervention systems

ISO 13628-8:2002(E)
Introduction
1) [1]
This part of ISO 13628 is a revision, major amendment and expansion of Annex C of API 17D .
The recommended practices for the selection and use of ROV interfaces have generally selected one
interface for a specific application. The inclusion of a particular approach or recommendation does not imply
that it is the only approach or the only interface to be used for that application.
In determining the suitability of standardization of ROV intervention interfaces for installation, maintenance or
inspection tasks on subsea equipment, it is necessary to adopt a general philosophy regarding subsea
intervention. This intervention philosophy is more fully described within this part of ISO 13628, as are the
associated evaluation criteria used in selecting the interfaces incorporated into these recommendations.
This part of ISO 13628 is not intended to obviate the need for sound engineering judgement as to when and
where its provisions are to be utilized, and users need to be aware that additional or differing details may be
required to meet a particular service or local legislation.
With this part of ISO 13628, it is not wished to deter the development of new technology. The intention is to
facilitate and complement the decision processes, and the responsible engineer is encouraged to review
standard interfaces and re-use intervention tooling in the interests of minimizing life-cycle costs and increasing
the use of proven interfaces.
This part of ISO 13628 does not cover intervention by remote operated tools (ROTs), which are dedicated
tools deployed on drill pipe or guidelines. Instead, it focuses upon defining the requirements of ROV interfaces
with subsea production systems, with further reference to ROT interfaces only being made where deemed
appropriate. The interfaces on the subsea production system can apply equally to ROTs and ROVs.

1) American Petroleum Institute, 1220 L Street NW, Washington D.C. 20005, USA.
vi © ISO 2002 — All rights reserved

INTERNATIONAL STANDARD ISO 13628-8:2002(E)

Petroleum and natural gas industries — Design and operation
of subsea production systems —
Part 8:
Remotely Operated Vehicle (ROV) interfaces on subsea
production systems
1 Scope
This part of ISO 13628 gives functional requirements and guidelines for ROV interfaces on subsea production
systems for the petroleum and natural gas industries. It is applicable to both the selection and use of ROV
interfaces on subsea production equipment, and provides guidance on design as well as the operational
requirements for maximising the potential of standard equipment and design principles. The auditable
information for subsea systems it offers will allow interfacing and actuation by ROV-operated systems, while
the issues it identifies are those that have to be considered when designing interfaces on subsea production
systems. The framework and detailed specifications set out will enable the user to select the correct interface
for a specific application.
2 Normative references
The following referenced document is 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 10423, Petroleum and natural gas industries — Drilling and production equipment — Wellhead and
christmas tree equipment
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
functional requirement
minimum criterion which shall be satisfied in order to meet a stated objective or objectives
NOTE Functional requirements are performance oriented and are applicable to a wide range of development
concepts.
3.1.2
guideline
recommendation of recognized practice to be considered in conjunction with applicable statutory
requirements, industry standards, standard practices and philosophies
ISO 13628-8:2002(E)
3.1.3
manufacturer
company responsible for the manufacture of the interface
3.1.4
operator
company which physically operates the ROV (delivery system)
3.1.5
remotely operated tool
ROT
dedicated tool that is normally deployed on lift wires or drill string
NOTE Lateral guidance can be by guide wires, dedicated thrusters or ROV assistance.
3.1.6
remotely operated vehicle
ROV
free-swimming submersible craft used to perform tasks such as valve operations, hydraulic functions and
other general tasks
NOTE ROVs can also carry tooling packages for undertaking specific tasks such as pull-in and connection of flexible
flowlines and umbilicals, and component replacement.
3.2 Abbreviated terms
CCO Component change-out
FAT Factory acceptance test
FMECA Failure mode effect and criticality analysis
HIPPS High integrity pipeline protection system
MQC Multi quick connect
MTBF Mean time between failures
ROV Remotely operated vehicle
ROT Remotely operated tool
SCM Satellite control module
TDU Tool deployment unit
4 Intervention philosophy and functional requirements
4.1 General
When designing interfaces for use on subsea production systems an intervention philosophy needs to be
established. The intervention philosophy should address the activities to be carried out, the method of
intervention for each task, the type of tool, the method of stabilization of the ROV by docking or positioning for
the effective performance of its intervention tasks, and access requirements. The intervention philosophy
should take into account the various intervention tasks, rationalizing them so that a consistent method is
adopted, as a number of tasks may be performed consecutively.
2 © ISO 2002 — All rights reserved

ISO 13628-8:2002(E)
Once the tasks to be carried out have been identified the ROV intervention method should be established.
Figures 1 to 34 show a variety of ROV systems and interfaces.
4.2 Intervention by ROV
ROVs are free-swimming submersible craft that can be used to perform tasks such as valve operations,
hydraulic functions, and other general tasks. ROVs can also carry tooling packages in order to undertake
specific tasks such as tie-in and connection functions for flowlines, umbilicals and rigid pipeline spools, and
component replacement. ROVs are essentially configured for carrying out intervention tasks in five ways:
 with manipulators for direct operation of the interface;
 with a manipulator-held tool;
 with TDUs;
 dual down line method (with ROTs);
 with tool skids or frames.
Interface tooling, so far as possible, should be designed to operate with a range of ROVs and not be limited in
application to one design only, thus allowing the use of ROVs and intervention vessels of opportunity. Figure 1
shows typical ROVs.
a) ROV with manipulators b) Twin-point docking tool delivery system

c) Underslung tool skid d) Single-point docking tool delivery system
Figure 1 — Typical work class ROV operationally configured
ISO 13628-8:2002(E)
Figure 2 shows ROV and interfaces on a typical tree.

Figure 2 — Interfaces on typical tree
4.3 ROV intervention task configurations
4.3.1 ROV intervention with manipulators
A manipulator is a mechanical arm complete with joints allowing degrees of freedom (see Figure 1). The arm
or arms are connected to the ROV vehicle frame. The more joints that the arm has, the more degrees of
freedom and consequently the more versatile the arm.
At the end of the arm there is a gripper, usually consisting of two or three fingers that allow handles, objects
and structural members to be grasped for the purpose of carrying out an activity or to stabilize the ROV.
Where a ROV is engaged in performing tasks, it can have two manipulator arms, one used for stabilising the
ROV itself and the second for carrying out the function or task.
Manipulator systems operated by ROV vary considerably in their functionality and controllability. For tasks to
be performed on a subsea production system using ROV manipulators or manipulator-held tooling, the
following number of issues require special consideration:
 location of the interface such that it is within the manipulator capability in terms of reach, i.e. the working
envelope (see Annex C for details of typical manipulator envelopes);
 pliancy between the tool body and the handle by which the manipulator holds the tool, to provide dexterity
during insertion or pull-out of the tool, such that the manipulator’s wrist angle does not have to move
precisely in tandem with the insertion or pull movement of the rest of the arm (see Figure 19 for an
example of design pliancy in the wire rope extension between a hot stab body and the manipulator
handle);
4 © ISO 2002 — All rights reserved

ISO 13628-8:2002(E)
 weight of any removable components such that they are within the manipulator capability in terms of the
arm's lift and handling capacity;
 precision, accuracy and repeatability in determining the difficulty of the task;
 sufficient access and space to allow tools to be inserted into the interface and allowable clearance away
from adjacent operations such as hot stabs, etc.;
 ability of the subsea equipment and component to resist the loads and torque reactions applied by the
manipulator, tool and/or ROV;
 protection for equipment against impact from the ROV.
Consideration of environmental conditions, which may affect successful intervention and the completion of
specific tasks identified above, will lead to the selection of one of the following stabilization methods:
 a flat horizontal platform area for the ROV to park, thrusting against the platform, adjacent to the
interface, allowing vertical or horizontal access;
 a horizontal or vertical bar, to allow the ROV grabber (limited degree of freedom manipulator arm) to take
hold (see Figure 6);
 ROV docking/receiver points (see Figures 7, 15, 16, 18 and 22);
 relatively flat, smooth surfaces for attaching suction cups.
Docking and interface points should be a minimum of 1,5 m (4,92 ft) above the clear local seabed level for
unhindered operations.
ROV platforms should be avoided where they need to be removed, opened or closed in order that other
intervention tasks can be performed.
The designer should take into account the various intervention tasks and rationalize these to adopt a
consistent means of ROV docking on the subsea facility, as the ROV could be required to perform a number
of tasks during the same dive.
In certain geographic locations, care needs to be taken in establishing the seabed level owing to soft mud and
the effect of ROV thruster wash on the seabed.
See Figure 8 for specific details related to local tool loads.
4.3.2 ROV intervention with a tool deployment unit (TDU)
4.3.2.1 General
A TDU is a specifically designed work package that is attached to the front or rear of the ROV frame to
accurately orient and position the tool by use of a Cartesian carriage arrangement (see Figure 3). The number
of degrees of freedom are one, two or three axis, depending upon the complexity of the task and the position
of the TDU's docking position relative to the tooling interface. The TDU can replace or be complementary to
the manipulator arm or arms.
4.3.2.2 Twin-point docking system
The TDU is used in combination with two docking probes that latch onto and attach the Cartesian carriage and
ROV to the subsea production equipment. The twin docked carriage system can access one or more
intervention interfaces from the same docked position and is particularly suitable when grouping interface
missions into panels. Figure 3 shows a typical twin-point TDU.
ISO 13628-8:2002(E)
4.3.2.3 Single-point docking system
The single-point system is similar to the twin-point docking system, but with some operating differences. The
single-point TDU is also a ROV-mounted work package, providing a similar means to accurately orient and
position interface tooling, in a y-z Cartesian configuration. The single-point docking system docks and attaches
much in the same way as two docking probes but has more flexibility to move freely around the subsea
equipment. It is recommended for interfaces which are situated singly (or in isolated pairs) or where there is a
limited amount of adjacent structure. Figure 4 shows a typical single-point TDU.

Figure 3 — Twin-point docking TDU

Figure 4 — Single-point docking TDU
4.3.2.4 General considerations for docking and TDU operation
In general, a single-point TDU has a maximum of two intervention interfaces that can be addressed from the
single docking point. Ideally, the interface or interfaces are vertically aligned directly above the docking point
(see Figure 10).
6 © ISO 2002 — All rights reserved

ISO 13628-8:2002(E)
Interfaces for use with a twin-point docking TDU have to be located in an envelope governed by operational
limits of the Cartesian carriage system and its relationship to the tooling interface points (see Figure 9).
Other considerations include the following:
 a single-point TDU generally requires lighter interface tool loading conditions than a twin-point TDU;
 a single-point TDU can impose more dynamic and static loading from the ROV into the docking structure
on the subsea equipment and interface tooling than a twin-point TDU;
 a twin-point TDU requires more access space to accommodate the Cartesian carriage from several
aspects — the ROV vehicle frame, the ROV deployment system (winch and surface handling equipment),
its tether maintenance system (or garage), and the subsea equipment — especially where the interfaces
are not externally located;
 the TDU frame needs to be designed for resisting loads and reaction torque generated by the
environment, the ROV, the TDU docking probes and the interface tooling;
 a twin-point TDU is normally mounted on the upper half of the ROV, which dictates the elevation of the
tooling interface points on the Cartesian carriage below (interface points should be a minimum of 1,5 m
(4,92 ft) above the clear seabed level for unhindered operation);
 a single-point TDU is normally mounted near the base of the ROV, which dictates the elevation of tooling
interface points above (the docking point should be a minimum of 1,5 m (4,92 ft) above the clear local
seabed for unhindered operation).
In certain geographic locations, care needs to be taken in establishing the seabed level owing to soft mud and
the effect of ROV thruster wash on the seabed.
Specific details related to local tool reaction loads are shown in Figure 8.
4.3.3 Dual downline intervention
4.3.3.1 General
The replacement of subsea components, such as control pods and chokes can be carried out by the use of a
lifting and handling frame, more commonly called a CCO tool (see Figure 23). Generally, a CCO tool is used
for component installation or recovery tasks that require surface lift capacity beyond that of a free-swimming
ROV. The CCO tool is deployed from an intervention vessel via a lift line or drill pipe, the first down line, which
is designed to support the weight and dynamic loads of the CCO tool and the component being replaced. The
second down line is the ROV's umbilical/tether maintenance system. It is recommended that these two down
lines be deployed from separate areas of the intervention vessel to avoid entanglement.
4.3.3.2 General considerations for dual downline operation
Lateral and rotational guidance of the CCO tool may be by guidelines/guideposts (at least two), a
guidelineless re-entry funnel, thruster assistance or the ROV nudging the tool into place. If guidelines are
used, additional care should be taken to ensure that these lines are heave-compensated and to avoid
entanglement with the lift line or ROV umbilical. For guidelineless re-entry, the funnel should have a built-in
helix that interfaces with an alignment key on the CCO tool to orient the CCO tool as it is landed in the re-entry
funnel.
Other considerations include the following:
 the lift line or drill pipe should be heave-compensated, especially from small heave-prone intervention
vessels, so that the CCO is not raised or lowered too quickly during a heave cycle (means to accomplish
heave compensation include an active heave-compensated crane or configuration of the lift wire in a lazy
S, located mid depth, using buoyancy cells to isolate heave motions from CCO tool movement below);
ISO 13628-8:2002(E)
 dynamic motions and loads caused by stretch and a snap in the line caused by intervention vessel heave
versus added mass sluggish movement of the CCO tool (and replacement component) need to be
quantified and necessary strength built into the lift line and CCO tool;
 the CCO tool should have either a soft landing damper or a hard stand-off feature so that final landing
and alignment with sensitive interfaces, such as hydraulic or electric couplers, is done in a controlled and
low-impact manner, independent of intervention vessel heave or initial landing of the CCO tool on the
subsea equipment;
 the helix for guidelineless re-entry typically accommodates ± 180° of orientation allowance in order to spin
the CCO tool into proper orientation (the ROV can help reduce the orientation angle by pre-orienting the
CCO tool in a rough orientation, for example, ± 45°, as the CCO tool is nudged over the re-entry funnel,
thereby reducing the size and complexity of the re-entry funnel);
 guidepost and CCO tool frame funnels should be examined with respect to funnel post clearance and the
angular tilt that could occur from that clearance (tilt angle of a CCO tool and the replacement component
could swing into adjacent equipment if access clearance is too close);
 CCO tool access is typically vertical from above, but horizontal access is also acceptable (vertical access
guidance framework needs to be open bottomed to allow settling debris to pass through);
 CCO tool landing points on the subsea equipment should be a minimum of 1,5 m (4,92 ft) above the clear
local seabed for unhindered operation.
In certain geographic locations, care needs to be taken in establishing the seabed level owing to soft mud and
the effect of ROV thrusters wash on the seabed.
An example of a guideline-deployed CCO tool interface is shown in Figures 24 to 28.
4.3.4 Tool skid intervention
4.3.4.1 General
The replacement of subsea components, such as control pods and chokes, can also be carried out by a
ROV-mounted lifting and handling CCO tool. Generally, a tool-skid CCO tool is used for component
installation or recovery tasks that demand isolated and controlled seabed operation without interference from
intervention vessel motions. Often the component requires a lift capacity beyond that of a free-swimming
ROV. Therefore the tool skid provides added buoyancy ballast or trim adjustment, or both, to that already on
the ROV so that detrimental effects from load transfer do not upset the hydrodynamic characteristics of the
ROV.
Another use for tool skid intervention is to provide added power (hydraulic, electric-augmented pressure, flow,
volume capacity, etc.) that is beyond the standard complement on the ROV alone, for various intervention
tasks such as hydraulic hot stab functioning of connectors, pressure testing, pressure wash cleaning, debris
vacuuming, etc.
4.3.4.2 General considerations for tool skid operation
A tool skid is designed to attach to the front, rear or bottom of the ROV frame (see Figure 1). Alternatively, the
tool skid may be attached to the tether maintenance system (garage) or deployed separately and integrated
into the ROV at the seabed. The ROV then manoeuvres the tool skid around in free-swimming mode at the
seabed. The mounting location of the tool skid should not impede the flow or bollard thrust of the ROV
thrusters (horizontal and vertical).
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ISO 13628-8:2002(E)
Other considerations include the following:
 component replacement using a CCO tool skid requires that the tool skid feature some form of variable
buoyancy system or fixed buoyancy and weight exchange system to maintain proper trim when the CCO
tool skid is empty or holding the subsea component;
 a CCO tool skid frame needs to be designed to resist CCO tool pick-up loads, weight transfer loads, ROV
and environmental loads, especially when there is added drag caused by the addition of the tool skid to
the ROV's hydrodynamic profile;
 a CCO tool skid should accommodate the ROV vehicle frame, the ROV deployment system (winch and
surface handling equipment), its tether maintenance system (or garage) and access to the component
and access around the subsea equipment;
 CCO tool skid access is either vertical from above or horizontal from the side (vertical access guidance
framework needs to be open bottomed to allow settling debris to pass through);
 CCO tool skid interface points on the subsea equipment should be a minimum of 1,5 m (4,92 ft) above
the clear local seabed for unhindered operation [higher when the tool skid is bottom-mounted so that the
tool skid is a minimum of 1,5 m (4,92 ft) above the clear local seabed level].
In certain geographic locations, care needs to be taken in establishing the seabed level owing to soft mud and
the effect of ROV thrusters wash on the seabed.
4.3.5 Other component interventions
4.3.5.1 General
In addition to control modules and chokes, other components that may be considered for installation and
replacement using a CCO tool include
 insert valves (manifold/pigging),
 valve actuator assemblies,
 pig launchers,
 hydraulic accumulator assemblies,
 insert multiphase meters,
 insert multiphase pumps,
 chemical injection modules/manifolds,
 debris covers and pressure caps, and
 tree or manifold sensors (pressure, temperature, sand, etc.).
Key considerations in determining suitable components for replacement are
 equipment location,
 water depth,
 frequency of replacement,
ISO 13628-8:2002(E)
 component size,
 component weight.
4.3.5.2 Flowline and pipeline connection
Flowline, pipeline and jumper connections using ROV-deployed systems are becoming a more frequent
occurrence. As yet, no common interface for flowline connection has been established.
The design of connection systems that can be operated by ROVs for subsea production equipment requires
not only local modifications to the equipment but can impact upon fundamental areas such as field layout of
components. Further reference to basic requirements for connection systems is addressed in Annex E.
4.3.5.3 Control jumper connection
A number of control system umbilical jumper (flying lead) connection systems exist that are deployed by
ROVs. These systems are manipulator deployed, or deployed by a TDU or a CCO tool skid. The support
plates for the electrical or hydraulic connections may vary, depending on the application and the number of
individual couplers inside the interface. As yet, these connections are not regarded as readily developed as
standards. However, the relationships and type of interfaces for deployment and connection of the jumper can
be developed into a form that can be deployed by intervention tools of flowline connection tools, reducing the
need to develop specific tools (see Figure 32 and Figure 33).
4.4 Subsea facilities system design
4.4.1 General
The primary consideration that impacts on the system design is access to the interface for the ROV and
tooling. Depending on the intervention method and interface location, access requirements can vary
significantly and therefore should be addressed early in the design and clearly recorded in the intervention
philosophy. Other, secondary, system design considerations are covered in Clause 6, while the recommended
process is shown in Figure 5.
The interfaces on the subsea production equipment described and set out in this part of ISO 13628 should be
capable of being accessed by a ROV or an ROT in either manipulator or TDU mode. Specific differences to
this general rule have been highlighted within this part of ISO 13628.
4.4.2 General design philosophy
ROV intervention should be accomplished in a reliable manner which minimizes potential damage to the
subsea equipment, the intervention tooling, the ROV, operating personnel and the environment. It requires
that the equipment be designed for effective execution of the intended purpose under the environmental
operating conditions in which it is to work.
4.4.3 Fail free
Interfaces and their associated operating equipment shall be designed such that, in the event of a power
failure to the ROV or intervention equipment, all devices which could attach the ROV to the subsea equipment
are released in a reliable and effective manner, allowing the ROV to be retrieved to the surface.
4.4.4 Minimizing damage potential
The interface should be designed such that the potential for damage is minimized during the positioning,
docking and operation of intervention equipment. The retrievable portion of the intervention interfaces, the part
attached to the ROV, shall be designed to yield before damage occurs to the portion fixed to the subsea
equipment.
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ISO 13628-8:2002(E)
4.4.5 Load reaction
The loads imposed on the interface by the intervention equipment shall be considered in the design.
Generally, interfaces where the loads are reacted directly into the structure are preferred to designs wh
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