ISO/DTR 27929
(Main)Transportation of carbon dioxide by ship
Transportation of carbon dioxide by ship
This document provides insights into the essential aspects of CO2 shipping and provides basic descriptions of how the CO2 carrier and technology therein is technically integrated with the CCS value chain. It also includes a description of specific challenges of transporting CO2 as cargo, how this differs from other gases transported by ships today, and how this influences the ship design and operation. Finally, this document introduces how CO2 ships are regulated within the existing international maritime regulatory framework. This document's main focus is on the technical aspects of CO2 shipping. Commercial, liability and financial aspects are intentionally kept out of this document. However, general reference to commercial impact is made where relevant. This document focuses on the ship transportation of CO2 between loading and offloading facilities where the system boundaries are at the ship manifold equipment that connects the ship to the other components in the value chain. In the document, the basis for the description of ship operation is transportation between two shore-based terminals. A high-level description of other relevant interfaces is given on a conceptual level as this has impact on the ship design. However, any further description of potential solutions upstream and downstream from the CO2 carrier is outside the scope. This document also gives a high-level description of the physical properties of CO2 streams at the conditions relevant for shipping and how relevant impurities can impact the ship and ship operation.
Transport de dioxyde de carbone par bateau
General Information
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Standards Content (Sample)
FINAL DRAFT
Technical
Report
ISO/TC 265
Transportation of carbon dioxide by
Secretariat: SCC
ship
Voting begins on:
2025-08-26
Voting terminates on:
2025-10-21
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
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BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
Reference number
FINAL DRAFT
Technical
Report
ISO/TC 265
Transportation of carbon dioxide
Secretariat: SCC
by ship
Voting begins on:
Voting terminates on:
RECIPIENTS OF THIS DRAFT ARE INVITED TO SUBMIT,
WITH THEIR COMMENTS, NOTIFICATION OF ANY
RELEVANT PATENT RIGHTS OF WHICH THEY ARE AWARE
AND TO PROVIDE SUPPOR TING DOCUMENTATION.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 3
5 Regulatory regime for maritime and inland waterways for CO transportation . 3
5.1 General .3
5.2 Maritime governance .4
5.3 Technical safety regime for maritime transportation of liquid CO .5
5.4 Greenhouse gas emissions .6
5.5 Trading and cross-border transportation .6
6 Ship transport of CO . . 7
6.1 General .7
6.2 CO cargo transport conditions .7
6.2.1 General .7
6.2.2 Low pressure .8
6.2.3 Medium pressure .8
6.2.4 High pressure .8
6.2.5 Density effects .9
6.2.6 Solid state CO (dry ice) .9
6.3 Cargo tank design .9
6.3.1 Cargo tank design considerations.9
6.3.2 Tank material .10
6.3.3 Novel materials .10
6.3.4 Design pressure .11
6.3.5 Insulation .11
6.4 CCS ship transport concepts.11
6.4.1 General .11
6.4.2 Ship terminal to terminal . 12
6.4.3 Barge terminal to terminal (inland waterways) . 12
6.4.4 Offshore floating storage and injection unit (FSIU) . 12
6.4.5 Offshore injection unit . 12
6.4.6 Offshore direct injection . 13
6.5 Multi-gas and dedicated carriers . 13
6.5.1 General . 13
6.5.2 Existing ship conversion . 13
6.6 Ship design . 13
7 Properties of CO , CO streams and mixing of CO streams influencing the ship
2 2 2
transportation .13
7.1 Thermodynamic properties of CO and CO composition . 13
2 2
7.2 CO impurities and trace components .16
7.2.1 Common impurities .16
7.3 Flexibility and mixing of CO streams from different sources .17
8 Ship operation . 17
8.1 Ship and terminal modes of operation .17
8.2 Compatibility and interface .18
8.3 Cargo operations . .19
8.3.1 Responsibilities .19
8.3.2 Manifold operations .19
8.3.3 Loading and offloading operations .19
8.4 Cargo management .19
iii
8.4.1 General .19
8.4.2 Cargo tank preparation .19
8.4.3 Cargo voyage management . 20
8.4.4 Cargo losses . 20
9 Technical gaps and development.20
9.1 Applicability and precision of existing requirements . 20
9.2 Identification of additional relevant requirements such as practices onshore . 20
9.3 Qualification and process for new technology .21
9.4 Gaps and need for development .21
10 Safety and risks .22
10.1 Health, safety and environment (HSE) . 22
10.1.1 Toxicity and asphyxiation . 22
10.1.2 Hazards of liquid CO . 22
10.2 Measures to mitigate risks .
...
ISO/TC 265
Secretariat: SCC
Date: 2025-05-0708-11
Transportation of carbon dioxide by ship
Transport de dioxyde de carbone par bateau
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
E-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
Contents
Foreword . iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 3
5 Regulatory regime for maritime and inland waterways for CO transportation . 4
5.1 General . 4
5.2 Maritime governance . 4
5.3 Technical safety regime for maritime transportation of liquid CO2 . 6
5.4 Greenhouse gas emissions . 7
5.5 Trading and cross-border transportation . 7
6 Ship transport of CO . 8
6.1 General . 8
6.2 CO cargo transport conditions . 8
6.3 Cargo tank design . 10
6.4 CCS ship transport concepts . 12
6.5 Multi-gas and dedicated carriers . 15
6.6 Ship design . 16
7 Properties of CO , CO streams and mixing of CO streams influencing the ship
2 2 2
transportation . 16
7.1 Thermodynamic properties of CO and CO composition . 16
2 2
7.2 CO impurities and trace components . 18
7.3 Flexibility and mixing of CO2 streams from different sources . 19
8 Ship operation . 20
8.1 Ship and terminal modes of operation . 20
8.2 Compatibility and interface . 21
8.3 Cargo operations . 22
8.4 Cargo management . 23
9 Technical gaps and development . 24
9.1 Applicability and precision of existing requirements . 24
9.2 Identification of additional relevant requirements such as practices onshore . 24
9.3 Qualification and process for new technology . 25
9.4 Gaps and need for development . 25
10 Safety and risks . 25
10.1 Health, safety and environment (HSE) . 25
10.2 Measures to mitigate risks . 26
10.3 Special risks with liquid CO as ship cargo . 26
11 Quantification and verification of CO2 cargo . 27
11.1 General . 27
11.2 Quantification and measurement . 27
11.3 Verification . 28
12 Summary status and development needs for CO ship transportation for CCS value chains29
Bibliography . 30
iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 265, Carbon dioxide capture, transportation, and
geological storage.
This second edition cancels and replaces the first edition (ISO/TR 27929:2024), which has been technically
revised.
The main changes are as follows:
— Figure 4 has been corrected to represent the correct phase diagram for CO ;
— Figure 5 has been revised to be consistent in wording.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
iv
Introduction
In a carbon dioxide capture and storage (CCS) value chain, the main means for transportation of CO from an
emitter to storage are by ships or by pipelines. Transportation of gas in liquid state is well established in the
shipping industry and has been done for decades. However, liquid CO2 is different from other gases carried by
ships and poses new challenges for both ship design and ship operation. Compatibility along the value chain
is an essential element in the development of CCS. It is important to have a common understanding of how
different aspects, such as cargo temperature and pressure, can influence the ship design and ship operation.
The purpose of this document is to support consistency and compatibility in the design of CCS value chains
and address important areas where future development and standardization can add value. This document
will discuss discusses CO ship types, ship logistics and interface-specific aspects related to the safe and
reliable design and operation of CO ships.
Transportation of liquified gas on ships is governed by the regulations, codes and conventions drawn up under
the International Maritime Organization (IMO) which is referred to under United Nations Convention on the
Laws of the Sea (UNCLOS). Ships carrying CO2 are regulated by the IMO International Code for the Construction
and Equipment of Ships Carrying Liquefied Gases in Bulk (IGC Code), which serves as the main technical
regulation for CO carriers under the International Convention for the Safety of Life at Sea (SOLAS).
Ship transportation of CO2 is currently limited to commercial trade for small-scale use in industries such as
the food or beverage industries and is served by a handful of small ships. However, the evolving industry
around CCS will demand transportation volumes of a different magnitude and involve development of new
ship designs and ship logistics concepts. These are introducing a need for knowledge-sharing related to type
of transportation concepts, CCS value chain compatibility, technical and operational reliability and the safety
of CO carriers.
Quantification, verification and reporting along the different elements in the CCS value chain will become
important. This document briefly describes the limitations and challenges to them and how they can be done
onboard the ship.
In this document, CO means a captured CO stream, including potential impurities following the capture
2 2
process, if not otherwise explicitly referred to as pure CO2.
v
Transportation of carbon dioxide by ship
1 Scope
This document provides insights into the essential aspects of CO shipping and provides basic descriptions of
how the CO2 carrier and technology therein is technically integrated with the CCS value chain. It also includes
a description of specific challenges of transporting CO as cargo, how this differs from other gases transported
by ships today, and how this influences the shipship's design and operation. Finally, this document introduces
how CO ships are regulated within the existing international maritime regulatory framework.
This document’s main focus is on the technical aspects of CO shipping. Commercial, liability and financial
aspects are intentionally kept out of the report.this document. However, general reference to commercial
impact is made where relevant.
This document focuses on the ship transportation of CO2 between loading and offloading facilities where the
system boundaries are at the ship manifold equipment that connects the ship to the other components in the
value chain. In the document the basis for the description of ship operation is transportation between two
shore-based terminals. A high-level description of other relevant interfaces is given on a conceptual level as
this has an impact on the shipship's design. However, any further description of potential solutions upstream
and downstream from the CO2 carrier is outside the scope. This document also gives a high-level description
of the physical properties of CO streams at the conditions relevant for shipping and how relevant impurities
maycan impact the ship and ship operation.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for u
...
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