SAFETY CONSIDERATIONSFOR ESTABLISHINGGREEN SHIPPING CORRIDORSSAFETY CONSIDERATIONS FOR ESTABLISHING GREEN SHIPPING CORRIDORS – MARCH 2024

Executive Summary
At COP26 the Clydebank Declaration was signed by 22 governments, pledging to “identify and explore
actions to address barriers to the formation of green shipping corridors. This could cover, for example,
regulatory frameworks, incentives, information sharing or infrastructure.” The Maritime Technologies Forum(MTF) identified that multiple reports are published focusing on feasibility for realization, barriers, costs, andfuel supply. However, safety had not yet been considered in detail for green corridors.
MTF have therefore conducted this study to facilitate information sharing on green corridor safety
considerations, with a focus on ship owners and port authorities planning to establish and operate
green corridors.
Proposed green corridor safety checklist will facilitate necessary safety considerations: The safety
considerations cover approval basis and regulatory framework, operation of vessels in international trade,risk to third-parties, port operations and bunkering, training and competence, as well as fuel specificconsiderations. All recommendations are summarized in the safety checklist.
In addition to the safety checklist, and based on the work done, the following six recommendations canbe given:
Early planning for safety assessments: Arranging introductory design and planning meetings between shipowners, ship flag, port authorities and other relevant stakeholders is key to provide efficient knowledge
sharing and plan for safety assessments.
Risk assessment of port operations and bunkering: Zone analysis and safe bunkering risk assessment arerecommended to be conducted as tabletop exercises where stakeholders and technical experts aregathered to discuss the operations prior to the first bunkering and depending on the circumstances,as necessary by the local authorities.
Use available standards to ease future port acceptance: Recognized safety standards detailed in IMO
guidelines, class rules, and local authority requirements, as applicable, should be used as basis for the ship
design as far as practicable. This will ease the potential safety vetting by a port authority and will limit theneed for extensive vetting prior to port calls or other operations.
Understanding the risk to third parties in ports not regulated for dangerous cargoes is essential to facilitate
acceptance from port authorities to enter ports, develop emergency response plans, and establish safety
procedures for port-operation and bunkering.
Sharing of information and invitation to emergency planning is recommended when the green corridor
is adjacent to the waters of intermediate States. While no formal agreement is required, accidents canoccur underway and emergency plans should be prepared for possible scenarios.
Develop and implement SMS fit for alternative fuels: The ship management company has the overarching
responsibility to ensure that the safety management system (SMS) is fit for purpose in addressing theelevated operational risk of alternative fuels. Senior management should understand that managing
the elevated operational risks requires them to systematically address changes needed throughout theorganization and ensure adequate resources are provided to maintain safe operation.
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Introduction and Objective
The Maritime Technologies Forum is a group of flag States and classification societies which aims to bridge
the gap between technological progress and regulatory process. This report provides recommendations
to industry stakeholders towards safe adoption of alternative fuels on board ships in green corridors.
Alternative fuels will be one of the key measures to reduce GHG emissions from shipping, and theirimportance will increase with the new net-zero emission target for shipping by 2050. The industrywide
introduction and use of alternative fuels in shipping, with some of them more hazardous thanconventional fuels, will lead to new safety hazards and associated risks. These risks must be addressedand controlled before operating a vessel with alternative fuels in a green corridor.
The establishment of green corridors allows for the multitude of barriers hindering the global uptake ofzero or near-zero carbon emission fuels (such as risks, costs, and supply) to be addressed and resolved
on a manageable scale. As identified in this report, the majority of safety considerations for establishinggreen corridors are linked to the interface between the ship and the port. To manage the additionalsafety hazards of alternative fuels, together with the lack of industry experience and detailed guidelines,
specific risk assessments should be conducted for bunkering and port operations. Limiting the numberof involved parties and establishing early collaboration through green corridors is key to manage thestakeholder complexity and provide efficient knowledge sharing and safety assessments.
Even though currently discussed alternative fuels, such as, e.g., methanol, ammonia and hydrogen havediffering physical and chemical properties from LNG, they require quite similar system designs and safety
standards. The safety procedures, experience and guidelines developed based on 20 years of operating
LNG vessels will therefore provide a solid foundation to assess the additional measures needed to address
the new fuel specific risks such as toxicity, third party risk and explosions. As regulations and proceduresfor LNG exist, this fuel is not explicitly discussed in the report, but applying the LNG knowledge forms thebasis for most recommendations.
This report highlights the safety concerns and considerations for the operation of ships sailing withalternative fuels in green corridors and provides suitable recommendations in a checklist to ship owners
and port authorities for adoption of alternative fuel when establishing green corridors. The checklist isintended to be used as a reference in the planning and assessment of the green corridor to ensure thatimportant topics are identified and covered.
MTF’s recent work and other reports can be found on our website: www.maritimetechnologiesforum.com.

Disclaimer
While the advice given in this report has been developed using the best currently available information,
it is intended to be used solely as guidance. No responsibility is accepted by MTF or its members forany consequences resulting directly or indirectly from the adoption of any of the recommendationsin this report.

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Green Corridors and the Clydebank Declaration
At COP26, the Clydebank Declaration was signed by 22 governments “recognising that a rapid transitionin the coming decade to clean maritime fuels, zero-emission vessels, alternative propulsion systems, andthe global availability of landside infrastructure to support these, is imperative for the transition to clean
shipping.” The goal of the declaration was to establish at least six green corridors by 2025, and scale
activity the following years.
While there are several definitions of green shipping corridors, the Clydebank Declaration states that they
are simply ‘zero-emission maritime routes between two (or more) ports. The interpretation in this report isthat ‘zero-emission’ means that any carbon-neutral fuel can be used in a green shipping corridor, suchas carbon-neutral methanol, methane, biodiesel, ammonia, and hydrogen, as well as battery-electric
propulsion, onboard carbon capture and nuclear propulsion.[1]To support the declaration the signatories pledged to “identify and explore actions to address barriers
to the formation of green corridors. This could cover, for example, regulatory frameworks, incentives,
information sharing or infrastructure.” MTF’s work in this report is to explore the regulatory frameworkand facilitate information sharing on the safety considerations for establishing green corridors. This
supports other green corridor projects undertaken by MTF members, such as the four green and digitalshipping corridor initiatives led by Singapore and the Port of Rotterdam, Port of LA/Long Beach,
Tianjin Port and Japan.
There are no fixed standards or procedures for governments on how to initiate and develop green
corridors. Either the industry can define the scope and the placement of the initiatives, or governments
take a more active role in defining the placement of future corridors through bilateral partnerships withother countries, or any collaboration initiative in between.[2]Independent of the initiative, the government’s responsibility for ensuring safety and enforcing existing
regulations will be the same. The benefit of involving and committing governments to green corridors is
ensuring early involvement in the permitting process for handling alternative fuels.
As of January 2024, 44 green corridors have been announced and in planning worldwide, however none
are currently in operation internationally.[3] As shown in figure 1 the announced corridors are covering alarge span of routes and shipping lanes, from domestic ferries to local feeder lines and deep-sea shipping
lanes. The focus of this report will be on international green corridors between two or more port States
as the regulatory framework and relevant safety considerations are more complex and universal thanThe signatory countries of the Clydebank Declaration are: Australia, Belgium, Canada, Chile, Costa Rica, Denmark, Fiji, Finland, France,
Germany, Ireland, Italy, Japan, Lithuania, Republic of Korea, Republic of the Marshall Islands, Morocco, Netherlands, New Zealand, Norway,
Palau, Singapore, Spain, Sweden, the United Arab Emirates, the United Kingdom of Great Britain and Northern Ireland, and the United Statesof America.

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for domestic routes. Further, the detailed safety considerations are presented for limited alternative fuels–ammonia, methanol and hydrogen – as these fuels are identified to be most relevant and have thehighest number of safety considerations to address. Nevertheless, the general findings in this report would
be relevant for all green corridors where use of alternative fuels is planned.
A green shipping corridor involves an ecosystem of many actors such as cargo owners and charterers,
ports, shipowners and operators, energy suppliers, financial institutions, and authorities [4]. Multiple studies
have been undertaken to explore topics such as feasibility for realization, barriers, costs, and fuel supply.
One of these is the extensive feasibility studies in the blueprint from Mærsk Mc-Kinney Møller Center for
Zero Carbon Shipping. [5] However little has been published on the topic of safety governance andregulatory framework to enable the safe bunkering of zero – and near-zero carbon emission fuels at scalealong corridors.

Figure 1. Map of announced green corridors. Source: DNV – Maritime Forecast to 2050

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Safety Considerations for Establishing Green Corridors
Green corridors enable technologies relevant to zero-emission shipping to be launched and tested
within a coordinated and limited scope. With industry and governments joining efforts to establish
green corridors they can reduce regulatory barriers and uncertainty, as well as providing early port
preparedness. This should facilitate advancement and learning while experience is still low, thereby
paving the way for new vessel designs, fuels and infrastructure. In this chapter, we present the identified
safety considerations and relevant regulatory framework for establishing safe green corridors.

Approval Basis and Regulatory Framework
As with all international shipping, it is a requirement that vessels with alternative fuel are approved by theflag State and classification society according to the applicable IMO Codes and Conventions, national/
regional regulations, and class rules and local authority requirements, as applicable and/or guidelines.
IMO provides an international mandatory regulatory framework for alternative fuels through theInternational Code of Safety for Ships Using Gases or Other Low-Flashpoint Fuels (IGF Code) which puts
internationally recognized safety standards in place to ensure safe use of natural gas as a fuel. However,neither methanol, ammonia nor hydrogen are currently covered by detailed technical requirements in
the IGF Code.
In order to obtain approval by flag State and classification society for ships with alternative fuels, the ship
designer and ship builder will have to demonstrate through extensive risk evaluations that the chosen
fuel system design solution meets the intent of the goal and functional requirements of the IGF Code.
They will also need to demonstrate that the design provides the same level of safety as having a newand conventional fuel oil system for propulsion and power generation. This risk-based approval process isdetailed in the IMO guidelines for the approval of alternatives and equivalents (MSC.1/Circ. 1455.) known
as the alternative design process.[6]Unlike conventional designs based on detailed technical requirements in IMO Codes, the final design
and arrangement of a vessel based on the alternative design process will vary determined by findingsin the risk assessment and safety analysis. Parties not directly involved in the approval process, e.g. port
authorities, Port State Control (PSC), or operators, must therefore reference the vessel specific approvalreport submitted by the flag State to IMO GISIS to get details on the scope of the approval and the ship
specific system design solutions. Compared to referencing a set of standard technical requirements,
such individual vetting will require more resources and higher competence from the party desiring tounderstand the system design and risk associated with the vessel. For green corridors where vessels areplanned to sail a fixed route, introductory design meetings and tabletop exercise meetings between shipowners, ship flag, class, port authorities and other stakeholders can provide efficient knowledge sharing.
The IMO is working in amendments to the IGF Code for methanol, and interim guidelines for hydrogenand ammonia are expected to be finalized and published early 2025. Further, class rules or guidelines
from a number of IACS Classification Societies are in place for methanol, ammonia, and hydrogen (eventhough not all have published their hydrogen rules to this date). Using the recognized safety standards
detailed in these guidelines and class rules/guidelines as basis for the ship design is recommended as far
as practicable to limit extensive vetting prior to port calls or other operations.
#

Checklist

1

Vessel is designed according to recognized safety
standards in relevant IMO guidelines, class rules/
guidelinesand local authority requirements, as applicable

2

Vessel is approved by flag State according to MSC.1/Circ.
1455 and the approval is submitted to IMO GISIS

15

Tabletop exercise conducted between ship owner andport to identify and understand potential hazards

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Transit in International Waters, Territorial Seas and Internal Waters
International green corridors calling at two or more ports will inherently pass through the waters of theStates involved in the green corridor. A goal of the green corridor should be facilitating the acceptanceof vessels entering internal waters and establishing potential restrictions or provisions for such operations.
In addition, a green corridor might pass through international waters and the territorial seas
(12 nm of the baseline) of intermediate States not part of the green corridor agreement. Whilea green corridor agreement does not need to be signed by intermediate States whose waters are
adjacent to the corridor, approaching such States to share information is regarded as good practice.
This is particularly relevant considering that ships with alternative fuels might encounter problems
underway and be in need of assistance and a safe harbour. IMO res. A.949(23) provide guidelines onplaces of refuge for ships in need of assistance. This guideline outlines the dilemma “What to do whena ship finds itself in serious difficulty or in need of assistance without, however, presenting a direct risk tothe safety of life of persons involved. Should the ship be brought into shelter near the coast or into a portor, conversely, should it be taken out to sea?” A vessel with ammonia as fuel, and a damage to the fuelsystem jeopardizing the integrity of its safety systems will pose a higher risk to its surrounding. Some port
States might be hesitant accepting a vessel with a damage. To facilitate the Master’s decision-making
process if the ship is in difficulty and provide information to the port State, emergency plans should be
prepared for possible scenarios.
Nuclear powered ships also have the right for innocent passage through the territorial sea but must follow
special precautionary measures established for such ships by international agreements. Conventional
nuclear technology (pressurized water reactor) results in an exclusion zone around the ship where
access is restricted, this increases the complexity of operation. Due to an inherently safer design, coming
generations of nuclear reactors (often referenced as 3rd and 4th generation) are envisioned to not
require an exclusion zone. However, there are no regulations in place for such reactors yet and thetechnology has a low maturity. This report will therefore not go into more detail on safety considerations
for nuclear green corridors.
#

Checklist

3

Emergency plans are developed for emergencies when
the ship is under way (ref. IMO res. A.949(23))

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Understanding Third-party Risk
One key safety consideration that distinguishes alternative fuelled vessels from conventional fuelled
vessels is the risk to third parties. Where a fire onboard a conventionally fuelled vessel normally is
contained within the ships’ sides and extinguished by on board crew. An accident on board a vessel withalternative fuels can pose an immediate danger to people in the nearby vicinity of the vessel. Examplesof this are release of toxic ammonia gas or an explosion from an uncontrolled leak of hydrogen.
The concept of third party risk is well known in the shipping industry and is relevant for all ships carrying
dangerous goods, gases, or chemicals as cargo. Vessels carrying such dangerous cargoes are normallyrequired to notify the harbour master prior to arrival, and normally have restrictions on where they canberth. Gas carriers and chemical tankers berth at designated tank terminals to load and unload. Theseterminals have specific provisions, local approvals, and emergency plans for handling large quantitiesof these dangerous cargos. To grant local approval and to develop emergency plans for these tankterminals, a common requirement is to perform quantitative risk assessments (QRA) and dispersion analysis
for the area. These analyses often result in risk contours that describes the frequency (e.g. 1.0 x 10-6/year)of a pre-defined consequence (e.g., fatality) in the specific area.
A difference between a ship carrying dangerous cargoes and a ship with alternative fuels is that thealternative fuelled vessel might be carrying cargoes or performing operations that requires berthing at
ports not regulated for dangerous cargoes.
Alternative fuel systems designed according to the gas safe principle prescribed by class rules/guidelines
and the upcoming IMO interim guidelines should most likely have a low risk of uncontrolled releases.
A series of passive and active safety requirements are designed to protect, contain and detect release,and shut down the fuel system, to minimize potential consequences from system failures. Some of thesesafety principles are secondary physical barriers containing leaks, requirements for detection andautomatic safety actions such as emergency shut down (ESD), ventilation of flammable gas to dedicatedvent masts, release mitigation systems for toxic gas and available personal protective equipment.
Other risk reducing requirements for bunkering are dry disconnect couplings, breakaway coupling,and emergency shut-down systems with ship-shore communication enabling automatic safety actions
on both land or bunker tanker and ship side.
Regardless of the number of technical safety systems in place, experience has shown that primarybarriers and safety systems can fail resulting in unintentional releases. The cause of such releases can be
operational human error, lack of maintenance or component failure. To reduce the consequence of
unintentional releases and to understand the actual risk to crew and passengers, a gas dispersion analysis
of credible leak scenario will be required. The primary goal of such gas dispersion analysis is to determine
ship arrangements and the safest locations for ventilation, bunker stations, mustering, and other systems
on board.
In addition, the gas dispersion analysis can also be used as an effective tool for developing an
understanding of and illustrate the extent of potential hazards to areas outside the ship’s side. A far
field analysis can produce ship specific dispersion contours. Examples for such dispersion contours areillustrated in figure 2 and figure 3 with ammonia concentrations in parts per million [ppm]. Normallysuch contours will not be perfectly round, as the true dispersion is affected by ship geometry, nearby
infrastructure, wind and direction of release. However, the generalized information may effectively
provide information about the potential hazard, and can be applied across different ports and areas
along the pier. This may reduce the need for detailed analysis for all possible locations and sailing routes
and provide valuable information to emergency response teams on land.
Transfer of fuel through flexible, non-permanent bunker hoses are inherently more prone to high flow leaks
than the permanent fuel system installed on board. This is reflected in the larger extent of the contours forbunkering in figure 2 than what is expected for normal operation shown in figure 3. As a possible outcome,the port authorities could allow normal loading and unloading of cargo with minor provisions, while
bunkering operations must take place at a designated area.

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The same principle with risk contours for identifying control zones is applied as an industry standard for
LNG bunkering. The Society for Gas as a Marine Fuel (SGMF) has developed a guide and program,
BASiL, for calculating the extent of LNG zones during bunkering. [7] Similar detailed analysis should bemade for alternative fuel bunkering operations in green corridor ports.
#

Checklist5

Gas dispersion analysis preformed and ship specificdispersion contours are available

6

Risk to third parties is quantified according to thechosen fuel, storage method and design solutions

Ship Owner

Port Authority© norgeibilder.no

Figure 2 – Illustration for a worst-case dispersion contour for ammonia bunkering.

© norgeibilder.no

Figure 3 – Illustration for a dispersion contour for ammonia operation.

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Port Specific Safety Considerations
The majority of safety considerations for establishing green corridors are linked to the interface between
the ship and the port. The scope of the maritime rules and regulations for ships’ fuel are generally limited
to the installation on board and stops at the bunkering connection of the ship, while the port and shoreside bunker installation pertain to different regulatory regimes.
One challenge in developing green corridors is that the shore side regulatory framework is local. Thisimplies that there will be differences in the regulations for each new port state and individual ports
in the green corridor. The regulations are for instance related to approval of bunkering infrastructureand handling of dangerous goods and are in addition enforced by multiple agencies. A study by the
Maritime & Coastguard Agency identified that 47 pieces of legislation relating to port governance andthe handling of hazardous good within the port environment exist in the UK.[8] For the stakeholders
developing green corridors this results in a complex regulatory landscape to navigate across different
states. To limit the scope of this report, shore side regulations for approval of infrastructure and local
zoning requirements has not been considered. For successful implementation of green corridors, strong
communication between ports and relevant government agencies is essential.
Port bylaws are local laws that specifies the powers of the harbour master and provide for the orderly
control of such matters as navigation, mooring, bunkering, and handling of goods and cargo. Amongthe provisions in bylaws are limitations to where a ship with dangerous goods can navigate and offload
cargo, requirements for gas fueled ships and bunkering procedures. For the ship owner it is important to
identify if there are any provisions in the bylaws prohibiting operations with toxic gas such as ammonia.
The port authority must ensure that the bylaws are updated with specific provisions for alternative
fuels. One example is that the Port of Gothenburg bylaw states that vessels with methanol fuel shall be
designed and approved according to the IMO methanol guideline, but has no reference to requirements
for hydrogen or ammonia. Port authorities establishing green corridors should revise the port bylaws tofacilitate for cargo operations and bunkering. And if necessary, provide specific restrictions for ships withalternative fuels. Restrictions should be based on the findings from a risk assessment and could include
limitations on bunkering parameters (pressure, flow rate, hose diameter), weather or local traffic. Ports
should strive to develop safe bunkering operations together with the ship owner and bunker provider
to limit the extent of restrictions.
Another issue identified is that a ship is required to report its dangerous cargo to the harbour mastertypically 12 hours prior to entering the port. However, as no such reporting is normally required for fuel,the harbour master could be unaware that a ship with ammonia as fuel is arriving since the vessel likely islisted as a dual-fuel engine with MGO as the primary fuel. The harbour master should make sure detailed
reporting of fuel on board or tracking of relevant ships with alternative fuel is established.
Four different modes of bunkering are envisaged for alternative fuels. Ship-to-ship bunkering, shore-based
terminal-to-ship, truck-to-ship bunkering and swapping of portable fuel containers. While the report will
not go in detail on the specific hazards for the different modes, some key differences to consider is thelocation of the bunker operation and the different safety systems. A common consideration is to ensurecompatibility between the ship and bunker manifolds, safety system and accompanying procedures.
The shore-based terminal-to-ship will be in a fixed designated location in the port with specific provisions,
local approvals, and existing emergency plans. As long as the vessel dispersion contours and safety zone
are within the approved terminal area, bunkering should be acceptable. The other three modes are not
fixed in location and bunker operations should be analysed individually for each location. Ship-to-ship
bunkering can be both alongside in the port or further out at the mooring. At mooring third parties at risk
could also include neighbouring ships moored downwind. Truck-to-ship introduces risk as the emergency
shut down system is that of the individual truck and this system can be different from truck to truck.
For swapping, portable fuel containers are lifted or rolled on board. Lifting operations introduces the
additional risk of a dropped container with full rupture of the tank and full release of the content.

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For analysing and managing the risk when bunkering at non-permanent locations, the industry
standards for zoning should be identified and applied. SGMF defines the following five zones forcontrol measures: [7]• Hazardous Zone is a three-dimensional space in which a highly toxic or explosive atmosphere canbe expected frequently enough to require special precautions. Generally, no persons should bewithin this zone when bunkering.
• Safety Zone can be defined as the three-dimensional envelope of distances inside which the
majority of leak events occur and where, in exceptional circumstances, there is a recognised
potential to harm life. Non-essential people should be excluded from this zone and essential staff
should be protected through the use of appropriate PPE and emergency covers.
• Marine Exclusion Zone is to protect the bunkering vessel from other marine traffic, primarily bydefining minimum distances and speeds for passing vessels.
• Monitoring Zone is defined as the three-dimensional space inside which activities (including people
and vehicle movements) need to be identified and monitored to ensure that they do not affectthe safety of the bunkering operation. People in this zone should also be aware of the ongoingbunkering, and evacuation procedures should be clearly defined.
• External Zone is defined by the level of risk general members of the public can be exposed to,based on local regulatory requirements. Port cannot influence how the general public behaves
outside the port area so the risk level outside must be kept low.
To facilitate the zone analysis and safe bunkering risk assessment, it is recommended to conduct
tabletop exercises where relevant stakeholders and technical experts are gathered to discuss theoperations prior to the first bunkering and depending on the circumstances, as necessary by the local
authorities. Further analysis could also include safety critical task analysis (SCTA) to assess human error
opportunities, working environment health risk assessment (WEHRA), and SIMOP reviews to analyse
simultaneous port activities.
Stakeholders should also reference the available guidance for LNG operation and bunkering as
basis for bunkering other alternative fuels. Even though methanol, ammonia and hydrogen havediffering physical and chemical properties from LNG, they require quite similar system designs andsafety barriers. The learnings and safety approaches from LNG bunkering will therefore provide a solid
foundation to assess the additional measures needed to address the new fuel specific risks. Industry
organizations are currently working on updating and developing new guidelines for alternative fuels
based on the existing experience from LNG. Before these new guidelines are published, the following
LNG guidelines can be recommended:• EMSA – Guidance on LNG Bunkering to Port Authorities and Administrations [9]• IACS – LNG Bunkering Guidelines Rec. No. 142. [10]• IAPH – LNG Bunker Checklists [11]• SGMF – Safety and operational guidelines – bunkering [12]• MPA – Technical Reference: LNG Bunkering (TR 56) [13]11 Maritime Technologies Forum

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Checklist

7

The ship’s bunker plan and operational manual should bespecific to the fuel9

Port Bylaws and local regulations are updated toaccommodate vessels with alternative fuels10

Restrictions and limitations on bunkering (pressure, flow rate,
hose diameter), weather or local traffic are identified

13

Bunker crew have available suitable PPE for handling,
responding, and escaping from a release of fuel.

14

A designated escape plan is developed, and safe havens
established if identified necessary

17

Safety zones and control measures for bunkering are
analysed and specified

18

Specific emergency plans are developed and agreed forwhen vessel is in port

19

SIMOP review conducted to analyse acceptable
simultaneous port activities is preformed

20

Safety critical task analysis (SCTA) and working environment
health risk assessment (WEHRA) preformed

Ship Owner

Port Authority

Training and Competence
Equally as important to the technical safety barriers installed are the crew and personnel operating
the fuel and bunker system. New and modified technical skills will be required for those directly involvedin managing the transfer or handling of alternative fuels. All personnel will need to be aware of thefuel specific properties and hazards. [14] It is stated that Seafarers on vessels operating with conventional
fuels will have to adopt the safety mindset of the tanker/gas fleet when working on ships with newfuel types. [15]
According to the requirements in the IGF Code, the ship owner or operator shall ensure that seafarers
on board ships using gases or other low-flashpoint fuels shall have completed training to attain theabilities that are appropriate to the capacity to be filled and duties and responsibilities to be taken
up STCW Code Part A / Section AV/3 (IGF Basic and IGF Advanced). Further the ship owner or operator
is responsible for providing appropriate ship and equipment specific training as specified in regulation
I/14 of the STCW Convention.
Currently no IMO model courses or official training from training providers are available for hydrogen,ammonia, and methanol as fuel. As a consequence of the non-existent STCW approved training andresponsibility on ship owners to provide appropriate ship and equipment specific training, it is anticipatedthat there will be inconsistent implementation of training across different vessels. The flag State should
follow up the crew training as part of the alternative approval and following ISM revisions. However,such revision cannot guarantee consistent training. These gaps are further elaborated in the MTF reporton safe operation of alternative fuels [16]. To mitigate these gaps flag states such as Singapore, andthe UN Maritime Just Transition Task Force, are developing training programs. [17] MPA is also looking at
developing a Training Facility which would be equipped to train seafarers working on board ships runningon alternative fuels and prepare them for the future.

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For the safe operation of green corridors, and especially bunkering of alternative fuels, it is crucial thatboth the crew on board and the onshore bunker personnel have undergone similar basic training andhave the same understanding of the fuel properties and safety barriers. Specifically, they need to havethe same situational awareness, communicate clearly, and make coordinated correct actions to mitigate
potential hazards. Crew and bunker personnel should therefore also be involved in the tabletop exercise
as far as practicable to familiarize them with the fuel and bunker systems and related hazards.
Emergency personnel such as paramedics and firefighters responsible for the local area around ports
establishing green corridors should be informed about the plan to accept ships with alternative fuels, andideally be included in the tabletop exercise. This is especially important for ports without prior experience
with handling dangerous goods. If not prepared and trained, emergency response team might not beable to respond correctly and swiftly to the hazard to save life and minimize the consequences. In a
worst-case scenario, the emergency response team could even escalate the accident by performing
wrong actions.
Training and competence are also relevant for personnel working in the land organization of companies
operating vessels on alternative fuels. The managing company has the overarching responsibility toensure that the safety management system (SMS) is fit for purpose in addressing the elevated operationalrisk of alternative fuels. Senior management should understand that managing the elevated operationalrisks requires them to systematically address changes needed throughout the organization and ensure
adequate resources are provided to maintain safe operation. Findings and identified hazards should bereflected in the vessel’s safety management system (SMS). Communication, learning, crew engagement,
and work practice adherence will be key to successfully maintaining a high level of safety. [14] The MTF
report on “Guidelines to develop and implement Safety Management System for alternative fuels on
board ships” elaborates this topic in further detail. [18]#Checklist

4

Ship owner has updated the SMS and relevant shipcertificate to reflect the additional risk from alternative fuel8

The ship’s crew are trained for responding to and limiting
potential releases.

11

Emergency personnel on land are trained and familiar withthe relevant fuel12

Port bunker crew are trained for responding to and limiting
potential releases.

16

Ship’s crew and bunker personnel are invited to thetabletop exercise to familiarize them with the fuel andbunker systems and related hazards.

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Fuel Specific Safety Considerations
This chapter will provide an overview of the specific properties for ammonia, methanol and hydrogen
related to safety. With an additional overview of the relevant storage methods and related safety
considerations. These considerations are relevant for all vessels with alternative fuels and not exclusively
green corridors. Further, the list of safety considerations is indicative and should not be regarded as an
exhaustive list for hazard identification.

Ammonia
Ammonia (NH3) is a gas at ambient temperature. It can be stored as a refrigerated liquid at or near its
boiling point (-33.4 °C) or at ambient temperature at pressure (8.6 bar at 20 °C). Ammonia is corrosive inwater solutions and has a characteristic odour that most people can smell already at 5 ppm.
The main risk with ammonia is toxicity. Ammonia is a hygroscopic compound, which means it seeks waterfrom the nearest source, including the human body. Mucous membranes, like the eyes, respiratory systemand skin, have high moisture contents and are especially at risk when put into contact with ammonia. [19]Several global standards have assessed the toxic impact on humans during an ammonia release. One of
the most well-established is AEGL (Acute Exposure Guideline Level), dividing the exposure [ppm] into time
and three consequence levels, as seen in table 1. These limits can be applied when assessing zoning as
discussed in the chapter on port specific safety considerations.
Table 1 – AEGL table for ammonia – Source: National Academies [20]Acute Exposure
Guideline Level

10 min[ppm]

30 min[ppm]

60 min[ppm]

AEGL 1

Notable discomfort

30

30

30

AEGL 2

Irreversible or other serious, long-lasting
adverse health effects or an impaired ability
to escape

220

220

160

AEGL 3Life-threatening health effects or death

2700

1600

1100

The gas phase ammonia is generally buoyant with a density around 0.70 relative to ambient air. This resultsin gas clouds rising and thus limiting dispersion concentration at ground level relatively rapidly. However,for certain situations ammonia vapour may form clouds denser than air. The situation which is of mostconcern is releases of pressurised warm liquid ammonia. In case of release of pressurized warm ammonia,
the gas will become two-phased after atmospheric expansion, forming a fine aerosol mist that is heavier
than air and travels along the ground for long distances. Multiple studies have identified the increased
risk with warm pressurized ammonia and increased resulting risk contours. [21,22,23] In the current
development of IMO guidelines for the safety of ships using ammonia as fuel, the recommendation is
to store and bunker ammonia as a refrigerated liquid at or near its boiling point.
Water spray systems can be used to dilute and reduce spreading of ammonia vapour clouds. However,water should not be added to liquid pools of ammonia as this will cause instant evaporation of large
amounts of gas. Personal protective equipment such as gas masks, protective clothing and face shields
should as a minimum be available for people or crew in areas where leaks can occur.
The combustion properties of ammonia are considerably different from those of other low flashpoint fuels
like methane and hydrogen. Because the lower explosion limit and minimum ignition energy of ammonia
are high, ammonia is more difficult to ignite, and thus there is a comparatively low probability of fires
caused by ammonia. [24] Fire and explosion risk for ammonia in open air may therefore be consideredas almost negligible.

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The industry has experience with handling ammonia, as around 20 million tons are carried on gas tankers
as cargo yearly. However, using ammonia as a fuel comes with many additional considerations, such as
bunkering, fuel preparation, piping, and ventilation, which lead to increased risks of leaks and exposurecompared with carriage as cargo. As a result, safety, including crew safety, is a key hurdle for the use ofammonia as a fuel in the maritime industry. Due to the similar physical properties, operational experiences
on LPG bunkering will provide additional useful guidance in creating ammonia bunkering procedures.
However, being chemically far from LPG, the safety aspect of ammonia will deserve a separate study
that may benefit from the established chemical industry, where safety precautions, material compatibility
and machinery are meticulously addressed. [22,25]

Methanol
Methanol (CH3OH) is a clear liquid at ambient temperature and pressure. As it does not requirepressurization or cooling, the liquid can be stored in standard tanks on board with only minor additional
requirements compared to MGO. Methanol is a toxic and highly flammable chemical. It is more
flammable than ammonia and burns with a flame that can be hard to see in daylight, creating a riskof undetected fires. Methanol has a low flashpoint (12 °C), this is the temperature at which vapoursevaporate to form an ignitable air mixture. The vapour is slightly heavier than air causing vapour toaccumulate close to the ground. Specific safety measures that prevent methanol vapours from forming
and the installation of appropriate ventilation, leak detection, heat detection and fire extinguishingequipment are recommended.[19] Its toxicity means safety protocols must be in place to protect
seafarers and port operatives from coming into contact with the fuel.
Following the first methanol-powered ship which came into operation ten years ago, experience inhandling methanol as a marine fuel has grown. Truck-to-ship bunkering of methanol was successfully
demonstrated in 2015, then shore-to-ship bunkering in 2016, barge-to-ship bunkering in 2021, and ship
to container ship bunkering in 2023. Methanol bunkering has since been validated in several different
locations and types of conditions, with 10 global ports now offering methanol bunkering and a further
11 planning to establish capability in the near term. [26, 27]

HydrogenHydrogen (H2) is a gas at ambient temperature. It can be stored as a refrigerated cryogenic liquid at its
very low boiling point (-253 °C), or as a gas under high pressure (200 – 700 bar) at ambient temperature.
The two storage systems are substantially different and should be approached as two distinct “fuels”.
The main risk with hydrogen is the wide flammability, low ignition energy and higher explosive potential
than other fuels. Hydrogen burns with an almost colourless flame almost impossible to identify indaylight. Ignition can be initiated by static electricity, and if hydrogen gas is allowed to accumulate toconcentrations ranging from 4% (LEL) to 75% ignition can result in an explosion. Compared to other fuels,hydrogen has higher explosion pressures and can cause substantial damage to nearby structures. [28]Hydrogen is much lighter than air and will rise and disperse quickly out in open air if not obstructed. One
key safety barrier is to ensure that possible leakage points for hydrogen are either enclosed and inerted orhave an unobstructed path of release. Hydrogen should not be able to accumulate under roof structuresor similar. For compressed hydrogen the initial jet vector from a potential leak will give momentum inthe respective direction, causing hydrogen to spread over a potential larger area before rising due tobuoyancy.
Liquid hydrogen will be stored in vacuum insulated type C tanks. Double wall piping must also be
insulated with a vacuum, or helium where a vacuum is not possible. Since the temperature of liquidhydrogen (-253 °C) is lower than the liquefaction temperature of oxygen (-183 °C) and nitrogen (-196 °C),air will become liquid if exposed to uninsulated surfaces. Nitrogen, as is normally used as inert gas for LNG,
cannot be used for liquid hydrogen systems as it will solidify in the pipes. If nitrogen gas is used for purging
liquid systems, the pipes must be cleared with warm hydrogen gas before introducing liquid hydrogen.
Some vessel projects are also exploring swapping fuel containers as the method of bunkering hydrogen.
If the fuel containers are to be lifted on board, the additional risk of a dropped fuel container must be
assessed in detail, as the consequence can be full loss of containment.
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A Green Corridor Safety Checklist
This checklist summarizes the key findings of this report. It is intended to be used by the ship owner andport authorities as a reference in the planning and assessment of the green corridor to ensure thatimportant topics are identified and covered.
#

Checklist

Ship Owner

Vessel Specific Considerations

1

Vessel is designed according to recognized safety
standards in relevant IMO guidelines, class rules/guidelines
and local authority requirements, as applicable.

2

Vessel is approved by Flag State according to MSC.1/Circ.
1455 and the approval is submitted to IMO GISIS

3

Emergency plans are developed for emergencies when
the ship is under way (ref. IMO res. A.949(23))

4Ship owner has updated the SMS and relevant shipcertificate to reflect the additional risk from alternative fuel5

Gas dispersion analysis preformed and ship specificdispersion contours are available

6

Risk to third parties is quantified according to the chosen
fuel, storage method and design solutions

7

The ship’s bunker plan and operational manual should bespecific to the fuel8

The ship’s crew are trained to respond to and limit
potential releases.
Port Specific Considerations

9

Port Bylaws and local regulations are updated toaccommodate vessels with alternative fuels10

Restrictions and limitations on bunkering (pressure, flow
rate, hose diameter), weather or local traffic are identified

11

Emergency personnel on land are trained and familiar withthe relevant fuel12

Port bunker crew are trained for responding to and limiting
potential releases.

13

Bunker crew have available suitable PPE for handling,
responding, and escaping from a release of fuel.

14

A designated escape plan is developed, and safe havens
established if identified necessary
Non-applicability

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Port Authority

SAFETY CONSIDERATIONS FOR ESTABLISHING GREEN SHIPPING CORRIDORS – MARCH 2024#

Checklist

Ship Owner

Collaborative Considerations
15

Tabletop exercise conducted between ship owner andport to identify and understand potential hazards

16

Ship’s crew and bunker personnel are invited in thetabletop exercise to familiarize them with the fuel andbunker systems and related hazards.

17

Safety zones and control measures for bunkering isanalysed and specified

18

Specific emergency plans are developed and agreed forwhen vessel is in port

19

SIMOP review conducted to analyse acceptable
simultaneous port activities is preformed

20

Safety critical task analysis (SCTA) and working
environment health risk assessment (WEHRA) preformed
Technical Considerations

21

Sensors for leak detection installed in port, e.g., gas
detection, thermal camera, or ultrasonic monitors

22

Bunker hoses, fixed piping, valves and manifolds are
certified for relevant fuel23

The bunker system is equipped with a safety break away
dry-disconnect coupling24

The ship shore link (SSL) and emergency shutdown (ESD)communication is compatible between port and ship
Non-applicability

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Port Authority

SAFETY CONSIDERATIONS FOR ESTABLISHING GREEN SHIPPING CORRIDORS – MARCH 2024

Conclusions
MTF identified that multiple reports on green corridors are published focusing on feasibility for realization,
barriers, costs, and fuel supply. However, safety had not yet been considered in detail for green corridors.
Therefore, MTF conducted this study to explore the regulatory framework and provide knowledge andrecommendations to ship owners and port authorities planning to establish and operate green corridors.
From the recommendations identified it can be concluded that green corridors enable zero emission
shipping to be launched and tested more effectively. As green corridors limit the scope of operation
to a finite number of ports, this allows the ship owner to initiate the recommended, resource intensive,
collaboration activities such as tabletop exercises. Through collaborative efforts between the industry
and governments, there is potential to reduce regulatory barriers and provide early port preparedness.
However, this also requires additional effort by stakeholder, which may not be typically required innormal operations.
The main high-level findings of the report can be summarized in the following six recommendations:• Early planning for safety assessments: Arranging introductory design and planning meetings between
ship owners, ship flag, port authorities and other relevant stakeholders is key to provide efficientknowledge sharing and plan for safety assessments.
• Risk assessment of port operations and bunkering: Zone analysis and safe bunkering risk assessment arerecommended to be conducted as tabletop exercises where stakeholders and technical experts aregathered to discuss the operations prior to the first bunkering and depending on the circumstances,as necessary by the local authorities.
• Use available standards to ease future port acceptance: Recognized safety standards detailed in
IMO guidelines, class rules, and local authority requirements, as applicable, should be used as basis
for the ship design as far as practicable. This will ease the potential safety vetting by a port authority
and will limit the need for extensive vetting prior to port calls or other operations.
• Understanding the risk to third parties in ports not regulated for dangerous cargoes is essential tofacilitate acceptance from port authorities to enter ports, develop emergency response plans, andestablish safety procedures for port-operation and bunkering• Sharing of information and invitation to emergency planning is recommended when the green corridor
is adjacent to the waters of intermediate States. While no formal agreement is required, accidents canoccur underway and emergency plans should be prepared for possible scenarios.
• Develop and implement SMS fit for alternative fuels: The ship management company has theoverarching responsibility to ensure that the safety management system (SMS) is fit for purpose inaddressing the elevated operational risk of alternative fuels. Senior management should understandthat managing the elevated operational risks requires them to systematically address changes needed
throughout the organization and ensure adequate resources are provided to maintain safe operation.
The recommendations summarized in the safety checklist for establishing green corridors are intended
to be used by the ship owner and port authorities as a reference in the planning and assessment of thegreen corridor to ensure that important topics are identified and analysed. The checklist is not intended
to be a comprehensive list of all operational and technical aspects concerning the safe uptake ofalternative fuels, and most of the recommendations listed will require detailed work and new specificchecklists.
MTF knows that other industry organizations are working on updating and developing new guidelines andspecific checklists for alternative fuels based on the existing experience from LNG. Going forward theseguidelines and specific checklists can be used in conjunction with the safety checklist and the high-levelrecommendations identified in this report.

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SAFETY CONSIDERATIONS FOR ESTABLISHING GREEN SHIPPING CORRIDORS – MARCH 2024

References:
1.

DNV, Energy Transition Outlook Maritime Forecast to 2050, 2023 edition

2.

Global Maritime Forum, National and regional policy for green shipping corridors 2023

3.

Global Maritime Forum, ANNUAL PROGRESS REPORT ON GREEN SHIPPING CORRIDORS 2023

4.

ABS, GREEN SHIPPING CORRIDORS: LEVERAGING SYNERGIES, 20225.

Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping, Green Corridors: Feasibility phase
blueprint, 2022

6.

DNV, State of play – status on regulatory development for zero-carbon fuels – Nordic Roadmap forthe introduction of sustainable zero-carbon fuels in shipping

7.

SGMF, FP02-01 Recommendation of Controlled Zones during LNG bunkering

8.

Maritime & Coastal Agency, Supporting the ports ecosystem in decarbonisation, 2022

9.

EMSA, Guidance on LNG Bunkering to Port Authorities and Administrations, 201810.

IACS, LNG Bunkering Guidelines No. 142., 201711.

IAPH, LNG Bunker Checklists, 201912.

SGMF, Safety and operational guidelines – bunkering FP07-01 rev. 3, 2022

13.

MPA, Technical Reference: LNG Bunkering (TR 56)

14.

LR and Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping, Human Factors Considerations:
Ammonia Fuel End-of-Stage Report, 2023

15.

DNV, INSIGHTS INTO SEAFARER TRAINING AND SKILLS NEEDED TO SUPPORT A DECARBONIZED SHIPPING
INDUSTRY - Report no.: 2022-0814, rev. 0

16.

MTF, OPERATIONAL MANAGEMENT TO ACCELERATE SAFE MARITIME DECARBONISATION

17.

UN Maritime Just Transition Task Force, Mapping a Maritime Just Transition for Seafarers, 2022

18.

MTF, Guidelines to develop and implement Safety Management System for alternative fuels onboard
ships, 2024

19.

DNV, Ammonia as a Marine Fuel Safety Handbook Rev.02, 2023

20.

National Academies, Acute Exposure Guideline Levels for Selected Airborne Chemicals Volume 6

21.

Green Shipping Programme – Report for pilot “Ammonia as Fuel”, 2021

22.

LR and MMMCZCS, Recommendations for Design and Operation of Ammonia-Fueled Vessels Basedon Multi-disciplinary Risk Analysis, 2023

23.

Nanyang Technological University, AMMONIA AS A MARINE FUEL – Bunkering, Safety and Release
Simulations, 2022

24.

ClassNK, “Part C “Guidelines for the Safety of Ships Using Ammonia as Fuel” of Guidelines for Ships
Using Alternative Fuels”, ClassNK Technical Journal No.5 2022

25.

ABS, SUSTAINABILITY WHITEPAPER AMMONIA AS MARINE FUEL, 202026.

Nanyang Technological University, METHANOL AS A MARINE FUEL – Availability and Sea Trial
Considerations

27.

Methanol institute, MARINE METHANOL Future-Proof Shipping Fuel28.

SGMF, Hydrogen as a marine fuel – an introduction, 2023

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SAFETY CONSIDERATIONS FOR ESTABLISHING GREEN SHIPPING CORRIDORS – MARCH 2024

Acknowledgements:
Organization

Name

ABS

Nikolaos Athanasoulis

ClassNK

Masao Yamasaki

DNV

Hilde Bølstad

LR

Samie Parkar

MCA

Keith Johnstone
Eddie Yeo
Hafiz Ramli

MPA

Raymond Lee
Minerva Lim

NMA

Simen Diserud Mildal (Project Manager)

For any enquires about this report please send a message to:contact@maritimetechnologiesforum.com.

20 Maritime Technologies Forum