E
SUB-COMMITTEE ON CARRIAGE OFCARGOES AND CONTAINERS
9th session
Agenda item 3

CCC 9/3/3
13 July 2023
Language: ENGLISH
Pre-session public release: ☒AMENDMENTS TO THE IGF CODE AND DEVELOPMENT OF GUIDELINES FOR
ALTERNATIVE FUELS AND RELATED TECHNOLOGIES
Proposed amendments to regulation 7.3.1.3 and 9.4.1 of part A-1 of the IGF CodeSubmitted by Liberia, United States, CLIA, EUROMOT, IACS, ICS,INTERTANKO and SGMF
SUMMARY
Executive summary:This document proposes amendments to paragraphs 7.3.1.3
and 9.4.1 of part A-1 of the IGF Code.

Strategic direction, if 2
applicable:
Output:2.3

Action to be taken:

Paragraph 13

Related documents:

NoneIntroduction
1The International Code of Safety for Ships using Gases or other Low-flashpoint Fuels(IGF Code), which was adopted by resolution MSC.391(95) and amended by resolution
MSC.422(98), provides an international standard for ships using low-flashpoint fuel, other thanships covered by the International Code for the Construction and Equipment of Ships Carrying
Liquefied Gases in Bulk (IGC Code). Part A-1 of the IGF Code addresses specific requirements
for ships using natural gas as fuel.
2
Based on the experience gained to date in the application of the IGF Code, thisdocument proposes amendments to paragraphs 7.3.1.3 and 9.4.1 of the IGF Code.

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CCC 9/3/3
Page 2Discussion
3Paragraph 7.3.1.3 of the IGF Code states:"7.3.1.3 All pipelines or components which may be isolated in a liquid full condition
shall be provided with relief valves."

4The co-sponsors note that, although the IGF and IGC Codes have similararrangements and safety goals, additional provisions on the relief valves’ discharging line
given in 5.2.2.4 of the IGC Code have been omitted in section 7.3 of the IGF Code. The IGC
Code paragraph 5.2.2.4 states:"5.2.2.4 Relief valves discharging liquid cargo from the piping system shall discharge
into the cargo tanks. Alternatively, they may discharge to the cargo vent mast, if
means are provided to detect and dispose of any liquid cargo that may flow into thevent system. Where required to prevent overpressure in downstream piping, reliefvalves on cargo pumps shall discharge to the pump suction."
5Furthermore, the co-sponsors note that paragraph 9.4.1 of the IGF Code requires all
the inlet and outlet connections to the storage fuel tank to be equipped with ESD valves, which
are to be automatically operated by the gas safety system required in 15.2.2. Paragraph 9.4.1of the IGF Code states:"9.4.1 Fuel storage tank inlets and outlets shall be provided with valves located as
close to the tank as possible. Valves required to be operated during normal
operation16 which are not accessible shall be remotely operated. Tank valves whether
accessible or not shall be automatically operated when the safety system requiredin 15.2.2 is activated."________
16

Normal operation in this context is when gas is supplied to consumers and during bunkering operations.

6
While normally left open inlet and outlet connection valves are automatically closed
in an emergency situation, thus fully isolating the storage fuel tank and preventing any return
flow towards it, including that from the safety relief valves’ discharging lines protecting thepiping system, as required in 7.3.1.3 of the IGF Code.
7
As, during an emergency shutdown, liquid in the piping system is likely to be present
with such an arrangement, any relief flow due to the rising pressure in the piping safety system
can only be discharged directly into the atmosphere through the venting system. Gas releases,
although directed by design to safe locations, regardless of how small these might be, pose apotential safety concern and furthermore always constitute an undesirable release ofgreenhouse gas.
8Noting paragraph 7.3.1.3 of the IGF Code and based on the experience gained by theindustry in the application of the requirements of 9.4.1 of the IGF Code for tank inlet relief valve
discharge lines, the co-sponsors propose as an alternative arrangement the use of non- returnvalves in lieu of the requirement for ESD valves, as these are deemed to provide an equivalentlevel of protection in such installations. Furthermore, it shall be noted that the requirements formeans of emergency isolation of fuel tank PRVs as per paragraph 6.7.2.6 of the IGF Codeapply to such installations.

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CCC 9/3/3Page 39Non-return valves are a simple and proven means of protecting small tank inlet
connections from an accidental reverse flow. During normal operation, reverse flow direction
relief of gas is prevented, as the valve is closed and there are no credible scenarios that could
inadvertently open the valve in the reverse direction when pressurised. Furthermore,
non- return valves cannot be unintentionally opened as there are no active means of operatingthem. Means for safe isolation shall also be provided.
10
In the event that the gas safety system as per requirement 15.2.2 of the IGF Code isactivated, non-return valves will prevent any gas from escaping from the tank, thus providing
an isolation of the tank contents equivalent to that from a remotely controlled ESD valve. In theevent that liquid is routed to the tank from the discharge of the piping safety valves, suchvolume would be very small and mostly flash when in the tank space. Hence it can be shown
that, for any combination of piping and tank size, the tank will not become liquid full due to aliquid relief flow from the piping safety valves.
11Consequently, the co-sponsors propose the following amendment 7.3.1.3bis to beadded to the IGF Code (new text is shown grey shaded):
7.3.1.3bis Pressure relief valves discharging liquid or gas from the piping system shalldischarge into the tanks whenever the tank pressure is lower than the setting of thepressure relief valves, in accordance with the arrangements in 9.4.1bis. Alternatively,
they may discharge to the vent mast, if means are provided to detect and dispose of
any liquid that may flow into the vent system.
12
Furthermore, the co-sponsors note that, by adding to the IGF Code the proposed
amended paragraph 7.3.1.3bis as per point 10 above, an additional paragraph 9.4.1bis is tobe added to the IGF Code (new text is shown grey shaded)
9.4.1bis Tank inlets from safety relief valve discharge lines, protecting the piping
system according to 7.3.1.3bis, shall be provided with non-return valves in lieu ofvalves that are automatically operated when the safety system required in 15.2.2 isactivated. Safe means for tank isolation during maintenance shall be available
according to 18.3.
Action requested of the Sub-Committee
13The Sub-Committee is invited to consider the foregoing and in particular the proposals
in paragraphs 11 and 12 above, and to take action, as appropriate.

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