Refrigerant and ODS Management Under MARPOL Annex VI

Refrigerant management is one of those areas of compliance that Chief Engineers either handle meticulously or ignore completely — there is rarely a middle ground. On a typical 50m+ superyacht, you might have six or more separate refrigerant circuits: main air conditioning chillers, provision refrigeration, freezer rooms, ice makers, wine coolers, and crew AC splits. Each of those circuits contains a controlled substance that is regulated under international maritime law, European environmental law, and the Montreal Protocol. Getting this wrong means port state control deficiencies, flag state non-conformities, and — increasingly — significant fines under the EU F-Gas Regulation.

This guide covers the full regulatory picture, the practical record-keeping requirements, and what surveyors actually look for when they open your refrigerant logbook.

The Regulatory Framework

MARPOL Annex VI, Regulation 12 — Ozone-Depleting Substances

Regulation 12 is the primary maritime instrument. Its requirements are straightforward:

Prohibition on deliberate emissions — Any deliberate emission of ozone-depleting substances (ODS) is prohibited. This includes venting refrigerant during servicing or disposal.
Ban on new installations — Equipment containing HCFC refrigerants (R-22, R-141b, R-142b) may not be installed on any vessel. Equipment containing CFC refrigerants (R-11, R-12, R-502) has been banned since 2005.
Record keeping — All vessels must maintain a list of equipment containing ODS, including the type and quantity of refrigerant in each system.
Maintenance records — Records of all recharging, servicing, repair, and disposal activities must be maintained in a dedicated ODS Record Book or equivalent logbook.

HCFC Phase-Out: While MARPOL allows existing HCFC equipment to remain in service, the EU banned the use of virgin HCFCs for servicing from 1 January 2010 and recycled/reclaimed HCFCs from 1 January 2015 under Regulation (EC) 1005/2009. If your yacht trades in EU waters and still has R-22 systems, you cannot legally recharge them — even with recycled refrigerant. Conversion or replacement is the only compliant path.

The Montreal Protocol

The Montreal Protocol on Substances that Deplete the Ozone Layer (1987) is the international treaty that underpins all ODS regulation. It established the phase-out schedules for CFCs, HCFCs, and halons. MARPOL Annex VI Regulation 12 implements the Protocol’s requirements for the maritime sector. The Protocol also introduced the Kigali Amendment (2016), which extends controls to HFC refrigerants based on their global warming potential — a development with direct implications for yacht HVAC systems.

EU F-Gas Regulation — Regulation (EU) 2024/573

The revised EU F-Gas Regulation (replacing the previous Regulation (EU) 517/2014) imposes additional obligations on vessels operating within EU jurisdiction and vessels flagged to EU member states. Key provisions include:

Requirement	Threshold	Detail
Leak checks	Systems containing 5 tonnes CO2 equivalent or more	Regular leak inspections required
Leak check frequency	5-50 tCO2e: annually; 50-500 tCO2e: every 6 months; >500 tCO2e: every 3 months	Reduced by 50% if automatic leak detection is fitted
Record keeping	All F-gas equipment	Records of quantity and type, leak checks, recovery, and disposal
Certified personnel	All service work	Only certified technicians may handle F-gas refrigerants
Phase-down schedule	Progressive	HFC quota reductions: 2024 (31.3% of 2015 baseline), 2027 (24.3%), 2030 (12.8%), 2034 (4.7%). Note: These phase-down targets are from Regulation (EU) 2024/573. Operators should verify current quotas as the schedule is subject to review.

Calculating CO2 Equivalent (tCO2e)

The F-Gas Regulation thresholds are expressed in tonnes of CO2 equivalent, not in kilograms of refrigerant. The conversion uses the Global Warming Potential (GWP) of each refrigerant:

tCO2e = Refrigerant charge (kg) x GWP / 1000

Refrigerant	GWP (AR5)	10 kg Charge = tCO2e
R-134a	1,430	14.3
R-410A	2,088	20.88
R-407C	1,774	17.74
R-404A	3,922	39.22
R-507A	3,985	39.85
R-32	675	6.75
R-290 (propane)	3	0.03
R-744 (CO2)	1	0.01

Yacht Reality Check: A typical superyacht with two R-410A chillers (each containing 25 kg) and an R-404A provision refrigeration system (15 kg) has a total GWP-weighted charge of: (2 x 25 x 2,088 / 1000) + (15 x 3,922 / 1000) = 104.4 + 58.83 = 163.2 tCO2e. This puts the vessel in the "every 6 months" leak check category. Many yacht engineers are surprised by how quickly the numbers add up.

Building Your Refrigerant Inventory

The foundation of compliance is a complete and accurate equipment register. Every refrigerant-containing system on board must be listed.

Equipment Register Format

Field	Description
Equipment ID	Unique identifier (e.g., AC-01, REF-03)
Equipment description	Main chiller No.1, Provision fridge, Crew AC split
Location	Engine room, lazarette, crew mess
Refrigerant type	R-410A, R-134a, R-404A, etc.
Design charge (kg)	Original charge as per manufacturer’s nameplate
Actual charge (kg)	Current charge (updated after each service)
GWP	Global Warming Potential of the refrigerant
tCO2e	Calculated CO2 equivalent
Manufacturer	Carrier, Dometic, Frigoboat, etc.
Model/Serial No.	From equipment nameplate
Date installed	Original installation or replacement date
Leak detection fitted	Yes/No — type (electronic, pressure monitoring)

Common Equipment Missed

Engineers frequently omit the following from the register:

Wine coolers and beverage fridges in guest areas (often contain R-134a or R-600a)
Ice makers in bars and galleys
Crew cabin split AC units (each may contain 1-3 kg of R-410A)
Hydraulic power pack cooling systems using refrigerant-based oil coolers
Watermaker pre-treatment chillers on some installations

Walk the vessel systematically. If it has a compressor, it contains refrigerant and it goes on the register.

Leak Detection and Inspection

Inspection Methods

Method	Application	Accuracy
Electronic leak detector	Pinpoint detection during service	High — can detect 3 g/year
Bubble solution (soap test)	Confirming suspected leak locations	Medium — visual confirmation only
UV dye injection	Long-term leak monitoring	High — but requires UV lamp and system access
Pressure decay test	Post-repair verification	High — quantitative
Automatic leak detection	Continuous monitoring (required for >500 tCO2e)	Varies by system

Leak Check Records

Each leak check must be recorded with:

Date of inspection
Equipment ID
Name and certification number of the person performing the check
Method used
Result (leak found / no leak found)
If leak found: estimated loss (kg), location of leak, repair action taken, post-repair verification

Practical Tip: Keep a running log of refrigerant top-ups. If you are adding refrigerant to the same system repeatedly, you have a leak — even if you cannot find it during a formal check. MARPOL and the F-Gas Regulation both require that leaks be repaired as soon as practicable. A system that loses more than 10% of its charge annually has a significant leak that must be found and fixed, not just topped up.

What Surveyors Check

Having conducted and supported hundreds of annual and renewal surveys, the following items are consistently examined:

Flag State / Class Annual Survey

ODS Record Book or Refrigerant Logbook — Is it on board? Is it current? Are entries legible and signed?
Equipment list — Does it match the physical equipment on board? Surveyors will spot-check 2-3 systems against the register.
Refrigerant type verification — Is any prohibited substance (CFC) still in service? Are HCFC systems flagged?
Recharge records — If refrigerant has been added, is the quantity, date, and source recorded? Is there a receipt from the supplier?
Disposal records — If refrigerant has been recovered, where was it sent? Is there a waste transfer certificate?

Port State Control

Port state inspectors may check:

Presence of the ODS Record Book (MARPOL Annex VI requirement)
Evidence of the last leak check (date and result)
Whether any CFC or HCFC equipment remains on board
Whether the vessel holds a valid International Air Pollution Prevention (IAPP) Certificate

EU F-Gas Compliance (EU Flag States / EU Ports)

Certified technician evidence for all service work
Leak check records at the correct frequency for the vessel’s total tCO2e
F-gas recovery certificates for any decommissioned equipment
GWP-weighted annual reporting (if required by the flag state)

Fine Risk: EU member states have implemented the F-Gas Regulation with national penalty regimes. Fines for non-compliance — including missing leak checks, uncertified technicians, or failure to maintain records — can be substantial. France, for example, has issued fines exceeding EUR 10,000 for individual violations. This is not theoretical risk; enforcement is active, particularly in Mediterranean ports.

Refrigerant Charge Calculations and Reporting

Annual GWP Reporting

Some flag states and port states require annual reporting of the total GWP-weighted refrigerant charge. Even where not formally required, maintaining an annual summary is good practice and demonstrates compliance to surveyors.

The annual report should include:

Item	Detail
Total refrigerant on board (by type)	Summed from equipment register
Total tCO2e	GWP-weighted total
Refrigerant purchased during the year	By type, quantity, supplier, and invoice reference
Refrigerant recovered during the year	By type, quantity, and disposal facility
Net change	Purchased minus recovered = approximate total leakage
Leak rate	Net change / total charge x 100 = annual leak rate (%)

An annual leak rate above 5% across the fleet of equipment on board indicates systemic issues — poor maintenance, aging systems, or vibration-related joint failures. Investigate and address the root cause rather than simply continuing to top up.

Transitioning to Low-GWP Refrigerants

The F-Gas phase-down means that high-GWP refrigerants like R-404A and R-410A will become increasingly scarce and expensive. For superyacht operators, the practical implications are:

R-404A replacement — Provision refrigeration and freezer systems should be transitioned to R-449A (GWP 1,397) or R-448A (GWP 1,273) at the next major service. These are near-drop-in replacements that halve the GWP.
R-410A replacement — Main AC chillers should be evaluated for conversion to R-32 (GWP 675) or R-454B (GWP 466) when equipment reaches end of life. Retrofit is generally not practical — plan for replacement.
Natural refrigerants — CO2 (R-744) and propane (R-290) systems are entering the marine market. Their near-zero GWP makes them future-proof against regulatory changes but requires specific safety considerations for installation on yachts.

Planning Ahead: When specifying new HVAC or refrigeration equipment during a refit, insist on low-GWP refrigerants. The additional upfront cost is marginal compared to the compliance risk and refrigerant cost exposure of installing another high-GWP system that may become unserviceable within its operational life due to refrigerant availability.

Regulatory References

MARPOL Annex VI, Regulation 12 — Ozone-Depleting Substances
Montreal Protocol (1987) and Kigali Amendment (2016)
EU Regulation 2024/573 — Fluorinated Greenhouse Gases (revised F-Gas Regulation)
EU Regulation (EC) 1005/2009 — Ozone-Depleting Substances
IMO MEPC.1/Circ.795 — Guidance on the Maintenance of Records of ODS
ISO 11650:1999 — Performance of Refrigerant Recovery and/or Recycling Equipment

Refrigerant management is detail work. The logbook, the equipment register, the leak check records, and the GWP calculations are not exciting — but they are what stands between you and a deficiency at survey. Keep the records current, fix leaks promptly, and plan your transition to low-GWP alternatives before the regulations force your hand.