Why Every Bunkering Operation Needs Dry Disconnects
Bunkering, which is the transfer of fuel between a supply facility (jetty or bunker barge) and a receiving vessel, is one of the most routine yet potentially hazardous operations in the offshore and maritime industry. A seemingly small failure during transfer, be it hose separation, pull-away, or overpressure, can rapidly become an environmental disaster, threaten crew safety, and impose large commercial and reputational costs.
Dry disconnect couplings are engineered safeguards that substantially reduce those risks by ensuring a drip-free, rapid shut-off when an abnormal condition is detected. Below, we explain how these devices are indispensable for safe bunkering and how they are typically arranged within a ship/jetty transfer system.
A quick technical primer: What is a dry disconnect coupling?
A dry disconnect coupling (also called a dry-break or dry-disconnect) is a mechanical coupling with two mating halves, each containing a valve. In normal operation, the valves are open and product flows through the mating interface. If the connection is forcibly separated, such as when a vessel drifts away or a hose is overstressed, the mechanical action triggers the valves to close almost instantaneously on both halves, trapping product inside the hose and preventing external leakage.
Breakaway couplings are a close relative of dry disconnect couplings. They are typically designed to separate at a predetermined axial load and then automatically seal. Many modern units are designed to be “drip-free”, minimise pressure surge and be reset or replaced without complex intervention. The main types of breakaway couplings are engineered to suit different applications, ensuring both safety and efficiency in transfer operations.
The role of dry disconnect couplings in bunkering
Dry disconnect couplings serve several critical functions in bunkering systems:
1. Immediate containment on disconnection
By providing positive shut-off on both sides of the separation, dry-breaks prevent product from escaping into the environment even when the hose remains full. This is the device’s primary value proposition in bunkering, where hydrocarbon release must be avoided at all costs.
2. Protection against pull-away or hose rupture scenarios
Mooring failures, sudden wind or wake, or human error can create axial loads that would otherwise rupture hoses or shear fittings. Breakaway couplings are calibrated to separate before the hose or fittings fail, protecting the integrity of the rest of the transfer system.
3. Integration with emergency shutdown and operational systems
Dry disconnects are typically used alongside emergency release systems (ERS), emergency shutdown (ESD) valves and stop-pumps. The coupling’s mechanical action buys precious time for operators to initiate remote shutdowns and thus reduces the volume of product at risk. Gaseous and cryogenic bunkering (LNG, ammonia) explicitly requires compatible dry-disconnect/ERS devices to minimise release during emergency disconnection.
4. Compatibility with modern bunkering standards and risk assessments
International technical advisories and port guidelines increasingly reference dry disconnects as part of an acceptable risk-mitigating layout for bunkering operations. Risk-based codes (for example, guidance associated with the IGF Code and ISO technical specifications for LNG bunkering) treat dry-breaks as a recognised engineering control to limit catastrophic consequences in the event of hose failure.
The consequences of not using dry disconnect couplings
Without a reliable dry disconnect or breakaway device in the hose train, several cascading consequences may follow:
- Immediate environmental release
A pull-away or hose rupture will generally allow substantial volumes of bunker to escape into the surroundings. Even small quantities can cause local pollution, harm wildlife, and trigger multi-agency response actions. Several regulatory advisories and risk studies model hose rupture scenarios and show significant consequence increases where no automatic shut-off is present.
- Higher clean-up and legal costs
Response, recovery, and fines following a spill can dwarf the upfront cost of safety hardware. Ports and insurers treat spills as high severity events, and the direct clean-up, offshore containment, civil penalties, and potential litigation can run into millions in major incidents.
- Operational disruption and reputational damage
A single accident can close berths, delay fleet schedules, trigger investigations, and damage commercial relationships. For ship operators and terminal owners, the indirect costs, which include loss of trading time, insurance premium increases, and reputational harm, are material.
- Increased personnel risk
A sudden uncontrolled release or subsequent ignition exposes crew and shore personnel to fire and toxic hazards. Dry disconnects reduce the volume released and therefore the likelihood of fires or vapour-cloud exposure following accidental separation.
Because these consequences escalate rapidly, it has become an industry best practice to treat dry disconnects and breakaway couplings as part of layered mitigation: engineering controls (couplings, drip trays, containment), administrative controls (permitting, checklists, communication protocols), and emergency response capability.
Common dry disconnect coupling arrangement for bunkering
A well-designed bunkering arrangement places the dry disconnect coupling so that it protects the most likely failure point while integrating cleanly with ESD and monitoring systems. A typical arrangement is:
- Jetty manifold/shore supply → 2. Fixed piping and isolation valves → 3. Emergency shutdown valve and/or emergency release coupling (if fitted to fixed arms) → 4. Dry disconnect/breakaway coupling → 5. Flexible hose → 6. Quick connect on vessel manifold (sometimes with a receiving dry-break).
In practice, dry disconnects are commonly fitted between the shore/jetty manifold and the flexible hose so that the mechanical separation point is upstream of the hose failure point; this ensures the hose contents are contained on separation.
The arrangement normally includes a drip tray or containment area under the connection point, local alarms, remote ESD, and a manual emergency stop on both berthing units to permit immediate cessation of pumping.
Selection of the coupling must consider working pressure, temperature, material compatibility, flow capacity (pressure drop), and maintenance/regeneration procedures. Non-closure “visual” breakpoints exist for non-hazardous transfers, but these are not appropriate where spillage is unacceptable; closures with positive valve action are the accepted norm for bunkering.
Conclusion
Dry disconnect couplings are far more than just auxiliary hardware; they are integral safety components that shored up bunkering operations against accidental spillage, environmental harm, and personnel injury. By combining high throughput capability, self-sealing action, electrical isolation, and compatibility with international standards (such as ISO 21593), these couplings significantly enhance operational safety.
Ensure your operations stay safe, efficient, and leak-free with Pharmchem Engineering’s premium dry disconnect couplings. Contact our experts today to find the custom solution perfectly tailored to your industry needs and keep your processes running smoothly without costly downtime.
