- With reference to the storage of volatile fuels, describe the construction and placement requirements of the storage tanks for aviation fuel, including tank ventilation.(10)
Storage of volatile fuels
Storing volatile fuels like aviation fuel on a superyacht requires stringent safety measures due to their flammability and potential for explosions. Here’s a breakdown of the construction and placement requirements for such tanks, with a focus on ventilation:
1. Construction Requirements:
- Material:
- Stainless Steel: Highly preferred due to its corrosion resistance, especially in marine environments.
- Other Materials: May be permitted with specific coatings or treatments to prevent fuel degradation and ensure compatibility.
- Baffle-Free Design:
- Baffles (internal partitions) are generally avoided to prevent excessive sloshing and potential stress on the tank structure.
- Cylindrical Shape:
- Cylindrical tanks are preferred for their structural strength and ability to withstand pressure.
- Leakproof:
- Tanks must be designed and constructed to be completely leakproof, with robust welds and secure fittings.
- Inspection Access:
- Adequate access points (manholes, inspection hatches) should be provided for internal inspection and maintenance.
2. Placement Requirements:
- Dedicated Space:
- Located in a designated, isolated area, separate from machinery spaces, accommodation spaces, and other potential ignition sources.
- This dedicated space should have adequate fire protection measures (e.g., fire suppression system).
- Remote from Ignition Sources:
- Positioned as far as practicable from potential ignition sources like engines, generators, electrical equipment, and galley spaces.
- Accessibility:
- While isolated, the tanks should still be accessible for inspection, maintenance, and refueling operations.
3. Tank Ventilation (Breather) System:
- Purpose:
- To prevent excessive pressure or vacuum buildup inside the tank during filling, emptying, or temperature changes.
- To allow for the safe venting of flammable vapors.
- Components:
- Vent Head: An approved vent head with a pressure-vacuum valve to regulate pressure and prevent air ingress.
- Flame Arrester: A device that prevents flames from entering the tank in case of a fire outside.
- Desiccant: A drying agent (like silica gel) to remove moisture from the incoming air and prevent condensation inside the tank.
- Vent Outlet Location:
- Located at least 2.3 meters above the weather deck.
- Positioned away from accommodation spaces, ventilation intakes, and any potential ignition sources.
- High-Level Alarm:
- An intrinsically safe level indicator and high-level alarm should be fitted to prevent overfilling.
4. Additional Considerations:
- Coaming: A raised lip or coaming around the tank area to contain any spills or leaks.
- Bonding and Grounding: Proper bonding and grounding of the tank and associated piping to prevent static electricity buildup.
- Fire Safety: Adequate fire protection measures, such as fire extinguishers or a fixed fire suppression system, should be provided in the tank storage area.
- Emergency Procedures: Clear procedures should be in place for dealing with fuel spills, leaks, or fires.
Key Regulations and Standards:
- The Large Commercial Yacht Code (LY3): Provides detailed guidance on the construction, placement, and ventilation of aviation fuel tanks on superyachts.
- Classification Society Rules: Classification societies like Lloyd’s Register or DNV have their own rules for fuel tank installations on yachts.
By adhering to these stringent requirements, the risks associated with storing volatile aviation fuel on board superyachts can be minimized, ensuring the safety of the vessel, its crew, and passengers.