Ship Cargo Hold CO2 System: NFPA 12, SOLAS II-2 and Total Flooding

Cargo hold fires on container and general cargo ships are a major risk - the 2019 Maersk Honam burned for a month. NFPA 12 (Carbon Dioxide Extinguishing Systems) and SOLAS II-2 cover fixed CO2 systems for holds, engine rooms and pump rooms. Battery banks of CO2 cylinders apply total flooding.

Total Flooding Concentrations

• General cargo hold: 30 percent
• Container hold: 30 percent
• Ro-Ro deck: 40 percent (gasoline vehicles)
• Engine room (diesel): 40 percent
• Engine room (gas turbine): 50 percent

CO2 Quantity Calculation

5,000 m3 hold, 30 percent concentration:

• Gross volume x factor (NFPA 12 Table 5.3.3)
• 5,000 m3 x 0.56 kg/m3 = 2,800 kg CO2
• 45 kg cylinders: 2,800 / 45 = 63 bottles
• Discharge 1 min (or 2 min for deep-seated fire)
• Hold time: 20 min minimum concentration

Battery Bank and Manifold

• CO2 bottle room: outside or fireproof compartment
• Manifold: parallel with check valves
• Pilot cylinder: manual release and backup
• Alarm: 20 sec delay (personnel evacuation)
• Pilot line: dual release stations

Cargo-Type Challenges

• Container: CO2 can't enter the box - only hold void space
• Lithium battery container: CO2 doesn't stop thermal runaway - only cuts oxygen
• Dangerous goods (IMDG): Class 3/4.1 separate deck/hold
• Hot hold: hold next to engine room hotter - easier ignition

2019 Maersk Honam Case

• Indian Ocean, 7,700 TEU container ship
• Calcium hypochlorite container - misstowed
• CO2 flooding ineffective - fire inside containers
• 5 crew died
• IMO MSC 101 stowage rules revised

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