Describe CO₂ fixed firefighting system for machinery and cargo spaces of a bulk carrier and explain safety precautions before releasing CO₂ to the engine room?

flowchart TD
    A[CO₂ Storage Cylinders] -->|Piping| B[Section Valves]
    B --> C[Distribution Piping]
    C --> D[Nozzles in Machinery Space]
    C --> E[Nozzles in Cargo Holds]
    F[Remote Release Panel] -->|Signal| B
    F --> G[Alarm System]
    G --> H[Time Delay]
    H --> I[Ventilation Shutdown]

• System type: carbon dioxide total-flooding fixed firefighting system for machinery spaces and cargo holds of bulk carriers
• Extinguishing principle: smothering agent that works by oxygen displacement
• Core components: CO₂ storage cylinders, distribution piping with section valves, nozzles in protected spaces, remote release controls, alarms, ventilation shutdown
• Regulatory basis: Fire Safety Systems Code Chapter 5 paragraph 2.2.2 for machinery spaces and cargo pump-rooms; Regulation 8 of Chapter 11-2 of the Convention for cargo spaces
• Quantity requirement: for applicable cargo spaces, at least 45% of the gross volume of the largest space as free gas, with at least two-thirds introduced within 10 minutes
• Safety precautions before release: ensure responsibility remains with owner unless delegated; issue suitable instructions for work on CO₂ system or in spaces with cylinders; guard against accidental release; evacuate personnel; close all openings; stop ventilation; activate alarms; man remote release station
• ETO accountability: ensure electrical release circuits, alarms and indicators are functional; maintain control panels and wiring; train crew on electrical operation; record tests