🔍 Key Concepts

• Classes of fire (A: ordinary combustibles, B: flammable liquids, C: energized electrical) and which agents are recommended for each • Physical properties of carbon dioxide (CO₂) as a firefighting agent (electrical conductivity and density compared to air) • How CO₂ actually extinguishes fire (smothering/displacement of oxygen)

💭 Think About

• For choice A, recall standard guidance: On which fire classes is CO₂ recommended and commonly installed aboard vessels? Is it typically relied on for Class A fires? • For choice B, think about why CO₂ is often used around electrical panels, motors, and control rooms. What does that tell you about its electrical conductivity? • For choice C, consider what happens to CO₂ when released in a space. Does it tend to rise, stay level, or settle low? How does that affect its ability to smother a fire in an enclosed compartment?

✅ Before You Answer

• Check your knowledge of which fire classes CO₂ is rated for under standard marine/firefighting practice. • Verify whether CO₂ conducts electricity or is considered safe around energized equipment. • Confirm whether CO₂ is denser than air, and how that influences where the gas concentrates in a compartment.