🔍 Key Concepts

• How a fixed CO₂ fire-extinguishing system actually puts out a fire (what happens to oxygen levels and temperature in the space) • The danger of re‑ignition (reflash) after a CO₂ discharge if the space is opened too soon • Standard fire boundary control: keeping a fire space closed and sealed versus opening it up quickly

💭 Think About

• Ask yourself: after CO₂ is released into a closed compartment, what happens if you open that space right away? How does that affect oxygen and the chance of reflash? • Which option best preserves the effectiveness of the CO₂ and protects the crew from hazards like lack of oxygen or toxic gases? • In the minutes immediately after extinguishment, is your priority to overhaul/remove debris, to cool boundaries, or to keep the fire space sealed?

✅ Before You Answer

• Verify which choice keeps the space closed and unventilated long enough to prevent fresh air from feeding a reflash • Check which option avoids sending people into a space that has just been flooded with CO₂ (low oxygen, toxic gases) • Confirm which action aligns with standard practice: maintain fire boundaries until they are confirmed cool and stable before opening the compartment