🔍 Key Concepts

• Properties of carbon dioxide (CO₂) as a smothering agent in fixed and portable systems • How CO₂ affects oxygen concentration and visibility in a space • The importance of ventilation shutdown when using gas-type extinguishing systems

💭 Think About

• Think about how CO₂ actually puts out a fire: what does it do to the air around the flames? • Consider which statements describe real advantages of CO₂ in marine fire systems, and which one would defeat how it works. • Ask yourself: if air is still freely moving through a space, will a gas agent that must displace oxygen stay concentrated enough to work?

✅ Before You Answer

• Verify which options describe known advantages of CO₂ (non-corrosive, storage life, use on live electricals). • Check how gas extinguishing systems are normally used: is ventilation usually kept running or shut down? • Confirm that the characteristic you pick would prevent CO₂ from building up to an effective concentration in the protected space.