🔍 Key Concepts

• Fixed CO2 fire-extinguishing systems for cargo spaces on cargo vessels • How CO2 quantity is related to volume of the protected space, not deck area • Relevant formula in 46 CFR for CO2 requirements per cubic foot of cargo space

💭 Think About

• Ask yourself: does CO2 need to fill the entire volume of the space to be effective, or just cover the deck? • Compare the answer choices that are based on cubic feet of volume versus those based on square feet of area—which better matches how gas actually spreads? • Think about whether the regulation uses a division by a constant to get pounds of CO2 from cubic feet, and what that constant roughly is.

✅ Before You Answer

• Verify in 46 CFR that the required CO2 is based on gross volume in cubic feet of the cargo space • Check that the regulation uses a formula of the form: gross volume (ft³) ÷ [some number] = pounds of CO2 • Eliminate any options that use square feet of deck area or one pound per cubic foot, as those do not match the standard CO2 system sizing method.