🔍 Key Concepts

• CO2 fixed firefighting systems displace oxygen and can create an immediately dangerous to life and health (IDLH) atmosphere • Difference between devices that measure air quality and equipment that protects the person in a bad atmosphere • Limitations of canister gas masks versus self-contained breathing apparatus (SCBA) in low-oxygen environments

💭 Think About

• In a space recently flooded with CO2, what is the main hazard to a person entering: toxic gas, lack of oxygen, or both? • Which choice, if any, allows you to be safe even if the air in the compartment is still not breathable? • Which testing devices listed, if any, are actually intended for shipboard compartment entry versus lab or boiler flue-gas analysis?

✅ Before You Answer

• Identify which options are protective equipment and which are testing instruments • Recall that gas masks/canister masks do NOT supply oxygen and cannot be used in oxygen-deficient spaces • Think about which method is approved and commonly required by regulations and training for entry into spaces that may be oxygen-deficient or contain CO2