🔍 Key Concepts

• Meaning of “gas free” in tank cleaning/entry procedures • Difference between ventilated, inerted, and gas free • Safety standards for flammable and toxic gas concentrations before entry or hot work

💭 Think About

• Ask yourself: does “gas free” mean a specific time period has passed, or a specific condition has been verified? • Think about which choice would make it safe for people to enter the tank or do hot work like welding. • Consider whether “gas free” allows for any dangerous level of flammable or toxic gases to remain in the tank.

✅ Before You Answer

• Verify which option clearly states that there are no dangerous concentrations left, not just reduced amounts. • Check whether “inerted” means the same thing as “gas free” in safety procedures. • Eliminate any choice that would still allow most or some dangerous gas to remain in the tank.