🔍 Key Concepts

• Purpose of an oxygen indicator in shipboard safety and gas testing • Difference between measuring oxygen content and detecting specific flammable gases • Typical use of an oxygen indicator before entry into enclosed spaces

💭 Think About

• Ask yourself: What is the ONE specific thing an oxygen indicator is designed to measure—does its name give you a clue? • Which option(s) talk about oxygen itself, and which talk about particular types of gases that might require different detectors? • Think about enclosed space entry procedures: what is the first atmospheric condition you must confirm before deciding if people can safely enter?

✅ Before You Answer

• Verify which device is used to measure oxygen percentage in the air • Check which options mention oxygen directly versus combustible or specific gases • Recall that flammable or toxic gases are usually checked with separate specialized detectors, not a basic oxygen indicator