A combustible gas indicator is used to...

🔍 Key Concepts

• Combustible gas indicator (CGI) – what it is designed to measure on tankers and gas-freed spaces • Difference between flammability (explosion/fire risk) and toxicity (health/poisoning risk) • What is typically checked before entering a confined space: oxygen level, flammable gas level, and sometimes toxic gases

💭 Think About

• Ask yourself: on board a vessel, when do you pull out a combustible gas indicator, and what specific hazard are you worried about at that moment? • Which instrument would be used for checking if air is breathable versus checking if an area is at risk of fire or explosion? • Look at the words ‘combustible’ and ‘flammable’ – how do they relate, and which choice uses that same idea most directly?

✅ Before You Answer

• Match the term combustible with the option that deals with fire or explosion risk, not breathing comfort or general health effects • Eliminate any choice that talks about oxygen or CO₂, since those are normally checked with different, specialized meters • Remember that toxicity and flammability are different hazards and are often measured with different instruments

A combustible gas indicator is used to determine __________.

if there is sufficient oxygen to support life

the toxicity of flammable gases or vapors

the amount of CO₂ present in flue gas

the presence of flammable gases or vapors in the air

🔍 Key Concepts

💭 Think About

✅ Before You Answer