🔍 Key Concepts

• Gas/vapor stratification in tanks – heavier-than-air vs lighter-than-air vapors • How structures inside a tank (floors, frames, webs) affect gas pockets and dead spots • Purpose of an explosimeter – to detect flammable mixtures throughout the space

💭 Think About

• Think about where dangerous flammable vapors are most likely to collect inside an enclosed tank space. • Would you want to check only one level/area, or as many different levels and corners as possible? Why? • How could internal structures (like webs and longitudinals) change how vapors are distributed in the tank?

✅ Before You Answer

• Verify how heavier-than-air vapors behave in enclosed spaces (where do they settle?). • Confirm whether safety practice requires sampling at multiple levels and locations in a tank, or only in one spot. • Consider whether avoiding certain areas inside a tank would make your overall gas reading more or less reliable.