Which classification includes liquids with flashpoint below 73°F and boil below 100°F?

Which classification includes liquids with flashpoint below 73°F and boil below 100°F?

• A. IA
• B. IB
• C. IC
• D. II

Answer: (A)

This question tests how flammable liquids are classified by flashpoint and boiling point. Liquids with a flashpoint below 73°F and a boiling point below 100°F are placed in the most hazardous subdivision of Class I, known as Class IA. The reason is that such liquids release ignitable vapors at room temperature and boil at very low temperatures, so the vapor can form flammable mixtures and ignite readily, requiring the strictest controls. A liquid with a flashpoint below 73°F but a boiling point at or above 100°F would fall into the next subdivision (IB), not IA. A liquid with a flashpoint at or above 73°F and a boiling point below 100°F would be Class IC, and liquids with higher flashpoints rise into Class II or III, depending on the system.

This question tests how flammable liquids are classified by flashpoint and boiling point. Liquids with a flashpoint below 73°F and a boiling point below 100°F are placed in the most hazardous subdivision of Class I, known as Class IA. The reason is that such liquids release ignitable vapors at room temperature and boil at very low temperatures, so the vapor can form flammable mixtures and ignite readily, requiring the strictest controls. A liquid with a flashpoint below 73°F but a boiling point at or above 100°F would fall into the next subdivision (IB), not IA. A liquid with a flashpoint at or above 73°F and a boiling point below 100°F would be Class IC, and liquids with higher flashpoints rise into Class II or III, depending on the system.