What is the primary distinction between a Class I and Class II flammable liquid?

• A. Class I covers liquids with a flash point under 100°F
• B. Class I covers liquids with a flash point over 100°F
• C. Class II liquids have lower vapor pressure
• D. Class II covers solids only

Answer: (A)

The primary distinction between Class I and Class II flammable liquids is indeed based on their flash points. Class I flammable liquids are defined as having a flash point below 100°F (37.8°C). This classification indicates that these liquids can ignite at relatively low temperatures, making them highly hazardous in fire situations.

Class I liquids are further divided into three subcategories: Class IA (flash point below 73°F), Class IB (flash point at or above 73°F and below 100°F), and Class IC (flash point at or above 100°F and below 140°F). Understanding this classification is critical for handling and storing these substances safely, as it helps responders and safety personnel make informed decisions regarding the risks associated with these liquids.

In contrast, the other choices do not accurately reflect the classification criteria. Class II liquids have a higher flash point (between 100°F and 140°F) and do not pose the same immediate fire risk as Class I liquids. Furthermore, the distinction does not lie in vapor pressure for Class II liquids or indicate that they only pertain to solids, as both classes consist of liquids. Understanding these distinctions is essential for ensuring proper safety protocols when dealing with flammable liquids.