🔍 Key Concepts

• Firefighting foam purpose – what types of fires it is designed for (especially flammable liquids, Class B) • How foam works – smothering, cooling, and forming a vapor-sealing blanket on liquid fuel surfaces • Class C fires – what they are (energized electrical) and why water-based agents or foam may be dangerous

💭 Think About

• Think about which class of fire foam is MOST commonly and safely used on, and which classes it is generally NOT used on • Consider what a foam blanket actually does when it sits on top of a flammable liquid – what problem is it solving? • Ask yourself whether increasing temperature of the burning liquid would make a foam blanket more stable or less stable

✅ Before You Answer

• Verify which fire class foam is primarily intended for: Class B (flammable liquids) versus Class C (electrical) • Check whether foam has any role in controlling leaks from compressed gas cylinders, or if that sounds outside its normal use • Confirm that one of foam’s main functions is to form a vapor barrier to keep flammable vapors from mixing with air above the liquid surface