FE Emergency Response & Extinguisher Selection Flashcards

Which agent is specifically designed for use on fires involving flammable metals such as sodium, potassium, and titanium?

Answer: Class D dry powder (e.g., sodium chloride, graphite-based)

Class D dry powder agents like sodium chloride or graphite-based compounds are specifically formulated for combustible metal fires.

What is a key limitation of using CO2 extinguishers outdoors?

Answer: Wind disperses the CO2 cloud, significantly reducing extinguishing effectiveness

Wind rapidly disperses the CO2 cloud, preventing it from building up the concentration needed to extinguish the fire.

AFFF (Aqueous Film Forming Foam) extinguishers are specifically effective on which type of fire?

Answer: Class B fires involving hydrocarbon fuels such as gasoline and aviation fuel

AFFF creates an aqueous film over Class B hydrocarbon fuels that seals vapors and cools the fuel surface, suppressing the fire.

When a fire extinguisher technician recommends an upgrade from a 2.5-lb CO2 to a 5-lb CO2 extinguisher, what primary benefit does this provide?

Answer: Longer discharge duration and greater extinguishing range for larger fire scenarios

A larger CO2 cylinder provides a longer discharge time and greater agent volume, allowing the operator to address larger fires more effectively.

Which factor most determines the correct minimum UL rating for an extinguisher in a given occupancy?

Answer: The hazard level (light, ordinary, extra) and the nature of the combustibles present

The occupancy hazard level and type of combustibles present determine the minimum UL rating required per NFPA 10 rating tables.

What is the primary reason clean agent (Halotron I, FM-200) extinguishers are preferred over CO2 for occupied server rooms?

Answer: Clean agents are effective at lower concentrations that are safer for occupants who may still be present

Clean agents suppress fires at concentrations below human safety thresholds, whereas CO2 at extinguishing concentrations is immediately dangerous to life.