Fire Safety Exam 4 Flashcards

Fire Extinguisher Classifications

• Fire extinguishers must display geometric shapes and class letters or pictographs for easy identification.
• Class A fires involve ordinary combustibles, represented by a Green Triangle.
• Class B fires consist of flammable liquids, indicated by a Red Square.
• Class C fires are related to energized electrical equipment, shown by a Blue Circle.
• Class D fires involve combustible metals, marked with a Yellow Star.
• Class K fires, for cooking oils, are represented by a Black Hexagon.

Fire Types

• Class A: Includes textiles, paper, plastic, rubber, and wood.
• Class B: Consists of flammable liquids, gases, and greases like gasoline and alcohol.
• Class C: Engaged in energized electrical equipment fires.
• Class D: Involves combustible metals like lithium and sodium.
• Class K: Related to cooking oils and fats burning at high temperatures.

Fire Extinguisher Types

• Pump Type Water Extinguisher: Used mainly for ground cover fires; utilizes a trombone-style slide pump.
• Stored Pressure Extinguisher: Useful for small Class A fires; may extinguish confined hot spots.
• Water Mist Stored Pressure Extinguisher: Uses deionized water, safe for energized equipment; produces a fine spray.
• Wet Chemical Stored Pressure Extinguisher: Designed for Class K fires; uses a potassium-based agent for soaponification.
• Aqueous Film Forming Foam (AFFF) Extinguisher: Effective for Class B fires, combats vapors from liquid fuel spills.
• Clean Agent Extinguisher: Leaves no residue; cools and smothers Class A and B fires; safe for Class C.
• CO2 Extinguisher: Best for Class B and C fires; stored as a liquefied gas, risk of reignition due to lack of vapor film.
• Dry Chemical Extinguisher: Suitable for Class A, B, and C fires; most common portable type.

Firefighting Techniques

• PASS technique for extinguisher use: Pull the pin, Aim at the base, Squeeze the handles, Sweep the nozzle.
• Conduction, Convection, and Radiation: methods of heat transfer influencing firefighting.

Fire Dynamics

• Flashover: Rapid transition where everything ignites in a room.
• Stages of fire: Incipient (initial stages), Growth (environment influenced), Fully Developed (all combustibles burn), Decay (fuel consumed).
• Rollover: Ignition of gases accumulated at the compartment's top.
• Backdraft: Explosive burning of gases when oxygen is introduced into an oxygen-depleted space.
• Smoke Explosion: Ignition of flammable combustion products.

Ventilation Methods

• Horizontal Ventilation: Channeling heat and smoke out through openings like windows or doors.
• Vertical Ventilation: Removing contaminated air from openings above the fire.
• Natural Ventilation: Using wind and convection currents without mechanical devices.
• Mechanical Ventilation: Involves blowers and smoke ejectors for air movement.
• Hydraulic Ventilation: Uses a spray stream to draw smoke from a compartment.
• Positive Pressure Ventilation: Blowing fresh air to create positive pressure and push smoke out.
• Negative Pressure Ventilation: Using smoke ejectors to pull smoke from structures.

Fire Hydrants

• Dead End Hydrant: Water flows from one direction only.
• Circulating Hydrant: Receives water from two directions, enhancing supply.
• Dry Barrel Hydrant: Has no water in the barrel when not in use, preventing freeze.
• Wet Barrel Hydrant: Contains water up to discharge outlets; used in non-freezing areas.

Fire Tools and Equipment

• Spanner Wrench: Used for tightening or loosening hose couplings.
• Minute Man Load: Allows easy carrying and maneuvering of hoses in tight spaces.
• Chaffing Block: Protects hoses from abrasion.

Deployment Methods

• Forward Lay: Hose is deployed from the water source to the fire.
• Reverse Lay: Hose is deployed from the fire to the water source.

Nozzle Characteristics

• Smooth Bore Nozzle: Operates at low pressures, less clogging, uses compressed-air foam; limited stream pattern selection.

Scene Assessment and Fire Attack Strategies

• Initial tasks include assessing hazards, identifying resources, and evaluating victim status at a scene (size-up).
• Vehicle fire response involves isolating ignition sources and extinguishing flames.
• Direct Fire Attack: Directly applies water or foam onto the fire.
• Indirect Fire Attack: Creates steam by targeting the ceiling to displace oxygen and cool the area.
• Combination Attack: Utilizes both direct and indirect methods for effective extinguishment.