Lesson 3
Fire Suppression
In This Lesson
1. Extinguishing Methods
Based on the fire tetrahedron, there are four primary methods to extinguish fire by removing one of its essential elements.
Cooling
Remove HEAT from the fire.
- • Primary method: Water application
- • Absorbs heat through vaporization
- • Most effective for Class A fires
- • 1 gallon water = 8,000 BTU absorbed
Smothering
Remove OXYGEN from the fire.
- • Agents: Foam, CO₂, dry chemical
- • Covers fuel surface
- • Excludes oxygen from reaction
- • Effective for Class B fires
Starvation
Remove FUEL from the fire.
- • Create fire breaks
- • Shut off gas/fuel valves
- • Remove unburned materials
- • Allow fire to burn out
Inhibition
Break the CHAIN REACTION.
- • Agents: Dry chemical, halons
- • Interferes with chemical process
- • Most effective for flaming fires
- • Does not cool effectively
2. Fire Extinguisher Types
Different fire classes require specific extinguishing agents for effective suppression.
Water Extinguisher
Works by cooling. Never use on Class B, C, D, or K fires.
Foam (AFFF) Extinguisher
Aqueous Film-Forming Foam. Smothers and cools. Creates vapor barrier.
Carbon Dioxide (CO₂) Extinguisher
Clean agent, no residue. Smothers by displacing oxygen. Short range.
Dry Chemical Extinguisher
Most versatile. Inhibits chain reaction. ABC-rated (multipurpose).
Wet Chemical Extinguisher
For cooking oil/grease fires. Creates soapy layer (saponification).
Dry Powder Extinguisher
For combustible metals. Special agents: Met-L-X, G-1, Lith-X.
3. PASS Method
The PASS method is the standard technique for operating portable fire extinguishers.
PULL the Pin
Remove the safety pin that prevents accidental discharge.
AIM at Base of Fire
Point the nozzle or hose at the base of the fire, not at the flames.
SQUEEZE the Handle
Press the handles together to discharge the extinguishing agent.
SWEEP Side to Side
Move the nozzle in a sweeping motion at the base of the fire.
Important Safety Tips
- • Keep your back to an exit
- • Stand 6-10 feet away from fire
- • Don't fight fire larger than you
- • Evacuate if fire doesn't diminish
- • Know your extinguisher's discharge time (8-25 seconds)
4. Hose Streams
Firefighters use different hose stream patterns depending on the situation and fire conditions.
Solid Stream (Straight Stream)
Characteristics:
- • Maximum reach and penetration
- • Compact, cylindrical pattern
- • Least heat absorption
Use For:
- • Exterior attack
- • Long-distance application
- • Breaking through debris
Fog Stream
Characteristics:
- • Fine water droplets
- • Maximum heat absorption
- • Creates steam
Use For:
- • Interior attack
- • Cooling hot gases
- • Ventilation (push smoke)
Caution: Can cause steam burns if used improperly in enclosed spaces.
Broken Stream
Water broken into coarse droplets (between solid and fog).
Use For: Combination attacks, reducing steam conversion while maintaining reach.
Hose Line Sizes
1½" Hose
40-150 GPM
Initial attack line
1¾" Hose
150-200 GPM
Common attack line
2½" Hose
200-350 GPM
Heavy fire conditions
5. Firefighting Tactics
Strategic approaches to fire suppression based on conditions and resources.
Offensive Attack
- • Direct interior attack
- • Enter building to fight fire
- • Primary focus: Fire suppression
- • Used when conditions allow
- • Requires adequate resources
Defensive Attack
- • Exterior operations only
- • Master streams from outside
- • Protect exposures
- • When interior is too dangerous
- • Structural collapse risk
Fire Attack Methods
Direct Attack
Apply water directly onto burning fuel. Most efficient use of water.
Indirect Attack
Apply water to hot gases and surfaces to generate steam. Cools environment.
Combination Attack
Short bursts into ceiling gases, then direct attack on fire.
Ventilation
Controlled removal of smoke, heat, and gases from a structure.
Horizontal Ventilation
- • Open windows/doors
- • Cross-ventilation
- • PPV fans
Vertical Ventilation
- • Open roof
- • Uses natural convection
- • Most effective method
BFP Fire Suppression Tips
- ✓Memorize PASS - the fire extinguisher operation method is always tested.
- ✓Know extinguisher types - match the agent to the fire class.
- ✓Understand hose streams - when to use solid vs. fog patterns.
- ✓Learn attack methods - offensive vs. defensive strategies.