1. Fire Behavior
&
Extinguisher Use

2. METHODS OF HEAT TRANSFER
TS 2–7
Conduction — Point-to-point transmission of heat energy
Convection — Transfer of heat energy by the movement of heated liquids or gasses
Radiation — Transmission of energy as an electromagnetic wave without an intervening medium

6. CHEMICAL REACTIONS (cont.)
TS 2–10b
Oxidation — Formation of a chemical bond between oxygen and another element
Instantaneous oxidation = Explosion
Rapid oxidation = Fire (steady state or free-burning)
Very slow oxidation = Rust

8. TYPES OF OXIDATION Instantaneous oxidation — Explosion
TS 2–11
Instantaneous oxidation — Explosion
Rapid oxidation — Fire (steady state or free-burning)
Very slow oxidation — Rust

10. OXIDIZING AGENTS
TS 2–12a
Those materials that yield oxygen or other oxidizing gases during the course of a chemical reaction
Oxygen rich atmospheres — Those with oxygen concentrations exceeding 21%
Health care facilities
Industrial occupancies
Private homes (where occupants use liquid oxygen breathing equipment)

11. OXIDIZING AGENTS (cont.)
TS 2–12b
Oxygen deficient atmospheres — Those with oxygen concentrations lower than 21%
Storage tanks
Silos
Pipes and vaults
Other confined spaces
High altitudes

12. FUEL CHARACTERISTICS
TS 2–13a
Fuel — Material or substance being oxidized or burned in the combustion process
Pyrolysis — Chemical decomposition of a substance through the action of heat
Surface-to-mass ratio — Surface area of fuel in relation to its mass
Vaporization — Transformation of a liquid to its vapor or gaseous state

13. FUEL CHARACTERISTICS (cont.)
TS 2–13b
Flammable range — Range of concentrations of fuel vapor and air in which combustion will occur
Lower flammable limit (LFL) — Minimum concentration of fuel vapor and air that supports combustion
Upper flammable limit (UFL) — Concentration of fuel vapor and air above which combustion cannot take place

19. CHEMICAL HEAT ENERGY
TS 2–14
Most common source of heat in combustion reactions
Self-heating (spontaneous heating) — Chemical energy that occurs when a material increases in temperature without the addition of external heat
Conditions that must be present for spontaneous ignition to occur
Sufficient heat production
Sufficient air supply
Sufficient insulation

24. COMPARTMENT FIRE DEVELOPMENT TERMS
TS 2–16
Compartment — Enclosed room or space within a building
Compartment fire — Fire that occurs within a compartment
Fuel controlled — Amount of fuel available to burn is limited
Ventilation controlled — Amount of available oxygen is limited

26. GROWTH STAGE Plume development Plume begins to develop
TS 2–18
Plume development
Plume begins to develop
Temperature of fire gases decreases as these gases move away from centerline of plume
Development of ceiling layer
Overall temperature in compartment increases
Temperature of gas layer at ceiling increases

28. FLASHOVER STAGE
TS 2–19a
Transition between growth stage and fully developed fire stage; is not a specific event
Preflashover condition — Radiant heat (red arrows in visual) from the hot ceiling gas layer heats combustible materials, producing vapors (green arrows in visual)

29. FLASHOVER STAGE (cont.)
TS 2–19b
Just prior to flashover —
Temperatures rapidly increase
Additional fuel packages become involved
Fuel packages release combustible gases
Flashover occurs when compartment temperature exceeds 900F (483C) and all combustible surfaces and gases are burning

31. FULLY DEVELOPED STAGE All combustible materials are involved in fire
TS 2–20
All combustible materials are involved in fire
Burning fuels release maximum amount of heat; produce large volumes of fire gases
If fire becomes ventilation controlled, large volumes of unburned fire gases are likely to flow into adjacent spaces where they may ignite if air is more abundant

32. DECAY STAGE Heat release declines as available fuel is consumed
TS 2–21
Heat release declines as available fuel is consumed
Amount of fire diminishes
Temperatures within compartment begin to decline
Fuel is reduced to a mass of glowing embers

33. FACTORS THAT AFFECT FIRE DEVELOPMENT
TS 2–22
Ventilation openings
Size
Number
Arrangement
Compartment volume
Compartment’s thermal properties
Ceiling height
Initial fuel package
Size
Composition
Location
Additional target fuels
Availability

35. FLAMEOVER / ROLLOVER
TS 2–23
Condition where flames move through or across the unburned gases during a fire’s progression and roll across the ceiling
Involves only fire gases, not the surfaces of other fuel packages (flashover)

37. THERMAL LAYERING OF GASSES
TS 2–24
Thermal layering — Tendency of gases to form layers according to temperature
Heat stratification — Hottest gases form top layers; cooler gases form bottom layers
Thermal balance — No disruption of heat stratification
Thermal imbalance — Disruption of heat stratification (hot gases mix throughout the compartment)

42. TEMPERATURE REDUCTION
TS 2–25
Is used on solid fuels and liquid fuels with high flash points
Is most common method of extinguishment
Reduces temperature of high flash point fuels
Creates negative heat balance
Cools with water

43. FUEL REMOVAL Is used on solid, liquid, or gas fuels
TS 2–26
Is used on solid, liquid, or gas fuels
Stops flow of liquid or gaseous fuel
Moves solid fuel out of fire path
Allows fire to consume all fuel

44. OXYGEN EXCLUSION OR DILUTION
TS 2–27
Is used on solid, liquid, or gas fuels
Prevents air from reaching fuel (smothering)
Dilutes or displacing oxygen with an inert gas

45. INHIBITION OF CHAIN REACTION
TS 2–28
Is used on gas and liquid fuels
Uses dry chemicals and halogenated hydrocarbons
Interrupts chemical chain reaction (stops flaming)

50. Video
Fire Behavior

52. Questions?