Fire Concepts and Behavior Flashcards
What is the definition of fire?
The term used to describe the rapid oxidation of combustible materials accompanied by a release of energy in the form of heat and light
What is the definition of combustion?
The self-sustaining process of rapid oxidation of a fuel, being reduced by an oxidizing agent along with the evolution of heat, gases, vapors, soot, and light
What are the 3 components of fire? (Fire triangle)
Fuel
Heat
Oxygen
How much oxygen is in normal air?
21%
How much oxygen is required for free burning and visible flame?
16%
Does oxygen burn?
NO
It supports combustion
What are the 3 physical states of matter?
Solids
Liquids
Gases
What influences the ease of ignition and rate of burning?
Size and shape of fuel particles
What is heat?
Form of energy that raises temperature
What is temperature?
Measurement of heat intensity
Fahrenheit or Centigrade (Celsius)
What is BTU?
British thermal unit
Amount of heat required to raise the temperature of one pound of water one degree fahrenheit
What are the 4 sources of heat energy?
Mechanical
Electrical
Chemical
Nuclear
What are the 4 methods of heat transfer?
Convection
Conduction
Radiation
Direct flame contact
What are the 4 products of combustion?
Flame
Heat
Smoke
Fire gases
Know as many fire gases as you can
Carbon Monoxide Formaldehyde Hydrogen Cyanide Hydrogen Chloride Nitrogen Dioxide Sulfur Dioxide Nitrous Oxide Phosgene
What are the 3 phases of fire?
Incipient
Free burning
Smoldering
For Incipient stage…
O2 level
Ceiling temperature
20-21%
Approx 100 degrees F
For free burning stage…
O2 level
Ceiling temperature
16-19%
Approx 1300 degrees F
For smoldering phase…
O2 level
Ceiling temperature
Less than 15%
Temperature throughout room approx 1000 degrees F
The main issue/concern of the incipient stage is the possibility of ____
Rollover
The main issue/concern of the free burning stage is the probability of ____
Flashover
The main issue/concern of the smoldering phase is the possibility of ____
Backdraft
Thermal balance is established during which phase?
Free burning stage
A room is totally filled with dense smoke and gases during which phase?
Smoldering
What are the 8 signs of backdraft?
Smoke under pressure Black smoke becoming yellow gray Confinement and excessive heat Little or no visible flame Smoke leaves room in puffs Smoke stained glass Muffled sounds Sudden inrush of air when opening is made
The less oxygen content, the ____ the smoke
Darker
What are the 5 classes of fires?
A- Ordinary solid combustables B- Flammable liquids, gases, and semisolids C- Energized electrical equipment D- Combustible metals K- Cooking oils and fats
What are the 4 principles of fire control?
Heat control or cooling
Oxygen dilution or exclusion
Fuel removal or consumption
Chemical chain inhibition
What are 6 extinguishing agents?
CO2- Displaces oxygen Dry chemical- Chain reaction inhibitor Halon agent- Disrupts chain reaction Foam- Fuel separation and chain reaction inhibitor Dry powders- For class D fires Water- Cools
What is rollover?
Hazard that occurs during incipient stage. Gasses are hot enough at ceiling to ignite and travel. May ignite fires behind you and cut off egress
What is flashover?
Hazard that occurs during free burning stage. All fuels in a room ignite spontaneously. Not survivable due to high temperatures
What is backdraft?
Hazard that occurs during smoldering stage. Sudden introduction of O2 into area that causes an explosion
What temperature is water when it’s a liquid/solid/gas?
Solid- Below 32
Liquid- 32 to 212
Gas- above 212
What is the law specific heat?
Same as BTU
Water is affected by what 2 laws of physics?
Law of specific heat
Latent heat of vaporization
What is latent heat of vaporization?
Amount of heat required to change water from a liquid to a gas
Water expands ____ times when converted to steam
1700
____ ____ for efficient vaporization
____ ____ for penetration
Fog streams
Straight streams
What are the 3 types of fire attack?
Direct
Indirect
Combination
What is direct fire attack?
Close fog pattern is applied directly to the seat of fire in short bursts until the fire darkens down
What is considered a close fog pattern?
30 degrees or less
What stage is direct fire attack used?
Incipient stage
Why during direct fire attack do we use short bursts?
So we don’t upset the thermal balance
What is indirect fire attack?
Use of latent heat of vaporization. Not desirable where victims may still be present.
What nozzle setting for indirect fire attack and where do you direct the stream?
30-60 degrees
Into the upper atmosphere
Indirect fire attack does not work without….
Super high temperatures and confined areas
What patterns are for combination fire attack?
T
S
O
Penetrating fog pattern
How should you move the stream with a combination fire attack?
Rotate clockwise with the stream edge touching the ceiling, floor, and walls
Define flash point
Temp at which liquid gives off sufficient vapor to flash but not continue to burn with an ignition source present
Define fire point
Temperature at which a liquid gives off sufficient vapor to flash and continue to sustain combustion with an ignition source present
Define ignition temperature/Auto ignition temperature
Temperature at which a material will self ignite without an ignition source present
Define flammable limits/range
Minimum and maximum concentrations of a gas in in air which will ignite
Define boiling point
The temp at which the pressure at the surface of a liquid becomes greater than atmospheric pressure
What is atmospheric pressure at sea level?
14.7psi
Define specific gravity
Molecular weight of a liquid compared to the molecular weight of water
Define vapor density
Molecular weight of a vapor compared to the molecular weight of air
Define solubility
Ability to mix with water or another liquid
