Chapter 1: Fire Dynamics Flashcards
Firefighters should have a_____understanding of combustion, fire, heat, and temperature.
Scientific
A chemical process of oxidation that occurs at a rate fast enough to produce heat.
Combustion
A rapid oxidation process.
Fire
Measure of the average kinetic energy.
Temperature
_____ are not combustible but will support or enhance combustion.
Oxidizers
__________ Is a chemical reaction involving the combination of an oxidizer, such as oxygen in the air, with other materials.
Oxidation
Rust, smoldering fire, methane burning, and explosion are all forms of what?
Oxidation
The energy that a moving object possesses.
Kinetic energy
Energy is measured in?
Joules (J)
Fire is an __________ Chemical reaction that releases energy in the form of heat and sometimes light.
Exothermic
Converting water from a liquid to a gas requires the input of energy resulting in an?
Endothermic reaction
Exothermic reactions release energy while endothermic reactions?
Absorb energy
Fire tetrahedron
Reducing agent (fuel)
Heat
Oxidizing agent (oxygen)
Chemical chain reaction
Fire must be in a____state to Burn.
Gaseous state
The chemical decomposition of a solid material by heating (Burning and turning the solid into a gaseous state)
Pyrolysis
Most common form of ignition
Piloted ignition
Occurs without any external flame or spark to ignite the fuel gases or vapors. The fuel surface heats up on its own and creates a combustion reaction.
Auto ignition
Smoke is a product of?
Incomplete combustion
_____Is a toxic in flammable products of the incomplete combustion of organic materials.
Carbon monoxide (CO)
CO2
Carbon dioxide
What does the acronym (HCN)mean?
Hydrogen cyanide
Colorless,toxic, and flammable liquid until it the reaches 79°F above that temperature it becomes a gas with a faint odor similar to bitter almonds.
Hydrogen cyanide
HCN is__ times more toxic than CO
35
____________ Is a product of complete combustion of organic materials.
Carbon dioxide (CO2)
Neither supports combustion or burns and is used in portable fire extinguishing class B or C fires by smothering or displacing the oxygen.
(CO2)
The Tendency or capacity of a liquid or gas to remain afloat or rise.
Buoyant
____Is the measurement of the average kinetic energy in a particular sample of matter.
Temperature
The boiling point of water is?
212° Or 100°C
____Occurs when the material is heated as a result of direct contact with the heat source.
Conduction
In the fire environment, __________usually involves the transfer of heat to the movement of hot smoke and fire gases.
Convection
The transfer of energy through electromagnetic waves.
Radiation
Radiation is a common cause of_____fires.
Exposure fires
__________ is the rate at which energy transfers.
Power
The minimum temperature at which a liquid gives all sufficient vapors to ignite.
Flash point
_________ the temperature at which a pilot ignition of sufficient vapors will begin sustain combustion.
Fire point
Four stages of fire development
- Incipient stage- Ignition
- Growth stage- More fuel becomes involved in the production of heat and smoke increase
- Fully developed stage- The fire is consuming the maximum amount of oxygen that it can.
- Decay stage- The heat release rate begins to decline
Rapid transition from the growth stage to the fully develop stage.
Flash over
Instantaneous explosion or rapid burning of superheated gases.
Backdraft
Doing flashover the environment of the room changes from a cooler condition to a____.
Single layer
Flash over occurs when the room temperature reaches?
1100°F
A significant indicator of flashover is?
Roll over
Roll over generally proceeds_____, but it may not always result in_____.
Flash over
The auto ignition temperature of (CO) is approximately.
1100°F
Hi neutral plane is an indicator of what stage of a fire?
Early stages of development
Mid neutral plane is an indicator of what stage of a fire?
Advanced growth stage
Low neutral plane is an indicator of what stage of a fire?
Approaching flash over or under ventilated. May indicate that the fire is reaching back draft conditions.
Air consist of what percent oxygen?
21 percent
The tendency of gases to form into layers according to temperature, gas density, and pressure.
Thermal layering
The interface between the hot gas layers and cooler layer of air is commonly referred to as?
The neutral plane
What neutral plane May indicate that the fire is an early stages of development?
High neutral zone
This neutral plane could indicate that the compartment has not yet ventilated or that flash over is approaching
Mid neutral zone
What neutral plane may indicate that the fire is reaching back draft conditions?
Low neutral plane
What is the critical temperature for Steel trusses?
1000°F
