Chapter 6 - Fire Behavior
What is the percentage of oxygen normally found in air?
21
Flammable liquid fires are Class:
B
What does smoke puffing in and out of a structure indicate?
Backdraft conditions
Which is a commonly used method of extinguishing Class B fires?
Excluding the oxygen
Which term is used interchangeably with flammability limits?
Explosive limits
The neutral plane is most directly associated with:
thermal layering
What is another term for fire point?
Flame Point
What is the lowest temperature at which a liquid produces enough vapor to sustain a continuous fire?
Flame point
What is the term for the lowest temperature at which a liquid produces enough flammable vapor to burn briefly?
Flash point
What is the term for temperature in a room reaching the point where all exposed surfaces in room ignite?
Flashover
Which is one of the three factors in solid fuel configuration?
Surface-to-mass ratio
Which geometric figure is used to represent the four elements required for a self-sustaining fire?
Tetrahedron
Which state must a fuel be in for combustion to take place?
Vapor
Which term refers to the weight of a gas compared to air?
Vapor density
Which is a common indicator of backdraft conditions?
Turbulent, pressurized smoke
The sudden introduction of air into an oxygen-depleted, superheated space may result in:
backdraft.
Heat traveling from one end of a steel beam to the other end is an example of:
conduction
Turbulent smoke is an indication of impending:
flashover
The volume of space in which the movement of cooler air enters through an inlet vent and the space where hot gases and smoke exit through an exhaust outlet is the:
flow path
The flash point of gasoline is:
-45ºF (-43ºC).
A gas with a vapor density of _____ will rise in air.
0.1
What is the vapor density of air?
1.0
What is the smallest unit of matter?
An atom
What is the relationship between resistance and heat as electricity flows through a wire?
As resistance increases, heat increases.
Matter exists in _____ states
3
Which form of heat transfer consists of kinetic energy moving from one particle to another in solid materials?
Conduction
Which is a component of a BLEVE?
A pressurized flammable liquid vessel
Which form of energy causes spontaneous heating of a pile of linseed oil-soaked rags?
Chemical
Which class of fire involves ordinary combustibles such as wood and paper?
Class A
Fires involving combustible cooking media, such as oils and grease, are Class:
Class K
What is a term for rapid oxidation that produces heat and light?
Combustion
Movement of hot fluid is an example of which method of heat transfer?
Convection
The movement of heated gases in a fire is an example of which form of heat transfer?
Convection
Upward spread of fire within a structure is primarily caused by which form of heat transfer?
Convection
The majority of fires are extinguished by which method?
Cooling the fuel
Which material has the highest thermal conductivity?
Copper
Which stage of fire results from decreasing oxygen and/or fuel supply?
Decay
Which hazard is of particular concern when attacking a Class C fire?
Electrical injury
Which effect on fire development is a result of modern construction techniques and materials?
Greater frequency of ventilation-limited fires
Flashover is a rapid transition into the ___________ stage of fire development.
Growth
What is the second stage of fire development?
Growth
Which is a component of the fire triangle?
Heat
Which toxic gas is commonly produced by fire?
Hydrogen cyanide
What is the lowest temperature at which a fuel-air mixture will ignite spontaneously called?
Ignition temperature
Which action has been shown to be a common cause in the rapid increase of intensity of a ventilation-limited fire?
Opening a door
In which process is a new compound created from the combination of oxygen and another substance?
Oxidation
What is the process called when a material decomposes upon being exposed to heat?
Pyrolysis
The majority of structure fires occur in which type of occupancy?
Residential
What is the term for the spontaneous ignition of hot gases at the upper level of a room?
Rollover
Which situation is indicated if you open a door and the smoke rises and the opening clears out?
The fire is above the level of the door.
Which situation is indicated when you open a door and the smoke thins, but the smoke still fills the door?
The fire is below the level of the door.
Which situation is indicated when you open a door and the smoke exits through the top half of the door and clean air enters through the bottom half?
The fire is on the same level as the door
Which form of heat transfer travels in all directions?
Thermal radiation
Smoke produced by some solid materials when they are first heated is typically which color?
White
An endothermic reaction is one that:
absorbs heat.
A Class C fire involves:
energized electrical equipment
A chemical reaction that produces heat is:
exothermic
The measure of the rate of transfer of heat from one surface to another is:
heat flux.
Friction is a form of __________ energy.
mechanical
Heat transfer in the form of invisible waves is called:
radiation.