A plume is also called what?
The convection column
Thermal updraft
Thermal column
Ceiling jet has been referred to as what?
Mushrooming
What is a ceiling jet?
Layer of hot gases that develops under a horizontal surface
What materials have a heat combustion more than twice the cellulose of wood?
Hydrocarbon-based synthetic materials
A floor is most likely to be heated by what heat?
Radiant
What is continuity?
Proximity of various fuel elements to one another
What effects the amount of air that is entrained and amount of cooling that takes place in a compartment fire?
Location and fuel package
What is the combustion zone?
Area where sufficient air is available to feed the fire
When a fuel package is not in the middle of the room what happens to the fire?
Expands vertically and higher plume results
What do heated surfaces around the fire do?
Radiate heat back toward the burning fuel
Where are the hottest gases found in thermal layering?
At the ceiling
Thermal layering is also known as what?
Heat stratification
Thermal balance
What can alter thermal layering?
Changes in ventilation and flow path
High pressure causes the hot gas layer to do what?
Spread downward and laterally through openings
What happens to air in the cool gas layer?
Moves inward from outside at the bottom as hot gases exit through the top
What is the neutral plane?
The interface between hot and cooler gas layers at the opening
The neutral plane only exists where?
At openings where hot gases are exiting and cooler air is entering
As the fire moves through the growth stage and becomes ventilation controlled what could be occurring in the hot gas layer?
Isolated flames
Increased smoke volume causes neutral plane to what?
Descend
As hot gases circulate to the outer edges of the plume what happens?
It finds sufficient oxygen to ignite
What are the stages of fire development?
Incipient
Growth
Fully developed
Decay
Stages of a fire development are a guide for what ___ occur but not a pattern for what ____ occur every time.
Could
Will
Firefighters should asses what what and not what in fire patterns?
Changing hazards
Fire conditions
Not assume the fire will follow the same pattern
A type of fuel involved in a combustion affects what?
Heat release rate (HRR)
In a compartment fire, one of the most fundamental class A fuel characteristics influencing fire developments is what?
Surface to mass ratio
Fires involving class b flammable/combustible liquids will be influenced by what?
Surface area and type of fuel involved
The increased vapor to a spill will do what?
Allow more fuel to ignite, resulting in a greater heat over a short period of time
Petroleum based products have a higher what than wood products?
Heat of combustion
Higher heat release rate (hrr)
Sources of thermal energy
Chemical
Mechanical
Electrical
Light
Nuclear
Sound
How does self heating increase the temperature the material without the addition of external heat?
The material must be heated to its autoignition temperature
What are the 4 forms of electrical energy
Resistance heating
Over current or overload
Arcing
Sparking
How does resistance heating occur?
When electric current flows through a conductor
When does overcurrent occur?
When current flowing through a conductor exceeds design limits
How are arcs generated?
When a conductor is separated or by high voltage, static electricity, or lightning
A rollover occurs when?
When fire gases ignite across the ceiling
Flashover occurs in what stage?
Typically growth
Fully developed stage
What nfpa is combustion, fire, heat, temperature, and fuel?
NFPA 921
What NFPA is an oxidizer?
NFPA 400
A BTU does what?
Raises lb 1 degree
How joules are required to raise 1 gram of water by 1 degree?
4.2 J
What temperature is higher? Autoignition or piloted ignition.
Autoignition
What is a reducing agent?
Fuel
What is in the fire tetrahedron?
Reducing agent, chemical chain reaction, heat, oxidizing agent