Fire Behavior and Combustion Principles Flashcards
7 cards from real F80 practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Fire Behavior and Combustion Principles flashcards as text
Which type of flame is produced when fuel and oxygen are mixed before reaching the combustion zone?
Answer: Premixed flame
A premixed flame occurs when fuel and oxidizer are combined prior to ignition, as in a Bunsen burner, producing a hotter and more complete combustion than a diffusion flame.
What is the upper flammable limit (UFL) of a gas mixture?
Answer: The concentration above which there is too much fuel and too little oxygen to ignite
The upper flammable limit is the maximum fuel concentration in air above which the mixture is too rich in fuel (oxygen-deficient) to support ignition.
A fire doubles in size every minute under certain conditions. This exponential growth phase is best described as:
Answer: Incipient (growth) phase
During the incipient or growth phase, a fire can grow exponentially as it gains access to additional fuel and oxygen before being limited by compartment conditions.
Which type of heat transfer does NOT require a medium (can occur through a vacuum)?
Answer: Radiation
Radiation transfers heat via electromagnetic waves and requires no physical medium, allowing it to travel through a vacuum unlike conduction or convection.
When comparing Class A and Class B fires, which statement about extinguishment is correct?
Answer: Class A fires benefit from water's cooling and soaking action on deep-seated embers
Water is effective on Class A (ordinary combustible) fires because it cools the fuel below ignition temperature and penetrates to extinguish deep-seated embers.
What structural fire behavior concept describes hot fire gases banking down from the ceiling, reducing the height of the survivable atmosphere for occupants?
Answer: Neutral plane drop
The neutral plane is the interface between hot upper gases and cooler lower air; as a fire grows, this plane drops, reducing breathable space for occupants and firefighters.
A fire in an oxygen-limited environment producing black, oily smoke most likely indicates:
Answer: Incomplete combustion with high carbon particle production
Black, sooty smoke results from incomplete combustion where insufficient oxygen causes unburned carbon particles (soot) to be released as products of combustion.