F80 Fire Behavior and Combustion Principles 2

Question 1

What is the lower explosive limit (LEL) of a fuel vapor?

Accepted Answer

The minimum concentration of fuel vapor in air required to sustain ignition

Answer

The flash point temperature of the fuel

Answer

The highest temperature a fire can achieve

Answer

The maximum oxygen level needed for combustion

Question 2

What is autoignition temperature?

Accepted Answer

The lowest temperature at which a material ignites spontaneously without an external ignition source

Answer

The temperature at which a sprinkler head activates

Answer

The temperature of a fully developed room fire

Answer

The boiling point of a flammable liquid

Question 3

Which phase of fire development follows the incipient (early growth) stage?

Accepted Answer

Free-burning stage

Answer

Decay stage

Answer

Flashover

Answer

Spontaneous combustion

Question 4

What does pyrolysis refer to in fire science?

Accepted Answer

Chemical decomposition of materials due to heat, producing combustible gases

Answer

Suppression of fire using foam agents

Answer

The spread of fire through structural walls

Answer

Temperature measurement within a burning compartment

Question 5

How does fire primarily spread within a structure via convection?

Accepted Answer

Through rising hot gases and smoke carrying heat to upper levels and adjoining compartments

Answer

Through direct flame contact with adjacent surfaces

Answer

Through electromagnetic radiation transmitted across open spaces

Answer

Through heat conduction along structural steel members

Question 6

What is the upper explosive limit (UEL)?

Accepted Answer

The highest fuel vapor concentration in air above which the mixture is too rich to ignite

Answer

The maximum temperature a fire can sustain

Answer

The maximum pressure rating of a suppression system

Answer

The highest flash point value of a combustible liquid