Chapter 4: Fire Dynamics

Question 1

Why is it important for firefighters to understand the principles of fire science?

Answer 1

It will provide knowledge needed to forecast fire growth at a scene and predict the likely consequences of various tactical options available for controlling a fire.

Question 2

What is the difference between a physical change and a chemical reaction?`

Answer 2

Physical change: When a substance remains chemically the same but changes in size, shape, or appearance.

Chemical reaction: When a substance changes from one type of matter into another, such as two or more substances combining to form compounds.

Question 3

What is the difference between the fire triangle and the fire tetrahedron?

Answer 3

The fire triangle contains fire, heat, and fuel. The fire tetrahedron adds a chemical reaction.

Question 4

What is the difference between piloted ignition and auto ignition?

Answer 4

Piloted ignition: Occurs when a mixture of fuel and oxygen encounter an external heat source with sufficient heat or thermal energy to start the combustion reaction.

Auto ignition: occurs without any external spark or flame to ignite the fuel or gases.

Question 5

List the various products of combustion that may be found in a fire?

Answer 5

Carbon Monoxide

Formaldehyde

Hydrogen Cyanide

Particulates

Sulfur Dioxides

Question 6

How does fire influence the pressure of the surrounding gases?

Answer 6

Heat increases the pressure of the surrounding gases. The increased pressure will seek to expand and equalize with areas of lower pressure.

Question 7

What is the difference between heat and temperature?

Answer 7

Heat: is the thermal kinetic energy needed to release the potential chemical energy in a fuel.

Temperature: is the measurement of heat.