CFI CFI Fire Dynamics & Behavior 2

Question 1

What is the stoichiometric ratio in fire chemistry?

Accepted Answer

The ideal fuel-to-air mixture ratio for complete combustion

Answer

The stoichiometric ratio is the theoretically perfect fuel-to-air mixture that allows complete combustion with neither excess fuel nor excess oxygen.

Question 2

Which fire behavior phenomenon describes the movement of flames along the underside of a ceiling or overhead accumulation of hot gases before flashover?

Accepted Answer

Rollover

Answer

Rollover (also called flameover) occurs when unburned gases that have collected at the ceiling level ignite and flames roll along the ceiling surface.

Question 3

The 'lower flammable limit' (LFL) of a gas refers to:

Accepted Answer

The minimum concentration of gas in air that can sustain combustion

Answer

The LFL is the minimum concentration (percentage by volume in air) of a flammable gas below which the mixture is too lean to ignite or propagate flame.

Question 4

In NFPA 921, what does the term 'fire pattern' specifically refer to?

Accepted Answer

Visible or measurable physical changes or identifiable shapes caused by a fire effect

Answer

Per NFPA 921, a fire pattern is a visible or measurable physical change or an identifiable shape caused by a fire effect such as char, smoke deposition, or heat damage.

Question 5

What is pyrolysis in the context of fire investigation?

Accepted Answer

The chemical decomposition of a material by heat without combustion

Answer

Pyrolysis is the thermal decomposition of a solid or liquid material into simpler chemical compounds through the application of heat without direct combustion.

(CFI) Certified Fire Investigator Practice Test

(CFI) Certified Fire Investigator Practice Test

CFI CFI Fire Dynamics & Behavior 2