NFST NFST Fire Behavior and Science 2

Question 1

Which extinguishing agent is most effective on a Class A fire involving ordinary combustibles like wood and paper?

Accepted Answer

Water

Answer

Water is the primary and most effective agent for Class A fires because it cools burning material below ignition temperature.

Question 2

What term describes the lowest temperature at which a liquid fuel produces enough vapor to ignite?

Accepted Answer

Flash point

Answer

Flash point is the minimum temperature at which a liquid gives off enough vapor to form an ignitable mixture near its surface.

Question 3

Smoke rising quickly and freely from a building generally indicates what about the fire conditions inside?

Accepted Answer

There is adequate ventilation and the fire is oxygen-rich

Answer

Smoke that rises quickly and freely indicates the fire has a good oxygen supply and is burning in a well-ventilated space.

Question 4

What is the primary purpose of ventilation during a structure fire?

Accepted Answer

To remove heat, smoke, and gases to improve visibility and reduce fire spread

Answer

Ventilation removes heat, smoke, and toxic gases from a structure, improving conditions for search and rescue and suppression efforts.

Question 5

Which phase of fire development is characterized by limited fuel and plentiful oxygen?

Accepted Answer

Incipient (growth) phase

Answer

During the incipient or growth phase, the fire is small, fuel is abundant but consumption is low, and oxygen is plentiful.

NFST Test Practice Test