NFSI Firefighting Knowledge 3

Question 1

What is the primary hazard associated with a backdraft condition?

Accepted Answer

Explosive ignition when oxygen is suddenly introduced to an oxygen-starved fire

Answer

Backdraft is a deflagration explosion triggered when oxygen is introduced to a superheated, oxygen-depleted compartment containing unburned combustible gases.

Question 2

Which fuel property describes how easily a material releases vapors that can ignite?

Accepted Answer

Flash point

Answer

The flash point is the lowest temperature at which a liquid produces enough vapor to ignite momentarily when exposed to an ignition source.

Question 3

When using a straight stream from a nozzle, what is the primary tactical advantage over a fog pattern?

Accepted Answer

It reaches deeper into a fire compartment with less steam conversion

Answer

A straight stream penetrates farther and generates less steam that could obscure vision or cause burns to firefighters in an enclosed space.

Question 4

What is the purpose of the incident command system (ICS) span of control guideline?

Accepted Answer

To ensure no supervisor is responsible for more than 3–7 personnel

Answer

ICS span of control (3–7 people per supervisor, optimal 5) prevents supervisors from being overwhelmed and ensures effective coordination.

Question 5

Which of the following best describes a 'two-in, two-out' rule?

Accepted Answer

At least two firefighters must be outside and ready to assist any time two or more are inside an IDLH atmosphere

Answer

The two-in, two-out rule (OSHA 29 CFR 1910.134) requires a standby rescue team outside whenever firefighters are operating in an immediately dangerous to life or health atmosphere.

NFSI - National Firefighter Selection Inventory Practice Test

NFSI - National Firefighter Selection Inventory Practice Test

NFSI Firefighting Knowledge 3