1. Fire Behavior

Question 1

How has the goal of the fire service evolved over its existence?

Answer 1

In the early days the goal was to extinguish all fires before they burned down the entire village. We have progressed to keeping the fire to the block of origin, then the building of origin, and now to the room of origin.

Question 2

Claims for definitive evidence of use and control of fire by modern humans range from ____ to ____ years ago. Only in the past ____ or so years, have formal, scientific studies been undertaken to gain an understanding of fire suppression and prevention.

Answer 2

• 1.7 million to 200,000

* 100

Question 3

In ____, in response to the ____ report written by the National Commission on Fire Prevention and Control titled ____, the US Congress passed US Public Law ____, which created ____, ____, and ____. This Law is also known as the ____.

Answer 3

• 1974
• 1973
• America Burning
• 93-498
• The National Fire Protection Association (NFPA)
• National Fire Academy (NFA)
• NIST
• Federal Fire Prevention and Control Act

Question 4

The Federal Fire Prevention and Control Act gave NIST the mission of ____

Answer 4

performing and supporting research on all aspects of fire, with the aim of providing scientific and technical knowledge applicable to the prevention and control of fires. The act required NIST to conduct research on the dynamics of flame ignition, flame spread, and flame extinguishment.

Question 5

Between the late 1970’s and 2009, the annual number of structure fires in the United States decreased by ____. During the same period, the overall number of firefighter deaths due to traumatic injuries also declined. However, the rate of firefighter deaths due to traumatic injuries on the fireground increased from ____ to ____ per 100,000 fires. This was an increase of more than ____.

Answer 5

• more than 50%
• 1.8 to 3
• 60%

Question 6

Change is best accepted in a ____ environment when leadership is ____.

Answer 6

• supportive

* leading by example

Question 7

Ambient

Answer 7

Someone’s or somethings surroundings, especially as they pertain to local environment. For example, ambient air and ambient temperature.

Question 8

Backdraft

Answer 8

A deflagration resulting from the sudden introduction of air into a confined space containing oxygen-deficient products of incomplete combustion (aka smoke explosion)

Question 9

Blast pressure front

Answer 9

The expanding leading edge of an explosion reaction that separates a major difference in pressure between normal ambient pressure ahead of the front and potentially damaging high pressure at and behind the front.

Question 10

Ceiling layer

Answer 10

A buoyant layer of hot gases and smoke produced by a fire in a compartment.

Question 11

Conduction

Answer 11

Heat transfer to another body of within a body by direct contact

Question 12

Fire dynamics

Answer 12

The detailed study of how chemistry, fire science, and the engineering disciplines of fluid mechanics and heat transfer interact to influence fire behavior.

Question 13

Fire spread

Answer 13

The movement of fire from one place to another.

Question 14

Flame

Answer 14

A body or stream of gaseous material involved in the combustion process and emitting radiant energy at specific wavelength bands determined by the combustion chemistry of the fuel. In most cases, some portion of the emitted radiant energy is visible to the human eye.

Question 15

Flashover

Answer 15

A transition phase in the development of a compartment fire in which surfaces exposed to thermal radiation reach ignition temperature more or less simultaneously and fire spreads rapidly throughout the space, resulting in full room involvement or total involvement or the compartment or enclosed space.

Question 16

Fuel load

Answer 16

The total quantity of combustible contents of a building, space, or fire area, including interior finish and trim, expressed in heat units or the equivalent weight in wood.

Question 17

Fuel-controlled fire

Answer 17

A fire in which the heat release rate and growth rate are controlled by the characteristics of the fuel, such as quantity and geometry, and in which adequate air for combustion is available.

Question 18

Gas

Answer 18

The physical state of a substance that has no shape or volume of its own and will expand to take the shape and volume of the container or enclosure it occupies.

Question 19

Heat

Answer 19

A form or energy characterized by vibration of molecules and capable of initiating and supporting chemical changes of state.

Question 20

Heat flux

Answer 20

The measure or the rate of heat transfer to a surface, expressed in kilowatts, kilojoules, or BTUs per second.

Question 21

Heat release rate (HRR)

Answer 21

The rate at which heat energy is generated by burning.

Question 22

Ignition

Answer 22

The process or initiating self sustained combustion

Question 23

Kilowatt

Answer 23

A measurement of energy release rate.

Question 24

Oxygen deficiency

Answer 24

Insufficiency of oxygen to support combustion (aka ventilation limited)

Question 25

Plume

Answer 25

The column of hot gases, flames, and smoke rising above a fire.

Question 26

Pyrolysis

Answer 26

A process in which material is decomposed, or broken down, into simpler molecular compounds by the effects of heat alone; pyrolysis often precedes combustion.

Question 27

Radiation

Answer 27

Heat transfer by way of electromagnetic energy.

Question 28

Rollover

Answer 28

The condition where unburned fuel (pyrolysate) from the originating fire has accumulated in the ceiling layer to a sufficient concentration (i.e. at or above the lower flammable limit) that it ignites and burns. Rollover can occur without ignition of, or prior to, the ignition of other fuels separate of the origin (i.e. flameover)

Question 29

Scientific method

Answer 29

The systematic pursuit of knowledge involving the recognition and formulation of a problem, the collection of data through observation and experiment, and the formulation and testing of a hypothesis.

Question 30

Smoke

Answer 30

The airborne solid and liquid particulates and gases evolved when a material undergoes pyrolysis or combustion, together with the quantity of air that is entrained or otherwise mixed into mass.

Question 31

Smoldering

Answer 31

Combustion without flame, usually with incandescence and smoke.

Question 32

Temperature

Answer 32

The degree of sensible heat of a body as measured by a thermometer or similar instrument.

Question 33

Ventilation

Answer 33

Circulation of air in any space by natural wind or convection or by fans blowing air into or exhausting air out of a building. A firefighting operation of removing smoke and heat from the structure by opening windows and doors or making holes in the roof.

Question 34

Ventilation-limited fire

Answer 34

A fire in which the heat release rate or growth is controlled by the amount of air available to the fire (a.k.a. ventilation controlled fire)

Question 35

Venting

Answer 35

The escape of smoke and heat through openings in a building.

Question 36

Fire dynamics

Answer 36

The study of how fire starts, spreads, and develops. ____ has the scientific measurements and calculations needed to explain fire behavior.

Question 37

Fire behavior

Answer 37

the way fire reacts and behaves to its environments.

Question 38

In todays structures, fire temperatures increase at a faster rate, causing ____

Answer 38

fires to reach flashover temperatures sooner.

Question 39

One of the keys in todays fires is ____ rather than the temperature.

Answer 39

• heat release rate
• A single candle compared to 10 candles, both have the same temperatures, but 10 candles have 10x the heat release rate.

Question 40

Heat is always transferred from ____ to ____.

Answer 40

The hotter object to the colder object.

Question 41

What are the different types of heat transfer?

Answer 41

Conduction, convection, and radiation.

Question 42

Convection

Answer 42

Heat transferred by circulation within a medium such as a gas or a liquid.

Question 43

Fire creates pressure and pressure moves from ____ to ____.

Answer 43

high to low

• High pressure is in the fire room and is created by the fire
• Low pressure is any opening that is created at a distance away from the fire.

Question 44

When a pressure gradient is created we have the making of ____

Answer 44

a flow path

Question 45

In a flow path, high pressure combustible gases (e.g. smoke) are forced ____ and ____ is drawing in the lower pressure air from ____

Answer 45

• across the upper parts of a compartment
• the fire
• a low pressure opening

Question 46

If we stop or control ____ , we reduce the temperature and slow the combustion process.

Answer 46

• the air from being drawn into the fire

Question 47

If we slow the combustion process, fire reduces in size along with the amount of combustible gases being produced. ____ will worsen, but ____ improve with lower temperatures and less or equal combustible gases.

Answer 47

• Interior visibility

* the rest of the interior conditions

Question 48

Pressure is at its highest point if the fuel/air mixture is allowed to ____

Answer 48

go above the LEL and gets closer to the ideal mixture.

Question 49

Legacy fire development is related to ____

Answer 49

fuel limited fires

Question 50

Modern fire development commonly relates to ____

Answer 50

ventilation limited fires

Question 51

Backdrafts most commonly occur in ____

Answer 51

attic spaces, knee walls, or any other void space

Question 52

Flow path

Answer 52

The space through which fire, heat, and smoke progress, moving from the high-pressure fire area toward lower pressure oxygen sources, such as door and window openings.

Question 53

Although a buildings openings are unpredictable, ____ should recognize imminent failure to a window or door.

Answer 53

a solid size up

Question 54

Interrupting the flow path involves tactics that are innovative and sometimes counterintuitive, but fire research shows that these methods can ____ within the structure, minimize the potential for ____, and greatly enhance ____

Answer 54

• reduce heat
• flashover
• the safety for firefighters

Question 55

The time between tactical ventilation and flashover could be as little as ____, compared to ____ in a traditional fire.

Answer 55

• 2 minutes

* 8 minutes

Question 56

Increasing ventilation by opening doors, clearing windows, or cutting the roof in a ventilation-limited structure fire may lead to ____

Answer 56

a rapid transition to flashover

Question 57

Its important to understand that ____ are what cause fire spread.

Answer 57

the smoke and fire gases

Question 58

The smoke is what we should be keeping our eyes on. Smoke ____, ____, ____, and ____ are essential components to understanding fire behavior.

Answer 58

• volume, velocity, density, and color