Fire Dynamics

Question 1

What is work

Answer 1

Force applied to an object over a distance

Question 2

Fire tetrahedron

Answer 2

Oxidizing Agent
Heat
Reducing Agent(Fuel)
Chemical Chain Reaction

Question 3

Off gassing in solids

Answer 3

Pyrolysis

Question 4

Off gassing in liquids

Answer 4

Vaporization

Question 5

AIT

Answer 5

Autoignition temperature. Temperature for autoignition is always higher than piloted ignition temperature.

Question 6

Types of combustion

Answer 6

Flaming
Non flaming

Question 7

Flaming Combustion

Answer 7

Fire
Gas Phase

Question 8

Open Burning

Answer 8

There is no inlet, fire just consumes

Question 9

Nonflaming Combustion

Answer 9

Slow and low temperature which produces a glow

Question 10

What is smoke

Answer 10

An aerosol of gases, vapor, and solid particles

Question 11

Smoke is the product of

Answer 11

Incomplete combustion

Question 12

Pressure is

Answer 12

The force per unit of area applied perpendicular to a surface

Question 13

Power is

Answer 13

The rate at which energy transfers

Question 14

Heat Release Rate is

Answer 14

HRR is the energy released per unit of time as a fuel burns

Question 15

What is heat flux

Answer 15

It measures the heat transfer per unit area and is measured in kilowatts per square meter

Question 16

What is required for spontaneous combustion?

Answer 16

• Material immediately surrounding fue must have insulation
• rate of heat production must raise materials to AIT
• air supply is needed in the right ratio

Question 17

Reducing agent

Answer 17

Fuel of a fire

Question 18

High vs low vapor pressure

Answer 18

Low means it puts off low amounts of pressure at ATM. If high it means it’s actively undergoing vaporization

Question 18

Flash point vs fire point

Answer 18

Flash is vapors that can ignite but will not sustain fire. Fire point is when sustained fire will occur

Question 18

Surface to mass ratio

Answer 18

surface areas of the fuel in proportion to its mass

Question 18

Chemical Flame Inhibition

Answer 18

Occurs when an extinguishing agent forms a stable product and terminates the combustion reaction

Question 19

Incipient Stage

Answer 19

Starts with ignition and combustion begins

Question 19

Growth

Answer 19

More fuel, more heat, smoke

Question 19

Fully Developed Stage

Answer 19

All combustible materials are burning at their peak HRR

Question 19

Decay Stage

Answer 19

HRR begins to decline

Question 20

Thermal Layering Factors

Answer 20

Temperature Gas Density Pressure

Question 21

Neutral Plane

Answer 21

Line at which net pressure is zero. Above will be fire and smoke

Question 22

Flashover temps

Answer 22

>=1100F

Question 23

Elements of Flashover

Answer 23

Transition in fire development Rapidity Compartment Pyrolysis of all exposed fuel surfaces

Question 24

Factors of Flashover

Answer 24

Ventilation Fuel

Question 25

Backdraft

Answer 25

Increase of ventilation causing explosively rapid combustion of flammable gases

Question 26

Flashover vs backdraft

Answer 26

Flashover everything is set then goes. Backdraft is missing a critical piece like oxygen

Question 27

Dangerous building conditions

Answer 27

- contribute to the spread and intensity of the fire - make the building susceptible to collapse

Question 28

Thermal Properties of the building

Answer 28

Insulation Heat Reflectivity Retention

Question 29

Heat from a fire does what to gases?

Answer 29

Increase gas pressure

Question 30

Autoignition

Answer 30

No externa flame of spark. Fuel surface reaches AIT

Question 31

All compartment fires start as

Answer 31

Fuel limited fires

Question 32

Fully developed stage

Answer 32

All combustible materials are burning at their peak HRR