FF1

Fire Behavior

Fire

A visible result of combustion

Combustion

a rapid chemical chain reaction between a material or a substance and oxygen that produces head and usually light

Heat Energy (thermal energy)

the potential energy of a combustible material and the kinetic energy released when heat is applied to the material

Exothermic

Chemical reaction that produces, or gives off heat

Endothermic

Chemical reaction that absorbs heat

What does a fire need to start and continue to burn?

Fuel, Oxygen, and heat must be present

Fuel-Limited fire

a fire that has sufficient oxygen for fire growth but has limited amount of fuel available for burning

Ventilation-limited fire

fire that has sufficient fuel for fire growth but as limited amount of oxygen available

Smoke

a product of incomplete combustion and it contains unburned hydrocarbons (Form of fuel)

What can happen if a column of hot black smoke comes in contact with an adequate supply of oxygen?

It can ignite suddenly and violently

conduction

process of transferring heat between solids that are touching each other

convection

transfer of heat in a gas or liquid by circulating the material from hotter areas to cooler areas.

During a fire, smoke and hot gasses generated by the fire move through the house?

Convection

4 methods of extinguishing fire

• Cool the burning material

• Exclude oxygen from the fire

• Remove fuel from fire

• Interrupt the chemical reaction with a flame inhibitor

Class A fires

involves ordinary solid combustible materials such as wood, paper, plastics, and cloth

Methods to extinguish Class A fires

cooling the fuel with water to a temp that is below the ignition temp or using ventilation and applying water

Class B fire

involves flammable or combustible liquids such as gasoline, kerosene, diesel fuel, grease, tar, ect

Methods to extinguish Class B fires

shutting off supply of fuel or by using foam to separate the oxygen in the air from the fuel

Class C fires

involves energized electronical equipment

Methods to extinguish class c fires

with agent that does not conduct electricity. Once power is cut off, treat it like type A fire

Class D fire

involves combustible metals such as sodium,magnesium,zirconium,etc

Methods to extinguish class D fires

Can’t be extinguished with water. Attack with agents that smother the fire and snuff out supply of oxygen

Class K fires

involves combustible cooking oils and fats and often occurs in kitchens

Methods to extinguish class K fires

Class K extinguishers contain a wet agent that combines with cooking oils to produce a soap-like substance

Pyrolysis

When solid fuels burn when they are heated sufficiently to change them into flammable vapor.

Rollover(flameover)

spontaneous ignition of hot gases in the upper level of a room or compartments. Rollover is a sign that temps are rising.

In a fire, what happens to hot gases

the hot gases rise to the top of the room

Flashover

rapid transition from a fire that is growing by igniting one type of fuel, to a fire where all of the exposed surfaces have ignited.

Stages of Fire

• Ignition

• Growth

• Decay begins as oxygen is depleted

• Change in ventilation allows oxygen to reach fire

• Fully Developed

• Decay begins as fuel is deleted

Backdraft

an explosion caused by the introduction of oxygen into a compartment where superheated gases and contents are hot enough for ignition but do not have sufficient oxygen

Superheated gases

gases heated above their ignition temp

Smoke Explosion

When it comes in contact with a source of ignition, the flammable mixture will ignite-often in violent matter