IFSTA Chapter 3 - Fire Behavior

anything that occupies space and has mass

• chemical reaction between two or more materials that changes the material and produces heat, flames, and toxic smoke
• (heat is released)

chemical reaction in which a substance absorbs heat energy

• energy that is stored but not is use
• energy that may be released in the future

• an exothermic chemical reaction that is a self-sustaining process of rapid oxidation of fuel
• produces heat and light

• heat
• fuel
• oxygen

• fuel
• heat
• oxygen
• self-sustaining chemical reaction

the energy possessed by a moving object

• unit of measurement for heat
• the amount of heat required to raise the temperature of 1 pound of water 1 degree Fahrenheit

the chemical decomposition of a substance through the action of heat

occurs when a mixture of fuel and oxygen encounter an external heat course with sufficient heat energy to start the combustion reaction

• occurs without any external flame or spark to ignite the fuel or gases or vapors
• fuel surface is chemically heated to the point at which combustion occurs

True

the temp to which the surface of a substance must be heated for ignition and self-sustaining combustion to occur

True

a form of chemical heat energy that occurs when a material increases in temperature without the addition of external heat

• resistance heating
• overcurrent or overload
• arcing
• sparking

heat energy generated by friction of compression

heat created by the movement of two surfaces against each other

• conduction
• convection
• radiation

physical flow or transfer of heat energy from one body to another through direct contact or an intervening medium from the point where heat is produced

the transfer of heat by the movement of heated fluids or gases, usually in an upward direction

the transmission of heat energy as an electromagnetic wave, such as light waves, radio waves, or x-rays, without an intervening medium

• materials that absorb heat but do not participate actively in the combustion reaction
• ex: fuel moisture - a well watered shrub will be slower to ignite than a dehydrated one

• fuels that do not contain carbon
• ex: hydrogen, magnesium

fuels containing carbon

• gasoline
• fuel oil
• plastics

• wood
• paper

• fuels that are already in the sate required for ignition
• ex: methane, hydrogen, acetylene

the density of gases in relation to air

the weight of a substance compared to the weight of an equal volume of water at a given temp

the process that charges a liquid into a gaseous state

minimum temperature at which a liquid gives off enough vapors to ignite, but not sustain combustion

the temperature at which sufficient vapors are being generated to sustain the combustion reaction

the extent at which a substance will mix with water

materials that are capable of being mixed

• the energy released per unit of time as a given fuel burns
• usually expressed in kilowatts

• Carbon monoxide (CO)
• Hydrogen cyanide (HCH)
• Carbon dioxide (CO2)

• involve ordinary combustible materials such as wood, cloth, paper, rubber, grass, and many plastics
• water is most commonly used on Class A fires

• fires involving flammable and combustible liquids and gases such as gasoline, oil, lacquer, paint, mineral spirits, and alcohol
• extinguished by cutting off gas supply, applying appropriate foam or dry chemical agents

• involve energized electrical equipment such as household appliances, computers, transformers, electric motors
• actual fuel burning is usually the insulation on wiring or lubricants
• always cut the power if possible

• involve combustible metals such as aluminum, magnesium, potassium, sodium, titanium
• in the right concentrations, airborne metal dusts can cause powerful explosions when given an ignition

involve oil and grease normally found in commercial kitchens

• a endothermic way to put out class k fires
• occurs when mixtures of alkaline-based chemicals and certain cooking oils come into contact and form a soapy film that absorbs heat

• incipient
• growth
• fully developed
• decay

• first stage of the burning process
• the substance being oxidized is producing some heat but has not spread to other substances nearby

• early stage of fire development during which fuel and O2 are virtually unlimited
• characterized by a rapid increase of heat

the outcome of combustion in a confined space in which gases tend to form into layers, according to temp (hottest gases at the top/ceiling, coolest gases as the bottom/floor)

the interface of the hot and cooler gas layers (where they meet)

condition where the unburned fire gases accumulated at the top of a compartment ignite and flames propagate through the hot gas later or across the ceiling

stage of a fire at which all surfaces and objects within a space have been heated to their ignition temp and flame breaks out almost at once over the surface of all objects in the space

stage of burning process where energy release in at maximum rate and is limited only by availability of fuel and O2

• state of fire development when fuel is consumed, energy release diminishes, and temp decreases
• fire goes from ventilation controlled to fuel controlled

instantaneous explosion or rapid burning of superheated gases that occurs when O2 introduced into an O2-depleted confined space

• fuel type
• availability and location of fuel in relation to the fire location
• compartment geometry (volume/ceiling height)
• ventilation and changes in ventilation
• thermal properties of the enclosure
• ambient conditions (wind, temp, humidity)

1,700

cooling with water