Matter
Anything that which has mass and occupies space
What are the three states fuel can be in?
Gas, Liquid, Solid
Exothermic Heat Reduction
Chemical reaction between two or more materials that changes the materials and produces heat, flames & toxic smoke
Endothermic Heat Reaction
Chemical reaction in which a substance absorbs heat energy.
Combustion
An exothermic chemical reaction that is a self-sustaining process of rapid oxidation of a fuel, that produces heat & light
Fire Tetrahedron
Model of the four elements/conditions required to have a fire. The four sides of the tetrahedron represent fuel, heat, oxygen, and chemical chain reaction.
Potential Energy
Stored energy by an object that can be released in the future to perform work
Kinetic Energy
the energy possessed by a moving object
Surface to mass ratio
Surface area of the fuel in proportion to the mass
Autoignition Temperature
Same as ignition temperature except that no external ignition source is required for ignition because ther material itself has been heated to ignition temp
Fire Tetrahedron
Oxygen, Fuel, Heat, Self sustained chemical chain reaction
Conduction
Physical flow or transfer of heat energy from one body to another through direct contact or an intervening medium from the point where the heat is produced to another location or from a region of high temperature to a region of low temp
What are the two types of ignitions?
Piloted Ignition and Auto-Ignition
Piloted Ignition
Occurs when a mixture of fuel and oxygen encounter an External Heat Source
Auto-Ignition
Occurs without any external ignition
Convection
the transfer of heat energy by the circulation or movement of a liquid or gas, usually in an upward direction to a solid surface
Radiation
transfer of thermal energy from one body to another body at a lower temp through intervening space by electromagnetic waves such as infrared thermal waves, & by electromagnetic waves
Sources of Heat Energy
Chemical, Mechanical, Electrical, Light, Nuclear. Most common sources are Chemical, Mechanical, Electrical
Specific Gravity
the density of a substance relative to the density of water at a given temp.
Specific Gravity less then 1
A substance lighter then water, flouts
Specific Gravity greater then 1
A substance heavier than water, sinks
Vaporization
the process by which a liquid or solid changes to a gas. The rate of vaporization depends on the substance involved, heat, and pressure
Flash Point
Minimum temperature at which a liquid gives off enough vapors to form an ignitable mixture with air near the liquid's surface.
Fire point
Temperature at which a liquid fuel produces sufficient vapors to support combustion once the fuel is ignited. The fire point is usually a few degrees above the flash point.
Miscible
Materials that are capable of being mixed
Solubility
a measure of how much solid, liquid, or gas can dissolve in a given solvent at a given temperature
Normal Air consists of what percent of Oxygen
21%
Whats the lowest oxygen % at which Materials can ignite & burn
14%
Flammable Range
The range between the upper flammable limit and lower flammable limit in which a substance can be ignited.
Proximity and Orientation
Solid fuel relative to the source of heat also affects the way it burns.
Carbon Monoxide (CO)
Colorless, odorless, poisonous & flammable gas produced by the incomplete combustion of carbon or organic fuels.
Carbon Dioxide (CO2)
Colorless, odorless, heavier than air gas that neither supports combustion nor burns.
Incipient Stage
First stage of the burning process in a confined space in which the substance being oxidized is producing some heat but the heat has not spread to other substances nearby. During this phase, the oxygen content of the air has not been significantly reduced
Growth Stage
The early stage of a fire during which fuel & oxygen are virtually unlimited. This stage is characterized by a rapidly increasing release of heat
Thermal Layering
Outcome of combustion in a confined space in which gases tend to form into layers, according to its temperature, with the hottest gas found at the ceiling & the coolest gases at floor level
Rollover
Condition in which the unburned combustible gases released in a confined space (such as a room or aircraft cabin) during the incipient or early steady-state phase and accumulate at the ceiling level. These superheated gases are pushed, under pressure, awa
Flashover
Stage of a fire at which all surfaces and objects within a space have been heated to their ignition temperature and flame breaks out almost at once over the surface of all objects in the space.
Fully Developed Stage
Stage of burning process where energy release is at maximum rate and is limited only by availability of fuel and oxygen.
Decay
Stage of fire development when fuel is consumed & temps decreased. this stage the gose from ventilation-controlled to fuel controlled
Backdraft
Instantaneous explosion or rapid burning of superheated gases that occurs when oxygen is introduced into an oxygen-depleted confined space. The stalled combustion resumes with explosive force. It may occur because of inadequate or improper ventilation pro
Pyrolysis
Chemical decomposition of a fuel through the action of heat
Class A Fires
Involve ordinary combustibles such as textiles, paper, plastics, rubber and wood. These can be easily extinguished with water by cooling.
Class B Fires
Involve flammable and combustible liquids, gasses, and greases such as alcohol, cooking oils, gasoline, lubricating oils, and liquefied petroleum gas. Extinguished with appropriately applied foam and/or dry chemical agents.
Class C Fires
Involve energized electrical equipment. Household appliances, computers, transformers, electric motors, & overhead transmission lines are typical sources for Class C Fires. Turn off the power and it becomes a Class A fire.
Class D Fires
Involve combustible metals such as magnesium, lithium, potassium or sodium. Identified by bright white sparks and emissions from combustion process. Special Class D Dry Chemical agents are used.
Class A, B, C, D,K Fires
A=wood, paper, cloth (ord. combustibles)
B=burning liquids (grease, oil, gas & solvents)
C=switches, motors & elec. equip.
D=combustible metals (aluminum, magnesium)
K=cooking appliances involving combustible cooking products like veg. or animal oils & fa
Class K Fires
Involve combustible cooking oils such as vegetable or animal fat oils that burn at extremely high temperatures. Wet Chemicals are used in the extinguishing systems and portable extinguishers or these fires.
Auto Ignition Temperature (AIT)
The temperature at which a mixture of flammable vapors and air will ignite without flame or spark. also, it is the temperature an ignition source must possess to ignite a given mixture of flammable vapors.
British Thermal Unit (BTU)
The quantity of heat that is required to raise the temperature of one pound of water one degree Fahrenheit. A measure of heat quantity.
Fire
A rapid oxidation chemical reaction that produces heat and light.
Chemical Change
A change in a substance that alters chemical and sometimes physical properties.
Class A fire
A fire that involves ordinary combustible materials such as wood, paper, vegetation, fabrics, and so forth.
Class B fire
A fire involving flammable or combustible liquids.
Class C fire
Class C fires involve energized electrical equipment.
Class D fire
Involves combustible metals such as sodium, magnesium and titanium.
Class K fire
Fires Involving cooking greases and animal fats.
Conduction
The transfer of heat within a substance with no visible motion in the substance: transfer of heat by molecular contact.
Convection
The transfer of heat by motion of heated gaseous or liquid matter.
Endothermic
A chemical reaction in which the involved substance takes in heat.
Exothermic
A chemical reaction in which the involved substance gives off heat. This is the most common type of chemical reaction
Explosive Range
The percentages in the atmosphere of a flammable or combustible vapor that is neither too lean nor too rich to burn: those concentrations of vapor between the lower explosive limit (LEL) and upper explosive limit (UEL).
Flammable Range
The percentages in the atmosphere of a flammable or combustible vapor that is neither too lean nor too rich to burn: those concentrations of vapor between the lower explosive limit (LFL) and upper explosive limit (UFL).
Fire Point
The temperature to which a flammable liquid must be heated to produce a sufficient quantity of vapors to burn continuously.
Fire Retardant
A substance that retards the spread of fire.
Flammable
A substance capable of igniting easily and burning at ordinary temperatures.
Flash Point
The lowest temperature at which the vapor of a combustible liquid can be ignited in air
Gas
Matter that had no definite shape, no definite volume, but has a mass. Will take the shape and volume of the container that holds it, but can also be condensed to have a smaller volume
Heat of Vaporization
The amount of heat necessary to convert a liquid to a gas.
Ignition Temperature
The temperature to which a substance must be heated to initiate self-sustained combustion.
Liquid
A phase of matter that has no specific shape, but a definite volume, and forms to the shape of whatever is holding it
Miscibility
The degree to which two liquids can mix.
Oxidation
The chemical reaction of oxygen with other substances
Radiation
The direct transfer of energy by electromagnetic waves.
Solid
A state of matter that has definite shape and volume that does not change under normal conditions.
Specific Gravity
The ratio of a substances weight to the weight of and equal volume of water. Used to determine if a substance will sink or float in water.
Spontaneous Heating
Self-ignition caused by oxidation of organic materials.
Temperature
A measure of heat intensity.
Vapor Density
Describes the density of gases in relation to air.
Products of Combustion
heat, flame, smoke and gases
Vapor Density less then 1.
Lighter then air, Rises
Vapor Density of Air.
1
Combustion yields
Heat and Light
Energy
capacity to perform work
Mechanical Heat Energy
Generated by friction or compression movement of two surfaces against each other creates heat of friction.
Passive Agents
Are materials that absorb heat but do not participate actively in the combustion reaction.
Fuel (Reducing agent)
fuel is the material or substance being oxidized or burned in the combustion process.
What has the most impact on firefighters?
Smoke and Heat
Plume
Hot gases raise and mix with cooler air, hot gases moves horizontally across the ceiling.
Factors that Affect Fire Development
Fuel type, Availability, Ambient Conditions, Ventilation, Compartment geometry, Thermal properties of the enclosure