Chapter 1-6 Flashcards
Potential energy
Stored energy possessed by an object that can be released in the future to perform work once released.
Heat of combustion
Total amount of thermal energy, heat, that could be generated by the combustion, oxidation, reaction if a few were completely burned. The heat of combustion is typically measured in kilojoules per gram or mega joules per kilogram.
Kinetic energy
Energy possessed by a moving object because of its motion.
Thermal energy
Kinetic energy associated with the random motions of molecules of a material or object; often used interchangeably with the terms heat and heat energy.
Fuel
A material that will maintain combustion under specified environmental conditions.
Oxidizer
Any material that readily yields oxygen or other oxidizing gas, or that readily reacts to promote or initiate combustion of combustible materials.
Matter
Anything that occupies space and has mass.
Energy
Capacity to perform work; occurs when a force is applied to an object over a distance, or when a substance undergoes a chemical, biological, or physical transformation.
Oxidation
Chemical process that occurs when a substance combines with an oxidizer such as oxygen in the air; a common example is the formation of rust on metal
Combustion
A chemical process of oxidation that occurs at a rate fast enough to produce heat and usually light in the form of either glow or flame.
Fire
A rapid oxidation process, which is a gas phase chemical reaction resulting in the evolution of light and heat in varying intensities.
Heat
Form of energy associated with the motion of Adams or molecules in solids or liquids that is transferred from one bahdie to another as a result of a temperature difference between the bodies, such as from the sun to the earth. To signify its intensity it is measured in degrees of temperature.
Temperature
Measure of the average kinetic energy of the particles in a sample of matter, expressed in terms of units of or degrees designated on a standard scale.
The rate at which a fuel releases energy overtime depends on many variables including
Chemical composition, arrangement, density of the fuel, availability of oxygen for combustion
There are many types of energy including
Chemical, thermal, mechanical, electrical, light, nuclear, sound
Joule
Unit of work or energy in the international system of units, SI,; the energy, or work, when a unit of force, 1 Newton, moves a body through a unit distance, 1 m,. Joules are defined in terms of mechanical energy. In terms of thermal energy Joules refer to the amount of additional heat needed to raise the temperature of a substance such as 4.2 J needed to raise the temperature of 1 g of water 1°C. Takes the place of calories for heat measurement, 1 cal equals 4.19 J,.
Exothermic reaction
Chemical reaction between two or more materials that changes in materials and produces heat
Endothermic reaction
Chemical reaction in which a substance absorbs heat.
1 BTU =
1,055 J
Fire triangle
Plane geometric model of an equilateral triangle that is used to explain the conditions/elements necessary for combustion. The sides of the triangle represent heat, oxygen, and fuel.
Fire tetrahedron
Model of the four elements, conditions required to have a fire. The four sides of the tetrahedron represent fuel, heat, oxygen, and self-sustaining chemical chain reaction.
Pyrolysis
The chemical decomposition of a solid material by heating. Pyrolysis precedes combustion of a solid fuel.
Vaporization
Physical process that changes a liquid into a gaseous state; the rate of vaporization depends on the substance involved, heat, pressure, and exposed surface area.
Piloted ignition
Moment with a mixture of fuel and oxygen encounters and external heat, ignition, source with sufficient heat or thermal energy to start to combustion reaction.
Autoignition
Initiation of combustion by heat but without a spark or flame.
Autoignition Temperature (AIT)
The lowest temperature at which a combustible material ignites in the air without a spark or flame.
Entrain
To draw in and transport solid particles or gases by the flow of a fluid.
Products of combustion
Materials produced and released during burning.
Incomplete combustion
Results of inefficient combustion of a fuel; the less efficient combustion, the more products of combustion are produced rather than burn during the combustion process.
Carbon-based fuels
Fuels in which the energy of combustion derived principally from carbon; includes material such as wood, cotton, coal, or petroleum.
Hydrocarbon fuels
Petroleum based organic compounds that contains only hydrogen and carbon; may also be used to describe those materials in a fuel load which were created using hydrocarbon such as plastics or synthetic fibers.
Asphyxiation
Fatal condition caused by severe oxygen deficiency in an excess of carbon monoxide and/or other gases in the blood.
Carbon monoxide, CO.
Colorless, odorless, dangerous gas, both toxic and flammable, formed by the incomplete combustion of carbon. It combines with hemoglobin more than 200 times faster than oxygen does, decreasing blood’s ability to carry oxygen.
Hydrogen cyanide, HCN.
Colorless, toxic, and flammable liquid until it reaches 79°F, 26°C,. Above that temperature becomes a gas with a faint odor similar to better almonds; produced by the combustion of nitrogen-bearing substances.
Carbon monoxide
Colorless, odorless gas. Inhalation of carbon monoxide causes headaches, dizziness, weakness, confusion, nausea, unconsciousness, and death. Exposure to as little as 0.2% carbon monoxide can result in consciousness within 30 minutes. Inhalation of high concentration can result in immediate collapse and unconsciousness.
Formaldehyde
Colorless gas with a pungent irritating odor that is highly irritating to the nose. 50 to 100 ppm can cause severe irritation to the respiratory tract and serious injury. Exposure to high concentrations can cause injury to the skin. Formaldehyde is a suspected carcinogen.
Hydrogen cyanide
Colorless, toxic, and flammable liquid below 79°F, 26°C, produced by the combustion of nitrogen bearing substances. It is a chemical asphyxiant that acts to prevent the body from using oxygen. It is commonly encountered in smoke and concentration is lower than carbon monoxide.
Nitrogen dioxide
Reddish brown gas or a yellowish brown liquid, which is highly toxic and corrosive.
Particulates
Small particles that can be inhaled and deposited in the mouth, trachea, or the lungs. Exposure to particulars can cause eye irritation, respiratory distress, in addition to health hazards specifically related to the particular substances involved.
Sulfur dioxide
Colorless gas with a choking or suffocating odor. Sulfur dioxide is toxic and corrosive, and can irritate the eyes and mucous membranes.
Carbon dioxide, CO2
Colorless, odorless, heavier than air gas that neither supports combustion nor burns; used in portable fire extinguishers as an extinguishing agent to extinguish class B or C fires by smothering or displacing the oxygen. CO2 is a waste by product of aerobic metabolism.
Pressure
Force per unit area exerted by a liquid or gas measured in pounds per square inch, psi, or kilopascals, kPa.
Buoyant
The tendency or capacity of a liquid or gas to remain a float or rise.
Heat release rate
Total amount of heat released per unit time. The heat release rate is typically measured in kilowatts, or megawatts of output.
Heat flux
The measure of the rate of heat transfer to or from a surface, typically expressed in kilowatts per square meter.
Self heating
The result of exothermic reactions, occurring spontaneously in some materials under certain conditions, whereby heat is generated at a rate sufficient to raise the temperature of the material.
Spontaneous ignition
Initiation of combustion of a material by an internal chemical or biological reaction that has produced sufficient heat to ignite the material.
Thermal equilibrium
The point at which two regions that are in thermal contact no longer transfer your heat between them because they have reached the same temperature.
Thermal conductivity
The propensity of a material to conduct heat within its volume. Measured and energy transfer over distance per degree of temperature.
Conduction
Physical flow or transfer of heat energy from one body to another, through direct contact or in intervening medium, from the point where the heat is produce to another location, or from a region of high temperature to region of low temperature.
Convection
Transfer of heat by the movement of heated fluids or gases, usually in an upward direction.
Radiation
Transmission or transfer of heat energy from one body to another body at a lower temperature through intervening space by electromagnetic waves.
Reducing agent
Fuel that is being oxidized or burn during combustion.
Power
Amount of energy delivered over a given period of time.
Watt
The SI unit of power or rate of work equal to 1 joule per second
Vapor density
Weight of pure vapor or gas compared to the weight of an equal volume of dry air at the same temperature and pressure. A vapor density less than one indicates a vapor lighter than air; a vapor density greater than one indicated vapor heavier than air..
Specific gravity
Mass, weight, of a substance compared to the weight of an equal volume of water at a given temperature. A specific gravity less than 1 indicates a substance lighter than water; a specific gravity greater than 1 indicates a substance heavier than water.
Vapor pressure
The pressure at which a vapor is in equilibrium with its liquid at a given temperature; liquids that have a greater tendency to evaporate have higher vapor pressure at a given temperature.
Flashpoint
Minimum temperature at which a liquid gives off enough vapors to form and ignitable mixture with air near the surface of the liquid.
Fire point
Temperature at which a liquid fuel produce is sufficient vapors to support combustion once the fuels ignites. The fire point is usually a few degrees above the flashpoint.
Solubility
Degree to which a solid, liquid, or gas dissolves in a solvent, usually water.
Miscible
Materials that are capable of being mixed in all proportions.
Polar solvents
Flammable liquids that have an attraction to water, much like a positive magnetic pole attracts a negative pole; examples include alcohols, esters, ketones, amines and lacquers.
Surface to mass ratio
Ratio of the surface area of the fuel to the mass of the fuel.
Flammable explosive range
Range between the upper flammable limit and lower flammable limit in which a substance can ignite.
Lower explosive (flammable) limit, LEL
Lower limit at which a flammable gas or vapor will ignite and support combustion; below this limit the gas or vapor is to lean or thin to burn, lacks the proper quantity of fuel,. Also known as lower flammable limit (LFL).
Upper explosive (flammable) limit (UEL).
Upper limit at which a flammable gas or vapor will ignite; above this limit the gas or vapor is too rich to burn (lacks the proper quantity of oxygen). Also known as the upper flammable limit (UFL).
Free radical
Electrically charged, highly reactive parts of molecules released during combustion reactions.
Chemical flame inhibition
Extinguishment of a fire by interruption of the chemical chain reaction
Open burning
Description of a fire burning and open with no restriction to it’s oxygen supply.
Exposure fire
A Fire ignited in fuel packages or buildings that are remote from the initial fuel package or building of origin.
Fuel limited
Fire with adequate oxygen in which the heat release rate and growth rate are determined by the characteristics of the fuel, such as quantity and geometry. Also known as fuel controlled. From NFPA 921–2011
Ventilation limited
Fire with limited ventilation in which the heat release rate or growth is limited by the amount of oxygen available to the fire. Also known as ventilation controlled. From NFPA 921–2011
Ceiling jet
Horizontal movement of a layer of hot gases and combustion by-products from the central point of the plume, when a horizontal surface such as a ceiling redirects the vertical development of the rising plume.
Entrainment
The drawing in and transporting of solid particles or gas is by the flow of a fluid.
Combustion zone
Area surrounding a heat source in which there is sufficient air available to feed a fire.
Thermal layering
Outcome of combustion in a confined space in which gases tend to form into layers, according to temperature, gas density, and pressure with the hottest gases found at the Ceiling and the coolest gases at the floor level.
Flow path
The space between at least one intake and one exhaust outlet. The difference in pressure determines the direction of the flow of gases through the space. Heat and smoke in a high-pressure area will flow toward areas of lower pressure.
Isolated flames
Flames in the hot gas layer that indicate the gas layer is within its flammable range and has begun to ignite; often observed immediately before a flash over.
Neutral plane
Level at which a compartment opening where there is an equal difference in pressure exerted by expansion and buoyancy of hot smoke flowing out of the opening any inward pressure of cooler, ambient temperature air flowing in through the opening.
Flashover
Rapid transition from the growth stage to the fully develop stage.
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; may occur because of an adequate or in proper ventilation procedure.
Rollover
Condition in which the unburned fire gases that have accumulated at the top of the compartment ignite and flames propagate through the hot gas layer or across the ceiling.
Smoke explosion
Form of fire gas ignition; the ignition of accumulated flammable products of combustion and air that are within their flammable range.
Fuel load
The total quantity of combustible contents of a building, space, or fire area, including interior finish and trim, expressed in heat units of the equivalent weight in wood.
Compartmentation
The way that the arrangement of the compartments creates or does not create a series of barriers designed to keep flames, smoke and heat from spreading from one room or floor to another.
