Introduction to Fire Protection and Arson Investigation

Vocabulary flashcards covering key concepts, terms, and definitions from the lecture notes on fire protection, combustion, extinguishment, and hydrants.

Fire

A state, process, or instance of combustion in which fuel or other material is ignited and combined with oxygen, giving off light, heat and flame; rapid oxidation with evolution of heat and light.

Pyro (Greek PYRA)

From the Greek word PYRA meaning glowing ember; the active principle of burning characterized by heat, light and combustion.

Cold Fire

Fire that burns below a temperature of 400 degrees; cooler than normal fire (e.g., alcohol produces a cooler flame than acetylene).

Fire Triangle

Three elements: Heat, Oxygen, and Fuel; fire continues to burn as long as all three are present.

Fuel

Any material that can burn; can be solids, liquids, or gases; fuels burn and sustain fire, and removing or limiting fuel can stop the fire.

Heat

The energy necessary to raise a fuel to its ignition temperature; can be produced by friction, chemical reactions, etc.; cooling lowers heat to suppress fire.

Oxygen

An element required for most fires; air is about 21% oxygen; extinguishers reduce or separate oxygen to stop combustion.

Fire Tetrahedron

An extension of the Fire Triangle that includes the chemical chain reaction as a fourth element, showing what sustains fires over time.

Chemical Chain Reaction

The ongoing exothermic reactions that sustain fire by providing heat; removing it helps extinguish the fire.

Ignition

The moment when the components of the Fire Tetrahedron combine to start combustion.

Growth

Stage after ignition where the fire plume develops and air is entrained into the rising column.

Fully-Developed

Stage when all combustible materials in the compartment are involved in the fire.

Decay

Stage where the fire slows as available fuel is consumed.

Flashover

A rapid transition between the Growth and Fully Developed stages (not a stage itself).

Combustion

An exothermic chemical reaction between a fuel and an oxidant, producing heat and often light; can be glowing or flaming.

Glowing Combustion

Combustion of solids that does not produce enough gas to sustain a flame, often with limited oxidant.

Flaming Combustion

Combustion of fuels that produce flames; commonly involves gaseous fuels; flame color can hint at fuel composition.

Spontaneous Combustion

Ignition of organic matter due to internal heat from rapid oxidation, self-heating without an external ignition source.

Explosive Combustion

Combustion that occurs when vapors, dust, or gases are premixed with air and ignite explosively.

Products of Combustion

Substances produced by combustion: Fire Gases, Heat, Smoke, and Flame.

Fire Gases

Gases produced during combustion; include various combustion byproducts such as CO2, CO, SO2, etc.

Smoke

Visible product of incomplete combustion; a mixture of gases, soot, and other particulates.

Flame

Incandescence of burning gases resulting from rapid oxidation; the luminous body of a burning gas.

Specific Gravity

Ratio of the weight of a solid or substance to the weight of an equal volume of water.

Vapor Density

Weight of a volume of a pure gas compared to the weight of a volume of dry air at the same temperature and pressure.

Vapor Pressure

The pressure exerted by vapor in equilibrium with its liquid (or solid) at a given temperature.

Temperature

Measure of thermal degree; the activity of molecules within a substance; a key factor in ignition and combustion.

Boiling Point

The temperature at which the vapor pressure of a liquid equals the atmospheric pressure.

Fire Point

The lowest temperature of a liquid at which vapors are evolved fast enough to sustain continuous combustion.

Flash Point

The temperature at which a liquid gives off enough vapor to form an ignitable mixture; e.g., gasoline ~ -50 F, kerosene ~ 100 F.

Auto-ignition Point

The temperature at which a flammable liquid forms a vapor-air mixture that ignites without an external flame.

Endothermic Reaction

A chemical change in which energy/heat is absorbed before the reaction proceeds.

Exothermic Reaction

A chemical change that releases energy/heat during the reaction.

Oxidation

A chemical change in which a fuel reacts with an oxidizing agent such as oxygen.

Pyrolysis

Decomposition of materials by heat, producing volatile gases; a combustion-related process.

Solid Fuels

Solid combustible materials (e.g., wood, paper, cloth).

Pyrolyzable Fuels

Solid fuels that produce vapors upon heating (pyrolysis) to sustain ignition (e.g., wood, paper).

Non-Pyrolyzable Fuels

Solid fuels that do not generate vapors via pyrolysis (e.g., charcoal).

Biomass

Replaceable organic matter such as wood, garbage, and animal manure used to produce energy.

Fabrics/Textiles

Fibers and textiles are generally combustible; classification includes Natural Fibers and Synthetic Fibers.

Natural Fibers

Fibers derived from plants, animals, or minerals.

Synthetic Fibers

Human-made fibers (organic/cellulose or inorganic like fiberglass); often more or less combustible depending on treatment.

Wood Ignition Factors

Physical Form, Moisture Content, Heat Conductivity, Rate and Period of Heating, Rate of Combustion, Ignition Temperature.

Moisture Content

Moisture level in wood; dry wood ignites more easily than freshly cut wood.

Heat Conductivity

How well a material conducts heat; good conductors ignite more readily.

Rate and Period of Heating

Directly affects ignition likelihood; less-flammable materials need direct contact.

Rate of Combustion

Speed at which fuel burns; more oxygen increases burn rate.

Ignition Temperature

The temperature at which a material will ignite.

Liquid Fuels

Flammable or combustible liquids that release vapors; their burning rate is affected by vapor pressure and other factors.

Flammable Liquids

Liquids with a flash point of 37.8 (units given in notes) and notable vapor pressures.

Combustible Liquids

Liquids with a flash point at or above 37.8 (units given in notes).

Latent Heat of Evaporation

The heat required to convert a liquid into vapor without a temperature change.

Gaseous Substances

Substances in gaseous state; examples include acetylene, propane, and butanes.

Gas Fuels

Gases used as fuels (e.g., acetylene, propane, butanes) with properties like compressibility and diffusion.

Natural Gas

Gas consisting chiefly of methane; colorless and odorless; often mixed with sulfur compounds for leaks; may include small amounts of butane/propane.

Manufacture Gas

Synthetic gas produced from coal, petroleum, or biomass; used when certain fuels are scarce.

Compressed Gas

Gas stored under pressure at normal temperature in a container.

Liquefied Gas

Gas that exists partly as a liquid and partly as a gas under pressure.

Cryogenic Gas

Gas stored at very low temperatures, far below ambient, with low to moderate pressure.

Flames

Incandescent gases produced during gas-phase combustion; a manifestation of fire.

Luminous Flame

Orange-red flame with soot; incomplete combustion; lower temperature; seen in candle flame center.

Non-Luminous Flame

Blue flame with complete combustion and higher temperature; outer part of flame.

Premixed Flame

Flame where air is thoroughly mixed with fuel before entering the flame (e.g., Bunsen burner).

Diffused Flame

Flame formed when fuel mixes with air after exiting a nozzle (diffusion flame; candle, oxyacetylene).

Laminar Flame

A flame with smooth, orderly flow of gas particles.

Turbulent Flame

A flame with irregular, chaotic flow of gases.

PASS System

Procedure for using a fire extinguisher: Pull, Aim, Squeeze, Sweep.

Fire Extinguisher

A portable device containing agents to stop fires by interrupting the chemical chain reaction or cooling the fuel.

Four Extinguishment Methods

Cooling (temperature reduction), Fuel removal, Oxygen dilution, Chemical inhibition.

Hydrant

A connection point to access a water supply for firefighting; part of active fire protection.

Water Hammer

A pressure surge when moving water is forced to stop or change direction abruptly.

Hydrant Components

Bonnet, Nozzles, Barrel, Stem, Flange, Threads, Port—parts of a fire hydrant.

Dry Fire Hydrant

Hydrant with a valve below the frost line; requires activation of water supply when used.

Wet Fire Hydrant

Hydrant with barrel always full of water; valve at bottom; used in non-freezing locations.