Fire Chemistry

Foams extinguish flames by suppressing ___.

vapors

The degree of rapidity with which a substance evaporates to a gaseous state

volatility

The physical property known as fire point is very similar to flash point. The only different is that at the fire point the vapors ignite and continue to burn. in fact, the definition is the same as for flash point, with one minor change:

"The fire point of a substance is the lowest temperature at which a substance produces ignitable vapors sufficiently fast enough to "flash" when exposed to an outside ignition source, AND THEN CONTINUES TO BURN

Wood products have a rather high flash and fire point range, over _____ degrees F

100

The fire triangle dates back to the early ___. It is still used today as a very simplistic way of describing the necessary ingredients for fire. However, we must remember that there is more to each side of the fire triangle than meets the eye.

1920s.

One pound of water will absorb 1 ___ of heat and will heat up ___ degree F

BTU (British Thermal Unit, a measure of heat production or absorption). -1 degree F

Chemical reactions can produce heat. Sometimes this heat is enough to ignite the chemicals or to ignite nearby combustible materials. When two or more chemicals combine and heat is produced, the result is "__"

"chemical heat energy"

Flash point is dangerously close to the point of continuous combustion. This is the significant features of flash point. In fact, the fire and chemical communities say this about flash point: (Think: Which point determines the flammability of all liquids and solids?)

"Flash Point determines the flammability of all liquids and solids"

It must be remembered that the determination of ignition temperatures is based on___. They represent only approximations of a particular substance's ignition temperature. Another varying criteria is the type of material being tested. Oak wood is hard and has an ignition temperature of about ___ F. Lighter pine wood may have ignition temperatures of ____ to ____.

-Laboratory tests -450 degrees F -325 degrees F to 375 degrees F

___, ___, and ___ are poor conductors of heat. Instead of conducting heat rapidly, they tend to store the heat. Notice on a hot day how "hot" metal surfaces seem to get. When you touch the metal the heat is rapidly conducted to your hand and it "feels" hot. On the other hand, when the sun goes down these metal surfaces cool off quickly. ___ and ___ retain the heat longer and will still feel "warm" hours after sunset.

-Masonry, stone, and brick -Brick and stone

Combustion is a chemical reaction. In order for that reaction to take place, the ___ that make up the substance must be heated up to a certain temperature. When the substance reaches its ignition temperature, the molecules in the substance are ready to combine with the __ molecule in the air. At this temperature, the combustion reaction or burning continues without the addition of any additional heat because the combustion process gives off enough heat so that the process is self-sustaining.

-Molecules -oxygen

Molecules in a liquid are always in ___.

-Motion

A colorless, odorless tasteless gas; nonflammable; renders all other substances flammable. Chemical symbol is:

-Oxygen (O2)

Modern "halon" extinguishing agents are the result of laboratory development in 1950 at ___. They are special types of gases that are confined in cylinders similar to carbon dioxide. When discharged, their vapors sink because they are ___, and replace the ___ need to the fire. The Halons also have some part in interrupting the ___ of a fire, thus leading to extinguishment. Some caution must be used with the Halons. ___ may be a problem

-Purdue University -because they are quite heavy and replace the oxygen need to the fire. -chemical chain reaction -Toxicity

When metals burn, they pose some very unique hazards. They burn extremely hot. They may actually react to ordinary extinguishing agents. Class D fires are fires involving such metals as ___, ___, ___, ___, and ___. The hazards of a metal fire are so unique that ordinary extinguishing should generally not be used. Instead, extinguishing agents for a Class D fire are....

-Sodium, Magnesium, Titanium, Aluminum, and Uranium -those that have been specifically designed and approved for that type of application

Another example of extinguishment in regards to removing the fuel from a fire could be a large transportation accident involving a flammable liquid tanker on fire. A valve is open and fuel is running down the street. An ideal approach would be to.... Sometimes at large refinery pipeline ruptures, the control and elimination of the fuel is the only choice of fire control and extinguishment the fire department has. The other two alternatives would not be effective.

-Somehow get in and turn off the valve.

The ____ of a substance refers to the tendency of a liquid or a solid to float or sink in water. It is a measure of the density of a liquid or solid, or "how heavy" it is. Some liquids and solids sink in water, such ___ and ___. Others float on water, such as ___, ___, and ___.

-Specific Gravity -Carbon Disulfide and Asphalt -Gasoline, Kerosene, and Wood

____ is another example of producing heat through chemical means. Most chemicals reactions produce heat. usually this heat dissipates into the surrounding air. However, if the material is contained in such a way that the heat cannot dissipate, the heat may build up very slowly, sometimes over hours or days. When the ___ temperature is attained, the materials ignites. For example: an oily (vegetable oil) rag may eventually ignite in the bottom of a wastebasket.

-Spontaneous Ignition -Auto-ignition

Even more amazing is the extent of heat absorption that occurs when water finally exceeds the boiling point and becomes steam. Altogether, each pound of water can absorb ___ BTU's by being heated from ___ degrees F to ___ degrees F and can absorb an amazing additional ____ BTU's on its transformation to steam at ___ degrees F

Each pound of water can absorb 180 BTU's by being heated from 32 degrees F to 212 degrees F and can absorb an amazing additional 970 BTU's on it's transformation to steam at 212 degrees F.

If the liquid is in an open container, the molecules released into the air will move away. This is called ___.

Evaporation

___ heat transfer is the most important and most frequently observed method of heat transfer responsible for the propagation of fires that involve combustible materials.

Conductive

The circulation of heat from an area of warmer temperatures to one of cooler temperatures through a gas or liquid median

Convection

The transfer of heat through a moving medium, such as a liquid or gas

Convection

What is the safest and safest extinguishment in most cases?

Cooling

Which is the most common method of extinguishment?

Cooling (the elimination of heat production)

When heat is transferred by direct contact from one material to another, this method of heat transfer is ___.

conduction.

There are only four sources of heat energy. A source of energy is...

one that produces or makes energy.

Heat rays pass through any visible transparent or ____, such as glass, air, water, and transparent plastics. These substances absorb only a very tiny amount of the radiant energy. The majority of the heat passes on through. Heat rays can be reflected by any shiny or mirrored surface. They may be concentrated by lenses like light rays. Heat rays can be more easily absorbed by a dark/black surface or by a light colored surface?

opaque medium -dark or black surface

Examples of fires starting from "contact with hot object or open flame" would include any ___, such as a match, or an exposure to fire that causes other combustibles to ignite. Combustibles can also ignite on contact with hot objects, for example hot metal surfaces or molten metal. Many people have witnessed a leaking carburetor on a car dripping gasoline onto a hot exhaust manifold. The result is always obvious and dramatic.

open flame

Carbon dioxide is nonflammable and thus a CO2 extinguisher removes the ___ side of the triangle.

oxygen

A "__ foam" utilizes a liquid concentrate that is mixed with water and then applied to the fire. This type of foam has considerable "___" or ___ to it, which provides the foam with strength. These types of foams usually have good water retention. The nozzle or ___ "aerates" the concentrate with the water creating tiny foamy bubbles. Which type of water can be used, fresh, salt water, or both? with what percentage mixed rate with water? The foam developed is dense, of high stability, has good heat resistance, and has good resistance to ___.

"protein foam" -"body" or weight -applicator -both; 3 or 6% -flashback

Properly generated, High Expansion Foam has an expansion ratio of up to ___ to 1. High expansion foam has application for total flooding of ___, ____, and replacement of all ___, ___, and ____ space. High expansion foam is particularly suited for... It is not useful on flammable ____

-1,000 -confined spaces, inaccessible places, and replacement of all smoke, heat, and air spaces. -indoor fires in confined spaces such as basements. -liquid fires

For example (Regarding explosive range), gasoline vapors have been found to have an explosive range of __ to __%. This is a range of mixtures from ___% gasoline vapors and ___% air to __% gasoline vapors and __% air. Gasoline vapors will ignite or explode only when mixed with air in this proportion. The lower limit is the least amount of vapor possible for gasoline. Any percent mixture less than the lower limit will not ignite. This is referred to being as "___". On the other hand, if the percent mixture is above the vapor limit, it is referred to being as "__". It will not ignite either. Only the mixtures between the lower limit and upper limit will ignite. All vapors of flammable and combustible materials have an explosive range.

-1.4 to 7.6% -1.4% gasoline vapors and 98.6% air to 7.6 % gasoline vapors and 92.4% air. -"too lean" -"too rich"

Flammable liquids can produce an amazing amount of heat when burned. Consider this comparison: One gallon of gasoline produces ___ BTU's when burned, and one gallon of water can absorb ___ BTU's of heat.

-130,000 BTU's -926 BTU's

In order to satisfy the second side of the fire triangle, we must have oxygen in sufficient quantity. In order to sustain life, the oxygen content of air must be no less than __%. Fortunately our atmosphere has __% oxygen. ___ or combustion needs oxygen too. It is a surprise to a lot of people to learn that an open burning needs the same amount of oxygen as that required to sustain ___. If the oxygen in a room that is on fire falls below __%, the fire goes into a ___ stage. In the case of flammable ____, the fire will go out.

-16% -21% -Rapid oxidation -life -16%; smoldering -liquid

The fire triangle explanation has been used since ___. The fire tetrahedron is a more detailed look at fire extinguishment using the fire triangle as its basis. The idea of adding a fourth side to the fire triangle came about in ___. This was a result of in-depth studies of the behavior of fire extinguishment conducted by the ___ and the private work of ___.

-1920 -1960 -National Bureau of Standards -Arthur Guise

The fire point of gasoline, by best approximation is ___. At this point, if the vapors of gasoline ignite, the fire ____.

-43 degrees F below zero. -will continue to burn

Flash points do NOT continue to burn. It merely "Flashes". An example would be gasoline in a beaker. we would note that gas has the unique ability to release flammable vapors at very low temperatures. Our question would be "How low?" Running this test would show gasoline actually begins to release flammable vapor at ___ degrees F below Zero. This is the best approximation of the flash point of gasoline. At this low temperature, an ignition source ignites these vapors, but the flash quickly goes out. This is because the vapors are not being produced fast enough to support continuous combustion.

-45 degrees F below Zero

If you place your hand directly over a candle flame (carefully), you can feel the convection of hot gases streaming upward. The hottest water in a hot water heater is near the top. However, convection air currents can move in ___ direction depending on other influences, such as ____ and ____

-Any direction -nearby temperature and action of a fan

The physical characteristics of substances are very important because they may affect whether or not a substance may enter a chemical reaction which will change its ___. Of course, the chemical reaction we are most interested in is the reaction which results in fire.

-Chemical Composition

When any substance burns, molecules of that substance enter a chemical reaction we call ___. For this to occur, the molecules of the substance must be free to react. Molecules are usually only free to react when the molecules exist in the form of a ___ or ___.

-Combustion -Gas or vapor

____ is also known as flammable range or flammable limits. This physical property refers to a mixture of of the flammable ___ and ___. It is oxygen in the air that helps "burn" substances. With no oxygen or the improper mixture of oxygen with the flammable vapors, the vapors will not ignite or burn. This is true even if a suitable ignition sources has been found. We must have a proper ratio of an ___ and ___ mixture.

-Explosive Range -vapors and air. -air and fuel mixture.

Moving mechanical parts generate heat. Gears, pulleys, belts, anything that moves over another surface produces ___ heat. Sometimes this heat is produced in such quantity or is stored up over such a long period of time that it can cause nearby combustibles to ignite.

-Friction

(List 5) all have vapors that are 1-1/2 to 2-1/2 times heavier than air.

-Gasoline -Kerosene -Jet Fuel -Acetone -Benzene

The vapors of most flammable liquids are ___ than air. If these vapors are not confined, they will....

-Heavier -sink and spread along the floor or lowest surface available. Any spark on the floor could be very dangerous.

There are two general ways that a substance can reach its ignition temperature. The first way is.... This is sometimes referred to as ___. The flame on the match actually heats the molecules of combustible vapors near the flame to their ignition temperature. The vapors then ignite. This larger flame heats more nearby vapors and the process continues. Of course, the flame must be hot enough to heat the vapors to a temperature equal to or greater than their ignition temperature.

-The introduction of an external source like a spark, match or open flame. -piloted ignition.

If the value has a vapor density less than 1, the vapor is ___ and will ___. An example is ____

-The vapor is light and will rise. -Hydrogen

A match set to a stick of wood probably won't ignite the wood. We have to consider several additional factors. For example, the wood has to be in the right "form". The smaller the pieces of fuel, the easier it will be to ignite. Dry wood ignites faster than green wood. Fuels ignite and burn faster when placed horizontally or vertically? This is particularly true of solid ___ than when placed as the opposite position, will behave almost as if they are fire resident.

-Vertically -Plastic

___ is a very poor conductor of heat. It absorbs rather than conducts heat. Depending upon the amount of heat it is absorbing, ___ may reach its ignition temperature and ignite. Many fires start this way. From poorest to richest, How good of quality are the conductors of each material? Why?

-Wood -Gas, liquid, then solid because the molecules are not close as they are in a solid.

Another factor regarding heat is the duration of flame or heat application to the fuel. Even though wood may ignite at ___ to ____ degrees F, the ___ degrees F of a match will not cause a toothpick to catch fire if the heat source is not held in place long enough. You can pass a sheet of paper through a candle flame and it won't catch fire. Hold the paper in place for a second and bingo, ignition.

-Wood may ignite at 350-450 degrees F, the 1,600 degrees F of a match...

Class A Fires include ordinary combustibles such as ___, ___, ___, ____, and ____. Class A fires normally involve fuels of an ___ nature. Extinguishing agents for Class A type fires include ___, ___, and ___.

-Wood, paper, fabric, solid plastics, and rubber -organic -water, some foam types, and dry chemical.

Fire spread from room to room or within other enclosures, such as ___ and ____, demonstrates fire spread by heat transfer through convection. This also demonstrates the movement of heated gases. When confined in enclosures, heated gases can travel in which direction/s?

-air ducts and piping -all

As the movement of the molecules increases (In liquid), some molecules leave the liquid and move into the ___. When this occurs, the liquid is releasing a ___ or ___. It is this collection of molecules that has the potential to burn.

-air. -gas or vapor

Other examples of electrical energy including ___, which is the discharge of electricity across a gap in a circuit or between electrodes. This could be nothing more than of an electrical switch, or it could be of a downed high voltage line.

-arcing

All matter consists of ___ and ___ that are in constant motion. They can transport ___ from one point to another. The conduction of heat is most efficient and most evident in ___ materials, though it can occur in a ___ or a ____ environment also. Therefore, conduction is often defined as... Heat always moves from an area of __ temperature to an area of ___ temperature

-atoms and molecules -heat -Solid materials, though it can occur in gaseous or a liquid environment also. -the transfer of heat through a solid medium -high to low temperature

Fire point and flash point refer to temperatures where combustible gases are.... This presents a potentially hazardous situation. However, we don't have a fire yet. For a fire to actually start, ____ must take place. This occurs when the substance "catches on fire".

-beginning to escape from a substance. -Ignition

A fire point will have continuous fire; it will not go out by itself. This is because the flammable vapors are being produced faster, at a rate sufficient to support _______. The fire point of a substance is usually ____ than its flash point.

-continuous combustion -just a few degrees higher

The third technique of fire extinguishment with the removal of heat is called ___. If the heat can be removed, or at least absorbed by some means faster than the rate of heat produced by the fire, the fire will go out. The best extinguishing agent available to fire departments to do this is ___.

-cooling -water

There is another form of oxidation called ___. This is when oxygen combines with fuel so slowly that the heat and light are not noticeable. The rusting of an old nail or the tarnishing of a piece of silvery jewelry are examples.

-slow oxidation

Class C fire is one that involves ____. Very special importance must be given to the ___ of the extinguishing agent. Only when the ___ have been de-energized may Class A and Class B extinguishing agents be used. Extinguishing agents suitable for Class C fires include ___, ___, and ___

-energized electrical equipment. -electrical nonconductivity -electrical circuits -Carbon dioxide, Dry Chemical, and Halon types

If the liquid is is in a closed container, the escaping molecules are trapped in the air space above the liquid. Some molecules will strike the surface of the liquid and re-enter the liquid. Eventually a point of ___ is reached where the number of molecules leaving the liquid equals the number of molecules returning to the liquid. The pressure exerted by the escaping vapor at the point of equilibrium is called the ___

-equilibrium -Vapor Pressure

Convection heat sets up convection currents. The liquid or gas heats up and begins to move, setting up a moving current of liquid or gas. Thus, the heat migrates by the movement of the liquid or gas. Heated air then ____ and ____. For this reason convection currents are generally upward or downward?

-expands and rises. -Upward

One of the objectives of a firefighter when using water as a cooling agent is to cool burning material to below its ____ or ____. If this is done, the fire goes out and cannot reignite. This is a very important principle of the theory of ____ and works best on solid materials.

-fire point or flash point -extinguishment

Application of the technique of smothering is very tricky and relatively uncommon. At the proper time and place, however, it can be effective. In a very large fire, such as an on-board ship fire below deck, ___ and ___ are locked down and sealed. The goal is to... On smaller scale fires, such as a trash can on fire, particular types of fire extinguishers function on this same principle. When using a ___ extinguisher, it's actually replacing the oxygen around the fire because it has a vapor density ___ than oxygen.

-hatches and bulkheads -isolate and eventually smother the fire -CO2 -greater

Water's key feature is its amazing ability to absorb ___. This is due to the "___" of water. In fact, it has one of highest known.

-heat -"specific heat"

The second way to test ignition temperature of a substance is to take a small portion of the substance and....

-heat it to a point where it ignites by itself. This is auto-ignition temperature.

The specific heat of a substance is its ability to absorb ___ per ___ volume.

-heat per unit volume

The third side of the fire triangle is heat, and it too must meet some special requirements. The most important is that the source of heat must be "hot enough" to ignite the fuel; that is, the fuel vapors must be heated to their ___. We only need ___ degrees F to ignite carbon disulfide. Gasoline requires ___ degrees F, and acetone needs 1,000 degrees F. Magnesium metal needs ___ degrees F heat before it will ignite.

-ignition temperature -212 -Gasoline requires 850 degrees F, and acetone needs 1,000 degrees F. -Magnesium metal needs 1,200 degrees F heat before it will ignite.

Class B fires include all flammable and combustible ___, ___, ___, and ___. One way to recognize a Class B fuel is by the ___. No Class B fuel retains its own ___. They must be in a strong rigid ____. Extinguishing agents for Class B type fires include ___, ___, ___, and ___.

-liquids, greases, oils, and gases -container -shape -container -Carbon Dioxide, Dry Chemical, Foam, and Halon types

These extinguishing agents are very specialized and are to be used only on ____. The theory of extinguishment is a combination of ___ elimination with some ___. One special class D extinguisher is called ___. It is composed of ____ and a ___. When applied to a metal fire, the (first term) melts and conducts away some of the heat production. The (Second term) melts and burns. It holds the (first term) together for efficient ___ and ___.

-metal fires -oxygen elimination with some cooling -Met-L-X; composed of sodium chloride and a powered plastic material. -cooling and smothering

Not all materials have the same heat conductivity. The best conductors of heat are ___, just as they are the best conductors of ___. In fact, there is a correlation between the two. The better a ___ conducts ___, the better it will conduct ___.

-metal; electricity -metal conducts electricity, the better it will conduct heat

Examples of heat energy would include any ___. Conveyer belts generate a lot of heat. Metal parts rubbing together or, for that matter, any two surfaces rubbing together will produce heat. Another example of mechanical heat energy is the heat of ___. When gases are ___, as in a gas cyliner, great amounts of heat are generated. Heat of ___ is yet another example of mechanical heat energy. This is the heating of a surface through repeated hammering.

-moving part -Compression; compressed -percussion

Whenever oxygen combines with molecules of a fuel, the fuel is said to be ___. A burning match is an example of ____.

-oxidized -Rapid oxidation

Fire is the rapid combustion of ___ and ___ in a chemical reaction which liberates large amounts of heat and light which is visible as a flame. Flames are a complicated phenomenon. They vary widely in their heat and light production. This is also called ____

-oxygen and fuel -rapid oxidation

The extinguishing property of carbon dioxide is ____. It is ___ times as dense as air, so it will have a tendency to sink down toward the base of flames. It can be very effective on ____. However, carbon dioxide is very poor on ____ because it lacks the cooling ability. The carbon dioxide gas can dissipate rather quickly, giving no permanent protection against ____. It is considered a quick and temporary extinguishing agent. CO2 extinguishers are contained in steel cylinders of ___ psi

-oxygen exclusion -1-1/2 -contained flammable liquid fires -combustible solid materials -ignition sources -850

It is possible in some instances to increase the rate of combustion or burning. More air or even ___ can be applied to the fuel. Drafts can be set up with blowers. The higher the percent oxygen, the faster the fuel will ignite and burn. For example, ___ use pure 100 percent oxygen in order to generate flame temperatures hot enough to cut metal.

-pure oxygen -cutting torches

The most popular dry chemical for many years was ___. "___" and "___" were developed in the early 1950's and had better extinguishing capabilities than (the first fill in word). All these agents were rated for __ and __ class fires. In 1960 the Germans developed a dry chemical suitable for all three common fire classifications, __, __, & __. It is called ___. The principle behind dry chemical extinguishment is direct interruption of a fire's chemical chain reaction. Contrary to popular belief, these extinguishers do not cool and have little effect on excluding the ___. The one main drawback of these extinguishers is...

-sodium bicarbonate -Purple K and Super K -B and C class fires -Class A B and C, It is called monoammonium phosphate -oxygen -the limited range the powder can be projected from the extinguisher nozzle.

The speed with which a fuel ignites and burns depends on the available ___. The more exposed, the easier the ignition and the faster the fire burns. Most combustible dusts such as ___, ___, and ___ can be made to burn or explode at a rate faster than TNT, even though they are a solid material. This is because of the enormous _____ exposed to the heat and available oxygen. This same rule also applies to ____. Consider the exposed surface of a bucket of gasoline as compared to the fuel being spilled out of the bucket and spread over several dozen square feet. With its much greater surface area, the spill can burn with tremendous speed.

-surface area -saw dust, corn starch, and metal dust -surface area -liquid fuels

Extinguishment through cooling is dependent upon variable fire ground factors. It must always be remembered that the best and fastest cooling is done when water is directed to the hottest part of the fire, that is, the ___ or the ____ of the fire.

-the embers or the "seat" of the fire

Removing the fuel from a fire or eliminating the continuous feeding of fuel to a fire can be effective. The objective here is to halt... Although the fire may continue to burn for awhile, when the remaining fuel is consumed, the fire will starve and eventually go out. For example, considered a fire in your fireplace. When you no longer want it to burn, you... Soon it will burn down and go out.

-the spread of the fire. -stop feeding it.

What is the vapor density of Hydrogen? What it rise or sink?

0.07, and it would rise very rapidly.

All examples of producing energy can be grouped into one of these 4 categories:

1. Chemical Heat Energy 2. Mechanical Heat Energy 3. Electrical Heat Energy 4. Nuclear Heat Energy

When heat is transferred from point to point, it does so without change. The three basic methods by which heat is transferred are:

1. Conduction 2. Convection 3. Radiation

The last source of heat generation is "nuclear heat energy". There are only two types:

1. Fission, which is energy produced by splitting an atom. This was done with our first atomic bombs. 2. Fusion, which is energy produced by combining two atoms to make one new atom. This is the energy produced by the sun and by the hydrogen bombs.

The fire triangle is a simple graphic representation of the components necessary to have fire. These components are:

1. Fuel 2. Oxygen 3. Heat

There are really only five sources of ignition. If you are an arson or fire investigator, knowing this makes your job of determining fire causes easier. The 5 sources of ignition are:

1. Mechanical 2. Chemical 3. Electrical 4. Nuclear 5. "contact with hot object or open flame".

Auto-ignition temperature is defined as:

A temperature a substance must be heated to in order to cause self-ignition.

The definition of explosive range is:

A mixture of flammable vapors and air, expressed as a percent, above or below which no ignition can occur.

Known as ATFF and as "light water". This is a very popular, completely synthetic foaming agent. This foam is capable of forming a unique water solution film on the surface of the flammable liquid. This is important because almost all flammable liquids will ___ on water. The foam that is produced is not as ___ as protein foam. It has less strength with fair heat resistance. What makes AFFF so unique is that a special kind of draining from the foam takes place. Bubble and liquid retention is ___. A light-water/water mixture slides over the surface of the flammable liquid. This action seals the surface from ___ and ____. Aqueous film forming foams are available ___ and ___ concentrates. They can be used with fresh or salt water through ____

Aqueous Film Forming Foam -float -dense -low -oxygen and sources of ignition. 3% and 6% film concentrates. -special nozzles

A chemical process in which a substance combines with oxygen to produce heat and light (oxidation)

Combustion

A colorless, clear liquid, very highly flammable, has a disagreeable odor of rotten cabbage

Carbon Disulfide

A product of incomplete combustion; a colorless, odorless, tastelass gas; very flammable and poisonous. Chemical formula: CO

Carbon Monoxide

What class of fire is the most common?

Class A

For many years the fire community acknowledge only three fire classifications. In 1960 the classifications were reorganized to show four fire classifications:

Class A Fires - Ordinary Combustibles Class B Fires - Flammable liquids, gases Class C Fires - Electrical Class D Fires - Combustible Metals

___ are very rapid oxidation reactions

Explosions

There are two schools of thought regarding the description of fire extinguishment. One is based on the explanation and understanding of the ___. and the other is based upon a relatively new concept, the ___.

Fire Triangle; Fire Tetrahedron

Physical Characteristics of Gasoline

Flash Point: -45 Degrees F Fire Point: -43 Degrees F Ignition Temperature: 850 Explosive Range: 1.4% - 7.6 % Vapor Density 3.00 Specific Gravity 0.75

Physical Characteristics of Acetone

Flash Point: 0 degrees F Fire Point: 2 degrees F Ignition Temperature: 1000 degrees F Explosive Range: 2.6% to 12.8% Vapor Density: 2.00 Specific Gravity: 0.79

Physical Characteristics of Kerosene

Flash Point: 100 degrees F Fire Point: 102 Degrees F Ignition Temperature: 400 degrees F Explosive Range: 0.7% to 5.0% Vapor Density: 2.80 Specific Gravity: 0.98

Physical Characteristics of Ethanol

Flash Point: 55 degrees F Fire Point: 57 degrees F Ignition Temperature: 800 degrees F Explosive Range: 4.3% to 19.0 % Vapor Density: 1.59 Specific Gravity: 0.79

___ are very similar to protein foams. In addition to the protein, they contain a fluorinated agent. This agent gives the tiny bubbles of the foam the ability to shed ___. For example, this type of foam is used for "below surface injection". The foam then floats to the surface, sheds flammable liquid film, and covers the surface. These foams are available at __ or __ concentrates, and may be used with fresh or salt water

Fluoroprotein Foams -fuel -3 or 6%

The definitions of Auto-Ignition and ignition temperature are not really different. What both definitions are trying to say is that if vapors produced by a material are heated to or come in contact with a source of heat equal to (or greater than) the ignition temperature, the vapors ignite. (Continue reading on back)

For example, gasoline has an average ignition temperature of 850 degrees F. This means if we heat the gasoline vapors to this temperature, they will ignite automatically. Or, we can set the vapors to flame by using a match. Since the match flame is at least 850 Degrees F (the ignition temperature of gasoline), we will ignite the vapors and have fire.

Heat is energy. Energy travels from one point to another. Therefore heat can travel too, and we can measure it. Heat travel is more correctly called ___.

Heat transfer

Every material or substance exists as either gas, a liquid, or a solid. This is the physical state of the substance. A substance has certain physical characteristics or properties. These characteristics change only when the substance is subjected to some external energy force, such as... (list 3). This can result in a change in the physical state of the substance (I.e. ice melt into water). This is not a change in the ____ of the substance. Water is still water whether it is in the state of liquid or a solid.

Heat, fire, and/or pressure. -Basic Composition

This foam is generated mechanically by fans or the passage of high volumes of air with water through a net or screen.

High Expansion Foam

As temperature increases, does it increase or decrease the motion of liquid?

Increase

The basic principle of the fire tetrahedron is the same as for the fire triangle, that is, if any of the sides of the tetrahedron is removed or eliminated, then the fire will go out. This theory of fire extinguishment is demonstrated on small fires with the "dry chemical" type extinguishment agents.

Just something to read

A __ is required to estimate the flash point of a substance.

Laboratory Test

___ is electrical heat energy. This is Mother Nature's static electricity and has caused countless fires.

Lightning

What type of extinguisher is suitable for all metal fires?

Met-L-X

A number of atoms that have chemically bonded together.

Molecules

The early studies of extinguishment also used the fire triangle. it was an effort to explain in very simple ways how a fire could be put out. To put out a fire, we must remove one, two, or three elements of the fire triangle?

One

Vapor Pressure is usually measured in ____ per _____

Pounds per square inch

The fire tetrahedron adds a fourth side to the fire triangle. The discussion of a "fourth side" developed in order to adequately explain the unique extinguishing capabilities of some fire extinguishing agents. It was discovered that some extinguishing agents actually interfere with the chemical chemical chain reaction that we call fire. (continue on back)

Putting it very simple, these extinguishing agents interrupt the chemical reaction between vaporized fuel and oxygen. This interruption occurs very near to the surface of the fuel. Obviously this is not cooling. Less obvious though, it is also not smothering or starving. We call it "chain reaction interruption". The objective is to upset or destroy the development of the molecules that would otherwise combine with oxygen.

A form of energy which travels through space as an electromagnetic wave.

Radiation

___ is electrical heat energy. Although the generation and buildup of it is often done by moving parts, the discharge of this energy is electrical, not mechanical.

Static electricity

One measure of the volatility of a substance is its flash point. This flash point is defined as:

The lowest temperature at which a substance begins to release ignitable vapors sufficiently fast enough to "flash" when exposed to an outside ignition source, but does not continue to burn.

Ignition can be defined as:

The process of initiating self-sustained combustion.

The definition of specific gravity is:

The ratio of the density of a liquid or solid, as compared to the density of an equal volume of water, with water having an assigned value of 1.

Definition of Vapor Density

The ratio of the density of a vapor, as compared to the desnity of an equal volume of air, with air having an assigned value of 1.

If a vapor has a vapor density value greater than 1, the vapor is ____ and will ____

The vapor is heavy and will sink.

Most flammable liquids float on water. Knowing whether a liquid or solid will float or sink in water is an important consideration in determining proper extinguishment techniques. If water is used on a flammable liquid which will float, what can happen?

The water may actually spread the liquid and the fire rather than put the fire out.

The measure of "how heavy" the vapor is as compared to air. Some are heavy and sink rapidly. Others may be very light and rise rapidly.

Vapor Density

Another factor to consider is the general flammable nature of the fuel. Some are hard to ignite no matter how hard we try. This has to do with several characteristics. One is called ____ or the ease with which the fuel evolves to a vapor.

Volatility

___ is by far the most efficient material for absorption of heat. It is inexpensive and has the widest versatility of application methods.

Water

___ is the most available and the most frequently used substance for extinguishment.

Water

To conduct a laboratory test for flash point, the ___ and ____content of the atmosphere must be constant. The substance being tested must be _____. Beginning at ____ temperature, the substance is heated very slowly. The substance gradually begins to produce vapors. Given an external ignition source (A test flame, for example), these vapors will eventually "Flash" or burn. The temperature at which this occurs is the flash point of the substance.

_The pressure and oxygen content -Pure -Very cold

Heat energy travels in __ direction from where it is generated. It flows unimpeded through all matter that makes our world and universe. The flow of heat cannot be totally stopped by any medium in the same manner in which the flow of water can be stopped in a pipe by a valve

all

The cooling effect of water can easily quench a wood fire to below its flash or fire point. The wood cannot reignite because vapors are no longer...

being produced fast enough to ignite or burn continuously.

A value of 1 for vapor pressure means the vapor is the same weight as air, and would tend to mix with air easily. An example would be ____, a very toxic and explosive gas.

carbon monoxide

All materials that will burn do not ignite at the same temperature. The temperature at which a material will begin to burn is characteristic of that particular material. It is determined by the physical properties of the material discussed earlier and by the ____ of the substance.

chemical composition

All electricity produces heat. Whenever electricity moves over a wire or through a light filament, heat is produced. Sometimes we want this heat, as with an ___. Sometimes we do not want this type of heat, as with ____

electric stove; overloaded circuits

If a firefighter has a good understanding of a substance's vapor density, he/she may be able to predict the spread or migration of the vapors. The firefighter should think ahead and possibly remove ____ that may be in the vapor's path, which is a very important objective all firefighters should remember. Success in this may depend on the knowledge of the vapor density of a given material.

ignition sources

Large fires can spread due to radiant heat. Nearby combustible materials can be heated to their ignition temperature due to absorption of radiant heat. The best way to protect exposures from radiant heat is to...

keep them cool with a spray of water

What does psi mean?

pounds per square inch

Removal of the oxygen side of the fire triangle is called ___.

smothering.

The technique of removing the fuel is called ___.

starvation

Anything that will burn has a flash point. However, the flash point of a substance we usually call "flammable", such as gasoline, is much lower than the flash point of a substance we wouldn't call flammable, such as ___.

steel

Radiant heat travels in ____. It radiates from a point source in all directions equally. Like light, radiant heat travels from its source at the speed of light.

straight lines

The kinetic energy produced by explosions can be enormous. Flames can propagate at ____ speeds

supersonic