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Fire Pumps, Fire Apparatus, Fire and Defense Equipment

Understanding CAFS, Class A Foam Nozzle Technology

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For years the fire industry has held on to many traditional views of fire suppression techniques and sometimes it's painfully slow in embracing new ideas. " We've always done it this way", or "This has worked for years", or "We were putting out fires before you were born." Sound familiar? Sometimes affectionately referred to as " tradition ". Sadly tradition is sometimes what we do when we have forgotten the reasons we do it! With all the new technology that has revolutionized our everyday existence, wouldn't it be fair to say that the fire service should have also benefited? If we can place a man on the moon, design and utilize a "smart" bomb, it stands to reason that there are definite advances that have been made in fire suppression tools and techniques. The first thing we have to do is to objectively look at changes with an open mind. The mind and the parachute are a lot alike, they both work best when they're open.

For most of us in the fire service I believe it goes without question that the most economical, available source for fire extinguishment is water. The problem with water is that we sometimes lack enough of it at a critical stage in fire suppression. I don't know of a single line officer that at one time or another has questioned the availability of adequate water supply in the heat of the battle. For the rural fire departments and departments short on apparatus and staffing the problem only magnifies itself. What if there was a way to reduce the common concerns about water supply, staffing, etc.? If you are willing to explore ideas and techniques that reduce these concerns with an open mind, the answers may be here today.

Let's look at a "typical" fire scenario. You're a volunteer fire department with uncertain staffing during the day. You have an engine with 1000gpm/1000gal. and a pumper-tanker (1000gpm/2000gal.). It's around 10:00 a.m. and the pager alerts you to a possible structure fire 3 miles from the station with no hydranted water available and all occupants out of the building. A total of six personnel arrive at the station and responds a 4-man crew in the first out engine and a 2-man crew in the pumper-tanker. As you near the scene the fires header becomes more obvious and your call goes out for mutual aid to assist. You arrive on scene only to find that there is a narrow tree-lined lane that will not allow you to position your equipment nearer than 700 feet from the exposure. Your mind is now going a hundred miles-an -hour calculating friction loss, etc. while your suppression team, packed-up and ready stretches your first hoseline from the attack engine. Meanwhile your tanker drops your portable water tank and sets up water supply from the tanker to the engine, awaiting mutual aid companies that should begin arriving in the next 15-20 minutes. The officer-in-charge now must weigh all the options: "Is my water supply sufficient?", "Do I have enough manpower for an interior attack?", "How long can I hold on until mutual aid arrives?", "Why does this have to happen to me?"

Does any of this sound familiar? Now let's look at how this fire evolution might typically play out.

Fire Stream Application vs. Fire Suppression-You Be the Judge!


X --- † -----------------------350 gpm required flow - -

X ---- † -------250 gpm sustained attack-------------------extinguished by 250 gpm flow------ ? ---- X

Ignition Self extinguished

Figure 1

Figure 1 represents a fire evolution, which begins at ignition and then grows until it reaches its peak, then diminishes to the point where it has consumed all available fuel and extinguishes itself. Your confrontation with fire is like a boxing match, except in this match the first three-minute round is the most important. If the match goes beyond the first round your typically the loser since you can't win by a decision and there are no draws! Refer to the fire curve and imagine that upon arrival at this fire, its size requires a fire stream flow of 350 gpm to achieve suppression. If you attack with the needed 350 gpm or greater you will overcome the BTU's being generated and achieve suppression relatively quick. If you attack with only a 250 gpm flow, you'll notice some darkening and think you're doing great, but the fire still grows, to a point where it appears you're gaining. Noticing the fire receding as your attack continues you announce that the fire is under control. You continue your fight until the fire is out and you're pleased because you did another great job of putting out the fire. Have you? Did you really attack the fire, or just prolong the inevitable? Your initial flow of 250 gpm was less then the required flow for extinguishment on the incipient stage of the fire. Your long hard fight slowed the fire, yet it continued its growth until reaching its peak, then diminished to the size where your 250 gpm flow rate finally extinguished it on the backside of the fire curve.

Fighting fire on the backside of the curve is jokingly referred to in the fire service as "saving foundations." With this in mind ask yourself a few questions and be honest with the answers.

Which attack method required the most time, water, manpower, equipment and associated expenses as well as a higher risk of injury? Which offered a possibility of saving cherished belongings? Most of all, which method stands a better chance of saving lives?

Before we begin I believe it's necessary to establish some common ground regarding the basic concerns we encounter during a fire evolution. First, what determines fire suppression? According to the NFPA, proper extinguishment by cooling with water is achieved by three factors:

* The Volume of Water Available

* Rate of Application

* Type of Stream Applied

The amount of water available will determine the size of fire that can be effectively extinguished. The rate of application determines the effectiveness of applying a sufficient volume of water to overcome the BTU's being generated by the fire. The stream type will directly effect the amount of heat absorption. Two common methods of increasing a stream's heat absorption is by breaking the stream into smaller droplets or increasing the number of droplets by increasing your rate of application. For maximum effect, the water droplet must be formed near the seat of the fire, or be large enough to have sufficient energy to reach the base of the fire despite air resistance, the force of gravity, and the fire thermal column. If droplets are too small they can easily be deflected by the fire plume, or evaporated prior to reaching the seat of the fire. A water droplet stream or fog pattern used in a heavy smoke environment will improve visibility by attachment of airborne carbon particles in the smoke to the water droplets thereby removing them from the air.

Let's first take a traditional look at what systems we use today, why they work, and possible problems encountered. It is very important to understand the function of the "fire tetrahedron". The fire tetrahedron ( Figure 2 ) is a model that describes the requirements of fire as a relationship between heat, oxygen, fuel, and a chemical chain reaction. In order to have a fire situation we must have the

elements of the fire tetrahedron present in sufficient quantities to result in ignition through free-burning state. Remove one ore more elements of the tetrahedron and you will achieve extinguishment.

Fuel Supply Heat

Fuel Supply Heat

Figure 2

Now let's look at why we use water as our extinguishing agent of choice. In most areas of population it is obvious that in order to sustain life water has to be in ready supply. This is the reason water is the most economical and available source for the fire industry. Also, as tradition would have it, "we've used it for years" and it seems to do the job! Water has a unique feature that in sufficient quantities it can effectively attack three sides of the fire tetrahedron- under the right conditions . I think we can all agree that water has an inherent ability to cool. Therefore, applied in the correct volume it may be able to absorb a sufficient amount of heat generated by fire, thus aiding in reduction or extinguishment ( remember water absorbs heat at a rate of 9550 BTU/Gallon ). Also, in sufficient quantities, water may isolate the fuel source as well as separate the oxygen supply from the fire- under the right conditions. On confined , horizontal surfaces water has an advantage of pooling, therefore utilizing all of its potential in eliminating three critical legs of the fire tetrahedron (isolation of fuel, heat absorption, and separating the source of oxygen to the fire). However if any of the affected surfaces take on a vertical or unconfined nature the task becomes more complicated. According to studies done by the National Wildfire Coordinating Group and the Boise Interagency Fire Center , water in its pure form is approximately 10% effective in straight stream applications on horizontal surfaces. If we factor in gravity the rate of effectiveness further diminishes, creating the need for more water to make up the deficiency! Even on horizontal surfaces water in its pure form tends to bead-up due to "surface tension" thereby reducing its effectiveness to spread out and penetrate. (Surface tension can be defined as an elastic-like force at the surface of a liquid which tends to minimize the surface area.) All this results in is a need for more and more water to complete the task at hand. Depending on the size and logistics of the fire this may never be effectively achieved in a timely fashion. Also if we attempt to "conserve water" for any reason other than defensive purposes, once again we will have reverted to "saving a foundation". One of the most common fears facing fire ground command is running out of water! Should this fear of running out of water be the determining factor in how we attack a fire?

Imagine a large trash can on fire. You have two full buckets of water. One bucket has a lid with a small hole in it and the other bucket has an open top. You get to pick one of the buckets for your extinguishment effort. Which bucket would you chose?

If only there was a way to make water do more, go farther, penetrate better, require less manpower to apply, or just work better. The fact is we can and we will discuss how. Even with its shortcomings the consensus is that water is the extinguishing agent of choice, so let's turn our attention to improving the quality of water itself.

One of the most exciting additions to come on the fire scene in recent years was the advent of "Class A Foam". Water still puts out the fire, Class A Foam enhances waters abilities as an extinguishing agent! While there are many people in the fire service that are familiar with "foam", it is generally a "Class B" or commonly referred to AFFF foam . This type of foam is more prevalent in industry&commonly used for flammable liquid fires, etc. which cannot be effectively extinguished with plain water. Again, we could dedicate an entire article discussing what type of foam, brand, etc. is best suited for the fire service. Specifically for the purpose of this report we will be studying low expansion Class A Foam.

Class A Foam has been around since the early to mid 1980's primarily used by the forestry service and was commonly referred to as "wildland foam." As forestry fire suppression teams encountered more structure fires in the wildland/urban interface it became apparent that Class A foam was applicable to structural fire suppression as well. What is it about Class A Foam that makes it so attractive? In the case of a Class "A" fire the foam solution:

1: Cools the burning surface.

2: Breaks water surface tension to permit deeper penetration.

3: Leaves a blanket that continues to release water.

4: Insulates and prevents reignition.

Class A Foam is a foam solution made from hydrocarbon-based " surfactants " therefore possessing excellent wetting properties . A surfactant is an abbreviation for Surface Active Agent Chemical that reduces the surface tension of water. If we reduce the surface tension of water by 60%, the wetting action can increase by 1,000 times! Surfactants are attracted to carbon (a byproduct of most fires) allowing water to hold onto carbon based materials. An example of a common surfactant is Hydrocarbon Surfactant also called "detergent". Essentially wetting agents that reduce the surface tension of water and allow it to soak into combustible materials easier than water . This simply demonstrates that Class A Foams possess the ability to penetrate deeply seated fires more effectively with less water resulting in quicker extinguishment and less collateral damage than plain water! Studies have also shown that Class A Foam is 3 times more effective in absorbing heat than water alone! This reduction in required water volume has another benefit in reducing risk of structural collapse to firefighters. Water applied at a rate of 250 gpm adds 1 ton/ minute of additional weight to the structure. Is it starting to make sense? We are taking our existing resource, water and making it a safer, more effective, and longer lasting extinguishing agent!

Why isn't Class A foam used more in the suppression of structural fires? Is it a cost factor? With retail costs ranging from $10-15/gallon this may be a contributing factor to departments with limited budgets. But is it a justifiable reason when utilization of such measures may actually save time, manpower, limit damage, etc.? Furthermore with the advent of the new proportioning systems and CAFS the application ratio can be as low as .1% and commonly applied at .3% ! Perhaps it's lack of education and knowledge relating to the use of Class A foam that prevents its being used more. To further understand the true value of Class A Foam a working knowledge of foam(s) in general is needed. It is important to understand the terminology of foam in its various references. Please refer to the following terms:

FOAM CONCENTRATE - The undiluted foaming agent as received from the manufacturer and which when diluted with water becomes foam solution. There are generally three types of foam concentrates available. LOW EXPANSION FOAM----------------------------- Expansion ratio of 1:1-------21:1

MEDIUM EXPANSION FOAM ----------------------Expansion ratio of 21:1-----200:1

HIGH EXPANSION FOAM---------------------------- Expansion ratio of 200:1---1,200:1

FOAM SOLUTION - A homogenous mixture of water and foam concentrate to which air is added to produce foam. Also one of five foam types : foam solution has no real bubble structure but some bubbles may occur due to agitation and impact.

FOAM TYPE - A combined measure of draintime and expansion used to describe the consistency, durability, viscosity, and density of low expansion foam. There are five basic types of finished foam ranging from wet to dry: foam solution, wet foam, fluid foam, dripping foam, and dry foam.

FOAM DENSITY - The amount of water in the foam expressed as the ratio of foam solution to the volume of foam produced.

FOAM DURABILITY - The effective lifespan of a foam.

FOAM VISCOSITY - The ability of foam to spread or cling.

WET FOAM- One of the five foam types whose bubbles are spherical masses of air enclosed in a solution. The bubble walls are separated by a large amount of solution, relative to the other types of foams. Wet foams have very fast drainage rates or draintime and minimal expansion of less than 5:1.

FLUID FOAM - A wet milky foam characterized by rapid draintime and expansion near 5:1.

DRIPPING FOAM - A smooth creamy foam having a moderate draintime and expansion ratio near 10:1.

DRY FOAM - A thick, dry foam whose bubbles are polyhedral in shape. The bubble walls are very thin with only small amounts of solution between the bubbles. These types of foam have very slow drainage rates or draintime with an expansion ratio near 15:1.

EXPANSION - The amount of air in the foam expressed as the ratio of the volume of foam to the original volume of foam solution.

DRAINTIME- The rate at which the foam solution is released by the bubble structure of the foam. Often referred to as "quarter drain time" or the time required in minutes for 25% of the total foam solution to drain from the aspirated foam. Basically it is a measure of the foam stability.

MIX RATIO- The ratio of foam concentrate to water, expressed in a percent. i.e.: .1%, 3%, etc.

Now that we have a basic working knowledge of the terminology associated with the use of foam agents, let's look at methods of application.

In the early days of firefighting water was applied from nothing more than buckets! As we progressed through the decades we improved our delivery system from horse drawn hand-pumps, to steam and chemically powered pumpers, to our modern day engine-driven centrifugal pumps. There were also vast improvements in fire hose and their ability to improve the delivery of water to the fire. Some of the most innovative and progressive developments have been in the terminal end of the delivery system--the nozzle. We have learned over the years as fire suppression and fire behavior became a "science" reasons why water works in extinguishing fires. The "traditional" method of application was done with a stream shaper or straight bore nozzle. This allowed firefighters greater stream reach and a heavier concentration of water at the seat of the fire. One distinct advantage of a straight bore nozzle is that it requires less nozzle pressure (usually 50 psi) to deliver an effective fire stream. This results in less fatigue for the hoseline crew and reduced workload on the pumping device. Through the course of trial and error we have found that by exposing more " water droplets" to the seat of the fire we increase the effect of suppression. A larger number of droplets expose more surface area of water thus creating an opportunity for greater heat absorption. Because of the effect of surface tension has on water applied in a traditional fire stream or straight stream, the ability in creating droplets is diminished. Therefore the fire service needed to resort to mechanical means to alter the shape of the water stream. One such method came about with the development of the fog and/or combination nozzle. The advantage to this type of nozzle is it allows the fire stream to be broken up into several smaller droplets, exposing more of the waters surface area. By exposing a larger surface area this will aid in rapid cooling or what we sometimes refer to as "conversion". While conversion in itself may aid in the reduction of fire spread it also poses a potential danger. Victims of entrapment or the firefighters themselves may be subjected to thermal burns caused by the environment suddenly being turned into a giant "steam bath".

Generally speaking this type of nozzle is commonly operated at 100 PSI nozzle pressure which often requires additional manpower. Any reduction in nozzle pressure adversely affects the application rate. Another disadvantage is that by breaking up the stream there is a shorter reach. Also in larger fires the thermal column absorbs a greater amount of the "fog or water curtain" prior to getting at the seat of the fire. The advantage of a combination or automatic nozzle is that you can achieve both types of fire streams as long as the nozzle is used according to manufacturers specifications! It is important to note that the combination nozzle is a mechanical device containing moving parts which must be monitored and serviced on a regular basis. One note of concern is that there are currently no performance tests required for nozzles. Unless you do your own independent testing and evaluation of your nozzles, you are at the mercy of the manufacturer. It is imperative to test your terminal gear with calibrated flow meters, pitot gauge and inline pressure gauges to see if your really getting the volume of flow as stated! As you can see there are pro's and cons to both types of common nozzles. The debate for which nozzle type is best could go on forever. Wouldn't it be great if we could take all the good characteristics of the various nozzles and apply it towards one delivery system? Or perhaps there might be some type of delivery system that would assist our present arsenal of nozzles in obtaining a more efficient application.

There are basically two methods of delivering Class A Foam, the High Energy System and the Low Energy System. The Low Energy System is a foam generation system that uses a single power source, such as a water pump, to create and propel foam. The foam can be pre-mixed in the tank or a device called an eductor (pre-connected or in-line) may be used to create a foam solution mix for final delivery. A critical factor in proper application is achieving the proper mix ratio for maximum application efficiency of the foam. This is normally done by some type of automatic or regulated proportioner . This is nothing more than a controlled device that maintains a desired mix ratio of foam concentrate to water over a range of water flows. In most low pressure systems the Class A foam is proportioned at a rate ranging from 1% through 6% to produce the finished foam product.

One common method of applying Class A foam is the combination or fog nozzle. Its application is limited due to the fact that this type of foam is more effective if there is air introduced into the foam prior to exiting the nozzle. Therefore the more common approach under a low energy system is the use of the air aspirated nozzle also referred to as N ozzle A spirated F oam S ystem or NAFS. This is an inexpensive and somewhat effective method of maximizing the properties of this type of low expansion foam. There are several air-aspirating nozzles on the market today claiming all types of expansion ratios, etc. I must caution you that the nozzle type alone will not determine the final application rate. Remember that this type of foam has varying expansion rates and concentration levels and must be thoroughly researched to determine which manufacturer can supply you with the proper foam for your equipment! I personally have tested a number of nozzles by a host of manufacturers with varying levels of success and disappointment. (However one nozzle in particular has proven to be very effective with minimal maintenance and training. This nozzle is called The Vindicator by First Strike Technologies, Inc. I was highly impressed with the foam production, stream reach, and water droplet formation in both low and high energy systems.) While the Low Energy Delivery system has a definite place in the fire service, it is somewhat limited to making only the "wetter" types of foam. In order to generate the full spectrum of foam type applications, let's take a look at what some feel is the ultimate weapon for structural firefighting, CAFS.

CAFS is an acronym which means C ompressed A ir F oam S ystem. CAFS has been around for decades with one of its pioneers being the Texas Forestry Department in 1978. A CAFS unit is capable of delivering water, water and foam solution, or water, foam solution,&compressed air. CAFS is a high energy delivery system because its foam generation uses a combination of power sources, such as a water pump and an air compressor to create and propel foam. In a typical CAFS unit employing a balanced system the foam solution is normally proportioned at a ratio ranging from .1% to .5% with .3% being the standard baseline for application. If you recall in a low energy system the amount of foam used is nearly 10 times as great ( from 1% through 6%)! In a balanced system the final output will be a ratio of one cubic foot per minute (CFM) of air for each gallon per minute (GPM) of water discharged. The operation of a balanced system CAFS is further simplified with the use of flowmeters on discharges utilizing CAFS. This eliminates the need for calculating friction loss (which is basically a non-factor in CAFS) and gives the apparatus engineer a clear understanding of nozzle application vs. available water supply. When the CAFS is fully initiated the hoseline actually becomes a vital link in the production of the final discharged product through the agitation process of foam, air, and water in the hoseline, referred to as scrubbing. This process of scrubbing along with the mix ratio of foam solution and air will ultimately determine the bubble structure. The greater the ratio of water&foam solution vs. air the "wetter" the foam will be due to the foam bubble being more spherical in shape. This type of application is needed to reach deeply seated fires with the additional penetration that a high energized foam system can create. By reducing the water&foam solution in relation to the volume of air, the foam takes on a "dryer" characteristic, even to the point of shaving cream consistency due to the bubble structure now being more polyhedral in shape. Also, the drier the foam consistency is the drain time is extended providing excellent prolonged wetting characteristics which aid in reducing the chances of rekindle. In looking back at the fire tetrahedron you can see that this system can do all of the following:

1. Absorb heat more readily ( At least 3 times more efficiently than plain water)

2. Remove the fuel source from the fire by sealing off vapors. (Bubble structure)

3. Remove the oxygen by utilizing the blanketing feature of generated foam. ( Bubble structure)

4. Greater insulation value due to the foams consistency and reflective qualities. ( At least 2 times more effectively than water )

There are a number of benefits realized by using a CAFS system on the fire ground. Friction loss is virtually eliminated due to the process of foam generation in the high energy delivery CAFS! Remember we are forcing foam, which is primarily air and water bubbles, down the hose at a constant balanced velocity. The net result is that the pressure equalizes throughout the entire hoseline allowing for nozzle pressures that are nearly equal to pump discharge pressures in typical fire hoselines! Because this is an energized system a longer, effective stream reach is attained while at the same time achieving a definite reduction in hose weight! This also results in less fatigue for hoseline crews and the pump itself can be operated at lower pressures thereby reducing wear and tear on the apparatus. In addition the balanced CAFS system can regulate the ratio of air to water to provide application of the various foam types, from very wet, to "shaving cream" consistency. This allows for a full range of firefighting tactics and maximum utilization of Class A foams capabilities. While it is possible to use a combination or automatic nozzle with CAFS, studies have shown that the most effective means of application is through a straight bore nozzle. Any restriction encountered tends to break up the bubble structure thereby reducing the effectiveness of the application, especially in the "drier" spectrum. Once again because a smooth bore nozzle is generally operated at a much reduced nozzle pressure there is less work load on engine and crew! Have you seen any advantages so far that might be of positive value?

CAFS has revolutionized the effectiveness of Class A foam. No longer is Class A foam just for the forestry service. We see CAFS-applied Class A foam being used in extinguishment and containment of small flammable liquid fires with studies being done in utilizing CAFS as an alternative to halon systems, etc. CAFS is also currently being used in mining operations due to its various application methods and rapid extinguishment capabilities. One of the more interesting tests of a CAFS system is the challenge of effectively controlling and extinguishment of burning tires. Fire evolution's utilizing CAFS in a two part approach have shown this system to be highly effective in extinguishing and containing the spread of tire fires. The initial application is made with a wet foam in order to penetrate and cool the burning pile(recall Class A adheres to carbon which is a byproduct of tire fires). Once cooled the CAFS system reverts to a drier, blanket-type of foam to smother and contain the fire while continuing to wet and cool because of the increased draintime. As you can see CAFS has taken a quantum leap in its application with many more challenges on the horizon.

Let's return to our fire evolution in Figure 1 and apply the same type of response, only this time you have a CAFS unit in your lead engine. What problems were encountered with the "traditional" approach that may have been overcome with CAFS?

1) Manpower - Having a CAFS system is like "gaining an extra man." Since there is nearly a one-third reduction in hoseline weight there is an increase in mobility, therefore possibly eliminating a need to commit an extra man or two to manhandle hoselines. Also because of lower reaction force at the nozzle this may allow fewer people needed to operate a high flow hand line! Your firefighters can fight the fire instead of fighting the hose!

2) Water Supply- Without a doubt a sufficient volume of water is the key element to extinguishment and the major source of concern to fireground operations. If you have read the previous material carefully it should be evident that by utilizing all of the elements of the CAFS system you are able to make your existing water supply last longer, penetrate better, absorb more heat, avoid rekindles, reduce structural fatigue, and be delivered to the fire with less effort! You're in a position to mount a more aggressive initial attack with less emphasis on the fear of conserving water!

How does CAFS improve my water supply?

In a typical CAFS system the proportioner is usually set at a .3% mix ratio. In simple terms this means for every 1,000 gallons of water used there will be 3 gallons of foam used. The typical application rate from an 1 3/4 " handline is 6o-80 gpm (water ) which will generate between 3-5 times that volume in foam production. This allows a tremendous amount of knockdown potential-and this is from one single handline being operated at 50-60 psi at the nozzle! To duplicate that flow you would have to pump between 180-400 gpm of water ( and at what psi? ) and unless your using a 2 1/2 " handline with additional manpower, it will be very difficult to duplicate these flow rates. As stated previously " Water still puts out the fire -Class A foam used in conjunction with a CAFS system and new nozzle technology will improve the extinguishing qualities of the water you're currently using!"

3) Friction Loss - In typical handline operations as we get further from the fire or additional hose is required to progress up in elevation, a smaller diameter handline is often not an option due to the friction loss created. In order to obtain large volume flow often times the only option is to use larger diameter hand lines. This may require more manpower and greater effort to manipulate on the fire scene. We sometimes place our people and apparatus in grave danger by trying to get as near to the fire as possible in order to avoid long hoselays or relay pumping. As described previously the CAFS unique delivery system virtually eliminates one of the firegrounds most common foes, friction loss.

4) Stream Reach - Due to the nature of the high energy delivery system the actual "reaching" distance of the fire stream can be enhanced in the "wetter" foams. It is imperative to have a good "footprint" (area of greatest concentration of water droplets) at the seat of the fire. You must recall there are a number of impediments to stream flow such as wind velocity, gravity, thermal column, and the fire plume itself. Keep in mind a good deal of stream reach is also dependent on nozzle type and size of water droplets in the firestream itself. It is a proven fact that a straight stream or open bore has the greater stream length and concentrated application. The two best performing nozzles for a typical CAFS application are the traditional straight bore with a minimum 1 3/8 " ball-valve opening or the Vindicator nozzle. The Vindicator is a hybrid straight bore nozzle that uses an air aspirating feature to form large droplets and increased stream reach without the addition of any moving parts. Because these types of nozzles are generally operated at a lower nozzle pressure there is a benefit of less fatigue to the hose crew and apparatus.

So why don't more departments use CAFS? I have polled a number of departments in my surrounding area and received a number of different replies. Most said they know very little or nothing about CAFS. A few have stated that they weren't sure if it was worth the extra money. There is a definite added cost to have a fully balanced CAFS added to an apparatus. Strictly referring to a typical structural fire fighting apparatus the cost can range from $20,000-$40,000 and up dependent on the type and size of proportioner , method of employment (PTO driven, etc.), and complexity&number of flow meters&discharges supplied. In the case of our department we opted for our 3 crosslays as well as the deck gun to operate with CAFS. This added approximately $25,000 to the base cost of the truck. Being a small volunteer fire department this was a serious commitment of limited funds. However, this was a commitment based on study, hands-on testing, and regard for the future. When you talk about having a new piece of apparatus for 15 or 20 years the additional cost is more than justified. The addition of CAFS has propelled this department into the future of firefighting. As a fireground officer I now have many more options than I had previously. I have been present at and involved in too many fire scenarios like the one in this text, which oftentimes led to less than envious results. No longer will I be swayed by decisions to "conserve water" based on fear of running out and coming under public ridicule. Perhaps the initial cost of going to a CAFS system is appears prohibitive, but the benefit gained far outweighs the cost. It is difficult to attach a cost to a system that allows a way to reduce fatigue on the firefighter, gain greater mobility, lower engine pressures, lessen the wear&tear on the engine, reduce fuel costs, lessen extinguishment time, conserve water, limit collateral damage, reduce clean-up costs, reduce the possibility of structural collapse, prevent rekindles, and at the same time promote a better public image. It's not new, it's CAFS, and it's available now!

In closing I would like to paraphrase a simple statement which remains as true to the fire service today as it has for years, and is one of the few " timeless traditions" to which I still subscribe.

" There is no way to effectively calculate the rate at which a fire may grow. Never forget that if you put more water on the fire faster, you will get extinguishment sooner! Guaranteed! "

What prevents you from doing the same?

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