NEW PUMPER DESIGN: FULL-SIZE AND COMPACT

BY JIM WILKINS

The fire service is an industry steepED in tradition, but from time to time it becomes prudent to stop and take a look at the progress of apparatus design needs, especially when considering the fast pace at which technological advancements become available in the marketplace.

The general theory of marketing teaches us that if someone goes out and finds a need and designs and builds a product that meets that need, he should be successful in the marketplace. However, when products are sold under a bid system process where written bid specifications are used in the purchase, there is frequently a collision between theory and reality. The common paradox is that you can write a bid specification only to purchase something that someone, and preferably more than one manufacturer, currently makes or is willing to make. If you don’t follow the system, you either won’t receive any bids or the bids received will not meet the requirements as set in your bid specification. Because of the written bid specification process, it frequently takes manufacturers a longer time to recognize when changes occur in the market and when a new need exists.

SOME HISTORY
For a considerable number of years, the maximum width law in states around the country for fire apparatus was 96 inches (8 feet or 244 cm). A few years ago, state laws began to change, increasing the maximum allowable width to 102 inches (8 feet 6 inches or 259 cm). On the one hand, more allowable space appears very appealing to fire agencies and departments since it can almost always be used. But, as many departments have now learned, increased width also creates or presents undesirable operating problems.

TODAY’S PROBLEMS
Increased width all too frequently exacerbates problems such as increased rear axle loading to the point of overloading. Maybe it’s time to expect the service brake system to perform like the stopping system it’s designed to be instead of as a slowing type of device. No matter where you are, many of you commonly experience serious service brake stopping problems in the form of severe brake fade. Increased width also frequently creates handling and maneuverability problems in many operating areas. To further compound this, pumper apparatus have also grown longer over the years; this frequently results in longer wheelbase length, which creates additional axle weight loading, braking, handling, and maneuverability problems.


“Inovative, three-axle compact apparatus.”

What good does the additional $20,000 (or more) spent for a mighty 500 horsepower (373 kw) engine do if your pumper is just inches too wide to squeeze through the traffic ahead or is too wide to make it past a car parked in a narrow alleyway? To keep housing prices down, many new homes today are built in subdivisions with narrower streets and smaller size cul-de-sacs so that more homes can be squeezed into a tract. Therefore, the pumpers of today frequently lose maneuverability, which results in a loss of precious response time because of the driver’s being forced to stop, back up, and then go forward again to successfully get through these tight areas. So much for the “advantage” of high (and expensive) horsepower engines to decrease response time. It’s a pretty simple and straightforward proposition that before a fire can be extinguished, the apparatus must first arrive at the fire.

Maybe it’s time to stand back and take a hard look at what’s wrong with this picture in many common applications of today. Is it possible to build an improved pumper that solves current handling, maneuverability, and braking problems? Is there now an opportunity to solve other serious operating problems? Let’s ask the big question, What would you like to have in a new pumper if you could really have your cake and eat it too?

NEW PRODUCT
How about a new pumper that has a total overall truck cab and apparatus body width (including over the mirrors) of only 108 inches (9 feet 0 inches or 274.3 cm) maximum? Instead of requiring 12-foot-wide (144.0 inches or 365.75 cm) fire station doors, this width allows for a narrower 10-foot-wide (120.0 inches or 313.0 cm) door clearance. Excluding the mirrors, the overall truck cab and apparatus body width would be 88 inches (7 feet 4 inches or 223.5 cm). How about a pumper with a very short 162-inch (411.5 cm) wheelbase and a front axle with a minimum 507 real turn angle that would provide the handling and maneuverability of a sports car? These characteristics would also reduce the wall-to-wall turning radius to less than 23 feet (701 cm). Excessive apparatus height can also be a problem. How about a maximum truck cab roof height of 93.5 inches (7 feet 9.5 inches or 237.5 cm) minus the cab roof lights and a maximum apparatus body height of 96 inches (8 feet or 244 cm) minus any lighting? Instead of a 12-foot-high (144.0 inches or 365.75 cm) fire station door clearance, this width requires only a 10-foot-high (120.0 inches or 313.0 cm) door clearance.


“Inovative, three-axle compact apparatus.”

A pumper of reduced height and width also reduces horsepower needs in terms of meeting vital wind resistance and aerodynamic requirements. Engine horsepower requirements remain about the same up to a speed of 30 mph (48 km/h). Above that speed, the vehicle of reduced height and width will begin to require considerably less horsepower, particularly when operating at speeds of 40 to 60 mph (64 to 96 km/h) and higher because of the overall reduced frontal area and resulting drag coefficient.

INCREASED PAYLOAD RATINGS
How about a pumper of all new design that also provides an increased payload capacity of about 3,500 pounds (1,588 kg)? This would include a slightly increased gross vehicle weight rating (GVWR) and a 1,200 pound (544 kg) or greater reduction in power train weight. Who can’t use increased payload capacity? And, greatly improved performance from the service brake system is invaluable.

In both the truck cab construction and apparatus body construction, it’s time to seriously attempt to reduce and/or totally eliminate the high costs of repairing corrosion and rust perforation problems. This source of downtime can be managed today with the use of advanced technological materials. Speaking of downtime, we want a highly dependable, reliable, low-maintenance pumper designed to provide a minimum 98 percent uptime availability value over a 25-year service life period.


Darley “PolyBilt” fire apparatus body.

The suspension system manufacturer should design and approve the front and rear suspensions for the increased severity of combination on/off highway and on/off road applications. How about a real design innovation in the form of a state-of-the-art suspension system designed to provide the premium ride quality of a fine bus? When the frequent problems of angle of approach, ground clearance, and angle of departure occur, what if the suspension system had the exceptional design capability to raise the chassis six inches (15 cm) when required, while on the go? This feature would include raising the chassis frame rails, truck cab and apparatus body, fire pump, and entire power train with the exception of the axles. With this feature, the suspension should also be capable of perfectly leveling the chassis, if required, when operating on relatively flat ground.

Today, the sizes of some of the engine covers in truck cabs have gone from the size of a doghouse to that of a room in your home. Let’s shrink the engine cover back down to a more comfortable, compact size.

Many pumpers around the country, from those operating in city traffic to those operating in off-road conditions, could handle and maneuver better with a sharply reduced turning radius and apparatus width. However, until now the design tradeoff has been that a narrower vehicle meant a reduced amount of equipment and gear that users either can’t or are unwilling to do without. That’s not an acceptable design standard; you need the compartment space.

In keeping with the goal of a new pumper’s using advanced technology design, it should also include as standard a highly efficient and effective compressed air foam system (CAFS). This system would use only a minimal amount of foam concentrate for better penetration into the fuels, reducing water and smoke damage. A highly effective CAFS can also sharply reduce the number of fire rekindles.

In brief, we want the new full-size compact pumper to provide design innovation in the form of better handling, maneuverability, and ride quality along with an increased overall payload capacity of approximately 3,500 pounds (1,588 kg). We demand increased performance from the service brake system in the form of quicker, shorter stopping power when required. We also want an end to common rust and corrosion problems and failures in the apparatus body and water tank in the form of a minimum 25-year vehicle service life period. Most importantly, we want all of this at an affordable, competitive price.

It’s now time to ask, Can we really have our cake and eat it too? Can all of this really be achieved in a new apparatus design today? What about purchase price? Is this affordable? The answer is yes.

Why hasn’t anyone built this pumper to date? The answer is technology. Until now, it would have been very difficult to build a pumper of this type that would have been acceptable in the marketplace.

If it didn’t occur to you when reading the information given above, the full-size compact pumper is a three-axle chassis. It is equipped with a new type of compressible-liquid hydraulic suspension system of advanced design. The fluid used in the suspension is liquid silicone, which works equally well in all ambient temperature conditions. To reduce size in the rear axle area, the tires are newer-technology, smaller-diameter, low-profile radials with high-load capacity capability. The rear tires are only 37.0 inches (94.0 cm) in diameter [as compared with typical 43.25 inches (110 cm)] and with four tires on the drive axle and only two tires on the tag axle. The centerline distance between the drive axle and tag axle is only 45.0 inches (114 cm). If it is a requirement in a bid specification, this distance meets minimum snow chain distance provisions for the tires on the drive axle as set by the Society of Automotive Engineers.

ADVANCED TECHNOLOGY SUSPENSION SYSTEM
Ordinarily, when placing smaller-diameter tires on axle centers this close to each other, a satisfactory ride quality cannot be achieved. Enter an all-new type of full hydraulic suspension system at all wheel positions fully controlled by a single microprocessor. Until now, virtually all suspension systems have been of passive-reactive type design—that is, they don’t act but react to road conditions. The microprocessor allows the suspension system to fully respond to varying road conditions as required. Each wheel is continually sensed by the microprocessor with required control adjustments made in mere milliseconds to meet specific individual wheel requirements. The computer is programmed to provide a host of the most desirable features including controlling optimal vehicle ride quality at all times and optimal chassis lateral roll stability for the specific vehicle with consideration to application. It can automatically aid in fine-tuning the adjustment of the weight loadings on each axle and, yes, it can raise and lower the apparatus up to six inches (15 cm) while on the go.

The exclusive suspension height adjustment feature should virtually end most angle of approach, ground clearance, and angle of departure problems commonly encountered in emergency operating conditions. Also programmed into the suspension system microprocessor is the capability to perfectly level the chassis, if required, when on relatively flat ground. The front and rear suspensions are also designed and approved by the manufacturer for the increased severity of combination on/off highway and on/off road applications.

INCREASED SAFETY, HANDLING, AND CHASSIS STABILITY
The rear tires with their six-inch (15 cm) reduction in diameter and the front tires with a two-inch (5 cm) reduction in diameter help reduce the key dimension of chassis frame rail height, which, in turn, helps contribute to a lower vertical center of gravity and increased chassis stability. Along with the programming of the suspension microprocessor, lowering the chassis’ vertical center of gravity can help reduce the potential for certain types of accidents. This new advanced technology suspension system and newer technology low-profile radial tires of high-capacity design are the key design elements in this new full-size compact pumper.

When going to a drive axle-tag axle setup, the drive axle is usually moved forward on the chassis as compared with a two-axle chassis. On a three-axle chassis with a tag axle setup, the wheelbase determines the turning radius. The wheelbase is now determined by the distance from the centerline of the front axle to the centerline of the drive axle, not the center of the two rear axles as in a dual-drive tandem axle. This explains the method used to shorten the wheelbase to a short 162 inches (411.5 cm). Significantly moving the drive axle forward on the chassis now transfers some of the front axle weight loading to the rear axles. This, in turn, provides increased balance in the overall chassis loading, which is very desirable for improved handling.

Adding the third axle also means another axle equipped with service brakes, more square inches of brake lining area, and increased brake system stopping capability when required. With the third axle, brake lining life should be extended for all axles, which will extend the interval for replacing the brake lining material. This increases uptime availability, critical in operating a fleet of fire apparatus.

The weight (and cost) of the drive axle is actually decreased somewhat by lowering the axle capacity rating from 24,000 pounds (10,886 kg) to 19,000 pounds (8,618 kg), which also includes smaller size (and less expensive) wheels and tires. However, there is the additional weight of more frame rail material and, most likely, another frame cross-member. There is also the additional weight of the tag axle assembly, including brake wheel ends, the additional suspension for the tag axle, another air reservoir to meet Federal Motor Vehicle Safety Standard 121 air brake requirements, and two (not four) additional wheels and tires.

In designing a chassis, the dimension from the ground to the top of the frame rail is one of the most important. Decreasing the diameter of the tires allows lowering the height of the frame rails three inches (7.5 cm) or more, which also lowers the overall vehicle vertical center of gravity. Lowering the overall vertical center of gravity increases operating safety by making the vehicle less susceptible to rollover. When the suspension system has the capability to raise and lower the height of the frame rails, it will also be simultaneously raising and lowering the truck cab, apparatus body, water tank, and pump height all at once. With the exception of the axles, it will also be raising and lowering the entire power train as well.

Getting the performance and operating efficiency of the service brake system to an effectiveness level you have long desired presents an opportunity for a lighter, less expensive auxiliary braking system to meet National Fire Protection Association (NFPA) 1901, Standard for Automotive Fire Apparatus—1999, requirements. This would be an engine brake for about $2,500 that also has the advantage of not increasing the overall length of the power train—a potential cost savings of $2,500 or more and a weight savings of 300 to 450 pounds (136 to 204 kg).

On the front steer axle, rated at 14,600 pounds (6,622 kg) capacity, is a slightly smaller-diameter tire that allows an increased axle turn angle with a minimum of 50° before the tire comes in contact with the chassis frame rail. Compare this figure with some apparatus with larger-diameter tires that often can realistically turn only 36° to 40°. The three-axle, full-size compact pumper should have a minimum wall-to-wall turning radius reduction in the area of 10 feet (305 cm), possibly more. When operating in a confined area, the combination of reduced vehicle width, a shorter wheelbase, and an increased front axle turn angle substantially increases handling and maneuverability. Now, we are fully ready to challenge those narrow streets and alleys as well as narrow winding roads!

AXLE WEIGHT LOADINGS
The front axle gross vehicle weight rating (GAWR) would be 14,300 pounds (6,486 kg) with a TRW model TAS-65 steering gear, the rear drive axle GAWR would be 19,000 pounds (8,618 kg), and the rear tag axle GAWR would be 11,000 pounds (4,989 kg)—a total GVWR of 44,300 pounds (20,094 kg) for the three-axle full-size compact pumper product.

In contrast, most two-axle pumpers today have either a 40,000- or 42,000-pound (18,144 or 19,051 kg) GVWR. This would include a 16,000- or 18,000-pound (7,257 or 8,165 kg) front axle and a 24,000-pound (10,886 kg) rear axle rating. If your state’s law demands strict compliance to legal axle loadings for emergency vehicles, compliance can frequently be difficult (if not all but impossible) to achieve with a two-axle pumper when loaded with full gear and equipment. In most cases, the three-axle, full-size compact pumper should meet legal axle-loading requirements.

Another interesting comparison is in the size of the service brake system. Most two-axle pumpers equipped with shoe and drum type brakes have a total of approximately 1,000 square inches (6,451 cm) of total brake lining area with a 40,000- or 42,000- pound (18,144 or 19,051 kg) GVWR. In contrast, the full-size compact pumper would have a total of approximately 1,470 square inches (9,484 cm) of lining area with a 44,300-pound (20,094 kg) GVWR, a healthy increase of more than 45 percent more effective lining area.

For the two-axle pumper with a maximum 42,000-pound (19,051 kg) GVWR, the square inch of lining area to GVW ratio is 42 to 1. In other words, each square inch of available brake shoe lining is required to slow or stop 42 pounds. In contrast, in the full-size compact three-axle pumper with a 44,300-pound (20,094 kg) GVWR, the square inch of lining area to GVW ratio is reduced to only 30 to 1. With a significantly reduced square inch of lining area to GVW ratio, the three-axle, full-sized compact pumper not only can stop in a shorter distance but should also have an increased lining maintenance change interval.

Have you ever experienced a pumper’s slowly creeping down a grade after the parking brake system has been applied? The three-axle, full-size compact pumper should solve this type of operating problem. Thirty-square-inch (193.55 cm) size parking brake chambers can be installed on both rear axles, thereby doubling the effective parking brake holding power on grades when required. The frequently overloaded rear axle parking brake chambers on the single rear axle pumper can be the primary reason the pumper is creeping or slowly moving when operating on steeper grade angles. This technique should solve yet another operating problem.

When comparing the three-axle, full-size compact pumper with the two-axle pumper of today, the axle and suspension cost differences should be as follows. The size of both the front steer axle and rear drive axle is smaller in capacity rating than that of the large two-axle pumper. This also includes such components as wheels, tires, and the power steering gear. The chassis of the full-size compact pumper, with its third axle and advanced technology suspension system, should net-out for about $9,000 maximum additional cost as compared with the traditional two-axle chassis after all price credits are accounted for in the costing.

In the power train area, the three-axle compact pumper should net-out for about $25,000 to $60,000 less as compared with the traditional two-axle pumper once all power train cost credits are accounted for. This would be as compared with two-axle pumpers equipped with the larger (and more expensive) heavy-duty class diesel engines with their larger (and more expensive) cooling systems, larger (and more expensive) transmissions, and larger (and more expensive) auxiliary braking systems. The $25,000 figure will vary according to the make and model of engine and transmission components and the type of auxiliary braking system.

When comparing the net cost difference of the high-strength, all-welded, one-piece integral polymer apparatus body and water tank of the full-size compact pumper with one manufactured of aluminum, this portion of the vehicle should net-out for about $4,200 to as much as $4,800 maximum additional cost. To maintain approximately the same number of square feet in the apparatus body and cubic feet of compartment space, the body’s length would be increased by about 32 inches (2 feet 8 inches or 81 cm). The overall length of the apparatus would also increase by the same amount because some compartment space is lost by adding the second rear axle and by narrowing the apparatus body. Most 102-inch-wide bodies offer about 25 inches (63.5 cm) of compartment depth. The compartment depth on the narrower full-size compact pumper would be about 19 inches (48 cm). Part of the added 32 inches (81 cm) of overall body length is needed for more compartments to make up for the loss in depth.

However, this added overall vehicle length doesn’t affect handling and maneuverability, since the wheelbase was shortened and the overall width of the vehicle was narrowed. Part of the programming of the suspension system microprocessor would include information and data to provide optimized chassis lateral roll stability.

Since the design of the three-axle, full-size compact pumper requires a narrowing of the truck cab and apparatus body, the overall vertical center of gravity should be reduced as much as possible to decrease weight and optimize chassis operating stability. For that reason, all parts of the pumper mounted above the chassis frame rails should be as light as possible without sacrificing the minimal amount of adequate structural integrity required for the pumper operational application, as defined in-house by appropriate department officers.

A low-profile style truck cab constructed of aluminum instead of steel would be preferable to lower the vertical center of gravity. A low-profile apparatus body constructed of reduced weight, all-welded polymer would also increase chassis operating stability. To further reduce cost and weight as well as the vertical center of gravity, the water tank should be integrally incorporated into the apparatus body design.

An apparatus body constructed of high-strength, all-welded polymer material that includes an integral water tank also ends once and for all the major corrosion and rust failures that all too often result in expensive maintenance and downtime operating costs over the apparatus service life. No more continually repairing damage from body corrosion and rust perforation; no more water tank rust-through perforation failures. This type of body product is a good example of advanced technology design and construction in new apparatus, since there is actually an increase in body and tank structural integrity coupled with a reduction in weight. Our design goals of ultra-low maintenance and a minimum 25-year service life can and will be achieved.

All of these design efforts significantly contribute toward reducing the potential of a rollover type accident and further aid in meeting the important goal of the apparatus’ meeting compliance with legal axle loading requirements. One of the primary concerns and goals of the fire service at all times for any task is maximum operating safety for personnel.

The total net increased operating weight created by adding the third axle assembly is in the range of 600 to 700 pounds (272 to 318 kg). On the three-axle, full-size compact pumper, all of this additional weight is not only below the centerline point of the vehicle’s vertical center of gravity but also below the chassis frame rails, which provides even more increased chassis operating stability. Even with this added weight, with a 44,300-pound (20,094 kg) GVWR, the net payload increase should be in the area of 3,500 pounds (1,588 kg) as compared with many two-axle pumpers of today.

Since the compact pumper concentrates on the latest in technology, a new pumper should be equipped with the most effective and efficient CAFS available. The image of your department would be enhanced with fast response time along with minimal damage from water and smoke once the unit arrives. Good, efficient CAFS also reduce the common problem of fire rekindles.

ENGINE AVAILABILITY
As for engine selection, many pumpers today are actually overpowered. When evaluating and selecting engines, first define the specific operational application. Then, don’t just review the maximum horsepower rating of engines; evaluate the maximum peak torque rating as well. This combination determines the speed going up a hill, not just horsepower. The result of overpowering a pumper with a high horsepower engine in many geographical areas often raises the safety issue of a potential serious accident when responding under emergency operating conditions.

Narrowing the width of the pumper will require a midrange class engine. It is physically smaller (particularly in length and height) and lighter than the 450-plus hp (336 kw) engines, which accounts for a substantially reduced engine cover size. This would include engines such as the Cummins models ISC and ISL and the Detroit Diesel Series 40. The ISC has a displacement of 504.5 cubic inches (8.3 L), whereas the ISL has 540 cubic inches (8.9 L), and the Detroit Diesel Series 40 has a displacement of 530 cubic inches (8.7 L). The maximum horsepower rating for these engines is that of the Cummins ISL, rated at 370 hp (276 kw). The maximum horsepower rating for the Cummins ISC engine is 350 hp (261 kw); the maximum horsepower rating of the Detroit Diesel Series 40 8.7 L is 340 hp (254 kw). The maximum peak torque rating of the Cummins ISL and Detroit Diesel Series 40 8.7 L is 1,200 ft. -lbs. (1,627N.m); the maximum peak torque rating of the ISC is 950 ft. -lbs. (1,288N.m).

All of these engines weigh in the area of 1,500 to 1,600 pounds (680 to 726 kg) vs. a range of 2,100 to 3,100 pounds (953 to 1,406 kg) for the larger heavy-duty class engines, and they all use smaller, lighter, and less expensive cooling systems. They also use the smaller, lighter, and less expensive Allison MD series transmissions in place of the Allison HD series transmissions.

In terms of minimum horsepower required to meet wind resistance and aerodynamic demands, this only becomes a factor on relatively flat ground at speeds over 30 mph (48 km/h). Above that speed, the power required to attain the same speed considerably decreases for a vehicle of reduced height and width because of the overall reduced frontal area and resulting reduced drag coefficient. In other words, the reduced horsepower of the full-size compact pumper will be somewhat offset by the decreased pumper height and width as compared with the two-axle pumper of today.

One might question if 350 hp (261 kw) and 950 ft.-lbs. (1,288N.m) of peak torque are adequate for emergency operating conditions. If so, consider this: Thirty years ago and beyond, five-axle truck-tractors with 18 tires on the pavement, pulling 75,000 pounds (34,019 kg) gross combined weight, equipped with 335 hp (250 kw) engines that produced only 650 ft.-lbs. (881N.m) of peak torque were the standard on the nation’s interstate highways. They operated hour after hour at speeds of 75 mph (120 km/h). A 350-hp (261 kw) rated engine capable of producing 950 ft.-lbs. (1,288N.m) of peak torque can easily provide a satisfactory level of performance for a single vehicle rated at 44,300 pounds (20,094 kg) GVW equipped with three axles and only eight tires on the pavement. Response time would not suffer; in fact, it could very well be reduced because of the size, handling, and maneuverability advantages of the full-size compact pumper.

PRODUCT LIMITATIONS
If your operational application includes climbing and descending considerable grades a good portion of the time—greater than 5 percent—particularly for some length and distance, such as in the Rockies or Sierras, the full-size compact pumper may be insufficient in horsepower and/or peak torque capability. Moving up to the Cummins ISL or Detroit Diesel Series 40 engines offering 1,200 ft.-lb. (1,627N.m) of peak torque may increase performance to a satisfactory level. However, with really steep grades, you are probably a candidate for and able to justify the higher horsepower engines; larger transmissions; and more effective, more expensive auxiliary braking systems.

Another possible limiting factor to consider relative to power is maximum fire pump size. When it comes to evaluating fire pumps for power requirements, only horsepower is considered; peak engine torque is not a factor. Minimum pump horsepower requirements vary somewhat from one fire pump manufacturer to another. Generally speaking, the largest size split-shaft, single-stage fire pump a 350 hp (261 kw) rated engine can handle is a 1,500-gallon (5,678L) size. Also, generally speaking, the largest size split-shaft, two-stage fire pump a 350 hp- (261 kw) rated engine can handle is a 1,250-gallon (4,731 L) size. Availability should not be a problem, since these size pumps are very popular and account for an extremely large portion of sales nationally every year.

Once again, you also have the option of moving up to the 370 hp (276 kw) version of the Cummins ISL engine to solve this problem. This engine should be adequate for up to a 1,750-gallon (6,624 L) size split-shaft, single-stage fire pump depending on the specific make and model pump. Also, when using the 370 hp Cummins ISL engine, it could also most likely power a 1,500-gallon (5,678 L) size split-shaft, two-stage fire pump depending on the specific make and model pump. If your application definitely requires a larger size fire pump than any of these, once again, the three-axle, full-size compact pumper may not be for you.

The overall length of most two-axle, four-door cab custom pumpers today is between 29 feet (884 cm) and 32 feet (975 cm). As discussed earlier, the length of the three-axle, full-size compact pumper will be approximately 32 inches (81 cm) longer than a traditional two-axle pumper. This added length will not affect handling but could possibly pose a problem in garaging. However, in comparison, a two-axle, four-door cab pumper built on a conventional style commercial chassis will have an added six feet of hood length and an overall length of between 35 feet (1,067 cm) and 38 feet (1,158 cm).

The final possible limitation of the compact pumper is cab passenger capacity. The standard cab would be limited to five personnel. With a slight lengthening, it could accommodate six people. This may be a limitation for some departments in some areas but not for the many departments that have a hard time finding just three or four people to go out on a call.

Once the new full-size compact pumper product is market available, it is estimated that it would account for a minimum of 20 percent, and possibly as much as 30 percent, of the total custom pumper market within five years of introduction. The reasons for this are the numerous innovative features and competitive pricing in comparison with the high horsepower, two-axle pumper and the overall value this type of product would offer. It is also estimated that within five years of the product’s introduction, at least six manufacturers would be producing three-axle, full-size compact pumpers.

Once available, many fire departments around the country may very well ultimately choose to operate with both the traditional two-axle pumper and the three-axle, full-size compact pumper in accordance with their specific needs.

It’s time to take full advantage of the advanced design technologies available today and what they offer the industry in an all-new pumper design—a pumper designed to effectively solve numerous operating problems at an affordable price. Enter the new era of the innovative three-axle, full-size compact pumper.

JIM WILKINS is a California-based fire apparatus specification consultant whose background is in apparatus design and development, particularly in the chassis and power train areas.

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