Aerials, Apparatus

The Boston (MA) Fire Department’s New Ladder Trucks

Issue 2 and Volume 24.

A critical part of public fire protection planning is to create and maintain the organization, resources, and equipment that will execute a fire suppression plan.

This plan uses tactical units—i.e., fire companies—to achieve its goals. Larger departments can specialize the functions of these companies—hence, the ladder company. The choice of apparatus can impact success of the plan, vis-a-vis fireground operations. The process of choosing the right one must employ several disciplines, considering such areas as engineering, operations, finance, and policy. A systematic process must be used. Having done all of that, the Boston (MA) Fire Department chose to standardize our ladder truck design. An old maxim states, “The truck will support your tactics, or your tactics will be dictated by the truck,” and this guided our decisions. The trucks had to be safer and more reliable in operation. Our goal was a maximum of 15 days out of service (OOS) per year at five years. This would be very good for a fire truck, and these trucks are averaging five to seven days (including accomodating preventive maintenance and testing).

I will describe some of the features of these trucks to give you some things to think about when spec’ing a new truck. Keep in mind that who “makes” the truck matters less than the type of truck; the buyer must employ due diligence in coordinating with dealers and manufacturers to address all of a department’s needs. The right truck starts with an honest assessment of what you need. We needed smaller, lighter, and more maneuverable ladder trucks while reducing costs, crashes, and the likelihood of a crash and improving overall reliability and operational capability.

I’ve summarized the major areas addressed: the truck’s driveline, its aerial and operations, and its vision systems.

DRIVELINE

A 450-horsepower (hp) motor (turbo diesel) was chosen, as it had adequate power and was cheaper and lighter than the more powerful (big block) engine. Since the truck is 6,500 pounds lighter than our previous standard truck, we have found it more than adequate. This motor also has excellent heat management characteristics in this application. This will add to reliability and reduce OOS time caused by heat-stressed alternators, oil coolers, and other components.

The braking system includes the driveline (motor, transmission) and air-operated foundation brakes. Drum brakes are used on the rear on a single axle. With a 31,000-pound axle, it has large brakes adequate for the challenges of response tasks. This was not the case before modern auxiliary braking systems. Auxiliary braking includes an automatic downshift feature (any time throttle is in zero fuel position, above approximately 12 miles per hour) of the automatic transmission and a top gear lockout feature. The engine brake is also part of this system. This is a game changer. Brake fade from heat, the bug-a-boo of fire apparatus, is a thing of the past—IF the systems are used (policy and training must support this). Automatic lockout of top gear prevents the untimely shift into fifth gear. That last shift cuts driveline braking in half (measured as braking horsepower), and that is BAD. So, our new design provides excellent control, and a truck is much less likely to experience catastrophic brake failure from overuse and the attendant heat. This is evidenced by the brakes lasting at least four times longer than before with no evidence of overheating.

Steel wheels are tougher than aluminum and cost less. (Photos by author.)

1 Steel wheels are tougher than aluminum and cost less. (Photos by author.)

AERIAL AND OPERATIONS

Boston is a built-up city with all types of construction. Predominant are residential multiple dwellings of wood-frame and ordinary construction. These are either attached or closely built and are situated on narrow streets. Northeast cities like Boston that grew in the age of the streetcar and earlier have a lot of secondary and side streets. These pose a big challenge for truck companies. There are narrow streets, parked cars, wires, poles, and wood-frame buildings with open stairwells. This last item requires that we rely on ground ladders for access to upper floors, rescue, search, and sometimes even roof access. All tasks, from response to execution of fireground operations, must be done in a timely and coordinated manner. These needs are often urgent. And, then it all gets worse when it snows. Ground ladders are relied on in our “built” environment, and while the 35-foot ladder is our workhorse, long ladders (40 and 50 feet) must be available. We carry a lot so that the first truck to arrive will have plenty of ladders close to the fire building. We carry 260 feet of ground ladders (28-foot, two 35-foot, 40-foot, 50-foot, 20-foot straight, 16-foot straight/roof, 12-foot straight mounted on the aerial, and collapsing type ladder) mounted in both the rear and on both sides. Because narrow streets and parked cars can impede access when they are needed, we can always reach one.

The ladder truck’s jacks are fully deployed on a tight street.

2 The ladder truck’s jacks are fully deployed on a tight street.

The truck’s 100-foot aerial (aluminum) is a rear-mount with an 11-foot jack spread, (a foot less than previous standard design) using four jacks. A half plate is welded to the jack, so normal use does not require use of jack pads. Jack pads are used for abnormal surfaces (sidewalks, unpaved surfaces). Narrow streets and parked cars pose a problem not only for cornering but also for using jacking systems. Since most of our operations are at 30- to 50-degree elevation and at 60- or 80-foot extension, our optimal configuration only needs a 325-pound tip load. The 325-pound tip load has worked for us. This load limit applies to any extension/elevation between horizontal and 82 degrees. The success rate at “getting the roof” is maximized by our truck’s design. The concept of “optimal” vs. “minimal/maximum” is an important concept when fitting the capability of a given design to a specific application, and this helped us in making choices.

The 100-foot aerial was chosen vs. the 110-foot aerial. In most of our applications (neighborhoods) and most of the time, we don’t need that extra 10 feet. The biggest problem was a truck’s inability to even get down the street because it was too big, too wide, too long, and with poor vision systems. Our new trucks have a 10-inch-shorter wheelbase and have a 6½-foot-shorter turning radius than the previous standard truck (tandem-axle, rear-mount, straight truck). The shorter aerial also has a low travel height—four inches lower. This is needed in some firehouses, and the design is optimal for a majority of our applications. All in all, we have improved our ability to meet our primary goal: make a corner, get down the street, get jacks down, and raise the aerial to the target. This is mission-critical: If it can’t get down the street, that’s mission failure and will decrease the efficiency of operations.

Grab rails are raised 10 inches, and the body is squeezed five inches on each side. The rub rail is ½ inch narrower.

3 Grab rails are raised 10 inches, and the body is squeezed five inches on each side. The rub rail is ½ inch narrower.

The extended clearance light.

4 The extended clearance light.

This lower-travel-height aerial has slightly lower handrails. While some would think that this makes an aerial less safe, I would argue otherwise. Consider where the risk comes in: from alighting the aerial onto a roof or into a window and, to a lesser degree, while climbing. Consider that lower rail heights allow easier exit from the aerial, and that one should use the rungs when climbing anyway. So, there is less risk in the first case and the same risk in the second. Prepiped waterways add climb over height, and we don’t use them for this reason.

An added benefit is that by standardizing design, there is a predictability that allows any of these trucks to cover any other firehouse or neighborhood in the city. Training is also standardized, leveraging the maximum benefit from the truck’s designed-in capabilities.

Boston (MA) Fire Department Ladder Truck Specs

  • Weight: 53,500 pounds
  • Width: 96 inches
  • Length: 38½ feet overall with a 220-inch wheelbase; leaf springs front and rear
  • Height: 10 feet 7½ inches
  • Steering: 45-degree cramp angle
  • Driveline: Cummins ISL9 450-hp engine, Allison five-speed transmission with auto downshift/top gear lockout
  • Aerial: 100-foot rear-mount, 16½-inch high fly section, 325-pound tip load at full horizontal extension

To increase outside clearance in cornering (reduce back swing), a narrowed “tail,” or rearmost section of the cabinet body, was designed along with mounting the grab rail higher. This added six inches of outside clearance. Together with mirrors and lighting, this has practically eliminated the back-swing type of fixed object collision.

The larger capacity rear axle allowed the use of a single axle on a shorter wheelbase (220 inches vs. 230 inches), improving maneuverability by reducing turning radius. Although the axle is wider in track, this makes a noticeable improvement in cornering stability. This also makes it very easy for drivers to “landmark” the axle (tire) when using mirrors to corner.

all three axes are in view, but not in the “bus” mirrors in photo 6.

5 6 In photo 5, all three axes are in view, but not in the “bus” mirrors in photo 6.

VISIBILITY AND VISION SYSTEMS

Visibility means the ability to SEE the truck and elements of the driving environment to safely drive the truck. Our goals had a number of key vision requirements. A systems approach led us to consider what we wanted to see and what the impediments were to this. Considering all elements together, we developed an optimal vision system. Some of these impediments were glide track on the window, seat position of the officer, and location and mounting (as well as use, function) of the mobile computer (a tablet vs. laptop eliminated one obstruction to clear view of the mirrors). A recessed grab rail improved the cornering mirror sightlines, and specific clearance lights, such as an extended light at the rear, are used to improve driver orientation of the truck vs. space. If a driver can see the truck, then he is less likely to hit something.

Other associated changes included fabricating a radius on the corners of “jack plates,” painting them with high-visibility paint, and adding a side view camera (vs. a lane change camera) that has an altered field of view focused on the side of the truck instead of the adjacent lane. The rear was reduced in width to reduce the clearance needed while entering a turn (back swing) by six inches. The front bumpers were configured to reduce front swing while coming out of a turn. The front view mirror (convex, mounted above the windshield in front of the officer) allows a view of the front corners, eliminating these impacts while cornering. We chose a 10-inch front view mirror vs. eight inches to improve view. It is focused on both corners of the bumper, eliminating these impacts and allowing the driver to use all of the space available.

In the interest of narrowing the truck wherever possible, the rub rail was reduced from 1½- to one inch, and cabinet steps were chosen that were 1½ inches less (per side). “Fenderettes” were limited to no more than1½ inches from the plane of the body sheet metal. Normally, this dimension is 2½ inches. The “barrier doors” make it easier to exit in heavy snows. Door latches (a potentially disastrous failure that could kill someone) have a reinforced escutcheon plate to eliminate flex and related distortion of critical components in the latching system.

The rub rail and radiused jack plates.

7 The rub rail and radiused jack plates.

The front view mirror.

8 The front view mirror.

“Vision Systems” sounds complex, but it refers to the interaction of the driver, the mirrors, lighting, views of particular key landmarks in space management, and any impediments to proper use. Door-mounted (West Coast) mirrors were used, as they have a taller flat mirror. This offers a far superior view of the three things a driver needs from his sight picture: the side margin of truck, the top and bottom of the back, and the horizon. Good drivers use these things to not only see what is there but also to compare the truck with their space. But often, there are impediments to use, such as window glide tracks, a computer and mount, and the officer. We moved the officer’s seat back; chose a clear-line-of-sight-type door (with glide track to the rear); and moved the computer and mount to a position where the officer wouldn’t have to lift his arms to use it, thus impeding the view of the mirror. The officer has more room as well.

The blind-side convex mirror is used for cornering to see the side of the truck. A larger convex mirror provided 40 percent more viewing area. One significant impediment to proper use of this mirror is the required grab rail for the officer’s door. It prevents seeing the side of the truck. By recessing this rail, we restored the ability to properly use this mirror.

So far, Boston has replaced 15 of our 20 ladder trucks with this design, with three more to arrive next summer, making for a total of 18 of our 20 trucks replaced. All of these changes allowed us to improve our operations and reduce fixed object collisions (by 90 percent) and attendant loss as well as associated OOS time. This has also made our trucks even more tactically reliable in operations. This predictability in operations helps an incident commander know he can count on a truck to get its job done.

Costs include acquisition, maintenance, incurred costs (property damage when the truck hits something), and projected life cycle [total cost of ownership (TCO)]. Boston has improved fireground operations while significantly reducing TCO. The incidences of crashes and attendant property damage have been reduced. OOS time and maintenance costs have been reduced.

Using a conscientious process, a department can get the right truck for its needs if it matches its needs with design capabilities. One of those capabilities is just getting there in a timely manner without hitting anything so we can get the job done.


JIM O’BRIEN is a project manager in the Boston (MA) Fire Department’s Fleet and Logistics Division. He is also a driver and trainer.