With this installment in The Apparatus Architect series we will return to our discussion on the design and use of aerial ladder apparatus. We have previously reviewed a brief history of aerial ladder apparatus and how the operational characteristics of ladder trucks have evolved since the 1930's. Since that time, aerial ladder design has been most influenced by a combination of electronic technology and the influence of the National Fire Protection Association (NFPA) fire apparatus standards. How your fire department will apply this technology and make it work for your benefit is where we want to start.
Before making any decision to purchase a new piece of aerial equipment or upgrade your present apparatus, you want to make sure that your truck committee has "defined the job" of the proposed new rig. While this might sound like a simple, mundane task to complete, you will not believe the everyday horror stories from fire departments that acquired new ladder trucks without covering all of the bases. Consider if you will that the normal life expectancy for aerial ladder trucks is 15 to 20 years. However, in many departments the ladder truck is the oldest rig in the fleet. Because of many factors, not the least of which is the high cost of new aerial apparatus, ladder trucks may often approach 25 to 30 years of front-line service. This is certainly where making a short-term decision will have a long-term impact on the ability of the fire department to effectively deploy and operate its ladder company apparatus.
The first step in this process is to carefully look at and evaluate your department's first-due area. What type of buildings do you protect, what is the height and setback of these structures and most important where would you position the ladder truck to use it during offensive operations? Do you have significant grades or slopes that could limit the use of the aerial device? These are just some of the questions that you need to ask before you begin to design your new ladder truck. If your department currently operates a truck company, go back and review the past two to three years' worth of run reports to see how you have used the truck in the past. These reports can also give you great insight as to what tools and ground ladders you have used most frequently. The answers to these questions will assist you in determining what your real needs may be, not just what you think your department may want.
Here is a real-life example of what can happen when you do not review and analyze the needs of your district and instead buy on impulse. A fire department outside New York City operated a single-axle ladder truck that was equipped with a full complement of hand tools and ground ladders. Since the truck was purchased back in the mid-1980s, the district had become more built up with a large shopping mall and numerous garden apartment complexes. As the present truck had only a 75-foot aerial ladder the truck committee felt that a longer device was necessary. As a result the department acquired a tandem-axle 95-foot mid-mount tower ladder quint complete with a 10-person cab. Once the new tower was placed in service, the firefighters discovered that the new truck would not fit into some of the apartment complexes that the old truck would. Also, while they gained 20 feet of operating height with the aerial device, the new truck carried fewer ground ladders and was so large that many of the members refused to drive it.
Sounds crazy, that we would pay over $750,000 for a new ladder truck only to find out that it really does less than the rig you were replacing! This is why it is so important that your truck committee do their homework, with the assistance of an apparatus architect before you begin to decide what type of ladder truck that you are going to purchase for your department.
The next step is to look at the fire station that will house the new truck to insure that you have sufficient space in the bay, particularly the clear height of the bay doors for the new ladder truck. Most all manufactures produce aerial equipment with a variety of overall travel heights, ranging from just under 10 feet to over 121/2 feet.
The travel height of ladder trucks is dependent upon many things, including cab height, suspension and frame heights, body design and ground ladder packaging, as well as the height of the handrails on the ladder or tower sections. Remember that mid-mounted aerial devices tend to have a lower travel height than rear-mounted aerial devices. If height in your jurisdiction is a major concern (i.e., low underpasses), this fact may dictate a major portion of the apparatus design. Always verify the clear height of your door opening and any other obstructions that may limit the design of the new rig. In addition, be careful to look at the ramp and angle of departure to insure that the ladder truck will move in and out of the apparatus bay without restriction.
If possible, do not design the apparatus to fit the fire station, but design or renovate the fire station to fit the apparatus. Some fire departments become very shortsighted when it comes to this issue. They will spend huge sums of money for the ladder truck and spend nothing to house the vehicle. Then everyone in the department is mystified when apparatus mirrors, doors and tower ladder buckets are ripped off and left on the apparatus apron. You are just asking for trouble by trying to house a modern-day aerial device in a turn-of-the-century fire station originally designed for horse-drawn apparatus. Dollars spent today to properly house the vehicle could save thousands of dollars on unnecessary apparatus repair bills.
There has been a dramatic trend in apparatus design over the past few years to do more with less. In the world of ladder truck design the quint has become one of the most common aerial ladder devices as it allows departments to bring everything with them on one rig. We will cover some of the design considerations of quints in a future article; however, their popularity bears some discussion at this point.
Some of the positive aspects of the quints are: it increases your pump capacity, increases the total number of available ladder companies, provides multiple master streams and generally places the ladder truck in front of the fire building. However, there are drawbacks to the quint and some of these may significantly impact the operations of your department. First, to be effective on the fireground you must train all of your personnel to be proficient in both engine and truck operations. Second, the apparatus positioning for the quint will be different depending upon its intended use and depending upon the design of the apparatus, compartment space and ground ladder storage will be less than a non-quint unit.
Before your committee decides to place a fire pump, tank and hosebed on your next aerial device, make sure that you have carefully considered the overall impact with a larger piece of apparatus. Also, by adding a pump you have decreased compartment space, added thousands of dollars to the cost of the apparatus and may have increased the apparatus wheelbase, which will in turn affect the vehicle's maneuverability.
The size of your ladder truck in terms of wheelbase, overall length and jack spread will have a direct impact on the ability of the unit to set up and operate on the fireground. Just because the apparatus will fit into your station is no guarantee that the truck will maneuver and operate in the first-due area. Bigger is not always better; however, you need to insure that the apparatus is properly designed to carry the necessary tools, equipment and ground ladders to protect your district. The NFPA minimum requirements for a ladder truck include a 50-foot vertical reach, 250-pound tip load, 1,000-gpm waterway, 40 cubic feet of compartment space and 115 feet of ground ladders.
In many cases, while the design features of the aerial device that you may be considering are important, after a careful review of your past incidents, you will find that the ladder company is used more often as a giant toolbox and the frequency of use for the portable ladders, hand tools and power equipment is much greater. For this reason the apparatus committee must carefully review and evaluate the equipment list for all tools that it wants the new apparatus to carry. Due to the tremendous cost of the apparatus the days of unloading equipment off the old apparatus and backing the new apparatus in and then trying to figure out where the equipment might fit are gone forever. If you do not agree with this logic, you will be doing your firefighters and your taxpayers a great disservice.
A review of one manufacturer's body and compartment designs revealed the following cubic-foot storage capacities for tools and equipment:
- Single-axle quint 172 cubic feet
- Tandem-axle quint 208 cubic feet
- Tandem-axle ladder 347 cubic feet
- Mid-mount tower ladder 272 cubic feet
- Mid-mount tower quint 209 cubic feet
- Tractor-drawn ladder 379 cubic feet
The enclosed compartment space on fire apparatus is some of the most expensive real estate that you will ever purchase, so it is important that we design an apparatus that will be adequate to meet the needs of the department not only now, but in the future as well. Only through a careful analysis of your department's needs can you then determine the type of aerial device and the compartment requirements that you must have.
In the next installment of The Apparatus Architect we will discuss some of the various types of aerial apparatus and their operational characteristics. Knowledge of the features and benefits of each type of aerial will help you choose the best one for your department.
Tom Shand, a Firehouse
