Alan M. Petrillo
In the seemingly age-old fire service debate between choosing a rear-mount or a midmount aerial device, sometimes fire department tradition dictates which type of aerial a department buys. But more often, other considerations come into play. These include the geography of the coverage area, the anticipated size of the completed vehicle, the types of structures to be protected, the size of the fire station where the aerial will be housed, and a number of other strategic and tactical issues.
Midmounts
Tim Smits, senior national sale manager for Pierce Manufacturing Inc., says that travel height, compartment space, and on-scene placement of vehicles are all driving factors when departments weigh the pros and cons of midmount aerials vs. rear-mount devices.
“A midmount ladder or platform will have a lower overall travel height because the ladder is not laying over the top of the cab,” Smits says. “Other considerations are if a department has a station height issue, lots of low-hanging trees in town, and even low bridges or train trestles they have to get under, then they probably will gravitate toward a midmount aerial.”
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(1) KME built this 100-foot midmount AerialCat platform for the
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The region of the country also has an effect on the choice of one type over the other, Smits observes. “For instance, the Fire Department of New York runs a lot of midmount ladders,” he says, “and many of the volunteer fire companies around New York City also run midmounts.”
Tony Mastrobattista, aerial sales manager for the north region at Spartan ERV, says that although rear-mount aerials are typically less costly than midmounts, a midmount’s biggest advantage is its lower overall height. “It can fit into the older stations and more easily negotiate areas with low bridges or low-hanging trees in historic districts,” he says.
Mastrobattista observes that among current Spartan ERV customers, midmount platforms are more popular than rear-mount platforms. “The rear-mount places the platform in the driver’s line of sight,” he says, “which can be intimidating and make it more difficult to see traffic signals or to size up placement of the vehicle at a scene. With a midmount, you don’t have that bucket in your face when you’re driving the truck.”
Although rear-mount aerials are the most common type that Ferrara Fire Apparatus builds, Paul Christiansen, Ferrara’s marketing director and aerial sales manager, says the midmount aerial is fast becoming a popular alternative, especially in the platform market. He notes that midmounts have better forward visibility for the driver and officer and adds that the shorter retracted length of the aerial device itself is another advantage.
“Midmounted aerials comprise four or five telescoping ladder sections as opposed to the three ladder sections usually found on rear-mount aerials,” he says. “The shorter retracted length provides greater ability to maneuver the aerial in congested areas and will enable the operator to place the ladder tip or platform closer to the ground or lower on the face of a building when buildings are closely spaced on the fireground. Also, the shorter length minimizes the space required to swing and rotate the aerial past trees, electric lines, and buildings.”
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(2) Rosenbauer makes a variety of rear-mount and midmount
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Chuck Glagola, aerial product specialist for Smeal Fire Apparatus, believes the debate between supporters of midmounts and those of rear-mounts will never be resolved as to which type is better. “A big factor that usually drives a midmount purchase is the design of the fire station,” Glagola says. “The station door height may be a problem, especially in a station that’s a historic building and the door height can’t be changed to accommodate a rear-mount aerial.”
Glagola points out that midmount aerials, because of their five-section ladder design, typically are heavier than similar rear-mount aerials that only have three ladder sections. “There’s also more movement with a five-section aerial,” he says, “which means higher cost in building it. As a rule of thumb, a midmount costs between $80,000 and $100,000 more than a rear-mount because of the five-section ladder, greater number of parts, and the greater number of work hours needed to build it.”
Joe Hedges, product manager of aerials and chassis at E-ONE, says his company sells a much higher number of rear-mount aerials than midmounts. But, he says, “If a department has travel height issues, that pretty much locks them into a midmount aerial, which has more complexity, at least one more ladder section, higher cost, greater weight, and an increased tail swing when cornering.” However, midmounts have some advantages, he adds, such as faster access into the bucket because typically there’s a staircase at the side of a midmount bucket.
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(3) The Plainfield (IN) Fire Department purchased
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Rear-Mount Aerials
Although midmount aerials have a number of advantages over rear-mounts, Mike Harstad, aerial products manager at Rosenbauer, says there are few applications where a midmount will perform better than a rear-mount. “If a department doesn’t have an overall height concern in its station or its territory, from an operational standpoint, the rear-mount will perform better.” Harstad maintains the operational envelope at an operator’s disposal is much greater with a rear-mount than with a midmount aerial ladder or platform. “The biggest advantage of a rear-mount is in over the cab operation,” he says. “With a mid-mount you can only get down to about eight degrees but can do zero degrees elevation with a rear-mount.”
He continues, “For below-grade operations, a midmount is limited to 45 degrees on the left and 45 degrees on the right because the turntable is in the middle of the truck. With a rear-mount you have more than 200-degree rotation below grade off the sides and back of the vehicle. And, Rosenbauer rear-mount platforms can go to negative 12 degrees below grade.”
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(4) Pierce Manufacturing Inc. offers this Dash 100-foot aerial
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But, Harstad concedes that if a department has height restrictions in its coverage area or a low station door, then a midmount is the answer, yet he believes it still compromises some operational maneuverability.
Christiansen points out that generally rear-mount aerials are shorter in overall length than their midmount counterparts, which is an important consideration if fitting inside a firehouse is a concern. However, he adds that often overhead restrictions in a station rule out a rear-mount aerial altogether.
Hedges notes that rear-mount aerials offer simplicity. “With a rear-mount, it’s a less-complicated and less-expensive machine and has more storage space for ground ladders and equipment because the turntable and body are higher,” Hedges observes. “That’s important to fire departments these days because they want to carry as much equipment as possible. Also the fly section is wider because there are fewer sections to the ladder.”
Hedges notes that a rear-mount aerial also has a large low-angle scrub zone. “The rear-mount shines in that scrub zone because it’s low around the entire rear of the truck,” he says. “On our HP100 aerial platform, we can go from zero to minus six degrees and rotate 270 degrees around the back of the truck. A midmount can only go low over the side of the truck.”
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(5) Although rear-mount aerials are typically less costly than
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Other Considerations
Pete Hoherchak, aerial product manager for KME, says that more rear-mount aerials were purchased this past year from KME than midmounts, but he attributes that to budgetary considerations. “A midmount aerial is more labor-intensive to build; the chassis is more complicated; and there are five sections to the aerial instead of three, so it’s more expensive,” he says.
Hoherchak notes that midmount aerials are believed to have a better reach than rear-mounts. “The turntable is behind the cab, so it can be positioned closer to the fire,” he says. “With a rear-mount, you might have a 260-inch wheelbase on the vehicle and might lose that reach. However, if you’re operating off the rear, the rear-mount has an improved horizontal reach.”
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(6) Because of their five-section ladder design, midmounts are
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Waterway flow is an important issue to consider, Hoherchak says. “One thing that changes on a midmount aerial platform is the rated water flows are less because you’re flowing through five ladder sections, meaning the friction loss is higher,” he notes. “On a rear-mount platform, we can give a waterway flow of 3,000 gallons per minute (gpm), but the maximum rate of flow on a midmount is 1,500 gpm.”
As for driving the two types of vehicles, Glagola says each has its own issues. “With a midmount you have to worry about the tail swing,” he says, “and with a rear-mount you have the platform out in front of the driver.”
ALAN M. PETRILLO is a Tucson, Arizona-based freelance writer and is a member of the Fire Apparatus & Emergency Equipment editorial advisory board. He served 22 years with the Verdoy (NY) Fire Department, including in the position of chief.
