Think of how difficult life would be without elbows. Being unable to bend your arms in the middle would restrict what you could do. The same is true for aerial devices. Without the ability to bend in the middle, straight aerials are restricted in certain situations.

The concept of aerials that bend in the middle isn't new. The first articulating-arm aerial device was introduced to the fire service by Chicago Fire Commissioner Robert Quinn in 1958, who adapted a bucket lift commonly used by tree trimmers and utility companies to deliver an elevated master stream for firefighting. In its first year of service with the Chicago Fire Department, the pioneering device was used more than 200 times. Other departments soon took notice, and several manufacturers introduced similar aerials over the following years. Early models included the Pitman Snorkel and Squrt, Mobile Aerial Towers Hi-Ranger, American LaFrance Aero-Chief, Seagrave Eagle, Calavar Firebird, and others. One of the reasons the concept became so popular was because the articulating arms gave a wider range of motion, allowing firefighters to reach over obstacles that blocked other aerial devices.

The same concept of up and over makes articulating-arm aerials popular today. Many of the old names are gone and new names have taken their places. Modern articulating-arm aerials include elevating platforms and water towers. Both types use turntable-mounted aerial devices with two or more booms or sections that articulate, or bend like an elbow. They also may telescope to achieve farther vertical and horizontal extension.

E-ONE offers several models of the Bronto RLP elevating platform with vertical heights of 100, 114 and 134 feet. The 100-foot model has a 90-foot horizontal reach and can be lowered 15 feet below grade. The NFPA tip-load rating for all models is 1,000 pounds for personnel plus 210 pounds for equipment without water flowing, or 750 pounds of personnel and 210 pounds of equipment when water is flowing at 1,000 gpm. The platform provides 22 square feet of space and can be swiveled 45° to each side for more accurate placement. To eliminate front and rear overhangs and reduce the overall vehicle length, the platform and outermost boom fold under the main boom in the stowed position. Other standard features include pumps to 2,000 gpm, 300-gallon water tanks, hosebeds and enclosed ground-ladder storage. Bodies without pumps or tanks and with extra compartment space also are available.

The Pierce Sky-Arm elevating platform consists of a 100-foot aerial ladder with a platform attached to an articulating fly section. It has a 92-foot horizontal reach and the platform and fly section can be lowered below the horizontal. The NFPA tip-load rating is 750 pounds for personnel without water flowing, or 500 pounds when flowing at 1,000 gpm. The platform has 16 square feet of space and can be swiveled 22° to each side. To provide easy movement of personnel between the platform and the turntable, the aerial ladder has full-width rungs and full-height handrails. Other standard features include pumps to 2,000 gpm, 300-gallon water tanks, hosebeds and enclosed ground ladder storage.

The American LaFrance 54-foot Squrt water tower is one of the products that has survived the test of time. It was introduced in the 1960s as a low-cost way to provide an elevated master stream and became popular with departments that wanted to enhance the attack capabilities of their pumpers but couldn't afford to buy or staff a full aerial. The turntable is mounted at the rear of the apparatus, which allows the use of two roughly equal-length articulating booms that provide good up, over and out reaches as far as 45 feet horizontally. The remote-control nozzle delivers 1,000 gpm in any position and can swivel 240° vertically and 90° horizontally for flexibility in stream placement.

The newest articulating-arm aerials are the 50- and 65-foot Snozzle water towers built by Crash Rescue Equipment Services and available from several apparatus builders. The design originally was developed for use on aircraft rescue and firefighting apparatus where fast, accurate placement of master streams was needed. It has become popular with municipal departments for exactly the same reasons. The turntable is mounted midship, just above the pump panel, which results in a shorter lower boom and a much longer upper boom that give excellent horizontal and below-grade reaches. The 65-foot model can deliver up to 1,500 gpm through two remote-control nozzles. An optional piercing nozzle on both models can penetrate roofs, walls, trash containers and vehicle sheet metal.

The many situations where departments can use articulating-arm aerials are just as impressive as their features. Whether it's fighting structure fires or performing difficult rescues, aerials with the ability to go up, over, out and down really prove their worth.

Start with up. The current generation of articulating-arm aerial platforms begin at 100 feet and go up from there. They are among the tallest aerials offered, and under the Insurance Services Office rating schedule, their length gives them the maximum points for an aerial device. (See “Aerial Flex Can Mean ISO Points,” below.) The extra length also helps ensure the aerials can reach the roofs even when landscaping, parked cars or other restrictions prevent them from being positioned close to the buildings. Height is also important for pumpers with water towers. The ability to deliver master streams at a height of 50 feet or more, instead of from ground level, often can result in more effective containment of larger fires and quicker knockdowns of roof fires and those on upper floors. They also can be used to deliver water over the tops of adjacent structures for direct attack or exposure protection. In many cases, the water towers will qualify as elevated master stream devices and give departments extra ISO points without operating separate truck or ladder companies.

Reaching over obstacles is where articulating-arm aerials really shine. Each aerial design has it's own boom configuration and range of motion, but all can be raised and angled to position the platform or master stream up and then out to clear obstacles. The most obvious obstacles are irregular rooflines, roof parapets and roof-mounted signs that would otherwise restrict the ability of straight aerials to reach portions of the roof. Overhead utility wires are another example of obstacles where careful placement of an articulating-arm aerial often can reach up and over safely. In some cases, departments need to reach over adjacent structures to perform rescue and firefighting operations on portions of multi-story buildings that otherwise are inaccessible to straight aerial devices — for example, positioning the platform or master stream along the sides of newer, taller buildings sandwiched between older, lower buildings on a busy downtown commercial block. The ability to reach over the tops of roofs and drop down to roof level on the other side with articulating-arm aerial platforms also lets firefighters conduct ventilation operations from the safety and stability of the platform when handling fires in buildings with lightweight truss construction.

Some departments have found that articulating-arm aerials are useful in situations where they need to reach out and down. Below-grade rescues are one obvious example, especially in situations involving flowing water or collapsed buildings, where emergency personnel need a stable work platform in order to avoid becoming victims themselves. For firefighting operations, the ability to extend water tower nozzles into the interior of structures through doors and windows can give firefighters greater fire suppression capabilities than would be possible with individual handlines. Some articulating-arm water towers even have piercing nozzles that can penetrate walls and roofs to quickly knock down fires in attics and other confined spaces.

To see if you could use an articulating-arm aerial in your department, look at all the buildings, bridges, parking structures, amusement parks and industrial plants in your town and ask yourselves how you would perform a rescue or firefighting operation on each of them. If the ability to reach up, over, out and down would be an advantage, maybe you should consider getting an articulating-arm aerial.

Aerial Flex Can Mean ISO Points

The Insurance Services Office evaluates the fire suppression capabilities of departments throughout the United States. Based on this evaluation, it assigns points for apparatus, equipment, personnel, communications, water supply and many other factors using the Fire Suppression Rating Schedule. The total number of points determines the ISO classification of the department. In turn, the classification often determines the fire insurance premiums paid by property owners within the department's jurisdiction — in general, a higher rating means a better ISO classification, which means lower fire insurance premiums.

For apparatus, the ISO Fire Suppression Rating Schedule also defines the criteria under which an aerial device and elevated master stream are needed based on the building height and several other factors. If an aerial and elevated master stream are needed, ISO specifies that they must be “… of sufficient height to reach the roof of any building or 100 [feet], whichever is less.” ISO also notes that it will “prorate the credit if existing equipment has insufficient reach.”

These are important points and are sometimes overlooked by departments when they specify aerials. It can become painfully apparent in situations where roof parapets, signs, adjacent structures and other obstacles make it impossible for straight aerials to reach the roof, even if they have sufficient height. To judge this, the ISO evaluator may select a particular building and request a demonstration. If the aerial or master stream cannot reach the roof because of an obstacle, the evaluator may deduct points.

In some cases, an articulating-arm aerial can solve these problems and maximize the number of ISO points by allowing firefighters to reach up and over obstacles and place the platform and master stream next to the roof edge. To determine whether a particular aerial device can reach the roof of a specific building, departments should contact potential manufacturers and request a chart of the horizontal and vertical operating envelope of the aerial to compare with measurements of the building and any obstacles. An actual demonstration would be even better.

For more information about the points assigned for various ladder company equipment, including the aerial device itself, contact your regional ISO office or go to the ISO Web site at www.isomitigation.com/ppc/3000/ppc3006.html.