Tanker or Tender Apparatus

Polypropylene (a co-polymer) is the material most commonly used in today’s fire apparatus tanks. These tanks offer excellent total life cycle costs and will not crack or corrode. They can be easily customized in a wide variety of shapes and can be designed with integrated foam tanks, ladder storage tunnels, and other useful features. Polypropylene tanks have a slight weight savings edge over stainless steel and fiberglass, and they generally come with a limited lifetime warranty.

Metallic tanks can be designed with higher strength than poly tanks and may be required if the tank will be subject to high system operating pressures or a vacuum style application. Steel tanks require yearly treatments against rust, which must be factored into the cost. These metals are also the heaviest material option, with propensities toward cracking and corrosion. Warranties for steel/stainless steel/aluminum tanks usually range from one to seven years.

The benefits of fiberglass include ease of integration of the tank and body structure into one unit, and increased tank volume due to few structural supports required. These tanks are highly resistant to corrosion, but the material itself is brittle which can lead to difficult and costly repairs if water is absorbed into the core material. Apart from this potential issue, fiberglass tanks are mostly considered maintenance free. Typically, they are lighter than stainless steel but heavier than polypropylene tanks. Warranties for fiberglass tanks typically range from one year to a limited lifetime.

Dryside tanks refer to a configuration in which the tank itself sits down inside of a painted outer body. This is a very common application for tankers/tenders. The most common shape of dryside tank is the T-style. These tanks are built to accommodate the space remaining once the compartments/placements are chosen. The general shape of a T-Style tank depends on the compartment options chosen by the department. One benefit of the dryside tank is that is separate from the body so that if the tank itself was ever damaged beyond repair it can be replaced without compromising the rest of the apparatus.

A Wetside tank application indicates that the tank itself is painted and exposed as part of the body. Since an outer painted body is not used in this case, a wetside tank apparatus can be more cost effective. A disadvantage with the wetside tank is that replacing the tank means you are replacing part of the body as well. A new tank will need to be finish painted after installation.

The Vacuum/Pressure System tank is typically a metallic (aluminum or stainless steel) tank that is completely sealed off to create pressure within the tank. When the time comes to discharge or draft water, it then uses that pressure to do so. A benefit of a vacuum tank is that it can fill itself with water without the need for a crew, freeing up personnel for other roles on the scene.

Elliptical style tanks are an aesthetic tribute to the past, when fire trucks were converted from old milk trucks. This body style is often chosen by departments who already have elliptical tank apparatus in their fleet and want to maintain a consistent image within the community. A disadvantage of the elliptical tank style is that may have a higher center of gravity than a rectangular tank apparatus of the same capacity. An option some manufacturers offer within the elliptical category, is to wrap the fiberglass or polypropylene tank with stainless steel. This is an aesthetic personal choice that makes the tank material indistinguishable from other stainless steel tanks in appearance.

Polypropylene is rust-proof, corrosion-proof, and highly resistant to dings and dents. The strength of this material is attributed to its thickness, and a mixture of polypropylene and polyethylene for additional impact resistance. Many departments choose this material for its durability and low-maintenance attributes.

Stainless steel, another common choice for body material, will not rust. However, corrosion can eventually occur due to the hardness of the metal. Because the metal is more brittle, joints must be designed properly to ensure long life. Many departments appreciate a stainless steel body for its appearance and sturdiness.

Aluminum, similar to stainless steel, will not rust but it will corrode. Being a softer metal, it can be more prone to wear and tear than stainless steel and polypropylene. However, it is not as heavy as stainless steel and thus provides considerable weight savings. This is also a very common body material depending on the application.

Mild steel is an option that is beginning to phase out within the industry. The main benefit of this metal is its affordability. However, it is prone to rust break down over time, reducing the longevity of your investment.

Power Take-Off (PTO) driven pumps receive power directly from the main engine or transmission, typically through a driveshaft. These pumps are generally limited to 1500 gpm. There are several advantages of a PTO driven pump:

• Allows for pump and roll operation
• If there was an issue with the pump PTO gearbox, usually the apparatus can continue to be driven
• Less expensive than other pump types
• Takes up less space

Easier install

Split Shaft or “Midship” pumps are integrated into the build of the drive line between the transmission and rear drive axle. Split shaft pumps provide very high flow ranges—up to 6000 GPM—and use the power train to provide the pressure required. A tanker/tender with a split shaft pump will have “road mode” and “pump mode” switches and will not provide pump and roll operation. Since the primary purpose is to transport water rather than pump water, the larger split shaft pump is not as appropriate for a tanker/tender.

Dedicated engine driven pumps have their own engine that is separate from the main vehicle engine. These are usually low horsepower pumps meant for lower volume flows—usually less than 500 GPM. The main advantage of the engine driven pump is that it can provide pump and roll capabilities independent of the speed of the vehicle.

Commercial chassis apparatus are those manufactured on a high-volume chassis produced by manufacturers such as Freightliner, International, Peterbilt, Kenworth, Ford, or GM. If desired, a commercial chassis cab can be ordered with a crew cab that can accommodate up to five firefighters. A two-door cab is also a common choice for rural departments who do not typically respond with more than two personnel on the apparatus. Another consideration for rural departments is that service centers may be more available for maintenance and repairs.

Custom built chassis are best known for their cab space and superior turning radius. These are most commonly a good fit for metro area departments with full time firefighters where the higher initial cost is offset by personnel efficiencies.