The Stuttgart Fire Department is making use of the Ötigheim off-road proving ground for testing its new fire fighting fleet
Drought and dryness with a higher risk of forest fires on one hand, and unusually heavy rainfall, high water and floods on the other: In the context of climate change, extreme weather has come to be one of the greatest challenges faced by fire departments and disaster relief services.
In response to these pressing challenges, the Stuttgart Fire Department recently decided to buy four new Mercedes-Benz Unimog trucks, including the compact U 323 RW-K and extreme off-road U 5023 RW-HG variant rescue vehicles to provide technical assistance, as well as two identical Unimog U 5023 TLF-W water tenders to be used to transport extinguishing agents off road.
Stuttgart Disaster Relief
Dr Georg Belge, Stuttgart Fire Department Chief explains, “The topographical situation in Stuttgart and the surrounding area, with the mountains, valleys, steep slopes and narrow roads, means that firefighting vehicles must be suited for extreme off-road operations. As such, the Unimog’s high off-road capability was a decisive factor during our procurement process, because it enables us to act quickly and effectively as a tactical unit in the event of a disaster or accident.”
Combined with two older water tenders, the new Unimogs can form a task force, the only one of its kind in Germany with the objective to effectively combat dangerous vegetation fires as well as to provide disaster relief in the event of flooding. The fire department’s Unimog fleet vehicles complement one another well, with the rescue vehicles (RW) providing technical assistance and the water tenders (TLF-W) rapidly delivering water for forest fires and the. This tactical unit’s Unimog will be used by the Stuttgart Fire Department for operations in the region and beyond.
Firefighter Training
At the end of July, 35 Stuttgart volunteer firefighters trained, under the supervision of the Stuttgart Fire Department, on using thee four new Unimogs in an emergency. The training took place at an off-road proving ground, known colloquially as the “gravel pit”, a site with challenging conditions used to test off-road vehicles in the municipality of Ötigheim, Baden-Wuerttemberg.
Under conditions designed to take off-road vehicle to the limits of their capabilities, these firefighters had a chance to gauge and become familiar with the Unimog’s performance envelope in extreme situations under the guidance of experienced trainers.
The Unimog’s operational capability through sand, mud and water, over tree trunks, down winding slopes, and up the steep ramps of the test site, which are up to 35 degrees, was met with an enthusiastic response by all participants.
“The Unimog exceeds our requirements for off-road capability,” says Christian Schwarze, Head of the Technology Department at the Stuttgart Fire Department. “The off-road training provided by the manufacturer in Ötigheim gave our drivers the opportunity to experience how the vehicle handles in extreme situations, and it did a great deal to build our confidence in the Unimog’s operational capabilities. It was a complete success – I saw happy faces everywhere in the gravel pit!”
Compact Response
The new fleet includes the first compact rescue vehicle (RW-K) designed for a crew of three firefighters and has a chassis width of only 2.20 meters. This enables the vehicle to reach most deployment areas quickly and was a requirement for Stuttgart as the region has many wine-growing and forest areas with very narrow and steep roads and paths.
The RW-K variant has a total weight of 12.7 tons, a wheelbase of 3.60 meters, and differential locks on the front and rear axle. It features an automatic shift manual transmission (EAS) with an engine output of 170 kW (231 hp). In addition, it has an increased trailer load of up to 20 tons to tow a centre-axle trailer, two LED headlamps on the cab roof, additional LED spotlights on the front body corners, and a pneumatic light tower. The U 323 also has branch deflectors to prevent damage as well as a winch on the front of the vehicle.
The RW-K variant is a rescue vehicle, which shares the same capabilities and characteristics as the larger RW-HG variant, which has a 14.5 ton gross vehicle weight, 3.85 meter wheelbase, 170 kW (231 hp) engine output, and automated manual transmission with off-road group. It has an all-steel cab for a three-person crew and uses torque tube technology with longitudinal/transverse differential locks and pipe rupture protection for the brake system.
The body’s design and the equipment for providing technical assistance are essentially the same as the RW-K. However, the portable gripper on the RW-HG has a higher tensile load of 32 kN. It is equipped with a tyre pressure control system so that the air pressure, and thus the tyre’s contact surface, can be adjusted with the push of a button when driving on different surfaces, allowing the vehicle to move steadily on both asphalt access roads and sandy or muddy ground.
With a fording capability of 1.2 meters, the rescue vehicle can be used in flooded areas and is capable of carrying up to ten people on the roof of the body in order to bring them to safety through floods.
Water Tenders
The Stuttgart Fire Department has the first two vehicles of a new type, which is specifically designed to fight vegetation/forest fires and can also be used for water disasters. Both vehicles feature the remarkably low Varus 4×4 body from Schlingmann in a stainless steel/aluminium composite design with a very low centre of gravity. The T-shaped extinguishing water tank, which has a volume of 3200 litres, is integrated into the body. The crew cabs each have space for a four-person firefighter crew including protective clothing and equipment. Two side equipment compartments and one rear equipment compartment are provided for storing necessary equipment. Roof boxes and other storage systems can also be used for additional space. Besides the tyre pressure control system, the wheels are equipped with beadlock rims in order to meet the specific requirements of driving on recently burnt vegetation, for example.
Up to 2,000 litres of extinguishing water per minute can be dispensed from two roof hatches above the rear seats. When driving through a forest fire, the vehicle crew is kept safe by the front spray bar as well as the spray nozzles in front of all four wheels and on the cab’s branch deflector.
This vehicle is also equipped with a centrifugal fire pump with venting device, a 60-litre foam tank for a wetting agent admixture, which reduces the surface tension of the water so that it can better penetrate the burnt material, and 20 pressure hoses.
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