by Adrian-Liviu Dorofte

Fire protection under the three-pointed star: The history of Mercedes-Benz fire-fighting vehicles and their predecessors - PART VI


Stuttgart, Germany, Jan 01, 2007

New tasks, new fields of operation, and new vehicle models from 1970 up to the present day

Metz turntable ladders on Mercedes-Benz chassis

The development of turntable ladders had been progressing continuously after the war. There were turntable ladders for vehicles with short cabs for small crews and for vehicles with longer four-door cabs. A conspicuous feature of the turntable ladder vehicles for large crews, set up by Metz on the short-wheelbase Mercedes-Benz conventional trucks from the fifties, is a rounded section of the rear cab roof edge. This is not a response to a request for a more appealing design but rather the only way to permit turning of the ladder through 360 degrees on this vehicle with its long front end.
Metz had been granted a patent on a hydraulically operated ladder as early as 1935 but the non-availability of appropriate hydraulic units did not permit this design to be introduced in practical operation. It was therefore not before 1958 that Metz was able to present its first fully hydraulic turntable ladder at the fire brigades’ convention in Cologne.

Metz had invested great diligence in developing this DL 30 h turntable ladder on an L 322 short-nose chassis from Daimler-Benz. Two hydraulic cylinders pushed out the first ladder section; the next two sections were moved by double wire cables. Control units on both sides, automatic engine rpm control adapted to requirements and security features without fall-hooks ensured simple and safe operation. A small panel of warning lights, similar to traffic lights, indicated the load limits.
The hydraulic system fully extended and contracted the ladder quietly and smoothly. This, however, required the rungs of the individual sections to be precisely one above the other. Again it was a question of dispelling the firefighters’ initial reservations, this time concerning the friction-locked connection rather than form-locking by fall-hooks.
It was the Hamburg fire brigade that first used the advantages of the hydraulic turntable ladder from Metz. Soon after the Cologne fair, it ordered two DL 30h turntable ladders on a Mercedes-Benz LP 329 Pullman cab-over-engine chassis. When Metz offered a hydraulic turntable ladder that also doubled as a crane with a load-bearing capacity of three tons and remote control for both ladder and crane, the Hamburg fire brigade again responded positively. Since then, all turntable ladders of the Hamburg fire brigade have been dual-purpose units.

1966 in Stuttgart: the first German articulated mast

The professional fire brigade of Stuttgart was the first in Germany to acquire a vehicle with an articulated mast with platform in 1966 – the sort of rescue equipment that had been replacing turntable ladders in America since 1958. Of the three European manufacturers of articulated masts at the time, two were located in Finland and the third in the UK – Messrs. Simon, with whom the Stuttgart fire brigade placed its order. They used a Mercedes-Benz 1920 two-axle chassis registered for a gross weight of 17 tons and with a 210 hp six-cylinder engine.

The rescue platform of the SS 85 (Simon Snorkel 85 feet) could be raised to a height of 24.5 meters. The articulated mast with the acronym designation GM 26-1 proved itself well in operation. However, the two-axle version with a rear axle load of ten tons was not really ideal for coping with the actual loads. That’s why the second articulated mast, acquired by the Stuttgarters in 1970, was set up on a Mercedes-Benz three-axle 1623 (6x2) chassis – and the first GM 26-1 was retrofitted with a second, non-driven rear axle in 1978.
Articulated masts with platforms can even be maneuvered over the roof of a building to the latter’s rear side. Their disadvantages include the somewhat more complicated operation and reduced lateral extension. Initially, the masts did not reach the height of turntable ladders, either, but they have meanwhile exceeded them by means of telescoping upper and lower arms.

The highest articulated mast with platform currently operated in Germany is owned by the factory fire brigade of Messrs. Merck in Darmstadt. The rescue vehicle – model F 68 HLA with 68 meter long articulated mast – was set up by Bronto-Skylift, today a leading manufacturer, on a Mercedes-Benz 5550 (10x6/2) chassis in 1995.
Articulated masts have been more successful with factory fire brigades than with professional fire brigades. German fire brigades have taken delivery of 85 articulated masts with platforms since 1966. More than 50 percent of the chassis were supplied by Daimler-Benz while the articulated masts themselves come from a variety of manufacturers, among them Simon, Nummela, Wumag, Bronto-Skylift and Decker.

The answer to the articulated mast: turntable ladder with platform

Turntable ladders have an unbeatable advantage over articulated masts in that they are light. This and their simple operation should be responsible for the fact that articulated masts are not widely used in Germany. After all, a higher gross weight means higher costs which cannot be amortized on comparatively rare assignments.
Very soon, however, turntable ladders adopted the rescue platform from articulated masts. As early as 1967, Metz offered a controlled, upright rescue platform for two people for its turntable ladders. Initially, the platform was attached to the ladder when required – and the ladder even “bent down” to pick up the platform. Then, in 1974, Metz sold its first turntable ladder with firmly mounted platform – christened tele-platform – to the voluntary fire brigade of Düren. It was mounted on an L 1819 chassis from Daimler-Benz.

The platform initially irritated the drivers, being mounted at the top of the ladder and hanging in front of the windshield when not in use. Since 1988, Metz has therefore been using folding platforms.
Support systems, low-built turntable ladders and the advent of electronics
In 1972, Metz for the first time presented a vertical/horizontal support system for its DL 30 turntable ladder of the sort that was already widely used for cranes at the time. This support system was also suitable for use under cramped conditions and soon became a standard feature of Metz turntable ladders.
Since 1980, the German fire brigades’ standard turntable ladders have designations which no longer merely indicate their length (e.g. DL 30) but provide information about both rated rescue height and rated reach – for instance DL 23-12. The latter – a run-of-the-mill model – was soon complemented by variants.

Magirus had in 1979 supplied the professional fire brigade of Munich with a low-built turntable ladder carrier, just 2.85 meters high and with a crew cab moved forwards, for testing. Metz followed suit with a remarkably simple system one year later: on the DLK 23-12 SE the ladder pointed backwards rather than forwards. This not only reduced overall height with respect to cab dimensions but also provided for more even weight distribution to the two axles and a lower center of gravity, resulting in improved handling characteristics.
Between 1980 and 1987, Metz produced a total of 14 turntable ladders of type DLK 23-12 S. All of them were mounted on Mercedes-Benz chassis of models 1419 F, 1422 F or 1632 – each with a wheelbase length of 4.80 meters.

Since 1990 the acronym “PLC“ (Program Logic Control) has been pointing to the electronic control of Metz turntable ladders. The DLK 23-12 PLC turntable ladders were initially mounted on Mercedes-Benz 1422 chassis; for the third generation – PLC III – the 1524 and 14.232 chassis were used from 1993.
Whereas low-built turntable ladders were primarily designed with low passages in mind, more recent deliberations focus on the vehicle’s turning circle. In 1995 and 1997, the voluntary fire brigades of Mutterstadt and Sangerhausen acquired Metz turntable ladders with a five-part instead of the conventional four-part ladder set. Since this shortens the vehicle’s overall length, the vehicle itself is more easily maneuverable.

A more complex solution is the use of a steered trailing axle. The first of this type was a Mercedes-Benz chassis with a Magirus ladder in 1995: with a wheelbase length of 3.15 + 1.75 meters, the vehicle had a turning circle of 13.96 meters when negotiating left-hand bends and of 14.45 meters in right-hand bends (16.4/17.03 meters when considering the front end of the ladder). The same 1124 F (6x2) chassis was used the following year as a backbone for a Metz turntable ladder. In its modified form, it had a turning circle of 12.5 meters related to the vehicle’s outer edge and of 14.45 meters related to the front end of the ladder. The Econic 1828 L/NLA chassis, used by Metz in 1998 for a turntable ladder for the professional fire brigade of Darmstadt, finally combined the advantages of low build with a small cornering radius.

New turntable ladder manufacturers on the German market

In post-war years, turntable ladders had exclusively been built by Metz and Magirus; they have been joined by new competitors on the German market since 1987. Messrs. Ziegler from Giengen an der Brenz, producers of pump water tenders, had been looking for a partner in turntable ladder sales since 1980 and finally joined forces with the French turntable ladder specialist Camiva. Ziegler was able to sell more than 50 Camiva turntable ladders – over 80 percent of them on Mercedes-Benz 1422 F and 1524 F chassis.

Since the early nineties, Messrs. Riffaud are also represented with several turntable ladders on Mercedes-Benz chassis in Germany. The acronym FGL by contrast stands for a fire-fighting equipment manufacturer from Luckenwalde, a company steeped in tradition that emerged from the factory founded by Herman Koebe in 1878 and taken into public ownership in 1948. After German reunification, FGL became a limited-liability company and produced turntable ladders that were predominantly supplied to voluntary fire brigades in the five new Federal States. Two thirds of them were set up on Mercedes-Benz 1120 F, 1422 F and 1524 F chassis.

FGL was acquired by Metz in 1996, and two years later, Metz Feuerwehrgeräte GmbH was in turn taken over by the Austrian company Rosenbauer, today one of the biggest fire-fighting equipment manufacturers in the world.

Help in emergencies: combined rescue and fire-fighting vehicles

Progressing industrialization, economic growth and increasing road traffic resulted in fire brigades having rendered technical support services to a growing extent since the fifties. Oil or fuel spills on roads were among the most frequent incidents for which special equipment carriers were developed. Accidents of vehicles engaged in hazardous goods transportation formed another field in which these carriers proved themselves.
The Duisburg fire brigade was a pioneer in developing combined rescue and fire-fighting vehicles. In 1969, it started operating its first LF-H – a modified Mercedes-Benz LP 1623 cab-over-engine chassis with Bachert superstructure. Although it was a 16-tonner, the frame and rear axle, including tires, corresponded to a 19-tonner.

This combined rescue and fire-fighting vehicle was equipped with a 2,500 liter water tank, 500 liters of foam agent, a foam/water thrower, a 100 kN rope winch and a 20 kVA generator with its own engine and light mast. The equipment equally included foam pipes and a hydraulic cutter. Instead of suction hoses, the vehicle carried vertical pumps.
Another two vehicles of this type followed in 1971 and then, the Duisburg fire brigade acquired two large pump water tenders with tanks from Metz, on Mercedes-Benz chassis – the sort normally used on airports. These vehicles were followed between 1975 and 1980 by seven combined rescue and fire-fighting vehicles with tanks, combining the properties of two types of vehicle in a single one.

These GTLH 5000 H vehicles, later renamed HLF 24/50, carried 5,000 liters of water and 700 liters of foam instead of the 7,000 – 8,000 liter tanks on large pump water tenders. The superstructures were again manufactured by Bachert and the backbone was the Mercedes-Benz 2632 AK (6x6) three-axle all-wheel-drive chassis.
This was followed in 1984 by a vehicle with as many as four axles – set up on the Mercedes-Benz 2636 A (8x6) chassis. Two steered front axles provided for the required ease of maneuvering. Foam capacity rose to 2,500 liters.
The professional fire brigade of Stuttgart opted for a somewhat different approach. It specified a 1624 cab-over-engine chassis from Daimler-Benz, with 4.5 meter wheelbase, and equipment from Bachert: FP 32/8 centrifugal pump and 2,400 liter water tank, complemented at a later stage by generator, light mast and hydraulically operated rescue equipment.

This the first rescue and fire-fighting vehicle in Stuttgart was specially fitted with a crew cab; in 1977, Bachert used a standard cab for the second vehicle of this type; the cab was linked to a crew compartment in the box-type body by means of a concertina-type section. Compared to the first prototype, the vehicle’s equipment was complemented by a 250 liter foam-agent reservoir, eight compressed-air breathing apparatus units in the crew cab and vertical pumps instead of the conventional suction hoses. The vehicle’s 320 hp engine by far exceeded the output of 12 hp per ton demanded at the time. Its technical refinements included a torque converter lockup clutch of the “Transmatic” type, with integrated retarder from ZF.

The Stuttgart fire brigade put six vehicles of this type into service until 1980 before procuring the second generation of combined rescue and fire-fighting vehicles in 1996. This time, Ziegler completed the MB 1931/38 chassis with a wheelbase of 3.8 meters into vehicles that were designated HLF 20/20-2; the short wheelbase was instrumental in significantly reducing the turning circle. The water tank had a capacity of 2,000 liters, the foam-agent reservoir contained 200 liters. At 20 hp per ton, specific engine output remained roughly the same. Power was transmitted by a ZF six-speed automatic transmission with retarder.

Demountable bodies in fire-fighting service

From 1970, the diversification in the fire brigades’ work had progressed to an extent that the use of demountable bodies suggested itself. Again, the professional fire brigade of Duisburg played a pioneering role: in the seventies, it acquired five vehicles with demountable bodies from Meiller and chassis from Mercedes-Benz.
The first of these vehicles was, in 1970, a skip loader on an LPK 2224 (6x4) chassis, followed in 1974 by a roll-off tipper, also on a 22 ton chassis but with 320 hp engine. Another skip loader and two additional roll-off tippers were set up on the larger 2632 (6x4) chassis.

Demountable bodies enable the fire brigades to mount the equipment-carrying box-body required for a given assignment in next to no time – without having to acquire a special vehicle for each and every purpose. The range of special-purpose box-bodies includes tank bodies with suction and pressurized reservoirs, powder-extinguishing systems, foam-agent bodies, hose-carrier bodies and breathing-apparatus bodies, hazardous goods bodies, radiation protection bodies and workshop bodies. Since recently, mobile cranes with demountable bodies have been available.
In 1996, the professional fire brigade of Dresden put such a multi-purpose salvage and crane vehicle into service. On a four-axle Mercedes-Benz 3838 L (8x4/4) chassis, an F600 crane from the Italian manufacturer Fassi and a demountable body frame from Hüffermann are mounted one behind the other.

Touchstone for fire-fighting equipment: the airport

Great potential danger in combination with the need for rapid intervention account for airports being a special case in fire fighting, reflecting the state of the art at any given point in time particularly clearly. It was not least via airports that extinguishing powder and foam agents were introduced in fire-fighting operations. And more often than not, new competitors among fire-fighting equipment manufacturers drew attention to themselves with airport fire-fighting vehicles.

High demands are equally placed on engine and chassis manufacturers – the crucial task being the distribution of large quantities of extinguishing agent on tanks full of highly explosive fuel within the shortest possible time. The specifications for airport fire-fighting vehicles therefore comprise not only extraordinary load-bearing capacities but also top-of-the-range engines and rapid acceleration, as well as all-wheel drive for operation off the tarred runways.

Through to the sixties, airport fleets were made up of standardized FLF 25 vehicles in Germany – built by Metz on Mercedes-Benz chassis since 1950. Carrying 2,000 liters of water, 200 liters of foam, an FP 25/8 centrifugal pump and rapid-intervention equipment predominantly on LA 3500 and LA 311 chassis, these vehicles resembled ordinary road-going vehicles. They were complemented by dry-agent tenders. The Unimog proved to be a particularly suitable backbone for these smaller TroLF-750 units.
The advent of purpose-built vehicles: large fire tenders in the seventies
The tanks of jumbo jets – operating between the world’s large airports since 1970 – have a capacity for up to 130,000 liters of kerosene. To be prepared for worst-case scenarios, airport fire brigades had to elaborate effective concepts rapidly. Initially, there was a trend towards large, heavy-duty pump water tenders and powder-extinguishing vehicles, carrying up to 20,000 liters of water and powered by engines which developed up to 1,000 hp.

Even today, such demands would go far beyond the spectrum of production vehicles. The chassis, usually made by Faun, were either powered by a single diesel engine with an output of 730 – 1,000 hp or by two identical engines of which one was also used to drive the pump. Motoren- und Turbinen-Union MTU, a company jointly founded by Daimler-Benz and MAN, supplied the enormous V10 engines for those vehicles which were powered by a single engine.

Mercedes-Benz engines were used on some of the large fire tenders on Faun LF 910/42 V (6x6) chassis which became somewhat lighter again in the mid-seventies. The two OM 463 engines for these vehicles each developed 320 hp. The bodies of two vehicles for the Berlin-Tempelhof airport were made by Saval-Kronenburg, another vehicle for Düsseldorf airport was completed by Rosenbauer. The water tanks had a capacity of 10,000 liters each, complemented by 1,000 liters of foam agent.
In 1987, Sides manufactured two large fire tenders with 14,000 liter water tanks and 2,000 liter foam reservoir for the Berlin-Tegel airport. The vehicles were powered by V12 engines from Mercedes-Benz, each with an output of 720 hp.

Trend reversed: high-speed airport fire tenders

With the launch of the light, easily maneuverable “Simba” airport fire-fighting vehicle at the fire brigades’ convention in Hanover, the Austrian producer Rosenbauer initiated a reversal of the trend. In much the same way as ‘large fire tender with tank’ is quite a mouthful, the vehicles themselves proved to be too slow and too clumsy in the long run. The Simba, by contrast, signalized speed by virtue of its shape, name and operation.

Rosenbauer supplied the first three- and four-axle versions of the Simba to the Cologne-Bonn and Frankfurt airports in 1985 – and the Simba became the model for all future airport fire-fighting vehicles. In 1988 Metz presented its “Firehunter” on a Mercedes-Benz 2350 AF (6x6) chassis – a vehicle, which did not have lasting success, however. Rosenbauer still occasionally uses Mercedes-Benz production chassis to set up vehicles like the “Buffalo” but airports have meanwhile become the domain of specialists who also dominate fire-fighting in general to a growing extent.
It is virtually impossible to deal exhaustively with the large diversity of fire-fighting vehicles, especially since standardization does not prevent almost every individual fire brigade from specifying its own, tailored vehicles or converting standardized vehicles to suit its particular needs. Nevertheless, vehicles and chassis from Mercedes-Benz continue to do valuable service – as mobile command centers, ambulance and a wide spectrum of purpose-built vehicles.

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