We’re all adults and fire and EMS professionals here, right? Good, because I’ve been an “ICS guy” my whole life — now NIMS compliant as well — so you’ll not see this word combination “tender/tanker” again in this piece. I’m from east of the Mississippi River and I get it: tenders are motor vehicles with large water-carrying capacity whose function is to provide water for firefighting in areas not serviced by a municipal water supply.
Tenders, and their unique operational characteristics, frequently do not get enough respect from firefighters. This is unfortunate because when one is well-designed, and properly used, a tender is a valuable water-supply asset.
For many years, tenders in many departments have been a home-grown resource. A department would obtain a retired milk or petroleum delivery vehicle and refurbish it to carry water: mount a portable pump on the newly painted truck and — voilà! — you have a tender.
These reincarnated tenders have served their departments, particularly volunteer departments serving rural areas, very well. Yet, there are operating problems that arise.
Different liquids have different weight. A truck designed to carry 3,000 gallons of heating oil is probably overweight when loaded with 3,000 gallons of water.
Trucks designed to deliver milk or gasoline weren’t designed for emergency responses that may take the vehicle off of a hard-surface road. These vehicles were originally designed with a high center of gravity, which makes them prone to rollover accidents when not operated properly. Tender rollovers account for a disproportionate number of vehicle accidents for fire and EMS departments each year.
Tender basics
The standard that most applies to the design and construction of new fire department tankers is NFPA 1901: Standard for Automotive Fire Apparatus. Key apparatus components for tenders that are addressed in the standard include, but are not limited to brakes, tank design and vehicle weight.
- Braking systems include service, parking, and auxiliary brakes.
- Because a tender’s primary missions is to haul large quantities of water to emergency scenes, the design and mounting arrangements for their water tanks are of greater interest than they are on other types of fire apparatus.
- The vehicle’s rated weight capacity is based on a combination of factors, including chassis frame; axles, including the front gross axle weight rating and rear gross axle weight rating; tires and wheels; spring and suspension system; and weight distribution between the front and rear axles.
NFPA 1901 says that so long as the Gross Axle Weight Rating (GAWR) is not exceeded, the load can be placed on the truck. However, the National Highway Traffic Safety Administration’s standards, and those of many states, stipulate that no more than 20,000 pounds should be carried on the front axle, no more than 19,000 pounds on a single rear axle and no more than 34,000 pounds on a tandem rear axle configuration.
Manufacturers, whether custom designed or built on a commercial chassis, are well aware of these factors. There are several options for them that will allow for heavier GAWR, and thus a heavier Gross Vehicle Weight Rating (GVWR).
A heavier GAWR axle is necessary to handle the heavy load when the vehicle is turning, the time when a tender is most vulnerable to a rollover accident. For an axle to be designated with a heavier GAWR, several components must meet minimum requirements, including:
- Frame members
- Suspension springs
- Brake components (including linings and shoe platforms)
- Wheels (and all related components)
- Tires
- Steering components such as tie rods, steering gears
Developing tender specifications
A department should work with its manufacturer during the vehicle specification process to accurately identify the environment where the new tender will operate as well as operational expectations. Many of the major apparatus manufacturers have specification templates or worksheets to assist in the process.
Among the things you’ll want to discuss with your manufacturer are:
- How much water must it carry?
- What type and size pump does it need?
- What type of roads will it operate on?
- Will its use be strictly as a tender, or must it have fire suppression capabilities — deployable hose lines?
This last point requires a great deal of thought. Are you designing a pumper within a tender or a tender within a pumper?
Many departments make the mistake of specifying multiple tactical functions — a water hauler, an equipment hauler, a firefighting foam transporter, and a pumper — within a single apparatus. Upon delivery, they find that they’ve bought a huge truck that is dangerous to drive and is not efficiently fulfilling every task it was equipped to do.
For more information about “everything tenders,” review the FEMS/USFA publication, Safe Operation of Fire Tankers. (I know, the title states “tankers,” but it was first published in 2003 so give them a break! The material is still very relevant to tenders.)
Tenders today
More departments are finding that they have a need for tenders because of urban sprawl and increasing human population of the wildland urban interface. Apparatus manufacturers are making concerted efforts to meet these demands and to address those previously mentioned safety factors for tenders. To do that, they are using all-aluminum bodies that promote longer vehicle life and help keep GVW within specified limits.
They are also using elliptical tanks constructed using polymer materials that help keep GVW within specified limits; allow for lower tank mounting (which lowers the vehicles center of gravity and reduces chance of a roll-over accident); and provides for longer tank life.
They have automated jet-dump capabilities that enable the operator to unload at dump site without exiting the cab, thus making for quicker tender turnarounds.
And many now come with PTO-driven pumps, which offer several significant advantages on tenders, including:
- The cost of the pump is about 50 percent less than a mid-ship pump.
- The manifolds on these larger PTO-driven pumps (the top end is 1,500 gpm) are quite simple, and manufacturers can prefabricate custom suction and discharge manifolds.
- The pump can be tucked underneath or immediately behind the cab, using often-wasted space.
- PTO-driven pumps make for compact pump modules, and there may not be a need for a pump module at all, freeing up compartment space in the vehicle. Many departments specify 500-gpm PTO-driven pumps on new tenders.
- The apparatus operator engages the pump by simply pushing a button in the cab, regardless of whether the truck is in drive, neutral or park. This is a big advantage on a tender, which in many cases is being operated by one firefighter.
I remember the instructor in my first rural water supply class — words that I’ve heard many others repeat — telling us, “An efficient rural water supply [using tenders] is accomplished through rapid loading [of the tender] at the fill site and rapid unloading [of the tender] at the dump site. You don’t do it by driving fast between those two points.”
Focus on that objective when specifying your next tender and you’ll likely not be disappointed.
