Tankers account for only a small portion of the apparatus operated by fire departments in the United States, yet they are involved in many of the accidents — a lot of them fatal. Here are 10 deadly mistakes that departments often make when specifying, building, operating and maintaining tankers.

1] Overloading the vehicle. This is a common mistake that happens when departments purchase a used tanker originally designed to carry another commodity, such as gasoline. Different fluids weigh different amounts per gallon, and tankers that were designed to carry one fluid may be overloaded when they carry another. To understand this, compare the approximate weight densities of several common fluids listed below.

• Milk: 8.6 pounds/gal
  
• Water: 8.3 pounds/gal
  
• Corn oil: 7.8 pounds/gal
  
• Heating oil: 7.5 pounds/gal
  
• Diesel fuell: 6.8 pounds/gal
  
• Gasoline: 6.0 pounds/gal

For example, gasoline is significantly lighter than water, so a used gasoline tanker would be grossly overloaded when filled with water. In fact, a 3,000-gallon gasoline tanker filled with water would be overloaded by about 6,900 pounds, or almost 3.5 tons. That kind of overload is extremely dangerous and can crack the tank, break the frame or suspension, and cause unstable handling. On the other hand, milk is actually slightly heavier than water, so a used milk tanker can safely carry water with all other factors being equal.

Another way departments overload vehicles is when they add a tank to a used chassis without comparing the weight distribution of the tank and water to the rated capacities of the front and rear axles and the overall vehicle. In some cases, the added weight will exceed the gross axle weight rating or gross vehicle weight rating of the chassis. There are no allowances or safety factors built into these ratings — if a vehicle exceeds them, it can't be operated safely and must be taken out of service.

Trying to compensate for a potential overload by only partially filling the tank never works during a sustained tanker shuttle. Eventually, someone is going to accidentally overfill the tank, and the driver will head off down the road without realizing the vehicle is now badly overweight. The best solution is to avoid the problem entirely by matching the chassis weight ratings to the combined weights of the tank and liquid being hauled.

2] Raising the center of gravity. This often happens when departments build their own tankers on used chassis. Converting a used dump truck, flatbed, or straight tractor by adding a tank can raise the vehicle center of gravity dramatically. Although the finished vehicle may look fine when it is sitting still, it can be dangerously unstable when making turns, running on high-crown roads, or negotiating side slopes. Using full-width rectangular or semi-elliptical tanks can lower the center of gravity. Switching to low-profile tires can help, too.

This problem also can occur on new tankers when departments decide to add extra equipment after delivery. Welding a hosebed on top of the tank and adding a full load of large diameter hose can add a half-ton of weight to the highest part of the apparatus and make it unstable. The best solution is to keep all weight low and tell the apparatus manufacturer about all equipment you plan to add later.

3] Omitting the tank baffles. It’s hard to believe that anyone would mount an unbaffled tank on a vehicle, but it can happen when departments obtain surplus property that was originally designed for static, ground installation. Just because it’s free does not necessarily mean it’s safe for a particular application. Departments need to understand that tanks mounted on vehicles must have adequate internal baffles to reduce the side-to-side and front-to-back surging of liquid inside the tank. Left uncontrolled, this surging produces significant forces that will cause handling problems and can literally flip an apparatus on its side.

4] Cutting and splicing the frame. Sometimes manufacturers and departments alike try to convert a used chassis into a tanker by cutting and splicing the frame rails in the middle of the vehicle to add length. That’s usually a recipe for disaster and should be avoided. Moving the suspension to the rear and mounting it on a spliced-on frame extension also can cause frame failures, no matter how many inserts or reinforcements are used.

Other frame modifications to avoid include welding on heat-treated frame rails, which can weaken the rails in the area of the weld and cause failures. Notching, relieving or profiling the rails to provide clearance for other components can also cause failures, as can drilling holes too close to the upper or lower frame flanges. Reusing old frame fasteners or using undersized or lower-grade frame fasteners can cause failures. The list goes on and on. The safest approach is to start with an appropriate chassis and leave the frame alone.

5] Not training drivers. In some departments, the last person to arrive at the station has to drive the tanker. In other departments, the tanker is considered to be a non-emergency support vehicle, and the job of driver is assigned to the youngest person. Both of these practices are bad because they potentially place the most dangerous vehicles in the hands of the least qualified persons.

Tankers handle differently than other vehicles because of their higher centers of gravity and shifting liquid loads. When operated in tanker shuttles, they often have to negotiate narrow roads and maneuver on congested fill and dump sites. These conditions require drivers with plenty of training and experience, not rookies. Drivers should be given both classroom and behind-the-wheel instruction under the guidance of more experienced personnel before they are allowed to make emergency responses.

6] Not limiting vehicle speed. The Insurance Services Offic limits tanker speed to 35 mph. In fact, they even go so far as to calculate tanker response times using a maximum speed of 35 mph, rather than have departments demonstrate it. Driving faster will not gain extra points and is really, really unsafe. Tankers are especially unstable when operated at excessive speed and a sharp turn or an unexpected steering maneuver can cause them to roll. Many accidents are caused when a tanker starts to drift off the road on the right, and the driver makes a sharp steering correction. The resulting sequence of events is predictable and often fatal. Limiting tanker speed can go a long way to eliminating this problem.

7] Not wearing seatbelts. Even a well-designed tanker with a well-trained driver traveling at a reasonable speed is going to have an accident when an impaired motorist suddenly pulls in front of the apparatus at a blind intersection. Everyone riding in a tanker should be seated in an approved seat and secured with an appropriate restraint system. On older apparatus, that may be a two-point seatbelt; on newer ones it should be a three-point safety restraint. Department members who refuse to wear seatbelts should be made to walk to the fire.

8] Not using ground guides when backing. This practice is all too common and often has tragic results. In the congestion and confusion of a busy dump site, drivers sometimes back up without having someone on the ground to guide them. If they’re lucky, nothing happens. If not, they run over someone — a another firefighter, a friend, even a relative. Ideally, all tankers should be equipped with side dump valves that allow the drivers to pull up, dump, and pull away without having to back up at all.

9] Not following NFPA 1901. Tankers are not second-class fire apparatus. They are defined as mobile water supply apparatus in NFPA 1901, and there are many requirements that apply to the chassis, cab, body, electrical system and other components. Among them are requirements for proper warning lights and reflective striping, non-slip step surfaces, seats, compartment space, hose and other equipment.

10] Not performing regular maintenance. Parking the tanker behind the station and ignoring it until the next call is another bad idea. Tankers need periodic inspections and maintenance the same as any other rig. At a minimum, tankers should be given daily or weekly inspections as part of a regular preventive maintenance program to detect and correct problems. Common items to check include tires, belts, lights, etc. The new NFPA 1911 also requires several annual tests, including a road test and a weight check that apply to all in-service apparatus, no matter how old.