Tanker Vehicles Practice Questions

Explanation: Without baffles to interrupt the flow, the liquid wave can build up speed and force as it travels the full length of the tank.

Explanation: Outage (or ullage) is the space left empty at the top of the tank. Liquids expand when they get warm; without outage, the tank could burst.

Explanation: Dense liquids weigh more per gallon. A tank filled to capacity with a heavy liquid will often exceed legal axle weight limits.

Explanation: Baffles typically run across the width of the tank to stop forward/backward motion. They do very little to stop side-to-side surge, which can cause rollovers in curves.

Explanation: Milk tankers are usually smooth bore because baffles are difficult to clean and sanitize properly (bacteria hides in the corners).

Explanation: Most of the weight (the liquid) is carried high off the ground, making the vehicle more top-heavy and prone to rolling over.

Explanation: Manhole covers allow human access to the tank. They must be fitted with gaskets and closed tightly to prevent leaks.

Explanation: Hazmat tankers must be equipped with remotely operated emergency shutoff valves to stop the flow of liquid in case of an accident or leak.

Explanation: A fully loaded tank is more stable than a partially loaded one because there is no room for the liquid to surge (slosh) around.

Explanation: Partial loads allow the liquid to move freely. In a smooth bore tank, this creates a powerful 'liquid hammer' effect that can push a stopped truck into an intersection.

Explanation: Unloading must be planned to maintain stability. Unloading only the front or rear can make the trailer unstable or overload the remaining axles.

Explanation: Hazmat must be transported in 'Spec Tanks' (e.g., DOT 406, 407, 412) designed and certified to withstand pressure, impacts, and leaks.

Explanation: The tank shell is the containment vessel. Dents or cracks can lead to catastrophic failure under pressure or load.

Explanation: You must calculate the load based on expansion (outage), density (weight limits), and tank capacity.

Explanation: DOT 406 tanks are the standard oval-shaped aluminum tankers used for gasoline and diesel.

Explanation: DOT 407 tankers are versatile, low-pressure stainless steel tanks used for chemicals, solvents, and mild corrosives.

Explanation: DOT 412 tanks carry heavy corrosives (acids). They are narrow cylinders with visible external stiffening rings.

Explanation: MC 331 tanks are high-pressure steel tanks with rounded ends (capsule shape), used for liquefied gases like propane.

Explanation: Leaks are serious. If it's a loose fitting, you may tighten it if trained/safe. Otherwise, the vehicle is out of service.

Explanation: Vents allow the tank to 'breathe'. Without them, pumping liquid out would create a vacuum that could implode the tank, and heat expansion could explode it.

Explanation: The entire containment system (tank + plumbing) must be inspected for integrity.

Explanation: Materials with high coefficients of expansion require more outage (empty space) to prevent overflow or tank rupture as they warm up.

Explanation: Portable tanks are bulk containers (often mounted in a frame) that can be loaded onto flatbeds or skeletal trailers. They must be secured with twist locks.

Explanation: Tankers have rollover protection structures (metal rails or cages) on top to prevent the manholes and valves from being sheared off if the truck flips.

Explanation:  Baffles have holes to allow flow; bulkheads are solid.

Explanation: Double bulkheads separate incompatible liquids. The void space between them allows leaks to drain to the ground rather than mixing with the other cargo.

Explanation: Fusible links melt at a specific temperature (during a fire), releasing the spring tension and snapping the internal valve shut to stop the fuel source.