Tank Vehicles
Tank Vehicles
The Tank Vehicles domain tests liquid-load behavior, stability, and safe loading. A tank endorsement is required, and the exam focuses on what makes a tanker different from a dry van.
Surge and baffles
Liquid moves inside the tank. In a smooth-bore tank, the surge is strongest; baffles and bulkheads reduce it but do not eliminate it. When you stop, the liquid surges forward and can increase the load on the steer axle and lengthen stopping distance. When you accelerate, it surges rearward. Side-to-side surge can destabilize the vehicle in a turn.
Stability and driving
Tank vehicles often have a high center of gravity. Slow down before curves, avoid sudden steering, and brake early and smoothly. Keep the load within the tank's outage limits so liquid has room to expand.
Worked example
A half-full unbaffled tanker approaches a red light. If the driver brakes hard, the liquid surges forward, adding force and making the stop longer and less stable. The correct approach is to reduce speed early, brake gently, and leave a larger gap.
Loading and unloading
Set the parking brake, chock wheels, and follow grounding and bonding procedures for flammable liquids. Check the dome cover and valves before moving. Do not smoke or use unauthorized equipment near a flammable load.
Traps that cost marks
- Believing baffles remove all surge.
- Driving a tanker like a dry van in curves.
- Forgetting outage space for expansion.
- Skipping grounding and bonding.