Texas CDL Surge, Bulkheads, and Baffles

Liquid shifts forward, backward, and sideways as speed or direction changes. Because tanks place heavy cargo high above the road, surge can increase stopping distance, push the vehicle through an intersection, or contribute to rollover. Smooth control is essential even when the tank is not full.

Bulkheads divide a tank into separate liquid-tight compartments. Loading across compartments changes axle weight and balance, so the driver must know which compartments are filled and how much each contains. A partly filled compartment can still surge.

Baffles contain openings that allow liquid to flow between sections while reducing forward-and-back surge. They do not eliminate side-to-side movement and do not make abrupt steering safe. Some sanitation tanks are unbaffled and can produce especially strong surge.

Liquids expand as temperature changes. Tanks need sufficient outage, or empty space, to prevent overflow or excessive pressure. The required outage depends on the liquid, temperature, tank, and loading rule. Never fill by visual guess when the product requires calculated capacity.

Respect gross and axle limits and avoid concentrating too much product in one area. Confirm product compatibility, compartment sequence, valves, closures, and leak condition. The driver must understand the load even when another person performs the loading.

Start, brake, steer, and shift smoothly; increase following distance; slow before curves; and brake early for stops. Avoid sudden lane changes and be prepared for a second push as liquid rebounds. On slippery roads or downgrades, reduce speed further and select the proper gear before descent.