CDL-10 Section 8 - Tank Vehicles
CDL-10 Section 8, Tank Vehicles, tests the special handling and loading rules for tanks carrying liquids or gases. The main hazards are a high center of gravity, liquid surge, and expansion.
Core rules
- Surge: liquid moves when you brake, accelerate, or turn. Baffles and bulkheads reduce surge but do not eliminate it. Start and stop smoothly.
- High center of gravity: tank vehicles roll over more easily. Slow down before curves, avoid sharp steering, and keep tires, brakes, and suspension in good condition.
- Outage: leave space in the tank for expansion. Fill only to the marked outage or the level allowed by the cargo's rules.
- Loading and unloading: follow the shipper's instructions, set parking brakes, chock wheels, and use grounding and bonding where required to control static electricity.
- Inspection: check tank, valves, hoses, domes, and emergency shut-offs. Do not drive with leaks or missing caps.
Worked example
A tank has a capacity of 9,000 gallons and a 2% outage. Two percent of 9,000 is 180 gallons, so the maximum fill is 8,820 gallons. Leaving the outage space gives the liquid room to expand without overflowing.
Traps
Do not think baffles make a tank vehicle handle like a dry van; do not brake hard to test surge; and do not skip bonding during loading. A smooth stop is safer and reduces the forward surge that can push the tractor.