Illinois CDL Tanker Endorsement Test flashcards

31 cards. Read the term and the definition here. The deck at the top of this page is optional.

What causes liquid surge?

Liquid in a partly filled tank moves opposite the direction of acceleration: rearward when accelerating, forward when braking. This moving mass adds force to the vehicle and lengthens stopping distance.

When is sloshing worst?

Sloshing is strongest in a partly filled tank, roughly half full. A completely full tank has little free surface, and an empty tank carries no liquid to move.

Do baffles stop side-to-side movement?

No. Baffles and bulkheads divide the tank front to back and reduce longitudinal surge. They do not prevent lateral sloshing, so a baffled tanker still rolls and shifts weight side to side.

Effect of surge on steering

Surge shifts weight between axles and can unload the steer axle on a partly filled tanker, reducing steering traction. Smooth acceleration and braking keep weight transfer small and predictable.

Total stopping distance formula

Total stopping distance equals perception distance plus reaction distance plus brake lag distance plus effective braking distance. Liquid surge lengthens the braking portion compared with a solid load.

Feet per second at 55 mph

At 55 mph a vehicle travels about 81 feet per second. Each second of perception or reaction time therefore covers roughly 80 feet before the brakes begin to slow the vehicle.

Braking on a long downgrade

Select a gear low enough that engine braking and any retarder hold the speed, and use short, firm brake applications. Continuous light brake pressure overheats brakes and can lead to fade or failure.

Why hold steady brake pressure?

Liquid keeps moving after the vehicle stops. Holding firm, steady pressure until the forward surge settles prevents the load from pushing the truck into traffic ahead.

Tanker rollover cause

Rollover occurs when cornering force exceeds the vehicle's stability. A high center of gravity and moving liquid raise that risk, so curves must be entered well below the posted advisory speed.

Handling a drive-wheel skid

Ease off the accelerator and steer in the direction you want to go. Do not stab the brakes, because locking the wheels removes the traction needed to recover.

Handling a trailer skid

Release the brakes so the wheels roll and regain grip, then steer to follow the tractor. Holding a locked brake keeps the skid going and can jackknife the combination.

Curve-and-downgrade ramps

Ramps that curve while descending are the highest-risk locations. Slow down before the ramp, not on it, because grade and surge both reduce the margin against a skid or rollover.

Shipping paper contents

Hazardous material shipping papers must show the proper shipping name, hazard class or division, UN or NA identification number, packing group, and total quantity, plus a monitored emergency response phone number.

Placard matching rule

Placards must match the hazard class shown on the shipping paper. A tank vehicle carrying a placarded quantity is a placarded vehicle and is subject to the associated rules.

Tank specification plate

The specification plate shows the tank's DOT specification, capacity, and working pressure, along with required test and inspection dates. An expired test date makes the tank ineligible for service.

Hazmat endorsement requirement

A hazardous materials endorsement (H) on the CDL is required to drive a vehicle carrying placarded quantities. A valid TWIC is also required where the regulations apply.

Bonding versus grounding

Bonding connects the vehicle to the storage tank to equalize static potential. Grounding connects the equipment to earth to drain the charge. Both are needed before opening domes or valves.

Ullage definition

Ullage is the free space left in a tank above the liquid. Confirm the receiving tank has enough ullage before transfer, because overfilling is a leading cause of tanker releases.

Unattended transfer rule

Never leave a transfer unattended. Stay at the controls so a failing hose, leaking fitting, or rising level can be shut down immediately before a spill or fire develops.

Static discharge prevention

Keep bonding and grounding attached throughout transfer and until all connections are closed. Removing them early can create a spark near flammable vapor and ignite the product.

Cargo tank specification examples

MC 306/DOT 406 tanks carry flammable liquids, MC 307/DOT 407 tanks carry corrosives, and MC 331 tanks carry compressed gas. The specification plate must be legible and current.

Portable tank securing

Portable tanks are not permanently attached to the vehicle. Check the securing devices and confirm the tank's test date is current before hauling it on public roads.

Compressed gas relief valves

Compressed gas tanks use relief valves to prevent overpressure. They must be undamaged, unobstructed, and directed away from the cab and from personnel during venting.

Cryogenic tank venting

Cryogenic tanks vent continuously to control internal pressure. Keep the vents clear and never block or plug a vent to stop visible vapor, which can cause dangerous overpressure.

Tank shell inspection

Inspect the tank shell for dents, cracks, corrosion, and leaks at seams and welds. A crack or leak in the shell or a compartment bulkhead is an out-of-service condition.

Vent inspection purpose

Vents must be open and unobstructed. A plugged vent lets pressure build or vacuum form, which can rupture the tank or collapse it during unloading.

Manhole cover check

Manhole covers and gaskets must seat fully and hatches must be closed and latched before moving. An unlatched hatch can leak or open during a rollover.

Hose inspection points

Check hoses for cuts, bulges, soft spots, and worn couplings, and confirm the correct gaskets are in place. A hose failure during transfer is a spill and fire hazard.

Required tanker emergency gear

Tankers need charged and mounted fire extinguishers, a spill kit, warning triangles, and any PPE the cargo requires, in addition to the equipment required on all commercial vehicles.

Smooth bore tank behavior

A smooth bore (unbaffled) tank produces the strongest longitudinal surge. Allow the greatest following distance and the lowest curve entry speeds when hauling one.

Speed selection with liquid loads

Posted speed is a maximum for ideal conditions. Rain, ice, or a partly filled tank requires a lower speed that keeps surge and stopping distance within safe limits.