FL CDL Tanker key terms

The forward and backward movement of liquid cargo inside a partly filled tank when the vehicle speeds up, slows down, or turns. It pushes against the tank ends and can make the rig hard to control.

An internal wall inside a tank that divides the liquid into smaller compartments to reduce front-to-back surge. Baffles have holes that let product flow slowly between sections.

A solid internal wall that separates a tank into distinct compartments so different products can be carried at once. Unlike a baffle, it blocks flow completely between sections.

A tank with no internal baffles or bulkheads, so the entire liquid load moves as one mass. Surge forces are strongest in these tanks, especially when they are only partly full.

The empty space left above the liquid in a tank to allow for expansion as product warms up. Too little outage can cause overflow or pressure buildup; too much increases surge.

A separate section of a tank trailer divided by bulkheads, each holding its own product and quantity. Drivers must track which compartment holds which product and how full each one is.

The shifting weight of liquid cargo that can push a tank vehicle forward at a stop or sideways in a curve. It is the main reason tank vehicles need longer stopping distances and slower turns.

The sideways force level at which a tank vehicle tips over, usually lower than for a dry van because of a high center of gravity. Staying well below it means slowing down before curves and ramps.

The point where the vehicle's weight is balanced. In a tanker it sits higher than in most trucks, and liquid movement can shift it, making the rig easier to roll over.

A rollover caused by taking a highway ramp or curve too fast, common with tank vehicles. The posted ramp speed is often too high for a loaded tanker, so drivers slow further.

A tank vehicle's resistance to tipping and skidding, affected by load weight, liquid movement, speed, and road banking. Drivers protect it by slowing in curves and avoiding sudden steering.

The distance a vehicle travels from the moment brakes are applied until it stops. A loaded tanker needs more distance because of its weight and because liquid keeps pushing forward.

The gap a driver keeps behind the vehicle ahead. Tank vehicle drivers should allow at least one second per ten feet of vehicle length plus one extra second at speeds over 40 mph.

A hazard placard showing a skull and crossbones that marks a poisonous or toxic material. It warns responders and the public that contact or inhalation can be deadly.

A diamond-shaped warning sign placed on tanks and vehicles that identifies the hazard class of the cargo. Placards must match the material being carried and be visible from the road.

A category assigned to hazardous materials by federal rules, such as flammable liquid, corrosive, or poison. The class determines the placard, packaging, and handling rules that apply.

Any substance the government classifies as posing a risk to health, safety, or property during transport. Tanker drivers must know its hazards, handling rules, and emergency steps before loading.

The document that describes the hazardous material being transported, including its name, class, and quantity. It must be kept within reach and shown to inspectors or responders on request.

A reference carried in the cab that lists initial response steps for hazardous materials by guide number. Drivers use it to find isolation distances, protective clothing, and firefighting advice.

The N endorsement added to a CDL that allows a driver to operate a tank vehicle. It requires passing a knowledge test and, in Florida, meeting the same medical and licensing rules as other CDL holders.

The H endorsement on a CDL that allows driving a vehicle carrying hazardous materials that require placards. It requires a knowledge test, a security threat assessment, and fingerprinting.

Commercial driver license, the credential required to operate large trucks and tank vehicles on public roads. Florida issues it under federal standards, including knowledge and skills tests.

A vehicle designed to carry liquid or gaseous materials in a permanently mounted tank, or a portable tank of 1,000 gallons or more. Driving one requires the tank endorsement.

The required check of the vehicle before driving, covering brakes, tires, lights, tank, hoses, and emergency equipment. For tankers it also includes checking for leaks, secure hatches, and placards.

An inspection of the tank, piping, valves, and hoses for drips or wet spots before and after loading. Any leak must be fixed or reported before the vehicle moves.

A fitting that controls the flow of liquid or vapor into and out of a tank. Valves must be closed and capped during travel unless the rules allow otherwise.

A system that captures fuel vapors displaced from a tank during loading instead of releasing them to the air. It uses hoses and fittings that must be connected and checked for tightness.

A flexible tube used to move product between the tank and storage. Hoses must be inspected for cracks, bulges, and worn couplings, and must be properly stowed before driving.

Inspection of tire pressure, tread depth, and sidewall condition. Underinflated or damaged tires on a tanker can overheat and fail, and they hurt stability when the load shifts.

A charge that builds up when liquids flow through pipes and hoses. It can spark and ignite flammable cargo, so tanks and equipment must be bonded and grounded before transfer.

Connecting the tank vehicle to the storage tank with a cable so both share the same electrical charge. This prevents a spark from jumping between them during loading or unloading.

Connecting the tank vehicle to the earth so static electricity drains away safely. It is done before product transfer begins and kept in place until transfer ends.

A liquid that gives off vapors that can catch fire easily at normal temperatures. It must be loaded, unloaded, and transported with bonding, grounding, and no smoking nearby.

A requirement that no one smoke or carry open flame near a tank vehicle carrying flammable cargo. It applies during loading, unloading, and while the vehicle is parked.

A record showing which product is in each compartment and how much. It helps the driver keep the load balanced and gives responders information after a crash.

A quick way to stop the flow of product during a spill or fire, using valves or an automatic system. Knowing where the controls are can prevent a small leak from becoming a major release.

The distance people should move away from a hazardous material release, based on the guidebook and the material. It protects the driver, responders, and the public from fire, vapor, or explosion.

Methods such as dikes, absorbents, and closed valves used to keep a released product from spreading. Drivers report the spill and keep people away while responders take over.