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Section 8: Tank Vehicles

This section has information needed to pass the CDL knowledge exam for driving a tank vehicle. (You should also study Sections 2, 5, and 6.) A “tank vehicle” is used to carry any liquid or gaseous material in a tank that is permanently or temporarily attached to the vehicle or chassis. However, this does not include portable tanks with a rated capacity of less than 1,000 gallons.

Before loading, unloading or driving a tanker, inspect the vehicle. This ensures that the vehicle is safe to carry the liquid or gas and is safe to drive.

8.1 Inspecting Tank Vehicles

Tank vehicles have special items that you need to check. Tank vehicles come in many types and sizes. Check the vehicleʼs operatorʼs manual to make sure you know how to inspect your tank vehicle.

Vehicles must be purged of hazardous materials 48 hours prior to testing with documentation verifying the purge.

On all tank vehicles, the most important item to check for is leaks. Check under and around the vehicle for signs of any leaking. Do not carry liquids or gases in a leaking tank. In general, check the following:

  • Tank body or shell for dents or leaks.
  • Intake, discharge and cut-off valves. Make sure valves are in correct position before loading, unloading or moving the vehicle.
  • Pipes, connections and hoses for leaks, especially around joints.
  • Manhole covers and vents. Make sure covers have gaskets and that they close correctly. Keep vents clear so they work correctly.
  • Special purpose equipment. If your vehicle has any of the following equipment, make sure it works:
    • Vapor recovery kits.
    • Grounding and bonding cables.
    • Emergency shut-off systems.
    • Built-in fire extinguisher.

Make sure you know how to operate your special equipment. Check the emergency equipment required for your vehicle. Find out what equipment you are required to carry and make sure you have it (and it works).

High Center of Gravity

Hauling liquids in tanks requires special skills because of the high center of gravity and liquid movement. A high center of gravity means that much of the loadʼs weight is carried high up off the road. This makes the vehicle top-heavy and easy to roll over. Liquid tankers are especially easy to roll over. Tests show that tankers can turn over at the speed limits posted for curves. Take highway curves and on-ramp/off-ramp curves well below the posted speed limits.

Remember: A vehicle inspection needs to be performed daily.
This should be memorized as it is frequently asked on the written exam. You must purge all tankers within 48 hours of hauling hazardous materials and you must have proper documentation of the purge.
Remember: Tankers have a higher center of gravity, making it easier for them to roll over. In addition, fluids will shift to the outside of the turn, further increasing the rollover risk. Posted speed limits for curves are not designed for tank vehicles.

CDL:

Commercial Driver's License (CDL)

A CDL is required to drive any of the following vehicles:

  • Any combination of vehicles with a gross combined weight rating (GCWR) of 26,001 or more pounds, providing the gross vehicle weight rating (GVWR) of the vehicle being towed is in excess of 10,000 pounds.
  • Any single vehicle with a GVWR of 26,001 or more pounds, or any such vehicle towing another not in excess of 10,000 pounds.
  • Any vehicle, regardless of size, designed to transport 16 or more persons, including the driver.
  • Any vehicle required by federal regulations to be placarded while transporting hazardous materials.

HOS:

Hours Of Service

HOS refers to the logbook hours of service regulations.

OWI:

Operating While Intoxicated

Review Questions - Click On The Picture To Begin...

All of the following require a Tanker endorsement, except:
  • Portable tank with a rated capacity of 10,000 gallons
  • Tank that is permanently attached to the vehicle chassis
  • Large tanks of more than 1,000 gallons enclosed in a box trailer
  • Portable tanks with a rated capacity of less than 1,000 gallons

Quote From The CDL Manual:

A "tank vehicle" is used to carry any liquid or gaseous material in a tank that is permanently or temporarily attached to the vehicle or chassis. However, this does not include portable tanks with a rated capacity of less than 1,000 gallons.

Next
Which statement below is false?
  • Liquid tankers are harder to stop in an emergency than other types of vehicles
  • Tanker vehicles have a higher center of gravity
  • All tankers have baffle devices to limit sloshing of liquids
  • Liquid tankers are easier to roll over

Quote From The CDL Manual:

Hauling liquids in tanks requires special skills because of the high center of gravity and liquid movement. A high center of gravity means that much of the load's weight is carried high up off the road. This makes the vehicle top-heavy and easy to roll over. Liquid tankers are especially easy to roll over. Tests how that tankers can turn over at the speed limits posted for curves. Take highway curves and on-ramp/off-ramp curves well below the posted speed limits.

Prev
Next
All of the following tanker-specific inspections are correct, except:
  • All of these inspections are true and correct
  • Make sure manhole covers and vents have gaskets and that they close correctly
  • Check pipes, connections and hoses for leaks
  • Make sure intake, discharge, and cut-off valves are in the correct position before loading, unloading or moving the vehicle

Quote From The CDL Manual:

On all tank vehicles, the most important item to check for is leaks. Check under and around the vehicle for signs of any leaking. Do not carry liquids or gases in a leaking tank. In general, check the following:

  • Tank body or shell for dents or leaks.
  • Intake, discharge and cut-off valves. Make sure valves are in correct position before loading, unloading or moving the vehicle.
  • Pipes, connections and hoses for leaks, especially around joints.
  • Manhole covers and vents. Make sure covers have gaskets and that they close correctly. Keep vents clear so they work correctly.
  • Special purpose equipment. If your vehicle has any of the following equipment, make sure it works:
    • Vapor recovery kits.
    • Grounding and bonding cables.
    • Emergency shut-off systems.
    • Built-in fire extinguisher.

Make sure you know how to operate your special equipment. Check the emergency equipment required for your vehicle. Find out what equipment you are required to carry and make sure you have it (and it works).

Prev
Next
On all tank vehicles, the most important item to check for is:
  • Placards (if required) are present and undamaged
  • Grounding and bonding cables are working properly
  • Baffles are not damaged
  • Leaks from the tank

Quote From The CDL Manual:

On all tank vehicles, the most important item to check for is leaks. Check under and around the vehicle for signs of any leaking. Do not carry liquids or gases in a leaking tank.

TruckingTruth's Advice:

While there are many other items which can be considered the "most important", most state manuals specifically state that checking for leaks is the most important inspection.

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