Tank Types and Construction Flashcards

For endorsement purposes, which description best fits a vehicle that needs a tank vehicle (N) endorsement?

Answer: A vehicle hauling a tank with an individual rated capacity over 119 gallons and an aggregate rated capacity of 1,000 gallons or more

Under federal rules, a tank vehicle carries liquid or gas in tanks with an individual rated capacity over 119 gallons and an aggregate rated capacity of 1,000 gallons or more. The tank may be permanently or temporarily attached.

A driver hauls several portable tanks on a flatbed. Each tank has a rated capacity of 100 gallons, and together they hold 1,200 gallons. Under the federal definition, is this a tank vehicle?

Answer: No, because no individual tank is rated over 119 gallons

Both conditions must be met. Each tank must be rated over 119 gallons and the aggregate must be 1,000 gallons or more. Here the individual tanks are only 100 gallons.

What is the main purpose of baffles inside a tank?

Answer: To slow the liquid's forward-and-back surge

Baffles are walls with holes in them. They let liquid pass through but slow its forward-and-back movement.

How does a bulkhead differ from a baffle?

Answer: A bulkhead divides the tank into separate compartments, while a baffle has holes that let liquid pass through

Bulkheads divide a tank into separate compartments, and liquid cannot flow between them. Baffles have holes that let liquid pass through while slowing its movement.

Which tank design has no baffles or bulkheads inside and allows the most liquid surge?

Answer: Smooth bore tank

A smooth bore tank has nothing inside to slow the liquid, so surge is greatest. Its interior is also easy to clean.

Why does a smooth bore tank call for especially gentle braking and acceleration?

Answer: The liquid can surge freely from end to end, which can push the vehicle

With no internal barriers, the liquid moves freely and its momentum can push the truck forward or back.

Why must a tank driver leave room for outage when loading some liquids?

Answer: To allow for liquid expansion as it warms

Liquids expand as they warm. Leaving outage, an empty space at the top, keeps the tank from overfilling or leaking.

Which statement about tank vehicles and rollover risk is correct?

Answer: Liquid cargo gives a tank vehicle a high center of gravity, which raises rollover risk on curves

Many tanks carry liquid high above the road, so the center of gravity is high. This makes rollovers more likely, especially on curves and ramps.

A baffled tank still has what remaining surge concern?

Answer: Liquid can still move side to side, which can contribute to a rollover

Baffles slow forward-and-back movement, but liquid can still move side to side. That sideways movement can contribute to rollovers.

A driver is loading a tank with several separate compartments. What is true of the surge in a bulkhead-divided tank?

Answer: Surge is limited to the liquid within each compartment

Bulkheads are solid, so each compartment acts as its own tank. Liquid can surge only within its own compartment.