CSLB General Building (B) — All Questions

What is 'liquid surge' in a tank vehicle?

• a.The buildup of vapor pressure inside a sealed tank
• b.The wave action of liquid that moves back and forth when the vehicle changes speed✓
• c.The foaming of liquid caused by rough road surfaces
• d.The leakage of liquid past a faulty valve

Liquid surge is the movement of liquid in partially filled tanks. When the driver brakes, the liquid surges forward and can push the truck ahead, then rock it backward. This wave action can strongly affect vehicle handling and control.

Why are unbaffled (smooth bore) tanks often used to haul food products such as milk?

• a.They hold more product than baffled tanks
• b.They eliminate liquid surge entirely
• c.Sanitation regulations make it difficult to clean the inside of baffles✓
• d.They are cheaper to manufacture than baffled tanks

Unbaffled liquid tankers, often called smooth bore tanks, have nothing inside to slow the flow of liquid. They are frequently used to transport food products like milk because sanitation rules would make it very hard to clean baffles thoroughly. As a result, drivers must be especially alert to strong surge.

What are baffles inside a tank designed to do?

• a.Control the forward and backward surge of the liquid✓
• b.Prevent side-to-side surge in curves
• c.Increase the total capacity of the tank
• d.Keep the liquid from freezing

Baffled tanks have bulkheads with holes that let liquid flow through them. The baffles help control forward-to-back liquid surge when starting and stopping. They do little to control side-to-side surge, which remains a concern in turns and lane changes.

Side-to-side surge in a tank is most dangerous because it can cause which of the following?

• a.Excessive fuel consumption
• b.Vapor lock in the engine
• c.The cargo to overheat
• d.A rollover✓

Side-to-side surge is the liquid moving toward one side of the tank and then the other, such as during lane changes or curves. Because tank vehicles have a high center of gravity, this surge can create enough force to tip the vehicle over. Rollovers are a leading cause of tanker crashes.

What does 'outage' refer to when loading a liquid tank?

• a.A pump failure during loading
• b.The empty space left in the tank so liquid can expand✓
• c.A leak detected at the dome cover
• d.The total weight of the cargo

Outage is the space you must leave in a tank because liquids expand as they warm up. Different liquids expand by different amounts and therefore require different amounts of outage. You must never load a tank totally full or the expanding liquid could rupture the tank.

Why must some tanks be only partially filled based on the liquid's weight?

• a.To reduce the risk of the cargo freezing
• b.To make the vehicle easier to steer at high speeds
• c.Because a full load of a dense liquid could exceed legal weight limits✓
• d.Because dense liquids evaporate quickly

The amount of liquid you can load depends on how much it will expand, the weight of the liquid, and legal weight limits. A dense (heavy) liquid may bring the vehicle over its legal weight before the tank is even full. You may only be able to fill part of the tank with a heavy liquid.

How does a tank vehicle's high center of gravity affect driving?

• a.It makes the vehicle more likely to roll over✓
• b.It improves braking on wet roads
• c.It lowers the risk of rollover
• d.It has no effect on a loaded tank

Tank vehicles have a high center of gravity, meaning much of the weight is carried high off the road. This makes the vehicle top-heavy and easy to roll over. Liquid surge combined with a high center of gravity makes tankers especially prone to tipping in curves and sudden maneuvers.

What is the danger of hauling a partially loaded tank compared to a full one?

• a.Partial loads always weigh more than full loads
• b.Partial loads cannot legally cross state lines
• c.There is no difference in handling
• d.Liquid surge is greater, making the vehicle harder to control✓

With a partially filled tank, the liquid has room to move and create surge. This surge can affect braking, acceleration, and turning, and may even shove the vehicle in the direction the liquid is moving. A full tank has far less room for the liquid to surge.

Which type of tank has nothing inside to slow the movement of the liquid?

• a.Baffled tank
• b.Smooth bore (unbaffled) tank✓
• c.Compartmented tank with bulkheads
• d.Insulated cargo tank

Smooth bore or unbaffled tanks have no bulkheads or baffles inside. Nothing slows the liquid, so surge is strong and immediate. Drivers of smooth bore tanks must be extremely cautious, especially when starting and stopping.

When a driver of a smooth bore tanker comes to a stop, what can the forward surge of liquid do?

• a.Lift the front wheels off the road
• b.Automatically apply the parking brake
• c.Push the vehicle forward after the driver has stopped✓
• d.Cause the tank to leak at the seams

In a smooth bore tank, the liquid surges forward when braking and can push a stopped vehicle out into an intersection. Drivers must allow extra stopping distance and remain alert to this push. This is one reason smooth bore tanks require special driving skill.

Compared to solid cargo of the same weight, why does bulk liquid raise rollover risk?

• a.The liquid can shift and surge, moving weight and adding force in turns✓
• b.Liquid weighs more per gallon than solid cargo
• c.The liquid lowers the vehicle's center of gravity
• d.Liquid tanks are always taller than dry vans

Unlike a fixed solid load, bulk liquid moves inside the tank. This shifting weight and surge adds sideways force during turns and lane changes. Combined with the high center of gravity of tankers, it makes rollover a serious and constant hazard.

How do baffled tanks handle side-to-side liquid movement?

• a.They completely stop all side-to-side movement
• b.They convert side surge into forward surge
• c.They increase side-to-side surge
• d.They do little to control side-to-side surge✓

Baffles have holes oriented to slow forward and backward surge. They do little or nothing to reduce side-to-side surge because the liquid can still move laterally around them. Drivers must still be cautious in curves and lane changes even with a baffled tank.

Three factors determine how much liquid you can safely load into a tank. Which set is correct?

• a.Road grade, tire pressure, and axle count
• b.The amount the liquid will expand, the liquid's weight, and legal weight limits✓
• c.Ambient temperature, engine size, and brake type
• d.Trailer length, hitch rating, and fuel level

You must consider how much the liquid will expand in transit, the weight of the liquid, and the legal weight limits. A dense liquid may reach the weight limit before the tank is full. Outage must be left for expansion regardless of how heavy the product is.

What happens to most liquids as their temperature rises during transport?

• a.They become denser and take up less space
• b.They turn to vapor and escape
• c.They expand and take up more space✓
• d.They lose weight through evaporation

Liquids expand as they warm. That is why tanks require outage, the empty space that lets the liquid grow without over-pressurizing or rupturing the tank. The warmer the loading and travel conditions, the more expansion room may be needed.

A tank divided into several separate compartments by bulkheads is used to do what?

• a.Carry different products or help distribute weight across the vehicle✓
• b.Increase liquid surge for faster unloading
• c.Eliminate the need to check axle weights
• d.Allow the tank to be loaded completely full

Compartmented tanks have bulkheads that create separate sections, which can carry different liquids or the same liquid loaded to balance weight. When loading and unloading, drivers must pay attention to how weight is distributed among compartments. Improper distribution can overload an axle or make the vehicle unstable.

When loading a compartmented tank, why must the driver check the weight distribution?

• a.To ensure the liquid stays at a constant temperature
• b.So no individual axle is overloaded and the vehicle stays balanced✓
• c.To reduce vapor pressure inside the tank
• d.To prevent the baffles from cracking

Loading too much weight in the front or rear compartments can overload an axle or make the vehicle unstable and hard to handle. The driver should distribute the load so axle weights are legal and the vehicle balances properly. Uneven loading also worsens surge effects.

Which combination of hazards makes tank vehicles especially unstable?

• a.Low center of gravity plus heavy weight
• b.Baffles plus large outage
• c.Full tanks plus low speed
• d.High center of gravity plus liquid surge✓

Tank vehicles combine a high center of gravity with the surging movement of liquid cargo. Together these make the vehicle unstable and prone to rollover, especially in curves, ramps, and quick lane changes. Drivers must slow down and steer smoothly to manage both hazards.

Why might you be unable to fill a cargo tank completely even when it is under the weight limit?

• a.The pump cannot reach the top of the tank
• b.Full tanks are illegal in all states
• c.You must leave outage space for the liquid to expand✓
• d.The baffles block the top of the tank

Even if weight is not the limiting factor, you must leave outage so the liquid has room to expand as it warms. Loading a tank totally full leaves no room for expansion and can rupture it. The required outage depends on the specific liquid being hauled.

On a smooth bore tanker, when is liquid surge typically the strongest?

• a.When starting and stopping, because nothing slows the forward-back movement✓
• b.Only when the tank is completely full
• c.When driving at a steady speed on a straight road
• d.When the parking brake is set

Smooth bore tanks have no baffles, so the liquid surges freely forward and back when speed changes. Starting and stopping produce the strongest surge in these tanks. This is why smooth bore tanks demand smooth, gradual speed changes and extra following distance.

How can the weight of a dense liquid limit how much you load?

• a.It causes the liquid to expand faster than the tank allows
• b.You may reach the legal weight limit before the tank is full✓
• c.It lowers the center of gravity below safe levels
• d.It requires the tank to be loaded completely full

A dense or heavy liquid adds a lot of weight per gallon. You may hit the legal gross or axle weight limit long before the tank is physically full. In that case you can only partially fill the tank, which also increases surge.

Which statement about baffled tanks is TRUE?

• a.They completely prevent all liquid surge
• b.They are required for hauling milk and food products
• c.They increase forward and backward surge
• d.They reduce forward-and-back surge but not side-to-side surge✓

Baffles have holes that slow the forward and backward flow of liquid, reducing that surge. However, they do little to control side-to-side surge in curves and lane changes. Drivers of baffled tanks must still be cautious of lateral movement and rollover.

What should a driver do when hauling a partially filled tank to manage surge?

• a.Brake hard and late to overcome the surge
• b.Accelerate quickly to keep the liquid pushed back
• c.Anticipate surge and drive smoothly, allowing extra space✓
• d.Fill the remaining space with air pressure

With a partial load, the driver should anticipate the surge that comes with every speed and direction change. Smooth braking, gentle acceleration, and extra following distance help keep the surging liquid from taking control of the vehicle. Abrupt maneuvers make surge worse and can cause loss of control.

Bulkheads with holes in them that let liquid flow through are called what?

• a.Baffles✓
• b.Domes
• c.Outage vents
• d.Manifolds

Baffles are bulkheads inside a tank that have holes to let liquid flow through while slowing its movement. They help control forward and backward surge. Tanks without them are called smooth bore or unbaffled tanks.

Why is understanding liquid density important before loading a tank?

• a.Denser liquids require less outage than light liquids
• b.A denser liquid weighs more, so you may load less to stay within weight limits✓
• c.Density determines the color of the required placard
• d.Denser liquids do not surge inside the tank

Density tells you how much a given volume of the liquid weighs. A high-density liquid reaches legal weight limits with less volume, so you can only load part of the tank. Failing to account for density can leave you overweight or unbalanced.