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Bulk Liquid Transport 101: A Complete Guide To Bulk Liquid Transport Equipment


Bulk Liquid Transport 101: A Complete Guide To Bulk Liquid Transport Equipment

The success or failure of any bulk liquid transport heavily depends on the kinds of equipment used. And so we wrote this complete guide to bulk liquid transport equipment to give you a good grip of what pieces of equipment you should expect to see when your carrier comes to load or unload your bulk liquid freight.

In this article, you’ll learn

What is Bulk Liquid?

Bulk liquid, or liquid bulk cargo, is a liquid transported in large volumes in tanks on ships, cargo planes, or trailer trucks. The carrier vessels transporting these liquids must have the necessary equipment to load and unload them safely, and also to keep them pure during transit. Examples of bulk liquids are:

What Are Bulk Liquid Transport Equipment?

Bulk liquid transport equipment comprises those tools and accessories that are used to aid the transport and storage of bulk liquid cargoes. Common examples of bulk liquid equipment and accessories are:

  • Tank trailers
  • Chassis
  • Hose
  • Center/rear unloader
  • Heat coils
  • Catwalk
  • Pump
  • Compressor
  • Vapor recovery system
  • Scully System
  • Camlock fitting, and more.

And in this article, you’ll learn about these types of equipment and how they contribute to safe and secure bulk liquid transport.

Tank truck top after a wash

Bulk Liquid Transport Equipment: Tank Trailer

A tank trailer, or a bulk tanker, is a tank that carries bulk liquid freight, such as gas, acids, agrichemical products, and hazardous materials, in a trailer pulled by a freight truck. The tanks are usually cylindrical

The cylindrical shape of the tanks eases the loading and unloading of the liquid content of the tanker. There are, however, some that come in other complex shapes with hoppers and valves that make unloading easier and faster.

Another peculiarity of tank trailers is most have their insides fitted with baffles. Baffles help to reduce the agitation of the liquid content during transit. They are very useful in preventing the full weight of the bulk liquid from destabilizing or tipping the trailer over.

What are the Types of Bulk Liquid Tankers?

Tank trailers have two major categories, depending on the content they transport or their structures. The types of bulk liquid tankers according to their structures are:

  • General-purpose tank trailers
  • General-purpose tankers with heat coils
  • Pneumatic tank trailers
  • Vacuum tanks
  • Rubber lined tank trailers
  • Aluminum tank trailers
  • Compartmentalized
  • Fiberglass reinforced plastic tanks, and
  • ISO tanks

And the tanker types according to their bulk liquid content are:

  • Petroleum tankers
  • Food grade tankers
  • Petrochemical tankers
  • Hot product tankers, and 
  • Corrosive tankers.

Tank Trailer Types By Structure

Tank trailers come in various structures which make them suitable for various shipping conditions. The common types are:

  1. General-Purpose tank trailer

The general purpose tankers are used to transport bulk liquids that don’t require special care or procedures when transporting. They are the usual steel tankers that can transport liquids such as water and juice. 

  1. General Purpose tankers with Heat Coils

General-purpose tankers with heat coils are a step ahead of the mere general-purpose tankers. As the name suggests, the heat coils help to raise or maintain the temperature of temperature-sensitive bulk liquid content during transit. Another name for these tankers is in-transit heat trailers.

The heat coils in general-purpose tankers run through the underbelly of the tank. Hot liquid is then run through this network of coils to heat the bulk liquid. 

  1. Pneumatic tank trailer

Pneumatic tank trailers are tanks that have a series of hoppers on their underbellies. Each hopper connects to a valve the chemical content of the tank unloads through. They also have manholes for loading the tank.

Pneumatic tank trailers are best for draining the tank of the bulk liquid content during unloading. This is its major advantage over cylindrical general-purpose tank trailers which have only one outlet and are prone to having heels under inclined unloading conditions.

Although pneumatic tank trailers are mostly used for the transport of dry bulk cargo, such as sand and cement, they are also effective for liquid bulk cargo.

  1. Vacuum tank trailer

The vacuum tank trailer has two important parts: the tank and the pump. With the pump, the tank trailer can suck the bulk liquid from underground or any other location into the tank. The most common use of vacuum tank trailers is in the transport of septage, industrial liquids, sewage sludge, and animal waste. 

  1. Rubber Lined Tank Trailer

Rubber-lined tankers transport bulk corrosive chemicals. Butyl rubber lining is the most commonly used material for this purpose because of its corrosion and thermal expansion resistance.

Thanks to the durability and thickness of rubber-lined tank trailers, they can last for years before they need to be replaced. 

  1. Aluminum tank trailer

Aluminum tank trailers are trailers that transport petroleum and petrochemicals. With their lightweight, you can carry more volumes of bulk liquid before reaching the tanker weight limit in your state or country.

Aluminum tankers also have low operating costs, as they don’t consume a lot of fuel and don’t corrode. 

  1. Compartmentalized tank trailer

Compartmentalized tank trailers have compartments in them that allow bulk liquid tanker carriers to ship different chemicals at once in separate compartments. 

Care has to be taken, however, when picking liquids to ship in adjacent compartments. For instance, the various chemicals in the various compartments of a trailer truck must have similar transit temperature requirements. Otherwise, temperature bleeds from one compartment to another could happen, potentially affecting any of the chemicals.

  1. Fiberglass Reinforced Plastic Trailer

Fiberglass reinforced plastic (FRP) tanker trailer is a trailer of choice for most food-grade bulk liquids and corrosive chemicals. FRP tankers are also used to transport hazardous materials (HAZMAT). 

  1. ISO tanks

ISO tanks are built according to the standards of the International Standard Organization for the shipping of most bulk liquids, including hazardous and non-hazardous ones.

Tank Trailer Types By Tank Content

The content of a tank is another way to classify it, as there are trailer tankers for specific purposes. And each type has tools and equipment articles that make it suitable for the kind of bulk liquid it carries. 

The types of tank trailers according to their content are:

  1. Petroleum tankers

The DOT 406 gasoline tanker transports gas and other fueling chemicals, such as propane and oil. And because of the flammability of the contents of petroleum tanks, they must have HAZMAT endorsement before they travel on the road. 

  1. Food grade tankers

Food grade tank trailers transport eatables. These trailer tankers are designed to keep their bulk liquid content in the most sanitary situations during transit. And they are usually steel tankers.

  1. Petro-chemical tankers

Petrochemical tankers, also known as DOT 407 trailers, transport bulk liquid crude oil products to and from refineries and oilfields. Some of the bulk liquid content of petrochemical trailer tankers are surfactants, friction reducers, and other oilfield exploration and production chemicals.

  1. Hot product tanks

Hot product tanks often have in-transit heat systems that help them keep products at a required temperature during transmission. These tankers are general-purpose tanks with heat coils or in-transit heat tankers.

  1. The corrosive tanks

Corrosive tankers carry chemicals, such as acids, which can corrode the walls of general-purpose tanks. These tankers must also possess HAZMAT  endorsement because of the toxic and corrosive nature of the bulk liquids corrosive tankers carry.

  1. Agricultural tankers

Agricultural tankers transport agrochemical bulk liquids, such as pesticides, herbicides, and fertilizers to agricultural sites. Depending on the type of agricultural product being transported, HAZMAT endorsement may be necessary.

Tank Trailer Handling Procedures

The proper handling procedures of a tank helps to ensure safe bulk liquid transport. It also mitigates the risks of disasters or losses to any of the parties involved in the transport of the liquid freight. And just like the carrier, you also have a part to play in these tank trailer handling procedures:

  1. Loading and unloading

The first thing to know about the loading and unloading procedures of any tank trailer is that only well-trained professionals should handle it. Both the shipper and the carrier must have a person each at the loading and unloading sites to ensure that everything goes according to plan. 

These people can confirm that the bulk liquids being loaded or unloaded are the right ones. The individual from the sipper’s end must also confirm that there has been no significant reduction in the quality of the bulk chemical freight during transit. All these have to be in place before you proceed with any loading or unloading activity.

Before loading, the carrier has to wash the tanker until it is clean, without odor, and dry. Also, the carrier should go around the tanker trailer to confirm that nothing is out of place before hooking up the hose for loading. And as soon as the loading is complete, every valve, dome, or opening should be closed. This is to prevent the wastage of bulk liquid products during transit.

There are two major methods of loading and unloading bulk liquid from a tanker: compressors and pumps. Unloading through a pump requires that the dome is open. Keeping the dome closed while the pump is running could force the pressure to damage the walls of the tanker. Conversely, close the dome when unloading through a compressor.

During loading and unloading, extra precautions have to be taken to ensure that there are no leakages. A drop of a strong acid could cause anything from 1st degree to 3rd-degree burns.

  1. Labeling

The law mandates the labeling of any trailer that carries hazardous materials. The labels help anyone recognize the kind of content the trailer is carrying so that they can take necessary precautions. And according to the FMCSA, all hazardous materials fall into nine major classes, with each class having its label.

The nine classes of hazardous materials according to the FMCSA

  1. Tank washing

Tank washing is the responsibility of the bulk liquid tanker carrier, and it must be done before every shipment. The only time when tank washing is not required is when a tanker is transporting the exact type of chemical it has most recently unloaded. Otherwise, the carrier must drive the tanker to a tank wash station for washing. 

At the tank washing station and after every thorough wash, they give each tank driver something called a wash slip. The wash slip is evidence that the tank has been thoroughly washed at the right facilities and is without risk of mixing chemicals from different shipments. It contains details of the wash type, the time, and the date of wash. Always ask to see the wash slip when the driver comes to load your bulk liquid product.

There are different washing facilities, depending on the tank trailer type. And each facility provides different wash types. The four common wash types are:

  • Regular Wash
  • Caustic Wash
  • Kosher Wash
  • Food Grade Wash

Proper washing prevents the accumulation of heels in the tanker. Heels are material residues after unloading. When heel accumulates in a trailer, it forms heel plaques that could be hard to wash off completely, And besides destroying the tanker, it makes shipping other bulk liquid products in the trailer risky. Getting rid of heels attracts additional charges by the wash station.

<<Average Tank Wash Cost Table Goes Here>>

Bulk Liquid Transport Equipment: Chassis

Drop frame tank chassis are long decks that tank trailers sit on. These chassis are usually low to the ground with a low center of gravity. Thus, providing better stability for the tank sitting on it while reducing the risk of content shifting or toppling at tight turns. 

Bulk Liquid Transport Accessories

Apart from the major equipment, bulk liquid transport would be almost impossible without the necessary accessories. Some of these accessories are:

  1. Hose

The hose of the trailer tanks is used to run fluids in and out of trailer tankers. One end connects to the trailer while the other connects to the loading or unloading tank. 

  1. Loading and Unloading Accessories

Many accessories make up the loading and unloading system of a tank trailer. Examples of these accessories include:

  • Butterfly valves are quarter-turn valves that regulate liquid flow by stopping, stopping, or slowing the flow. Like butterfly valves, gate valves also regulate the flow of liquid. One difference between these two is that butterfly valves can be used in limited space settings while gate valves can’t. Another type of valve used in the loading and unloading of bulk liquid is the emergency valve. The emergency valve is used to halt liquid flow in emergencies. 
  • The sight glass is a level sensor through which an operator can observe the level of the bulk liquid in the tank.
  • Delivery elbows are used to unload liquid from a tank into underground storage tanks. 
  • Other loading and unloading accessories include testing equipment, dome lids, and API adapters.
  1. Heating Coils

Heating coils are hollow tubes that run on the underbelly and the side of in-transit heat trailers. When the liquid freight needs to be heated, hot liquid is run through the coil to heat the liquid freight. The source of the heat is often the engine of the truck itself. 

  1. Catwalk

Catwalks help operators to get to the top of their trailer tankers. A task that would be otherwise impossible because of the height and cylindrical shape of trailer tankers. With a catwalk, operators can have a safe place to stand and walk as they work on the trailer tankers.

  1. Pump

Pumps are used to suck bulk liquid products out of tanks. They are very effective for all kinds of liquids except the corrosive ones. This is because the insides of a pump comprise metals that could corrode when corrosive liquids come in contact with them.

  1. Compressor

Air compressors are used to blow liquid products out of tanks and through a connected hose. Just like pumps, air compressors work for a wide variety of bulk liquids. But you should never use air compressors with flammable liquids.

  1. Vapor Recovery System

During loading and unloading of some chemicals, such as petrol, the release of vapor is almost unavoidable. During loading, the vapor could take up space in the upper part of the tank. And during unloading, the vapor could escape into the environment. But whether in the tank or the environment, we need to get rid of the vapor.

The vapor recovery system of a trailer truck helps to recover unwanted vapor before it gets into the environment. This system can also be used to extract vapor from the tankers to keep the liquid freight pure and safe for transport.

  1. Scully System

The Scully system on a trailer tanker ensures the safety of the vehicle and those around it by detecting retained product, preventing overfills, and grounding the vehicle so that it is safe to unload. The Scully system also provides a means of verifying the identification information.

  1. Camlock Fittings

The Camlock fitting, also called the cam and groove coupling, allows you to easily connect and disconnect hoses without the use of tools. It is a safe means of attaching a hose with no risks of accidental decoupling which could lead to waste of the liquid freight.

Factors to Consider for Safe Transport of Bulk Liquid

The safe transport of bulk liquid products relies on three major factors: volume and weight requirements, pump or compressor needs, and temperature requirements. When all these three are well-considered and planned for, the chances of successful bulk liquid transports are already high. 

But how exactly do these three factors contribute to the safety of your bulk liquid freights?

  1. Volume and Weight Requirements

The volume of your bulk liquid freight helps the carrier know what tank trailer size, or how many trailers to bring. You and the carrier should be clear on the volume requirements so that miscommunications don’t lead to losses for you or the carrier.

And although we don’t often mention the weight of the tank trailer as much as volume, it is still very important. Because according to the US Department of Transportation (USDOT), the gross weight of any vehicle on a commercial road must never exceed 80,000 lbs. Because of this limit, the volume of a very dense liquid you would carry at once in a trailer tanker would be lower than the volume of light liquid. But just to be safe, never load more than 45,000 lbs on the truck at once.

  1. Pumps and Compressors

Pumps and air compressors are two main methods of loading and unloading bulk liquids into and from tank trailers. Pumps suck the liquid out of the tank while air compressors rely on pressure to force out the liquid from the tank. 

However, you have to be careful to not use air compressors for flammable liquids. It could cause static electricity to build up and cause a spark. Instead, pumps are better for loading and unloading flammable liquids. But pumps are not perfect as well. They can corrode, making pumps useless for corrosive liquids. 

There are also some cases where we use both methods to force the liquid out. This is common when dealing with highly viscous liquids. Here, the air compressor forces the liquid toward the pump. The pump then sucks it out.

  1. Temperature Requirements

The temperature requirement of every bulk liquid should be known and taken into consideration during transit. Otherwise, the shipping of temperature-sensitive materials under the wrong temperature conditions could lead to revenue losses on the part of the shipper and the carrier. 

Knowing the temperature requirements of bulk liquids is mostly important for the shipping of liquids like oils and molten naphthalene, which solidify at low temperatures. Unloading these liquids in their solidified states could require extra cost and labor. So, it is best to communicate the in-transit temperature requirement of a bulk liquid with the carrier to help them know what tanker types and equipment to bring to the party.

Some trailers are equipped specifically for transporting temperature-sensitive chemicals. Some make use of steam, while others have in-transit heat systems. While in-transit heating systems only maintain the temperature of the bulk liquid, steam heating systems can help raise their temperatures.

Key Questions to Determine the Optimal Bulk Liquid Equipment

These questions would help reduce ambiguity between you and your carrier. Your answers to these questions give the carrier a better picture of what equipment to ship your bulk liquid product with. Some of these questions are:

  • What bulk liquid do you intend to transport?
  • Is the freight hazmat?
  • Is the freight temperature sensitive?
  • What volume are you transporting?
  • Can the loading facility accept a center or rear unload trailer?
  • Does the tanker truck need special connectors?
  • Is a pump or compressor required for unloading?
  • Can the customer accept air compressor offload?
  • What pressure can the tanker unload at?
  • Does the product require a rubber-lined trailer?
  • Are there any prior content restrictions we need to be aware of?
  • Will you require a dropped trailer?
  • Do you need any extra hoses for loading or unloading?
  • What are the pre and post-wash requirements?

Besides these questions, go through these tips on how to find a reliable chemical tanker capacity

Bulk Liquid Transport Equipment FAQ

The frequently asked questions about bulk liquid transport equipment are:

Why Do Tanker Trailers Have a Cylinder Shape?

The cylindrical shape of tank trailers makes the unloading of bulk liquid products easier. Also, cylindrical tanker trailers have a lower center of gravity, higher stability, and are easy to wash.

How much liquid does a tanker truck hold?

The volume a tanker truck can hold depends on the size of the trailer. With that said, the US Department of Transportation has an 80,000 lbs gross weight limit for tanker trailers. And to be on the safe side, limit the weight of your tanker to about 45,000 lbs.


The transport of bulk liquids could be a hassle without the right equipment. Using the wrong equipment could lead to excessive loss in revenues. That is why it is important to always communicate with your bulk liquid carrier to avoid these losses. But the challenge is how to transport your bulk liquids with all the right equipment to maintain product quality and safety without having to spend a fortune. Total Connection has a solution to this.

Total Connection

Total Connection is a third-party logistics company that has had almost three decades to build experience and expertise in bulk liquid transport. And in that time, we have improved our services and perfected the bulk liquid supply chain of all of our clients.

You can trust Total Connection for the best solutions customized to your business needs and budget without compromising quality or efficiency. In addition, we have an extensive network of partnerships with which we can secure the best deals and products for your company. And our expert array of staff is always ready to support your liquid bulk transport.

Thanks to these, we successfully ship over 10,000 liquid bulk loads per year for the hundreds of companies that have entrusted their bulk liquid transport to us. They have never regretted it. You too can be a part of them and learn not to lose sleep over your shipments when you contact us by filling out the quote form below:


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