Look around you.
The paint on the wall, the condiments in the fridge, the adhesive under the carpet…just about everything you can see began inside a liquid bulk tank trailer. It’s why transporting liquid freight is so critical to today’s supply chains. But the process is drastically different than moving cartons in a dry van.
Even if you’ve shipped liquids in drums or totes, that doesn’t prepare you for the ins and outs of managing liquid bulk. For newcomers to liquid bulk transport (and even those who just want to bone up), this article covers the equipment, the processes and the responsibilities of managing liquid bulk shipments – along with tips on choosing the right partners to help.
Bulk liquids, especially hazardous chemicals, also carry more risk than other loads. Have an accident with a trailer full of groceries and you lose two pallets of Cheerios. In contrast, a tanker truck collision could trigger the shutdown of a multimillion-dollar production line because a crucial raw material has washed over three lanes of Interstate 80.
Other factors that make bulk liquid shipments different from dry van shipments include:
Longer lead times: There aren’t as many tankers on the road as box trailers, so when you need a truck, it might take longer to find one.
Different driver requirements: Compared to regular dry van trucking, it’s much longer process to become a bulk truck driver. Drivers don’t simply go to truck driving school and then get behind the wheel of a liquid or dry bulk tanker truck. Due to the higher risks and costs involved (e.g., insurance premiums), most carriers won’t take a chance on a new driver until he or she has at least 4 years of flawless dry van driving. And, even then, you’re looking at 3-6 months of training until the driver is on his or her own.
More insurance: A carrier hauling a hazardous bulk liquid must carry at least $5 million in liability insurance. For non-hazardous commodities, the minimum is $1 million. Those figures come on top of the cargo insurance you’ll require, which varies with the value of the load.
Liquid bulk freight transportation also costs a good deal higher than dry van for many reasons.
When working with a bulk freight transport provider, ask about these cost factors:
The typical liquid bulk trailer holds 6,000-7,000 gallons. It can be made of stainless steel or aluminum. It can be insulated, to protect temperature-sensitive products, or non-insulated. It may consist of a single compartment, or be divided into two to four compartments for hauling different commodities at once.
There are also special food-grade trailers for products such as fruit juice, vegetable oil and food ingredients. Some carriers offer “tight fill” tanks that hold only up to 5,000 gallons. By filling these smaller tanks completely, you ensure that the liquid won’t get agitated in transit, reducing the chance of forming foam.
At the top of the tank is a dome, which is opened for loading the trailer. It’s extremely important to make sure that nothing but a hose and the liquid product pass through that dome.
In-transit heat
To protect temperature-sensitive and/or viscous liquids, most insulated trailers come with steam coils. When the trailer is parked, you can attach these coils to a source of steam, which then circulates through the coils, helping to maintain the temperature of the product in the trailer.
The main purpose of in-transit heat is to maintain a product’s viscosity so that it is acceptable for unloading. Bulk liquid tankers with in-transit heating capabilities have a series of steam coil lines that run along the floor of the tank. The truck heats and circulates coolant through these lines in a continuous cycle. When running at full strength – typically after 4 hours of continuous driving – this system will reach optimal full capacity working to maintain temperatures of materials that are rated for unloading at 150˚F or below.
Importantly, this in-transit system does not actually heat the liquid in the tank. Rather, it assists in maintaining the product’s temperature. In other words, it seeks to minimize the loss of heat during transit.
Steaming
Tank steaming occurs at most tank wash stations as well as other facilities (e.g., railyards). Such facilities have steam lines that connect a boiler to an external hook up of the tank’s coil heating system (only after the tanker’s lines have been flushed out if the in-transit heat system was charged). Once this connection is made, the boiler system will apply and build pressure through the steam lines before releasing it.
Ideally, the tank will be heated to a temperature above the required delivery temperature so that the driver has a “buffer” to allow for natural temp decreases. Steaming must be performed carefully as you can scorch the product by applying too much steam too quickly.
Although weight matters a lot in a dry van move, in liquid bulk the key measurement is volume. When you book liquid bulk freight, you don’t tell the carrier or broker how many pounds you need to move; you tell them how many gallons. That’s the only way to figure out whether you need one truck, or two, or more.
Weight does matter, however, when it comes to complying with federal regulations. Given the weight of the typical bulk liquid trailer and the tractor pulling it, don’t count on loading more than 45,000 lbs. on one truck if you want to stay within the Department of Transportation’s 80,000-lb. limit on gross vehicle weight.
Also, be sure to note the DoT’s maximum weights on single and tandem axles. You might be used to the idea that you can move product around inside a trailer to rebalance the weight across the axles. In a tank trailer, that tactic is impossible. Liquid seeks its own level, and there’s no rearranging it.
Companies use either air compressors or pumps to load and unload bulk liquids. An air compressor uses compressed air to blow liquid through a hose. Most people prefer to use an air compressor when possible because it’s more convenient than a pump, it makes less of a mess and you don’t have to clean it afterwards.
Unfortunately, you can’t use an air compressor to move flammable liquids, since it produces static electricity, which can create a spark.
A pump is the equipment of choice for those flammable commodities, as well as for certain other liquids that simply flow more easily when pumped than when pushed by air. The drawback to a pump is that the liquid passes through it. This means that you need to clean it after each use. It also means you can’t use a pump for corrosive liquids, which will eat through the metal and eventually ruin it.
Some very viscous liquids need both methods. The air compressor blows the liquid toward the pump, which then moves the product into the hose.
Just as important as having the right equipment is making sure proper procedures and oversight are in place during loading and unloading. It starts with simple communication.
Put your carrier or broker in touch with at least one person at the pickup site, and one at the delivery site, who understands all the necessary requirements. Your service partner will reach out to that point of contact to confirm details about procedures and equipment.
See the loading process in action:
If your driver is responsible for loading and unloading, make sure you have someone supervising that work at all times. The driver might be in charge, but if something goes wrong, the headache is yours.
Every time you prepare to load, first inspect the trailer. It needs to be clean, dry and odor-free. Also, make sure the driver knows if you’ll be loading the product out of a tank, a series of drums or other containers, and verify that he has the right equipment to do the job.
When a liquid bulk shipment arrives for unloading, the receiver should first take a sample to confirm that the truck has brought the right product, and that the product is in good condition. As the driver attaches the hoses, the receiver should double check to make sure the product will be flowing into the right tank or other container.
There are two primary methods for unloading a trailer, using a compressor or a pump. Air compressors and pumps work pretty much the same way for unloading as for loading, and they’re subject to the same restrictions for flammable and corrosive liquids.
Some trailers unload from an opening at the center; others unload from the rear. The difference can be important. If your truck is parked on a surface that pitches upward, toward the rear of the truck, and you’re unloading from the rear, some of the liquid will stay stuck in the front end of the trailer.
That leftover bit, called the heel, can prove expensive: if you can’t get it out, you’ll need to dispose of it elsewhere. To avoid waste, make sure the mechanism for unloading fits the environment where you’ll be using it.
Another important precaution: if you’re unloading with a pump, make sure the dome is open. Otherwise, the vacuum created by the pump could collapse the trailer walls, ruining a piece of equipment worth over $100,000. On the other hand, if you’re unloading with a compressor, make sure the dome is closed.
One of the biggest differences between liquid freight and other kinds of freight is the need to wash the trailer. After dropping a load, the driver might have to travel an hour or more—maybe even to another state—to reach a tank wash station.
This requirement adds extra time to every shipment. It also adds cost, partly because every shipment includes deadhead miles, and partly because the shipper pays for the wash.
Not every washing facility is designed to clean every liquid bulk tank. Some handle chemicals only, while others are designed only for food-grade loads. The wash station may use detergent, steam or a caustic wash to clean the tank, depending on the last product hauled. Along with the trailer, the station also washes pumps and hoses.
When a driver arrives to pick up your load, you should not only inspect the tank, but also ask the driver for a washout slip from the wash station. This document tells you exactly how the equipment was washed, letting you know if it was done correctly.
The cost of washing the trailer may appear on your freight bill as a separate charge. For some products, the carrier will apply a standard washing charge. For others, the carrier will pass along the actual dollar amount that the wash station charges. To avoid surprises, ask about this charge when you book the load.
Plenty needs to be done to ensure liquid bulk loads ship and arrive correctly and safely. It’s important to know where specific responsibilities lie to avoid finger pointing. This table delineates the responsibilities for each party.
| Shipper Responsibilities | Receiver Responsibilities | Carrier Responsibilities |
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Typically, the shipper is responsible for loading a liquid bulk shipment, and the receiver is responsible for unloading. But that’s not always the case.
When you book a load, establish up front who will load and unload so there are no misunderstandings when the truck arrives.
The downside risk of choosing an unqualified carrier is significantly greater for tanker truck loads. Don’t take chances. Sometimes all it takes is a conversation, peppered with the right kinds of detail-seeking questions, to spot the real experts from the posers.
When qualifying tanker truck carriers to haul for your company, consider the following:
Here are some of the biggest advantages of working with a 3PL as opposed to a carrier.
Cut freight costs. Most freight 3PLs have very large networks of carriers. A 3PL can leverage the size of its network to find the best carrier for a shipper’s load based on experience, equipment and cost. A 3PL can essentially ‘comparison shop’ on behalf of their shipping customers.
Move freight fast. Again, the large size of a 3PL’s carrier network allows for greater flexibility in meeting the timelines of shippers. From there, communication is vital to iron out schedules that work for shippers and destination facilities. This scheduling may also need to account for stops for scales for weighing as well as tank washes.
Remove demands of traffic management. When a shipper books a load with a carrier, that shipper typically must allocate internal resources to track that load and manage the timeline and stakeholder expectations. 3PLs can handle those tasks on the shippers’ behalf.
Provide multiple transportation modes. Some 3PLs, like Bulk Connection, that specialize in bulk freight shipping can handle transportation across liquid and dry bulk freight; effectively giving shippers a ‘one-stop-shop’ for their transportation needs.
Maintain carrier information. For shippers going it alone and working with different carriers directly, there can be a lot of work that goes into maintaining the carriers’ licensing, insurance and regulatory compliance information. Some 3PLs even have dedicated teams whose sole responsibility is to keep these records updated. This ensures that the 3PL’s TMS system assigns shippers’ loads ONLY to carriers that are up-to-date and qualified to handle them.
Perform coordination among stakeholders. When a bulk freight 3PL is a true expert, it understands that there are so many details that make the difference between a successful and unsuccessful load. As such, these 3PLs will guide you through the entire load. This includes calling both the loading and unloading facilities to confirm key items like operating hours, on-site staffing, and the necessary equipment. It also means staying in contact with these stakeholders until the load is completed.
So many of our customers are in heavily regulated industries. For chemical and food ingredient shippers, for example, compliance is not optional — it’s mission-critical.
So, we’re very adept at the following:
But it’s not just paperwork. Our risk management also focuses on equipment cleanliness and compatibility, and preventing cross-contamination. Also, we are ISO-9001 certified, so everything we do is aligned completely with the most rigorous quality control standards in existence.
Shippers can and do use both carriers and freight 3PLs. Often, a shipper will have a comfort level with a specific carrier in a specific lane(s). As capacity is needed for new lanes however, shippers can lean on 3PLs to source them and/or lean on 3PLs to simply explore options in these new lanes. Some shippers may also choose to augment existing carrier arrangements with 3PL-based loads within the same lane so that they are not too reliant on a single carrier.
There are other times where a shipper may have a new product that is outside of its regular carrier’s wheelhouse and, again, a 3PL can step in and handle transportation for that product.
Before you start looking for equipment to move a liquid bulk shipment, know the answers to these questions your carrier or broker will ask:
If you do not know an answer, involve the appropriate facility contact before booking. Discovering a missing adapter or incompatible unloading setup after the truck arrives can delay the entire shipment.
Use this checklist when booking your next load:
Planning a bulk liquid shipment? Contact Bulk Connection with your product details, shipment quantity, origin, destination and required dates. We’ll help you work through the equipment and transportation requirements.