Complete Guide to Tanker Trailers

13 Jun.,2022

Looking to safely transport liquids, gases, or bulk dry goods? Check out this complete guide to tanker types to learn which is right for your next job.


Chemical Tank Trailer

When it comes to truck trailers, there are many options to choose from depending on your needs: dry vans, reefer trailers, lowboys, flatbeds and more. But when you need to safely transport liquids and other sensitive contents, tanker trailers are your best bet.

Known by their unique, cylinder-shaped tank, these trailers are commonly spotted at gas stations and are primarily used for heavy duty hauls and gives drivers and fleet managers options when it comes to needing to transport specific cargo, like HAZMAT materials.

If you’ve been looking for tanker trailers for sale and need more information on tanker types, sizes and uses, this is the guide for you. Continue reading to learn more and how to choose the best tanker trailer for your needs!

What is a Tanker Trailer?

A tanker trailer is a heavy-duty truck-trailer with a tank body that is typically approved to carry the following contents:

  • Chemicals
  • Liquids
  • Gases
  • Beverages (such as milk)
  • Dry/bulk goods (such as grains, sand, cement, plastic pellets, etc.)

Tanker sizes range from small to large, depending on your hauling needs and product weight, which is measured by gross vehicle weight rating (GVWR), or the vehicle weight after it’s loaded.

The largest tankers have a gross vehicle weight rating (GVWR) greater than 33,001 pounds, or 14,969 kilograms. These are also known as tractor trailers and considered a Class 8 commercial vehicle subject to guidelines from the Federal Motor Carrier Safety Administration (FMSCA), who sets regulations on commercial vehicles.

One of those regulations is that any driver who is hauling a tanker with over 1,000 gallons of liquid, must have an endorsement on their commercial driver’s license (CDL). This involves taking a knowledge test to show they can safely operate a tanker trailer.

What is GVWR and How Does it Affect Tankers?

In accordance with the Federal Highway Administration’s (FHWA) and its guidelines, heavy trucks and other vehicles must adhere to certain standards to optimize roadway safety. One of these guidelines is the GVWR, which sets standards for the maximum amount of weight that a tanker trailer was designed to safely carry. The GVWR’s are given in pounds so it’s recommended to take special care when translating the weight of liquids that are measured in gallons or the weight of dry bulk material, which is measured in cubic feet. Be sure to check that you are within legal limits.

The general guidelines for commercial truck-trailers are as follows:


Class 1: GVWR of 0–6,000 pounds

Class 2: GVWR of 6,001–10,000 pounds

Class 3: GVWR of 10,001–14,000 pounds


Class 4: GVWR of 14,001–16,000 pounds

Class 5: GVWR of 16,001–19,500 pounds

Class 6: GVWR of 19,501–26,000 pounds


Class 7: GVWR of 26,001 to 33,000 pounds

Class 8: GVWR of greater than 33,001 pounds; includes all tractor-trailers

Most tanker types will fall into the “heavy” category.

Tanker Types Explained

Tanker trailers are used for a variety of purposes and generally fall into one of the following categories:

  • Chemical tankers
  • Petroleum tankers
  • Agriculture tankers
  • Liquid food and beverage tankers
  • Water tankers
  • CNG (compressed natural gas) tankers
  • Compartmentalized (combined cargo) tankers

Additionally, there are further distinctions for tankers that make them useful for certain types of contents:

Insulated Tankers

When you’re transporting temperature-sensitive liquids, like dairy, an insulated tanker is used. This helps to regulate the temperature in the tank to keep it safe during transport.

Food Grade Tankers

Food grade tankers are designed to keep products sanitary throughout transport, while accommodating special goods such as Kosher and organic products. They are stainless-steel tankers, which provide sanitary conditions.

Asphalt Tankers

When transporting contents that need to remain hot, an asphalt tanker offers superior temperature control aided by insulation and sometimes a heating device.

No matter which tanker type you need, there’s one thing they all have in common: their cylinder shape.

Pneumatic Tankers

Pneumatic tankers, or dry bulk tanks, are those which empty via a pump and a blower with forced air. A series of cone-shaped hoppers are used to unload product beneath the tanker itself. They are vacuum-sealed and fully enclosed, ideal for transporting building materials, dry food, and chemicals.

Agricultural Tankers

These trailers often carry fertilizers or pesticides to agricultural sites, and may also include a water trucks equipped with side-spray capabilities for irrigation purposes or to minimize dust.

Why Do Tanker Trailers Have a Cylinder Shape?

The unique shape of a tanker trailer offers a number of benefits when carrying liquids and gaseous materials, which are the primary types of cargo they transport. Here are a few reasons why tankers are shaped like cylinders:

  • More stable: rounded edges don’t require as much reinforcement as a typical container that has corners and straight sides, meaning less pressure on the tank itself.
  • Lower center of gravity: ideal when carrying flammable materials like fuel and oil
  • Helps prevent liquid ‘surge’: liquid naturally moves around in the tanker, but the cylinder shape helps to prevent excessive surging. Some tankers have bulkheads within the tank to help minimize surge as well. Since tankers have weight limits, they cannot be completely filled, meaning liquid surge is always a factor for drivers to consider.
  • Easier extraction and cleaning: the rounded sides of a cylindrical tanker make for easier extraction since liquid can move down towards the low point. It also prevents material from getting stuck in hard-to-clean corners. Less product left over in the tank after a load means less contamination for the next load.

Tanker Types: DOT Codes for Trailers

Tanker trailers typically fall into one of the following U.S. Department of Transportation (DOT) categories for cargo tankers:

DOT 406

  • Petroleum products (jet fuel, gasoline, diesel), water, or milk
  • Tanker type has max 4 psi
  • Often a multi-compartmental tanker

DOT 407

  • Used for hauling mild, acids, or combustible products
  • Up to 40 psi

DOT 412

  • Used for corrosives and very heavy products
  • -5 to 25 psi

The maximum capacity for each type of trailer is dependent on your local market.

Tank Trailer Maintenance

If your fleet suddenly encounters a worn-out or damaged tank trailer, you may need a good refurbishing to return the trailer to its glory. Replacing the entire trailer can be a costly endeavor, but refurbishing gives owners and fleet managers the option of keeping the trailer for a fraction of the cost of buying new.

Refurbishing gives you the opportunity to update lighting and electrical, the brake system, and suspension. Many tank trailers, especially those made for food-grade transport, are designed to last. As long as they don’t have severe damage to the tank barrel or other structural issues, you may be able to refurbish and get years more added to the life of the tank trailer.

It’s important to find qualified tank trailer technicians that are certified to perform specific repairs and inspections. Look for NBIC R-Stamp certification when choosing a repair partner to ensure that they can meet all necessary repair requirements on both coded and non-coded tanks, including:

  • Petroleum
  • Chemical
  • Crude
  • Dry bulk

Hale Tank Services is an official R-Stamp repair shop and carries an extensive inventory of tank parts. If you’re looking to have your tank trailer serviced, get in touch with the experienced technicians at Hale Tank Services.

Find the Best Tanker Type for Your Fleet with Hale Trailer

If you’re looking for a tanker trailer for rent or purchase, or simply have questions about your options for tankers, then Hale Trailer is your best resource. Each of our locations is staffed with experts who can help you choose the best trailer for your needs and we even offer trailer maintenance services. Think of us as your local one-stop-shop for all things commercial trailers.

Call us for questions or details today: 800-232-6535.