Transporting and storing materials can be much more complicated than simply finding a drum or tote and filling it with your contents. The U.S. Department of Transportation (DOT) and the United Nations (UN) have specific guidelines that companies must follow to comply with their regulations. However, it isn’t just red tape — these rules ensure the public, transportation workers and the environment stay safe and remain healthy and productive.
To make sure you’re ready for your next DOT inspection, we’ve put together some of the more common definitions and rules required so you can be fully prepared to select your shipping or storage containers and ensure they are ready for their next voyage to or from your warehouse.
Definition of a DOT-Approved Container
The U.S. Department of Transportation is a federal agency responsible for the regulation and enforcement of transportation safety standards across America. It oversees numerous administrations, each responsible for different transportation sectors, including aviation, railways, highways and ports. Among its many priorities, the DOT defines which types of materials can be transported and how. Of particular interest are hazardous materials, such as flammable, corrosive, toxic or other dangerous goods that can pose severe safety threats if improperly handled during transportation.
DOT-approved shipping containers are transport vessels that meet the DOT’s current standards for safely shipping hazardous and other materials. DOT shipping containers must be designed to securely transport high-risk materials, such as fluids and gases, to ensure that they arrive safely.
Safety threats when shipping certain materials can include fire, explosions, corrosion, infections and other hazards. Transporting hazardous materials in a U.S. DOT-approved shipping container greatly reduces the risk of these threats becoming a reality.
How Does the U.S. DOT Define “Hazardous Materials”?
DOT hazardous materials are any material that the DOT has defined as having the potential for threats like fire, explosions or other health and safety risks. The DOT organizes its hazardous material classification by type of product and determines how that type of material can be shipped.
There are nine DOT classes of hazardous materials, and every hazardous material being shipped is assigned to one of these nine classes. Each of the nine classes may also be subdivided into divisions based on their specific chemical properties, such as whether they are flammable or toxic.
The nine U.S. DOT hazardous materials are:
- Class 1 — Explosives: There are six divisions of explosive materials, ranging from materials having a mass explosion threat to insensitive materials that aren’t a mass explosion hazard.
- Class 2 — Gases: Transported gases can be rated as flammable, toxic or non-flammable and non-toxic.
- Class 3 — Flammable and Combustible Liquids: Flammable and combustible liquids are rated based on their flashpoint from 0 degrees up to 141 degrees Fahrenheit.
- Class 4 — Flammable Solids: Flammable solids are considered purely flammable, spontaneously combustible or dangerous when wet.
- Class 5 — Oxidizers and Organic Peroxides: Class 5 materials are rated as either oxidizers or organic peroxides.
- Class 6 — Poison (Toxic) Substances and Infectious Substances: Class 6 materials are divided into either poisonous (toxic) materials or etiologic (infectious).
- Class 7 — Radioactive Materials: Any material that spontaneously emits radiation is considered radioactive.
- Class 8 — Corrosives: Corrosives are any liquids or solids that harm human skin or have a high corrosive rate on metals.
- Class 9 — Miscellaneous and Dangerous Materials: Any other material that presents a threat during transportation but doesn’t fit into the above categories is considered class 9.
With DOT shipping of hazardous materials, the packaging must be labeled with the appropriate hazardous placard containing the class and division of material. Accurately reporting which materials are contained in the transportation vessels saves lives because it lets cargo handlers know the material’s proper handling instructions. By shipping contents in DOT-approved containers for hazardous waste, you can ensure you comply with DOT regulations while protecting people and the planet.
Container Requirements for DOT Approval
DOT-rated containers are used in a wide variety of industries. The DOT rating system uses a set of codes to determine if a container possesses the required safety parameters to be used in transportation. The DOT uses a rating system to prevent a container from spilling its contaminants or causing fire or explosion. The DOT-rated containers are often required for certain contents that pose a higher than average risk during transportation.
Many of the DOT standards focus on preventing a container from cracking or rupturing in an accident. This means that a DOT-rated container is specifically designed to sustain higher forces, including vibrations or impacts, as well as extreme temperatures or pressures.
To better understand the DOT rating system and how it applies to containers, we will discuss the common transportation containers and how the DOT standards apply to them.
UN/DOT Rating System for Containers
When transporting liquids and solids, containers receive a DOT code broken down into five or six sections, which each specify something different about the container. These DOT codes specify which types of products and how much can be stored in each container.
The first section of the code indicates the type of container it is by using a number. Some of the container types include:
- Composition packaging
The first section of the code also identifies the container’s material by assigning a letter. Containers are usually made of metal or plastic, but the DOT code allows manufacturers to construct the container from many materials. Some types of container materials can include:
- Natural wood
- Glass or porcelain
The last part of the first section of the code specifies if the container has an open or closed head, meaning whether the container opens using a latch or is permanently sealed and requires special tools or cutting to be opened. After the letter used to describe the material, the number 1 is used to indicate a closed head, and 2 is used to indicate an open head.
The second section of the code indicates the packing group and the maximum amount of weight the container can carry. The packing group is designated by an X, Y or Z and indicates high, medium or low hazard contents, respectively.
After the packing group designation, the maximum weight of the package is denoted in kilograms. For example, a high hazard container with a maximum packing weight of 25 kilograms would be denoted “X25.”
The third section of the DOT rating system is used to specify if the container can contain liquids or solids. The letter S is used to indicate that the package cannot contain free liquids. If the container can contain semi-liquids, there will be a number instead of an S to indicate the maximum specific gravity of the substance permitted in the container.
The fourth, fifth and sixth sections of the DOT rating system are used for the year of manufacture, country of manufacture and the manufacturer’s code, respectively.
Types of DOT Containers
DOT-rated containers are used to transport materials by road, rail, air or sea.
What makes the DOT/UN rating so important is their safety requirements, which greatly increase the container’s ability to undergo disruptive conditions and remain intact and not spill or leak its contents.
To get a better understanding of how the DOT and UN rating system affects containers’ design, we will explore the different types of containers.
Drums are one of the most popular DOT container types due to their easily transportable size and stackable design. Many companies use drums to store and transport a wide variety of liquid and semi-liquid materials.
The biggest reason why companies choose to use drums to store materials on-site is that their unique dimensions allow them to be stacked on top of each other and remain secure and stable. Also, drums typically use a latch lid system, allowing them to remain completely sealed if they get tipped over.
Although drums come in many sizes ranging from 15 gallons to several hundred gallons, the 55-gallon drum is considered the most popular. The 55-gallon drum was developed in the 1850s during the oil prospecting era in Pennsylvania. Oil prospectors selected 55 gallons or 45 imperial gallons due to the ideal compromise between storage weight and maneuverability. At this weight, a person could move it around by themselves using a wheel dolly.
The drum’s material depends on the drum’s contents and the desired service duration of the drum. For hazardous contents, the drum must consist of material that the contents cannot degrade or interact with chemically. For instance, steel drums are often used to transport or store petroleum products, such as crude oil or diesel fuel, rather than wood. Steel is much better at resisting the degrading effects that petroleum products often have on wood.
A big consideration of the DOT/UN rating for drums is to ensure that the drum will not fail in any way during transportation. To accomplish this, DOT codes specify certain design requirements for drum manufacturers, including:
- Material selection
- Drum thickness
- Latch or closing mechanism
In addition to design requirements, DOT/UN ratings also include strict rules for drum labeling. These labels specify which of the nine DOT classes of hazardous materials the drum contains. Labels must also follow the size and color requirements from the DOT/UN convention.
DOT/UN-Rated IBCs and Totes
When it comes to DOT- and UN-rated intermediate bulk containers (IBCs) and tote tanks, stainless steel tanks are usually preferred due to their increased toughness and resistance to failure compared to plastic containers.
There are, however, a few common features that a DOT-approved tote tank must have to pass a DOT inspection. Some of these features include:
- Testing every 30 months
- Fusible vents
- Secondary closure outlet
For a tote container to be DOT approved, it must undergo a leak-proof test and an extensive visual inspection every 30 months. In addition, every tote must also undergo a thickness test every 60 months where the material thickness of the tank is measured throughout to ensure it remains structurally safe.
Fusible vents are typically 3 inches in diameter on the top of the tote container. In a fire or other emergency, the vents will break and allow pressure relief from inside the tank to prevent an explosion. It’s important to note that these fusible relief vents should only activate in extreme circumstances to prevent a catastrophic explosion. They’re not meant to be used as a relief valve to vent gases that can build up due to fluctuating temperatures.
IBCs and totes typically have a drain valve on the bottom to release their contents. DOT requirements state that this release valve must have a secondary mode of opening up to ensure the contents can be released. This is usually achieved by having another release valve threaded into the cap of the first release valve.
Packaging for Radioactive Contents
When transporting contents that might be radioactive, it’s essential to use DOT-approved waste containers. In addition, the DOT requires that special precautions be taken. First, the material must be classified into one of three categories:
- Industrial packaging
- Type A packaging
- Type B packaging
Objects that might be slightly contaminated with radioactive material, such as clothing, laboratory samples and smoke detectors, must be transported in industrial packaging. Industrial packaging is defined as “strong and tight containers.” Although this definition doesn’t give an exact prescription of the packaging requirements, it’s safe to assume that a secure and robust container should be acceptable.
DOT Type A containers are required for materials with a higher specific activity level, meaning materials with more radioactive intensity than materials requiring just industrial packaging. Type A packaging must withstand various tests without releasing any of the radioactive materials contained within them. Typical contents that require DOT Type A shipping containers include radiopharmaceuticals and certain regulatory qualified industrial products.
DOT Type B containers are reserved for materials that exceed the limits of Type A packaging requirements. Items that require Type B packaging include any materials that would present a radiation hazard to the public or environment if a major release from them should occur. This means Type B packaging needs to withstand testing during normal transportation of radioactive goods and testing that simulates a catastrophic accident during the transportation of those goods. Type B packaging is reserved for materials containing a high level of radioactivity, such as spent fuel from nuclear power plants.
Choose Sharpsville Container for Custom DOT Approved Containers
For high-quality, DOT-approved shipping containers, choose Sharpsville Containers. Since we’re an ISO 9001 company, you can rest assured that our containers are expertly engineered and tested to ensure our customers meet DOT shipping standards for all materials, including hazardous contents.
Serving a wide range of industries, including food and beverage, dairy, pharmaceuticals and more, Sharpsville Containers offers a broad range of containers to meet your needs. In addition to stainless steel tanks, high-pressure cylinders, UN/DOT transport vessels and reactors and fermenters, we also offer custom engineering solutions so you can get the exact container for your application.