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- Steel drums are durable and long-lasting.
- Open head drums are better for solids, semi-solids and viscous substances.
- Closed head drums are better for liquids and low-viscosity fluids.
- Both types can be used to transport hazardous materials.
Although very similar at first glance, open head versus closed head steel drums fulfill very different purposes and applications, and neither is fully interchangeable with the other. Understanding the similarities and differences between these two steel drum configurations can help you determine which types are most suitable for your business and when they are the most useful.
General Facts About Drum Containers
Steel drums belong to the general category of drum containers, one of the most frequently used container types worldwide. They are a commonplace fixture in warehouses, depots and other industrial environments.
Like other containers, such as hazmat shipping boxes, drums are highly versatile and employed to transport nearly any product, from foodstuffs to dangerous goods.
A typical drum container’s internal dimensions are standardized to 22.5″ diameter by 33.5″ height, granting them an internal volume of 13,320 cubic inches, or approximately 57.66 gallons (218 liters) of water if filled to the brim. However, drums are typically only filled to 55 gallons to prevent overfilling and leave enough headspace for liquids that expand when exposed to changing temperatures.
Most drums on the market are either plastic or steel, and steel drums are usually made of either stainless steel or carbon steel. Although heavier than plastic, steel drums are valued for their durability, reusability and long service life, making them highly versatile and cost-effective.
Specific custom shipping boxes can fit open head and closed head steel drums for transportation or long-term storage, such as overpack containers.
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Open Head Steel Drums
An open head steel drum (1A2 drums or open top drums) features a fully removable top cover or lid.
Open head steel drums do not possess hinged lids. Instead, the top cover is secured to the drum’s body with one of two typical locking mechanisms: a lever lock drum or a bolt ring. Both are UN (United Nations) and DOT (U.S. Department of Transportation) approved and are safe for industrial and transportation applications.
An open head steel drum with the top cover removed gives you easy access to the contents, making them more convenient to fill and empty as needed.
Typical Applications for Open Head Drums
Although you can use open head drums to transport liquids, they are best suited for semi-solid and fluid-like substances (e.g., sand, dirt, soil, gravel, etc.) due to the ease of operating the lid and the wide opening with the top cover removed.
Unlike closed head drums, there is no need for specific equipment or apparatuses for filling and emptying an open head drum. If necessary, they can even be loaded or unloaded by hand.
In addition, an open head drum is one of the only practical containers for the transportation of thick fluids and viscous substances (e.g., syrups, certain types of oils, glues, absorbents, some solvents). Such products cannot be reliably delivered through a pump or a piping system and would be challenging to remove from a closed head drum.
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Closed Head Steel Drums
A closed head steel drum (also called 1A1 drum or tight-head drum) does not feature a removable top cover. The top side of a closed head drum is solid and integrated with the drum’s body, forming a permanent seal similar to the bottom end. The only way to access the contents of a closed head drum is through a port called a bung opening.
Standard-size bungs on 55-gallon drums are typically 2″ in diameter, although they may range between 1″ and 3″, depending on the drum’s form factor. They feature appropriate steel screw caps, typically made of the same metal as the drum for maximum durability.
Most drums also feature a second opening known as a vent hole. Vent holes are about ¾” in diameter; their purpose is to allow gases produced by certain petrochemical products to vent out, preventing the drum from bursting. If you’re not using your drums for transporting such products, you can fit the vent hole with an appropriate vent cap, sealing it.
Although they are less convenient or readily reusable than open head drums, closed head steel drums are exceptionally durable and resistant to corrosion, especially if made of 304 or 316 stainless steel. Their life expectancy is 20 years, on average, although you can further extend it with proper cleaning and maintenance.
Typical Applications for Closed Head Drums
Closed head drums are best suited for low-viscosity liquids, such as water, gasoline, crude oil and other flammables and liquid combustibles. The 2″ bung is intended to fit appropriate piping and pumping systems, ensuring safe loading and loading of each drum without spilling.
Because closed head drums are typically associated with liquid hazardous materials, they generally are UN-rated and possess appropriate hazmat labels. For example, the most well-known application for this drum type is transporting crude oil, requiring a Class 3 hazmat label (flammable liquid).
Choose Air Sea Containers as Your Packaging Partner
At Air Sea Containers, we understand the importance of using the most reliable containers possible. We offer a wide selection of open head and closed head drums, compliant with all relevant national and international regulations. Whether you need to transport water or hazardous materials, we have the packaging you need.