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When selecting UN rated drums for shipping hazardous materials (HazMat), the type of drum closure is an important consideration. Open-head and closed-head drums have different designs, making them suitable for different applications.
Understanding the differences between these drum types can help you identify suitable packaging for your hazardous materials and ensure the correct packaging is selected for transportation.
What Is an Open Head Drum?
An open head drum, also known as a removable head or open top drum, has a removable lid that provides full access to the inside of the drum. The lid is secured using a closure system, such as a bolt ring or lever-lock ring, to help create a secure seal.
Open head drums are commonly used for solid materials and substances that require wider access for filling or emptying. Their removable lids can also make them easier to inspect and clean.
For UN rated steel drums, the packaging code 1A2 identifies a steel drum with a removable head. For plastic drums, 1H2 identifies a plastic drum with a removable head.
What Is a Closed Head Drum?
A closed head drum, also known as a tight head or non-removable head drum, has a permanently fitted top with smaller openings, typically fitted with threaded closures known as bungs.
These openings allow the drum to be filled or emptied without removing the entire top. Closed head drums are commonly used for liquids, where the closure system must provide a suitable seal during transportation.
For UN rated steel drums, the packaging code 1A1 identifies a steel drum with a non-removable head. For plastic drums, 1H1 identifies a plastic drum with a non-removable head.
Open Head vs. Closed Head Drums: Key Differences
The main difference is the design of the drum’s top and the access it provides to the contents.
- Open head drums: Have a removable lid, providing full access to the drum interior. They are commonly used for solids and applications that require easier access.
- Closed head drums: Have a non-removable top with smaller bung openings. They are commonly used for liquids that require a suitable, secure closure.
The appropriate drum depends on the substance being shipped, its compatibility with the packaging, and the applicable dangerous goods transport regulation requirements.
How Do You Choose the Right UN Rated Drum?
When choosing between an open head and closed head drum for hazardous materials transportation, consider the following:
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The contents
Consider whether the material is a solid or liquid and whether its properties are compatible with the drum material.
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The required closure
The drum’s closure must be suitable for the substance and meet the applicable packaging requirements. The relevant packing instructions may specify permitted packaging types and closure requirements.
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UN performance requirements
Where UN specification packaging is required, check that the drum’s UN marking and performance rating are suitable for the material being shipped. Requirements can include packing group, maximum gross mass, liquid density and hydrostatic pressure performance, as applicable.
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Transportation regulations
The packaging must meet the requirements applicable to the shipment, for the relevant mode of transport, including IATA, IMDG and DOT 49 CFR, where applicable.
Frequently Asked Questions
Is an open head drum the same as an open top drum?
Yes. Open head drums are also commonly called open top or removable head drums because the entire lid can be removed.
What is the difference between 1A1 and 1A2 drums?
Both codes identify steel (1A1) drums (1A1). 1A1 identifies a drum with a non-removable head, while 1A2 identifies a drum with a removable head.
Are closed head drums only used for liquids?
Closed head drums are commonly used for liquids, but the correct application must be determined by the drum’s UN approval, the substance being shipped and the applicable packing instructions. Do not select a drum based on its closure type alone.
Does an open head or closed head drum need to be UN rated?
No. not all drums are UN approved. However, where the applicable dangerous goods regulations require UN specification packaging, the selected drum must be UN approved and bear a UN Mark. A drum’s UN marking alone does not establish suitability for every hazardous material.
Need Help Selecting a UN Rated Drum?
Choosing suitable packaging involves more than selecting a removable or non-removable lid. The drum material, UN specification marking, performance rating, substance compatibility and applicable dangerous goods transportation requirements must all be considered.
Air Sea USA supplies UN rated packaging for hazardous materials transportation. Contact our team for guidance on selecting suitable packaging for your application.
