All About Drum Chimes: What They Are Plus Other Key Hazmat Definitions

hazardous materials in drums

If you are someone who is involved in the transportation of hazardous materials, it is necessary for you to be aware of the technical and non-technical terms that are used in hazardous materials regulations, otherwise known as hazmat definitions, so that you have a clear idea of what is expected of you as a hazmat employee, meet all the regulatory requirements, and do your job safely and effectively.

Given the wide range of terms used in hazmat regulations, every once in a while you might come across a term that you might not be familiar with. If and when you do, it’s crucial to find out what it means and understand the context in which it is used in the regulations, so that you can avoid mistakes that can lead to non-compliance.

One such word is ‘chime’ – which is used in reference to drums. Normally, the word chime is used to describe the sound made by a bell or gong. Tuned gongs – commonly referred to as chimes – are attached to drums and other percussion instruments and used in musical bands and orchestras – particularly in Southeast Asia.

On the other hand, in the hazmat industry, the term ‘chime’ is used only in relation to drums. It refers to the rounded circle (with its outer edge projecting out of the surface) around the edges of a drum or container, where they are joined to the body.

The top chime connects the body of the drum to the top head and the bottom chime connects the body to the bottom head. The drum contains four chimes with their outer edges projecting out of the drum’s surface.

Hazmat regulations say that any package which is in the shape of a drum must be subjected to drop impact tests to make sure it is strong and durable enough to transport hazardous contents. These tests include:

  • Dropping it diagonally on the top chime
  • Dropping it on the bottom chime
  • Dropping it flat on the side

What it goes to show is that anyone who is associated with the hazmat industry cannot afford to remain complacent as far as regulatory requirements are concerned. No matter how long you have been involved in hazmat transportation, there are terms that you might not have come across before and terms that you might not know the definition or meaning of.

It is one of the reasons why people in the hazmat industry are required to go through hazmat training on a regular basis and update their knowledge on compliance requirements imposed by the United States government agencies as well as international organizations.

Why Technical Terms and Hazmat Definitions Matter in the Hazmat Industry

Many of the technical terms used in hazmat regulations might sound similar or even synonymous to the average person. However, as someone who works in the hazmat industry, you are required to know these hazmat definitions and why certain terms are only used in certain contexts.

For example, the terms ‘package’ and ‘packaging’ are often used interchangeably by many people. However, in the hazmat industry, these two terms cannot be used interchangeably, as they each have a very specific definition and meaning.

According to hazmat regulations, the packaging is the receptacle or container which is used to transport hazardous materials. Package, on the other hand, refers to the packaging as well as the hazardous materials it contains. Depending on the material being transported, the package might require inner packaging as well as outer packaging – which is commonly referred to as combination packaging.

Apart from choosing the right type of packaging, hazmat shippers also need to make sure that the packaging meets the necessary specifications and is closed properly in accordance with the instructions of the manufacturer. If the wrong type of packaging is used or if the packaging does not meet the necessary standards, it can result in non-compliance, as a result of which the shipper might have to pay thousands of dollars in civil penalties. More importantly, failing to use the right kind of packaging can increase the risk of hazmat incidents significantly.

Similarly, the term ‘net mass’ refers to the weight of the contents in hazmat packaging. The term ‘gross mass’, on the other hand, refers to the weight of the contents as well as the packaging.

The Importance of Knowing the Hazmat Definitions of Non-Technical Terms Used in Hazardous Materials Regulations

Apart from technical terms, a large number of non-technical terms are also used in hazmat regulations. These are terms that are commonly used by people who are not associated with the hazmat industry. Taking this into account, when used within the industry, these terms have a hazmat-specific meaning.

For example, the term ‘cylinder’ is commonly used by people to describe any object which is cylindrical in shape. In the hazmat industry, a cylinder is defined as a pressure vessel with a circular cross-section that is designed for pressures higher than 40 psi.

Similarly, the term ‘person’ is generally used to describe human beings. In the hazmat industry, the term is used to refer to any entity involved in transporting hazardous materials. It could be an individual, association, firm, partnership, joint-stock company, corporation, or any other private or public organization.

Key Technical and Non-Technical Hazmat Definitions You Should Know

employee handling hazardous materials


It refers to the Administrator of the Pipeline and Hazardous Materials Safety Administration (PHMSA), an agency that comes under the Department of Transportation (DOT) and is responsible for developing, overseeing, and enforcing hazardous materials regulations.


It refers to a container that consists of a pressurized gas that is liquefied, compressed, or dissolved. In order to fit the definition, the container must be non-refillable, must be designed to dispense a non-poisonous liquid, paste, or powder (other than materials that come under Division 6.1 of Packing Group III), and must contain a self-closing mechanism.

Agricultural Product

It refers to a hazardous material that comes under Division 2.1, 2.2, 5.1, or 6.1 of Class 3, 8, or 9 and is used in the production of agricultural commodities like fertilizers, pesticides, soil amendments, and fuel.


It refers to the authorization from the Associate Administrator of the PHMSA or an official designated by the Associate Administrator to perform a function that needs to be authorized by the Associate Administrator.

Asphyxiant Gas

It refers to a gas that can deplete the concentration of oxygen in the air or displace the oxygen present in the atmosphere.

Atmospheric Gases

It refers to the different types of gases that the earth’s atmosphere is composed of – including nitrogen, oxygen, argon, krypton, neon, and xenon.


It refers to packaging which is produced from paper, textiles, plastic film, or similar other materials and is flexible in nature.


It refers to an inner packaging whose neck has a smaller cross-section compared to the body and has an opening that can hold a closure so that the contents can be retained safely.


It refers to a polygonal or rectangular-shaped packaging that can be from wood, reconstituted wood, plywood, fiberboard, plastic, metal, and a number of other equally suitable materials. The packaging can contain holes to meet hazmat classification requirements or to make it easier for hazmat employees to handle it or open it – as long as its structural integrity or durability is not compromised.

Bulk Packaging

It refers to any large packaging (except a vessel or barge) into which hazardous materials can be loaded with or without an intermediate form of containment like inner packaging. Packaging must meet the following criteria in order to be classified as bulk packaging.

  • Must have a maximum capacity greater than 119 gallons (for liquids)
  • Must have a maximum net mass greater than 882 pounds and a maximum capacity greater than 119 gallons (for solids)
  • Must have a water capacity greater than 1,000 pounds (for gases)

Cargo Aircraft

It refers to a type of aircraft which is used only for the purpose of transporting cargo.

Cargo Tank

It refers to bulk packaging that meets the following criteria:

  • It’s not made under the specification for cylinders, intermediate bulk containers, portable tanks, tank cars, or multi-unit tank car tanks.
  • It’s a tank that is fitted with appurtenances, reinforcements, closures, and other accessories and is designed to transport liquids and gases.
  • It can be permanently attached – or not attached – to a motor vehicle.
  • It can be loaded and unloaded without having to detach it from the motor vehicle.


When used as a hazmat definition, it refers to a device that is designed to close an opening in a container.

Combination Packaging

It refers to a type of hazmat packaging which contains one or more inner packaging and outer packaging.

Composite Packaging

It refers to a type of hazmat packaging which contains an inner container and an outer packaging, which are designed to form a single integral packaging. Once assembled, the inner container cannot be removed from the outer packaging and it is loaded, unloaded, and transported as a single unit.

Consumer Commodity

It refers to a substance that is suitable for consumption and can be sold through retail sales agencies or other outlets. The substance can be intended for therapeutic use (like a drug or medicine) or for other purposes (like personal care or household use).

Flash Point

It refers to the lowest temperature at which a liquid can vaporize and form a combustible mixture with air.

Hazard Class

It refers to the category assigned to a hazardous material on the Hazardous Materials Table. There are a total of nine different hazard classes including explosives, gases, flammable liquids, flammable solids, oxidizing substances and organic peroxides, toxic and infectious substances, radioactive substances, corrosive substances, and miscellaneous hazardous materials.

Hazardous Material

It refers to any material which – due to its nature or characteristics – can pose an unreasonable risk to the health and safety of people and is capable of causing property damage when transported in commerce. It can be a hazardous substance, hazardous waste, marine pollutant, or any other substance which is categorized as hazardous under section 5103 of Federal hazardous materials transportation law, listed as a hazardous material on the Hazardous Materials Table and has been determined as hazardous in nature by the Secretary of the DOT.

Inner Receptacle

In the context of hazmat definitions, it refers to a container or vessel which is capable of containing hazardous contents only when it is secured with outer packaging.

Intermodal Container

It refers to a freight container that is constructed in such a way that it can be used in two or more modes of transport.


It refers to the information provided on the outer packaging of hazardous materials including a descriptive name, identification number, weight, handling instructions, warnings, and more.


It refers to a method of transporting hazardous materials from one place to another – locally or internationally. The different modes of transportation include rail, highway, air, and water.


It refers to the process of physically transporting hazardous materials from one place to another – through a motor vehicle, rail, cargo aircraft, or vessel.

Outer Packaging

It refers to the outermost layer of a composite or combination packaging. It’s designed to protect the inner layer of packaging or the inner container as well as the contents within it. It might contain cushioning, absorbent materials, and other materials needed to make sure the contents are safely contained within the inner packaging.

Packing Group

It refers to a system of classification which is designed to divide hazardous materials into different categories based on the extent and severity of the danger they pose. There are three parking groups – Group I, Group II, and Group III – which include substances that present a high level of danger, a medium level of danger, and a low level of danger respectively.


It refers to Pounds per Square Inch – which is a measure of pneumatic pressure (of gasses) as well as hydraulic pressure (of liquids).

Shipping Papers

It refers to a shipping order, manifest, bill of lading, and other documents that provide critical information about the hazardous contents being transported – particularly for emergency response purposes.

Special Permit

These hazmat definitions refer to the authorization given to a person by the Associate Administrator or a person designated by the Associate Administrator to perform a function that the person is otherwise not authorized or approved to perform.

Unintentional Release

It refers to the release or escape of contents in a hazmat package that happens under unexpected or unplanned circumstances. It can happen due to substandard packaging materials, failure to contain the materials within the receptacle properly, improper packing or packaging, human error, collision with another object, or any other reason.


For hazmat definitions, it refers to a watercraft that is capable of transporting cargo or people on the water.

Water Resistant

It refers to the ability of a substance to resist the damage caused by water.

Stay Updated on Hazmat Definitions and Terminology with Hazmat University’s Online Training Courses

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The regulatory and compliance requirements for transporting hazardous substances and hazmat definitions are revised, updated, and amended on a frequent basis to ensure the safe transportation of hazardous substances as well as to streamline the process of transportation so that these substances can be shipped locally as well as internationally in a fast and efficient manner.

If you are someone who handles or transports hazardous materials, if you are involved in any capacity in the transportation process, or if your job functions have an impact on hazardous material transportation and safety, you need to go through hazardous material training on a regular basis. Failing to update your knowledge on hazmat regulations can not only make it harder for you to do your job safely and effectively but can also increase the risk of non-compliance, which can have serious consequences.

At Hazmat University, we offer comprehensive web-based training courses which are designed to provide you with all the information you need to know about the regulatory requirements specific to your job. Our wide range of online hazmat training courses includes hazardous materials safety training courses, security awareness training courses, function-specific training courses, general awareness courses, and in-depth security training courses.

Our online courses are developed by highly skilled professionals with decades of experience in the hazmat industry and our course material is reviewed and updated constantly so that you can stay updated on the latest regulatory and compliance requirements from the International Civil Aviation Organization (ICAO), Title 49 of the Code of Federal Regulations (49 CFR), and the International Maritime Organization (IMO).

Hazmat University’s online hazmat training courses are based on an industry-leading Dynamic Learning Environment, which makes learning interactive, engaging, and even fun. Our course developers make it easier for you to learn and understand the regulatory requirements and other information specific to the job you perform.

If you have any questions about our online courses or if you wish to know about the initial or recurrent hazmat training requirements specific to your job, call us today at 844-801-2765 or fill out our online contact form.