The Australian Government Civil Aviation Safety Authority defines dangerous goods as any items or substances that pose a risk to the safety and health of the public, property, or the environment. They include flammable, explosive, toxic, corrosive, and infectious materials.
These materials require unique handling when being transported by land, by air, or by sea. The Australian Dangerous Goods Code defines the technical requirements for land transport of dangerous materials. Both the Civil Aviation Safety Authority and the Australian Maritime Safety Authority also have their own requirements when transporting dangerous goods via air and sea, respectively.
Dangerous goods are classified into nine classes by the National Transport Commission.
Class 1: Explosives
An explosive substance is a solid or liquid substance, or mixture of substances, that is capable of undergoing a chemical reaction that can produce gas at a certain speed, temperature, and pressure which could cause significant damage to its surroundings. Pyrotechnics, though they do not change into a gaseous state, are included in this class.
Class 1 is further divided into six divisions. These are:
- Division 1.1: Substances in this division contain a mass explosion hazard.
- Division 1.2: Substances in this division are considered projection hazards.
- Division 1.3: Substances in this division contain a fire hazard and either a minor blast or a minor projection hazard, or both. These substances, however, are not a mass explosion hazard. These substances can give off significant radiant heat.
- Division 1.4: Substances in this division have no significant danger, and pose only a small hazard when ignited or initiated while on transport. These effects are mostly confined to the package, with no harmful projections of large fragments.
- Division 1.5: These are substances that are insensitive yet pose a mass explosion hazard. They have little probability of being set off during transport under normal conditions.
- Division 1.6: These are extremely insensitive substances or articles that do not contain a mass explosion hazard. They pose a negligible threat of being set off during transport.
Class 2: Gases
Gases are substances that have a vapour pressure greater than 300 kiloPascals at 50°C or are completely in a gaseous state at 20°C at standard atmospheric pressure of 101.3kPa.
Gases can be transported in either as a compressed gas, liquefied gas, refrigerated liquefied gas, dissolved gas, or adsorbed gas. Compressed gas is a substance that is gaseous at 50°C when packed under pressure.
Liquefied gas refers to a gas that is partially in a liquid state at temperatures above 50°C. They are further classified into high pressure and low-pressure liquefied gases. Refrigerated liquefied gases are gases that are made partially liquid when packaged for transport.
Dissolved gases are dissolved in a liquid solvent when packaged for transport. Lastly, adsorbed gases are adsorbed into a porous material for transport.
Class 2 is further subdivided into two divisions.
- Division 2.1: Flammable Gases
These are gases that are ignitable at 20°C and standard atmospheric pressure when mixed with air.
- Division 2.2: Non-Flammable and Non-Toxic Gases
These include gases that are asphyxiant, oxidising and do not fall under the other divisions of gases.
Gases that are considered unstable would not be packed for transport unless necessary precautions are taken to prevent dangerous decomposition which can produce toxic gas.
Class 3: Flammable Liquids
Liquids in this class are those that produce flammable vapour at 60°C or less. This group also includes liquids at temperatures above their flashpoint when transported. Flashpoint temperature is the temperature at which a liquid gives off an ignitable vapour.
As with gases, unstable flammable liquids will not be approved for transport unless precautions are taken that will prevent dangerous decomposition.
Class 4: Flammable Solids
Flammable solids are substances that pose risks of spontaneous combustion and will produce flammable gases when put in contact with water.
Flammable solids are further subdivided into three divisions.
- Division 4.1: Flammable Solids. Under certain conditions, these self-reactive solids are readily combustible.
- Division 4.2: Substances Liable to Spontaneous Combustion. These substances can catch fire if they comes into contact with air and warm up.
- Division 4.3: Substances that produce flammable gases when in contact with water
Class 5: Oxidising Substances and Organic Peroxides
This class is subdivided into two divisions:
- Division 5.1: Oxidising Substances
Substances in this division are not combustible by themselves but can help in the combustion of other materials present.
- Division 5.2: Organic Peroxides
These are thermally unstable substances that can undergo swift decomposition and may burn rapidly. They are sensitive to impact and friction and may react dangerously with other substances. They can also damage the eyes.
Class 6: Toxic and Infectious Substances
This class is divided into two divisions, which are:
- Division 6.1: Toxic Substances
These substances can cause death or serious injury to humans when ingested, inhaled, or comes in contact with the skin.
- Division 6.2: Infectious Substances
These are substances that contain pathogens such as bacteria, parasites, viruses, and fungi among many others, which can result in diseases, both in humans and animals.
Class 7: Radioactive Materials
The transport of radioactive materials is not under the National Transport Commission’s jurisdiction, except when it is being transported along with other classes of materials. The Australian Radiation Protection and Nuclear Safety Agency outlines the regulations and guidelines that must be followed when transporting radioactive materials by road, rail, or seas.
Class 8: Corrosive Materials
Corrosive materials are substances that can produce significant damage when in contact with living tissue. In the event of leaks, they can damage other goods and even the materials of the means of transport used.
Class 9: Miscellaneous Dangerous Substances and Articles
These are substances and articles which can pose a serious danger during transport but are not covered by the other classes. They can include asbestos, polymeric beads, plastic moulding compound, lithium batteries, capacitors, and life-saving appliances.
Assignment of Placards and UN Numbers
Dangerous substances are assigned a placard, which specifies the class it belongs to. They are also assigned a UN number that is indicated in the label and transport document that comes with the substance.
Get your Dangerous Goods Awareness Certification at CSTT.
The transport of dangerous goods requires specific knowledge and skillset to ensure the safety of the personnel and the other transported goods as well. Specific training must be given to drivers who will handle the transport of dangerous substances and articles. For more information on Dangerous Goods License Course and Dangerous Goods Awareness class, contact Chris Shilling Transport Training Services at 0434-366-758.