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What Are The 9 Classes Of Dangerous Goods?

The coverage of dangerous goods will encompass a comprehensive exploration of the classification and characteristics of hazardous substances, shedding light on the diverse categories and associated risks.

What Falls Under The Category Of Dangerous Goods?

Dangerous goods encompass materials or items possessing hazardous properties that, without appropriate handling and control, can pose potential threats to human well-being, safety, infrastructure, or the transportation system.


These hazardous materials, often referred to as dangerous goods, can include pure chemicals, combinations of substances, manufactured products, or articles. If not handled correctly during use or transport, they have the potential to jeopardize the safety of individuals, animals, or the environment.


Classification of Dangerous Goods

The UN Model Regulations employ a classification framework wherein each dangerous substance or item is categorized into a class, determined by the type of risk it poses. These categories consist of 9 main classes, with some further subdivided into sub-classes.



Disclaimer: this information is provided for convenience only. Please consult ICAO and IATA regulations for the latest, up-to-date information.



HAZARD CLASS 1 - EXPLOSIVES

Explosives are characterized as reactive substances or items, including devices, holding a significant store of potential energy. When suddenly released, this potential energy can trigger an explosion, typically accompanied by the generation of light, heat, sound, and intense pressure.


Based on test methods, substances and articles of Class 1 have been divided into 6 classes of explosives.

Division 1.1

Substances and articles which have a mass explosion hazard






Division 1.2

Substances and articles which have a projection hazard but not a mass explosion hazard.





Division 1.3

Substances and articles which have a fire hazard and either a minor blast hazard or a minor projection hazard or both, but not a mass explosion hazard: (a) combustion of which gives rise to considerable radiant heat; or (b) which burn one after another, producing minor blast or projection effects or both.



Division 1.4

Substances and articles which present only a slight risk of explosion in the event of ignition or initiation during carriage. The effects are largely confined to the package and no projection of fragments of appreciable size or range is to be expected. An external fire shall not cause virtually instantaneous explosion of almost the entire contents of the package.


Division 1.5

Very insensitive substances having a mass explosion hazard which are so insensitive that there is very little probability of initiation or of transition from burning to detonation under normal conditions of carriage. As a minimum requirement they must not explode in the external fire test.



Division 1.6

Extremely insensitive articles which do not have a mass explosion hazard. The articles predominantly contain extremely insensitive substances and demonstrate a negligible probability of accidental initiation or propagation.



Examples of Commonly Transported Explosives

Examples for explosive dangerous goods are ammunition/cartridges, fireworks/pyrotechnics, flares, blasting caps/detonators, fuses, primers, explosive charges (blasting, demolition etc.), detonating cord, igniters, rockets, trinitrotoluene (TNT).



HAZARD CLASS 2 - GASES


Gases can be a pure gas or a mixture of one or more gases. They are defined by dangerous goods regulations as substances which have a vapour pressure greater than 300 kPa (3 bar) at 50°C, or which at a standard pressure of 101 kPa are completely gaseous at 20°C.


Substances and articles of Class 2 have been assigned to one of the following divisions:


Division 2.1

Flammable gas






Division 2.2

Non-flammable compressed gas






Division 2.3

Toxic gas




Subdivision of Gases

Gases are sub-divided into compressed gases, liquefied gases, refrigerated liquefied gases, dissolved gases, aerosol dispensers and receptacles, other articles containing gas under pressure, non-pressurized gases subject to special requirements (gas samples), chemicals under pressure and adsorbed gas.


Except for aerosols and chemicals under pressure, Class 2 gases are divided between the following groups according to their hazardous properties:


A - Asphyxiant

O - Oxidizing

F - Flammable

T - Toxic

TF - Toxic, flammable

TC - Toxic, corrosive

TO - Toxic, oxidizing

TFC - Toxic, flammable, corrosive

TOC - Toxic, oxidizing, corrosive


Reasons for Regulation

Gases can pose serious hazards due to their flammability, potential as asphyxiants, ability to oxidize and/or their toxicity or corrosiveness.


Examples of Commonly Transported Explosives

Examples for Class 2 dangerous goods are aerosols, compressed gas, fire extinguishers, refrigerant gases, lighters, acetylene, carbon dioxide, helium, hydrogen, oxygen, nitrogen, natural gas, petroleum gases, liquified, butane, propane, methane, ethylene.



HAZARD CLASS 3 - FLAMMABLE LIQUIDS

Substances and Articles of Class 3 do not have any divisions.


The dangerous goods regulations predominantly define flammable liquids as a liquid or a mixture of liquids that have a flash point of not more than 60° C, however diesel fuel, gasoil, heating oil (light) including synthetically manufactured products that have a flashpoint above 60° C but not more than 100° C shall also be deemed substances of the Class 3 flammable liquids list.


Class 3 Flammable Liquids can also be liquid substances and molten solid substances that have a flashpoint of more than 60° C, and which are transported whilst heated at temperatures equal to or higher than their flashpoint and liquid desensitized explosives, these being explosive substances which are dissolved or suspended in water or other liquid substances.


When transporting Class 3 flammable liquids by sea, the IMDG Code requires that the flash point is shown as part of the dangerous goods description.


Packing Groups

Although Class 3 dangerous goods do not have any other divisions, flammable liquids have been assigned a packing group which indicates the degree of danger.


Packing Group I: Substances presenting high danger

Packing Group II: Substances presenting medium danger

Packing Group III: Substances presenting low danger


Packing Group Initial Boiling Point Flashpoint (closed cup)

Packing Group I Initial boiling point ≤ 35º C --

Packing Group II Initial boiling point > 35º C Flashpoint < 23º C


Packing Group III Initial boiling point > 35º C Flashpoint ≥ 23º C - ≤ 60º C


Reason for Regulation

Flammable liquids give off a flammable vapour which, when mixed with air, can ignite or explode. Based on their flashpoint and boiling point, they can be extremely flammable, highly flammable or flammable.


Examples of Commonly Transported Flammable Liquids

Acetone, adhesives, paints / lacquers / varnishes, alcohols, perfumery products, gasoline / petrol, diesel fuel, aviation fuel, heating oil, kerosene, resins, tars, turpentine, ethanol, benzene, butanols, isopropanol, methanol, octanes.



HAZARD CLASS 4 - FLAMMABLE SOLIDS


Substances and Articles of Class 4, have been assigned to one of 3 sub-classes.


Flammable solids; Substances liable to spontaneous combustion; Substances which, in contact with water, emit flammable gases

Hazard Class 4.1 - Flammable Solids, Self-Reactive Substances, Polymerizing Substances and Solid Desensitized Explosives

Flammable solids are readily combustible solids and solids which may cause fire through friction. Readily combustible solids are powdered, granular, or pasty substances which are dangerous if they can be easily ignited by brief contact with an ignition source, such as a burning match, and if the flame spreads rapidly. The danger may come not only from the fire but also from toxic combustion products. Metal powders are especially dangerous because of the difficulty of extinguishing a fire since normal extinguishing agents such as carbon dioxide or water can increase the hazard.

Self-reactive substances are thermally unstable substances liable to undergo a strongly exothermic decomposition even without participation of oxygen (air).

Polymerizing substances are substances which, without stabilization, are liable to undergo a strongly exothermic reaction resulting in the formation of larger molecules or resulting in the formation of polymers under conditions normally encountered in carriage.


Hazard Class 4.2 - Substances Liable to Spontaneous Combustion

Pyrophoric substances are substances, including mixtures and solutions (liquid or solid), which even in small quantities ignite on contact with air within five minutes, and self-heating substances and articles which are substances and articles, including mixtures and solutions, which, on contact with air, without energy supply, are liable to self-heating. These substances will ignite only in large amounts (kilograms) and after long periods of time (hours or days).


Hazard Class 4.3 - Substances Which, in contact with water, Emit Flammable Gases

Class 4.3 are substances which react with water to emit flammable gases liable to form explosive mixtures with air. They are easily ignited by all ordinary sources of ignition that produce a spark. They are often referred to as 'dangerous when wet'.


Packing Groups

Classes 4.1, 4.2 and 4.3 have been assigned a packing group which indicates the degree of danger.


Packing Group I: Substances presenting high danger

Packing Group II: Substances presenting medium danger

Packing Group III: Substances presenting low danger


Examples of Commonly Transported Class 4.1 / 4.2 / 4.3 Dangerous Goods

Alkali metals, metal powders, firelighters, matches, calcium carbide, camphor, celluloid, desensitized explosives, nitrocellulose, phosphorus, sulphur.



HAZARD CLASS 5 - OXIDIZING SUBSTANCES & ORGANIC PEROXIDES


Substances and articles of Class 5 have been assigned to one of 2 sub-classes.


Hazard Class 5.1 - Oxidizing Substances

Class 5.1 are substances which, while in themselves not necessarily combustible, may, generally by yielding oxygen, cause or contribute to the combustion of other materials and articles containing such substances. Oxidizing substances can be both a solid or liquid form.


Packing Groups

Class 5.1 has been assigned a packing group which indicates the degree of danger.


Packing Group I: Substances presenting high danger

Packing Group II: Substances presenting medium danger

Packing Group III: Substances presenting low danger


Examples of Commonly Transported Oxidizing Substances

Ammonium nitrate, chlorates, nitrates, nitrites, peroxides, calcium hypochlorite, calcium nitrate, calcium peroxide, hydrogen peroxide.


Hazard Class 5.2 - Organic Peroxides

Substances of Class 5.2 are sub-divided into: P1: Organic peroxides, not requiring temperature control P2: Organic peroxides, requiring temperature control


Organic peroxides are liable to exothermic decomposition at normal or elevated temperatures. The decomposition can be initiated by heat, contact with impurities (e.g., acids, heavy metal compounds, amines), friction or impact. The rate of decomposition increases with temperature and varies with the organic peroxide formulation. Decomposition may result in the evolution of harmful, or flammable, gases, or vapors. For certain organic peroxides the temperature shall be controlled during transport. Some organic peroxides may decompose explosively, particularly if confined. This characteristic may be modified by the addition of a diluting agent or using the appropriate packaging. Many organic peroxides burn vigorously and contact with the eyes and skin is to be avoided. Some organic peroxides will cause serious eye injuries, even after brief contact, or will be corrosive to the skin.


Packing Groups

Class 5.2 dangerous goods have not been assigned any packing groups.



HAZARD CLASS 6 - TOXIC & INFECTIOUS SUBSTANCES


Substances of Class 6 have been assigned to one of 2 sub-classes.


Hazard Class 6.1 - Toxic Substances

Class 6.1 dangerous goods are substances that in relatively small quantities, are able by a single action or by an action of short duration to cause damage to human health, or death by inhalation, absorption, or ingestion. Toxic substances can be either a solid or liquid form.


Packing Groups

Class 6.1 has been assigned a packing group which indicates the degree of danger. Packing Group I: Substances presenting high danger Packing Group II: Substances presenting medium danger Packing Group III: Substances presenting low danger

Examples of Commonly Transported Toxic Substances

Arsenic, chloroform, cyanide, lead, numerous mercury substances, nicotine, numerous types of pesticides.


Hazard Class 6.2 - Infectious Substances

Class 6.2 dangerous goods are substances which are known or are reasonably expected to contain pathogens. Pathogens are defined as micro-organisms (including bacteria, viruses, parasites, fungi) and other agents. Infectious substances can be biological products, cultures, medical and clinical waste or patient specimens and when transported in a form that when exposure to it occurs, it can cause permanent disability, life-threatening or fatal disease in otherwise healthy humans or animals.


For example, in humans:

  • Ebola virus

  • Hepatitis B virus

  • Rabies virus

  • Yellow fever virus

For example, in animals:

  • African swine fever virus

  • Foot and mouth disease virus

Infectious substances are sub-dived into two categories, Category A and Category B and are assigned UN No’s 2814, 2900, 3291, 3373 or 3549.



HAZARD CLASS 7 - RADIOACTIVE MATERIALS

Class 7 radioactive materials are defined in the dangerous goods regulations as any material containing radionuclides where both the activity concentration and the total activity exceeds certain pre-defined values. A radionuclide is an atom with an unstable nucleus, and which consequently is subject to radioactive decay.


There are no divisions or sub-classes within Class 7 hazardous materials, however transport labels and cargo transport placards can vary dependent on the calculated transport index. In most instances, cargo transport placards conform to model 7D.


Examples of Commonly Transported Explosives

Class 7 radioactive material examples are density gauges, depleted uranium products, fire suppression systems, smoke detectors, medical isotopes, x-ray machinery.



HAZARD CLASS 8 - CORROSIVE SUBSTANCES

The dangerous goods regulations define corrosive substances as a substance that by a chemical action, causes irreversible damage to the skin, or in the case of a leakage, will materially damage or even destroy other goods or the means of transport. Corrosive substances can be both a solid and liquid form.


Class 8 hazardous materials do not have any divisions but could be an acid or an alkali. Acids have a pH less than 7, and Alkalis have a pH greater than 7 while neutral substances have a pH equal to 7.


Packing Groups

Although Class 8 dangerous goods do not have any other divisions, corrosive substances have been assigned a packing group which indicates the degree of danger. Packing Group I: Substances presenting high danger Packing Group II: Substances presenting medium danger Packing Group III: Substances presenting low danger


Packing group Exposure time Observation period Effect

I ≤ 3 min ≤ 60 min Full thickness destruction

of intact skin


II > 3 min ≤ 1h ≤ 14 d Full thickness destruction

of intact skin


III > 1 h ≤ 4h ≤ 14 d Full thickness destruction

of intact skin.


III -- -- Corrosion rate on either

steel or aluminium surfaces

exceeding 6.25 mm a year

at a test temperature of

55 ºC when tested on both

materials


Examples of Commonly Transported Explosives

Class 8 dangerous goods examples are acid batteries fluid, alkali batteries fluid, formaldehyde, hydrochloric acid, iodine, methacrylic acid, nitric acid, sulphuric acid.



HAZARD CLASS 9 - MISCELLANEOUS DANGEROUS GOODS

Miscellaneous dangerous substances and articles are substances and articles which, during transport, present a danger not covered by the other classes of dangerous goods. It includes environmentally hazardous substances of Class 9, but also all other classes except for Class 7 radioactive material. The substances and articles of Class 9 do not have any divisions but are sub-divided as follows:

  • Substances which, on inhalation as fine dust, may endanger health

  • Substances and articles which, in the event of fire, may form dioxins

  • Substances evolving flammable vapour

  • Lithium batteries

  • Life-saving appliances

  • Environmentally hazardous substances

  • Environmentally Hazardous Substance, Solid, N.O.S

  • Environmentally Hazardous Substance, Liquid, N.O.S

  • Genetically modified microorganisms and organisms

  • Substances transported or offered for transport at elevated temperature

  • Liquid

  • Solid

  • Other substances or articles presenting a danger during transport, but not meeting the definitions of another class

Packing Groups

Although Class 9 hazardous substances do not have any other divisions, miscellaneous dangerous substances and articles have been assigned a packing group which is a degree of danger. Packing Group II: Substances presenting medium danger Packing Group III: Substances presenting low danger


Placarding, labelling, and marking of Class 9 dangerous goods

Class 9 placard and label

Packages containing Class 9 dangerous goods, and cargo transport units, containers, bulk containers, tank containers, portable tanks and multi-element gas containers containing Class 9 dangerous goods, shall be durably marked with the Class 9 label/placard.


Class 9A label for packages or unpackaged articles containing lithium batteries




Environmentally hazardous substance/marine pollutant mark

Packages containing environmentally hazardous substances/marine pollutants, and cargo transport units, containers, bulk containers,

tank containers, portable tanks and multi-element gas containers containing environmentally hazardous substances/marine pollutants, shall be durably marked with the environmentally hazardous

substances/marine pollutant mark.


Lithium battery mark for packages containing lithium cells or batteries prepared in accordance with Special Provision 188

(Not applicable for air transport)



Examples of commonly transported miscellaneous dangerous goods

Class 9 dangerous goods examples are air bag modules (safety devices, electronically initiated), asbestos (amphibole and chrysotile), battery powered equipment, battery powered vehicles, chemical kits, dangerous goods in machinery or apparatus, dry ice (carbon dioxide, solid), environmentally hazardous substances (liquid and solids), first aid kits, genetically modified organisms, genetically modified micro-organisms, life-saving appliances (self-inflating and non-self-inflating), lithium ion batteries, lithium metal batteries, seatbelt pretensioners (safety devices, electronically initiated).

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