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ADR Classes – Dangerous Goods Classes

Class 2 Gases

Class 2 consists of compressed gases, gases in their liquefied form, refrigerated gases, mixtures of gases with other vapours, and products charged with gases or aerosols. These sorts of gases are often flammable and can be toxic or corrosive. They’re also hazardous because they can chemically react with oxygen. They are split into three sub-divisions:

  • Class 2.1 Flammable gas
    Examples: Hydrogen, Butane, Methane, Ethylene
  • Class 2.2 Non-flammable and non-toxic gases which could cause asphyxiation
    Examples: Nitrogen, Carbon Dioxide, Compressed Air, Helium
  • Class 2.3 Toxic gases
    Examples: Chlorine, Carbon Monoxide, Chlorine, Fluorine
ADR Classes - 2

Class 3 Flammable Liquids

A flammable liquid is defined as a liquid, a mixture of liquids, or liquids containing solids that require a much lower temperature than others to ignite. These temperatures are so low that there is a high risk of the liquids igniting during transportation. This makes flammable liquids very dangerous to handle and transport, as they are very volatile and combustible. Flammable liquids are usually used as fuels in internal combustion engines for motor vehicles and aircraft. This means they make up the largest tonnage of dangerous goods moved by surface transport. Many household products also contain flammable liquids, including perfumery products and acetone (which is used in nail polish remover).
Examples: Petrol, Diesel, Acetone, Benzene

ADR Classes 3

Class 4 Flammable Solids

Class 4 dangerous goods are classified as products that are easily combustible and likely to contribute to fires during transportation. Some goods are self-reactive and some are liable to spontaneously heat up. There are 3 sub-divisions for Class 4 dangerous goods:

  • Class 4.1 Flammable solids, self-reactive substances, and solid desensitised explosives
    Examples: Magnesium, Metallic Sodium, Aluminium Powder, Firelighters
  • Class 4.2 Substances liable to spontaneous combustion
    Examples: White Phosphorus, Iron Powder, Magnesium, Cotton
  • Class 4.3 Substances that, in contact with water, emit flammable gases
    Examples: Calcium, Potassium, Sodium, Calcium Carbide
ADR Classes 4

Class 5 Oxidising Agents and Organic Peroxides

Class 5 dangerous goods are subdivided into ‘oxidising agents’ and ‘organic peroxides’. These are often extremely reactive because of their high oxygen content. They react readily with other flammable or combustible materials, which means fires may break out and continue in confined spaces. These materials are also incredibly difficult to extinguish, which makes them even more dangerous.

  • Class 5.1 Oxidising substances
    Examples: Ammonium Nitrate, Hydrogen Peroxide, Perchloric Acid, Chromium Nitrate
  • Class 5.2 Organic peroxides
    Examples: Acetyl Acetone Peroxide, Dicumyl Peroxide, Diacetyl Peroxide
ADR Classes 5.1
ADR Classes 5.2

Class 6.1 Toxic Substances

Toxic substances are liable to cause death because they’re, as the name suggests, toxic. They can cause serious injury or harm to human health if they enter the body through swallowing, breathing in, or absorption through the skin. Some toxics will kill in minutes; however, some might only injure if the dose isn’t excessive.
Examples: Mercury, Lead, Cyanide, Dichloromethane

ADR Classes 6.1

Class 6.2 Infectious Substances

These are goods that contain micro-organisms that cause infectious diseases in humans or animals, otherwise known as pathogens.

Examples include medical waste, clinical waste, and acids.
Examples: Medical Waste, Blood, Virus’

ADR Classes 6.2

Class 8 Corrosive Substances

Corrosives are highly reactive materials that produce positive chemical effects. Due to their reactivity, corrosive substances cause chemical reactions that degrade other materials when they encounter each other. If these encountered materials happen to be living tissue, they can cause severe injury. 
Examples: Hydrofluoric Acid, Sulphuric Acid, Hydrochloric Acid

ADR Classes 8

Class 9 Miscellaneous Dangerous Substances and Articles

This category covers substances that present a danger not covered in the other classes. Examples include dry ice, GMO’s, motor engines, seat belt pretensioner, marine pollutants, asbestos, airbag modules and magnetised material.
Examples: Asbestos, Flares, Car Air Bags, Elevated Temperature Substances
ADR Classes 9

For further information about the ADR courses we run please click here.

Enterprise Transport Training offer the following courses – Driver CPC, ADR, Operator CPC, DGSA, Operator Licence Awareness Training (OLAT) and Transport Manager Refresher. Click here for further information.