The classes of dangerous goods according to European Agreement concerning the International Carriage of Dangerous Goods by Road (ADR)
Class 1 Explosive substances and articles. The heading of Class 1 covers:
- explosive substances: solid or liquid substances (or mixtures of substances) capable by chemical reaction of producing gases at such a temperature and pressure and at such a speed as to cause damage to the surroundings;
- pyrotechnic substances: substances or mixtures of substances designed to produce an effect by heat, sound, gas or smoke or a combination of these as the result of non-detonating self-sustaining exothermic chemical reactions;
- explosive articles: articles containing one or more explosive or pyrotechnic substances;
- substances and articles not mentioned above which are manufactured with a view to producing a practical effect by explosion or a pyrotechnic effect.
Definition of divisions:
1.1 Substances and articles which have a mass explosion hazard (a mass explosion is an explosion which affects almost entire load virtually instantaneously);
1.2 Substances and articles which have a projection hazard but not a mass explosion hazard;
1.3 Substances and articles which have a fire hazard and either a minor blast hazard or a minor projection hazard or both, not a mass explosion hazard: combustion of which gives rise to considerable radiant heat; or which burn one after another, producing minor blast or projection effects or both;
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;
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;
1.6 Extremely insensitive articles which do not have a mass explosion hazard. The articles contain only extremely insensitive detonating substances and demonstrate a negligible probability of accidental initiation or propagation.
Class 2 Gases. The heading of Class 2 covers pure gases, mixtures of gases, mixtures of one or more gases with one or more other substances and articles containing such substances. A gas is a substance which:
- at 50°C has a vapour pressure greater that 300 kPa (3 bar);
- is completely gaseous at 20°C at the standard pressure of 101.3 kPa.
The substances and articles of Class 2 are subdivided as follows:
- compressed gas: a gas which when packaged under pressure for carriage is entirely gaseous at -50°C (this category includes all gases with critical temperature less than or equal to 50°C);
- liquefied gas: a gas which when packaged under pressure for carriage is partially liquid at temperatures above -50°C (a distinction is made between high pressure liquefied gas: a gas with a critical temperature above -50°C and equal to or below +65°C and low pressure liquefied gas: a gas with a critical temperature above +65°C);
- refrigerated liquefied gas: a gas which when packaged for carriage is made partially liquid because of its low temperature;
- dissolved gas: a gas which when packaged under pressure for carriage is dissolved in a liquid phase solvent;
- aerosol dispensers and receptacles, small, containing gas (gas cartridges);
- other articles containing gas under pressure; non-pressurized gases subject to special requirements (gas samples).
Substances and articles (except aerosols) of Class 2 are assigned to one of the following groups according to their hazardous properties, as follows:
- asphyxiant (gases which are non-oxidizing, non-flammable and non-toxic and which dilute or replace oxygen normally in the atmosphere);
- oxidizing (gases, which may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does);
- flammable (gases which at 20°C and a standard pressure of 101.3 kPa are ignitable when in a mixture of 13% or less by volume with the air or have a flammable range with air of at least 12 percentage point regardless of the lower flammable limit);
- toxic (gases which are known to be toxic or corrosive to humans as to pose hazard to health or are presumed to be toxic or corrosive to humans);
- corrosive (gases or gas mixtures that is considered to be toxic due to the combined effects of corrosivity on toxicity has a subsidiary risk of corrosivity when the mixture is known by human experience to be destructive to the skin, eyes or mucous membranes).
Aerosols are assigned to one of the following groups according to their hazardous properties, as follows:
- asphyxiant;
- oxidizing;
- flammable;
- toxic;
- corrosive.
The classification depends on the nature of the contents of the aerosol dispenser.
Class 3 Flammable liquids. The heading of Class 3 covers substances and articles containing substances of this Class which are liquids, which have at 50°C a vapour pressure of not more than 300 kPa (3 bar) and are not completely gaseous at 20°C and at standard pressure of 101.3 kPa, and which have a flash-point of not more than 60°C. The heading of Class 3 also covers liquid substances and molten solid substances with a flash-point of more than 60°C and which are carried or handed over for carriage whilst heated at temperatures equal to or higher than their flash-point. The heading of Class 3 also covers liquid desensitized explosives. Liquid desensitized explosives are explosive substances which are dissolved or suspended in water or other liquid substances, to form a homogeneous liquid mixture to suppress their explosive properties. The substances and articles of Class 3 are subdivided as follows:
- flammable liquids, without subsidiary risk;
- flammable liquids (toxic, corrosive);
- liquid desensitized explosives.
Class 4.1 Flammable solids, self-reactive substances and solid desensitized explosives. The heading of Class 4.1 covers flammable substances and articles, solid desensitized explosives and self-reactive liquids or solids. The following are assigned to Class 4.1:
- readily flammable solid substances and articles;
- self-reactive solids or liquids;
- solid desensitized explosives;
- substances related to self-reactive substances.
The substances and articles of Class 4.1 are subdivided as follows:
- flammable solids, without subsidiary risk;
- flammable solids (oxidizing, toxic, corrosive);
- solid desensitized explosives, without subsidiary risk;
- solid desensitized explosives, toxic;
- self-reactive substances.
Flammable solids are readily combustible solids and solids which may cause fire through friction. Self-reactive substances are thermally unstable substances liable to undergo a strongly exothermic decomposition even without participation of oxygen (air). Substances are not considered to be self-reactive substances of Class 4.1 if they are explosives according to the criteria of Class 1 or if they are oxidizing substances according to the criteria of Class 5.1 except that mixtures of oxidizing substances which contain 5% or more of combustible organic substances.
Class 4.2 Substances liable to spontaneous combustion. The heading of Class 4.2 covers:
- pyrophoric substances which are substances, including mixtures and solutions (liquid or solid), which even in small quantities ignite on contact with air within five minutes;
- 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 amount (kilogrammes) and after long period of time (hours or days). The substances and articles of Class 4.2 are subdivided as follows:
- substances liable to spontaneous combustion, without subsidiary risk;
- substances liable to spontaneous combustion, which, in contact with water, emit flammable gases;
- substances liable to spontaneous combustion, oxidizing;
- substances liable to spontaneous combustion, toxic; substances liable to spontaneous combustion, corrosive.
Self-heating of these substances, leading to spontaneous combustion, is caused by reaction of the substance with oxygen (in the air) and the heat developed not being conducted away rapidly enough to the surroundings. Spontaneous combustion occurs when the rate of heat production exceeds the rate of heat loss and the auto-ignition temperature is reached.
Class 4.3 Substances which, in contact with water, emit flammable gases. The heading of Class 4.3 covers substances which react with eater to emit flammable gases liable to form explosive mixtures with air, and articles containing such substances. Substances and articles of Class 4.3 are subdivided as follows:
- substances which, in contact with water, emit flammable gases, without subsidiary risk, and articles containing such substances;
- substances which, in contact with water, emit flammable gases (liquid, solid, self-heating, oxidizing, toxic, and corrosive).
Certain substances in contact with water may emit flammable gases that can form explosive mixtures with air. Such mixtures are easily ignited by all ordinary sources of ignition (naked lights, sparkling hand tools or unprotected light bulbs). The resulting blast wave and flames may endanger people and the environment.
Class 5.1 Oxidizing substances. The heading of Class 5.1 covers substances which, while in themselves not necessarily combustible, may, generally by yielding oxygen, cause or contribute to the combustion of other material, and articles containing such substances. The substances of Class 5.1 are subdivided as follows:
- oxidizing substances without subsidiary risk or articles containing such substances;
- oxidizing substances, solid, flammable;
- oxidizing substances, solid, self-heating;
- oxidizing substances, solid which, in contact with water, emit flammable gases;
- oxidizing substances toxic;
- oxidizing substances, corrosive;
- oxidizing substances, toxic, corrosive.
Class 5.2 Organic peroxides. The heading of Class 5.2 covers organic peroxides and formulations of organic peroxides. The substances of Class 5.2 are subdivided as follows:
- organic peroxides, not requiring temperature control;
- organic peroxides, requiring temperature control.
Organic peroxides are organic substances which contain the bivalent –O-O- structure and may be considered derivatives of hydrogen peroxide, where one or both of the hydrogen atoms have been replaced by organic radicals. 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, and amines), friction or impact. Decomposition may result in the evolution of harmful, or flammable, gases or vapors. Some organic peroxides may decompose explosively and burn vigorously.
Class 6.1 Toxic substances. The heading of Class 6.1 covers substances of which it is known by experience or regarding which it is presumed from experiments on animals that in relatively small quantities they are able by a single action or by action of short duration to cause damage to human health, or death, by inhalation, by cutaneous absorption or by ingestion. Substances of Class 6.1 are subdivided as follows:
- toxic substances without subsidiary risk;
- toxic substances, flammable;
- toxic substances self-heating, solid;
- toxic substances, which, in contact with water, emit flammable gases;
- toxic substances, oxidizing;
- toxic substances, corrosive;
- toxic substances, flammable, corrosive.
Class 6.2 Infectious substances. The heading of Class 6.2 covers infectious substances. For the purposes of ADR, infectious substances are substances which are known or are reasonably expected to contain pathogens. Pathogens are defined as microorganisms (including bacteria, viruses, rickettsiae, parasites, fungi) and other agents such as prions, which can cause disease in humans or animals. Substances of Class 6.2 are subdivided as follows:
- infectious substances affecting humans;
- infectious substances affecting animals only;
- clinical waste;
- biological substances.
Infectious substances are divided into the following categories:
- an infectious substance which is carried in a form that, when exposure to it occurs, is capable of causing permanent disability, life-threatening or fatal disease in otherwise healthy humans or animals;
- an infectious substance which does not meet the criteria for inclusion in the first category.
Class 7 Radioactive materials. Radioactive material means any material containing radionuclide where both the activity concentration and the total activity in the consignment exceed 70 kJ per kg.
Class 8 Corrosive substances. The heading of class 8 covers substances and articles containing substances of this class which by chemical action attack epithelial tissue – of skin or mucous membranes – with which they are in contact, or which in the event of leakage are capable of damaging or destroying other goods, or means of transport. The heading of this class also covers other substances which form a corrosive liquid only in the presence of water, or which produce corrosive vapour of mist in the presence of natural moisture of the air. Substances and articles of Class 8 are subdivided as follows:
- acid substances;
- basic substances;
- other corrosive substances;
- corrosive substances flammable;
- corrosive substances self-heating;
- corrosive substances which, in contact with water, emit flammable gases;
- corrosive substances oxidizing;
- corrosive substances toxic.
Class 9 Miscellaneous dangerous substances and articles. The heading of Class 9 covers substances and articles which, during carriage, present a danger not covered by the heading of other classes. The substances and articles of Class 9 are subdivided as follows:
- substances which, on inhalation as fine dust, may endanger health;
- substances and apparatus which, in the event of fire, may form dioxins;
- substances evolving flammable vapour;
- lithium batteries; life-saving appliances;
- environmentally hazardous substances;
- elevated temperature substances;
- other substances presenting a danger during carriage, but not meeting the definitions of another class.
Dangerous goods list, special provisions and exceptions related to limited and excepted quantities may be seen here:
