Chemical & Process Safety Management > Chapter-3 > Safe Handling of chemicals > U.N Classification of Dangerous Goods

 U.N Classification of Dangerous Goods 

IS 1446:2002 is the Indian standard  for CLASSIFICATION OF DANGEROUS GOODS

'Hazardous Goods' are the materials or items with Hazardous properties which ,if not properly controlled ,present a potential hazard to human health and safety , Infrastructure and/or their means of transport. 

The U.N has classified the hazardous goods in following 9 Categories-  

1. Explosives 

2. Gases

3. Flammable Liquids 

4. Flammable Solids 

5. Oxidizing substances and organic peroxides

6. Poisonous ( toxic ) and infectious substances 

7. Radioactive Substances

8. Corrosives Substances 

9. Miscellaneous dangerous substances and articles 

Class 1 -  Explosives 

Explosives are the materials or substances which have the ability to rapidly conflagrate or denote as consequence of chemical reaction. 

Division 1.1 : Substances and articles which have amass explosion hazard that is, one which affects virtually the entire load practically instantaneous. 

Division 1.2 : Substances and articles which have a projection hazard but not amass 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.

This division comprises of substances and articles:

a) which give 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 no significant hazard, but only a small hazard in the event of ignition or initiation during transport. That is, the effects are confined Iargely.to the package and no projection of fragments of appreciable size or range is to be expected. An external fire must not cause practically instantaneous explosion of virtually the entire contents of the package. 

Division 1.5 : Very insensitive substances, that is, substances which have a mass explosion hazard, but so insensitive that there is very little probability of initiation or of transition from burning to detonation under normal conditions of transport. 

Division 1.6 : Extremely insensitive article which do not have a mass explosion hazard. 

Class 2 -  Gases 

Division 2.1: Flammable gases

Gases which at 20”C and a standard pressure of 101.3 kPa

a) are ignitable when in a mixture of 13 percent or less by volume with air, or

b) have a flammable range with air of at least I2 percentage points regardless of the lower flammable limit. Flammability shall be determined by tests or by calculation in accordance with methods given in IS0 10156

Division 2.2: Non-flammable, non-toxic gases

Gases which are transported at a pressure not less than 280 kPa at 20”C or as refrigerated liquids, and which :

a) are asphyxiant — gases which dilute or replace the oxygen normally in the atmosphere, or

b) are oxidizing — gases which may, generally by providing oxygen, cause or contribute to the combustion of other material more than air does, or

c) do not come under the other division. 

Division 2.3: Toxic gases

Gases which :

a) are known to be so toxic or corrosive to humans as to pose a hazard to health, or

b) are presumed to be toxic or corrosive to humans because they have an LC50 value equal to or less than 5000 ml/m3 (ppm). 

Class 3 -  Flammable Liquids 

Flammable liquids are defined by hazardous goods regulation as a liquids , mixtures, mixtures of liquids containing solids in solution or suspension which give off a flammable vapors at a temperature of not more than 60-65 degree C , liquids offered for transport at temperature at or above their flash point or substances transported at elevated temperatures in a liquid state and which give off a flammable vapor at a temperature at or below the maximum transport temperature. 

Division: No subdivisions in Class 3,Flammable Liquids 

Class 4 -  Flammable Solids 

Flammable solids; substances liable to spontaneous combustion; substances which, on contact with water, emit inflammable gases.

Division 4.1: Flammable solids — Solids, which under conditions encountered in transport, are readily combustible, or may cause or contribute to fire through friction, self reactive substances which are liable to undergo a strongly exothermic reaction, desensitized explosives which may explode if not diluted sufficiently.

Division 4.2: Substances liable to spontaneous combustion — Substances which are liable to spontaneous heating under normal conditions encountered in transport, or to heating up in contact with air, and being then liable to catch fire. 

Division 4.3: Substances which, in contact with water, emit flammable gases —Substances which, by interaction with water, are liable to become spontaneously flammable or to give off flammable gases in dangerous quantities.  

Class 5 - Oxidizing substances & Organic Peroxides 

Oxidizers are defined by hazardous goods regulations as substances which may cause or contribute to combustion, generally by yielding oxygen as a result of a redox chemical

reaction. Organic peroxides are substances which may be considered derivatives of hydrogen

peroxide where one or both hydrogen atoms of the chemical structure have been replaced by

organic radicals.

Division 5.1: Oxidizing substances other than organic peroxides

Division 5.2 : Organic peroxides 

Class 6 - Poisonous (Toxic) & Infectious Substances 

Division 6.1: ​Toxic substances are those which are liable either to cause death or serious injury or to harm human health if swallowed, inhaled or by skin contact. Infectious substances are those which are known or can be reasonably expected to contain pathogens. Hazardous goods regulations define pathogens as microorganisms, such as bacteria, viruses, rickettsia, parasites and fungi, or other agents which can cause disease in humans or animals. 

Division 6.1: Poisonous (Toxic)

Division 6.2: Infectious substances — Substances containing disease producing microorganisms 

Class 7 - Radioactive Substances 

​Hazardous goods regulations define radioactive material as any material containing radio nuclides 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.

Division: ​There are no subdivisions within Class 7, Radioactive Substances

Class 8 - Corrosive Substances 

Corrosives are substances which by chemical action degrade or disintegrate other materials upon contact. 

Division: ​There are no subdivisions within Class 8, Corrosives.

Class 9 - Miscellaneous dangerous substances and articles 

​Miscellaneous hazardous goods are substances and articles which during transport present a

danger or hazard not covered by other classes. This class encompasses, but is not limited to, environmentally hazardous substances ,substances that are transported at elevated temperatures ,miscellaneous articles and substances , genetically modified organisms and microorganisms and (Depending on method of transport) magnetized materials and aviation regulated substances. 

Division: ​There are no subdivisions within Class 8, Corrosives. 

References: 

IS 1446:2002 

Google.com