Correlations between TDG and GHS
Little Pro on 2016-07-19
The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) and the UN Recommendations on the Transport of Dangerous Goods Model Regulations (TDG) are the most important guidance documents on chemical hazard communication in the world. Most of countries have adopted GHS and TDG via their own national regulations. In this article, we will summarize the correlations between GHS and TDG, and compare GHS with TDG in terms of classification critiera and labelling requirement.
Comparison of TDG and GHS
| Item | UN TDG | GHS |
|---|---|---|
| Scope | Both chemicals and articles | Mainly chemicals |
| Classes | 9 dangerous goods classes | 27 hazard classes |
| Hazard communication | Labelling & marking, placarding, dangerous goods declaration | Pictogram, GHS labels and safety data sheets |
| Name | UN orange book | UN purple book |
To fully understand the correlations between TDG and GHS, you need to know the definitions of hazardous chemicals, GHS classified chemicals and dangerous goods
- Chemicals meeting GHS classification criteria are hazardous chemicals;
- Chemicals and articles on dangerous goods list or meeting dangerous goods classification criteria are dangerous goods;
- Not all dangerous goods are chemicals or GHS classified (i.e., batteries, airbags, etc);
- Chemicals that belong to dangerous goods are usually GHS classified/hazardous chemicals.
Comparison of GHS Classification and Transport Classification
| GHS Classification | Dangerous Goods Classification |
|---|---|
| Unstable explosives | Not allowed for transport |
| Explosives, Division 1.1, 1.2, 1.3, 1.4, 1.5, 1.6 | Class 1 explosive substances and articles, Division 1.1, 1.2, 1.3, 1.4, 1.5, 1.6 |
| Flammable gases category 1//Pyrophoric gases category 1/ | Class 2 Division 2.1: Flammable gases |
| Flammable gases category 2/Chemically unstable gases category A/B | Not dangerous goods |
| Aerosols category 1 and 2 | Class 2 Division 2.1: Flammable gases |
| Aerosols category 3 | Class 2 Division 2.2: Non-flammable, non-toxic gases |
| Oxidizing gases category 1 | Class 5 Division 5.1: Oxidizing substances |
| Gases under pressure | Class 2 Division 2.2: Non-flammable, non-toxic gases |
| Flammable liquids, category 1, 2, 3 | Class 3 Flammable liquids, packing group I, II, III |
| Flammable liquids, category 4 | Not dangerous goods |
| Flammable solids category 1, 2 | Class 4 Division 4.1: Flammable solids, packing group II, III |
| Self-reactive substances, Type A | See explosives. May not be allowed for transport. |
| Self-reactive substances, Type B,C,D,E,F | Class 4 Division 4.1: Flammable solids |
| Self-reactive substances, Type G | Not dangerous goods |
| Pyrophoric solids category 1 | Class 4 Division 4.2: Substances liable to spontaneous combustion |
| Pyrophoric liquids category 1 | Class 4 Division 4.2: Substances liable to spontaneous combustion |
| Self-heating substances and mixtures, category 1, 2 | Class 4 Division 4.2: Substances liable to spontaneous combustion, Packing group II, III |
| Substances which on contact with water emit flammable gases category 1, 2, 3 | Class 4 Division 4.3: Substances which, in contact with water, emit flammable gases, Packing group I, II, III |
| Oxidizing liquids category 1, 2, 3 | Class 5 Division 5.1: Oxidizing substances, Packing group I, II, III |
| Oxidizing solids category 1, 2, 3 | Class 5 Division 5.1: Oxidizing substances, Packing group I, II, III |
| Organic peroxides type A | See explosives. May not be allowed for transport. |
| Organic peroxides type B, C, D, E, F | Class 5 Division 5.2: Organic peroxides |
| Organic peroxides type G | Not dangerous goods |
| Corrosive to metals category 1 | Class 8 corrosive substances, Packing group III |
| Acute toxicity category 1, 2, 3 | Class 6 Division 6.1: Toxic substances, Packing group I, II, III |
| Acute toxicity category 4,5 | Not dangerous goods |
| Skin irritation/corrosion category 1 (1A/1B/1C) | Class 8 corrosive substances, Packing group I, II, III |
| Skin irritation/corrosion category 2 & 3 | Not dangerous goods |
| Serious eye damage/eye irritation category 1/2A/2B | Not dangerous goods |
| Respiratory or skin sensitization category 1 | Not dangerous goods |
| Germ cell mutagenicity category 1A/1B/2 | Not dangerous goods |
| Carcinogenicity category 1A/1B/2 | Not dangerous goods |
| Reproductive toxicity category 1A/1B/2 | Not dangerous goods |
| Serious eye damage/eye irritation category 1/2A/2B | Not dangerous goods |
| Target organ systemic toxicity - single exposure category 1, 2 and 3 | Not dangerous goods |
| Target organ systemic toxicity - repeated exposure category 1 and 2 | Not dangerous goods |
| Aspiration toxicity category 1 and 2 | Not dangerous goods |
| Hazardous to aquatic environment (acute) category 1 | Class 9 miscellaneous dangerous goods: marine pollutant or environmentally hazardous substances, packing group III |
| Hazardous to aquatic environment (acute) category 2 and 3 | Not dangerous goods |
| Hazardous to aquatic environment (chronic) category 1 and 2 | Class 9 miscellaneous dangerous goods: marine pollutant or environmentally hazardous substances, packing group III |
| Hazardous to aquatic environment (chronic) category 3 and 4 | Not dangerous goods |
| Hazardous to the Ozone layer | Not dangerous goods |
Note 1: Most of health hazards in GHS are not covered by dangerous goods regulations. Class 6 division 6.2 infectious substances and class 4 radioactive substances in TDG are not covered by GHS.
Note 2: The correlations between GHS hazard classes and dangerous goods classes above are general cases. There are exceptions.
Comparison of Dangerous Goods Label and GHS Label
| Item | TDG | GHS |
|---|---|---|
| Basic info |
|
|
| Label size | There are requirements on the minimum dimension of hazard labels. (i.e, 100mm x100mm for >25kg packages.) | Various requirements (See global GHS label size requirement). |
| Exceptions | Dangerous goods packaged in limited quantities or excepted quantities do not require hazard labels. | Some GHS elements may be omitted from GHS label for small containers. |
| Example | Dangerous goods label | GHS label |
A chemical product may be packaged in multi-layer packages in which case inner packages need to be labelled according to GHS while the outer packaging shall meet the provisions of TDG. Outer packages may also be labelled according to GHS (This is mandatory for single packagings such as drum). Where the GHS hazard pictogram(s) relate to the same hazard as dangerous goods hazard label, the GHS pictogram(s) need not appear on the outer packaging.
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Tags: Topics - TDG, Dangerous Goods