Understanding the danger of UN Packing Group

For the packing group, substances other than those of Class 1, 2, 5.2, 6.2, 7, and other than the self-reactive substance of class 4.1 are assigned to be a packing group according to the degree of danger. 

Dangerous goods are assigned into three packing groups (also known as UN Packing Group) by the degree of danger they present:

• Packing Group I: represents a high danger
• Packing Group II: represents medium danger
• Packing Group III represents low danger.

Principal of Classification 

The dangerous goods covered by the heading of a class are defined based on their properties according to the sub-section of the relevant class. Selection of one or several subsidiary risks (s) to a dangerous substance or article is made according to the requirements of the class or classes corresponding to those risks, as mentioned in the appropriate sub-section(s). 

The packaging provisions for dangerous goods allotted to UN packing group I are much higher than the hazardous goods allocated to packing groups II and III. This section will show you how to assign the packing groups for dangerous goods.

The classes of dangerous goods according to ADR are the following:  

Class 1 Explosive substances and articles  

Class 2 Gases  

Class 3 Flammable liquids  

Class 4.1 Flammable solids, self-reactive substances and solid desensitized explosives  

Class 4.2 Substances liable to spontaneous combustion  

Class 4.3 Substances which, in contact with water, emit flammable gases  

Class 5.1 Oxidizing substances  

Class 5.2 Organic peroxides  

Class 6.1 Toxic substances  

Class 6.2 Infectious substances  

Class 7 Radioactive material  

Class 8 Corrosive substances  

Class 9 Miscellaneous dangerous substances and articles  

Note: Sections and some dangerous goods (Class 2, Division 6.2, and Class 7) are not selected into 3 packing groups I, II, and III, based on the degree of danger they present.

Why Is UN Packing Group Important?

UN packing group can assist you in finding adequate packages more promptly. The packing group also defines the degree of protective packaging required. Containers and boxes for dangerous goods that have surpassed rigorous performance testing usually bear UN specification marks (see example below). It will show X, Y, and Z whether the package is suitable for all three packing groups or simply one packing group.

How to Assign UN Packing Group?

For various dangerous goods usually transported, you can quickly find its packing group from column 5 of the Dangerous Goods List. See column 5 in the example below.

When the dangerous goods list provides more than one packing group for hazardous material, the packing group shall be determined based on test results following test methods given in the UN Manual of Tests and Criteria. A packing group will be assigned based on hazard test results for substances that cannot be identified in the Dangerous Goods List.

Class 1 Explosives Packing Group

All class 1 dangerous goods (explosives) are assigned to packing group II.

Class 3 Flammable Liquids Packing Group

Class 4 Division 4.1 Flammable Solids Packing Group

Flammable solids classified under the various entries shall be assigned to packing groups II or III on the basis of test procedures of the Manual of Tests and Criteria, Part III, sub-section 33.2.1, in accordance with the following criteria:  

Readily flammable solids which, when tested, have a burning time of less than 45 seconds over a measured distance of 100 mm shall be assigned to:  

 Packing group II: if the flame passes the wetted zone;  

Packing group III: if the wetted zone stops the flame for at least four minutes; (b) Metal powders or powders of metal alloys shall be assigned to:  

Packing group II: if, when tested, the reaction spreads over the whole length of the sample in five minutes or less;  Packing group III: if, when tested, the reaction spreads over the whole length of the sample in more than five minutes.  

For solids that may cause fire through friction, the packing group shall be assigned by analogy with existing entries or in accordance with any special provision.  

Class 4 Division 4.2 Packing Group for Substances Liable to Spontaneous Combustion

Substances and articles classified under the various entries in Table A of Chapter 3.2 shall be assigned to packing groups I, II, or III on the basis of test procedures of the Manual of Tests and Criteria, Part III, section 33.3, in accordance with the following criteria:
(a) Substances liable to spontaneous combustion (pyrophoric) shall be assigned to packing group I;
(b) Self-heating substances and articles in which, in a 2.5 cm sample cube, at 140 °C test temperature, spontaneous combustion or a rise in temperature to over 200 °C is observed within 24 hours, shall be assigned to packing group II;
Substances with a temperature of spontaneous combustion higher than 50 °C for a volume of 450 liters are not to be assigned to packing group II;
(c) Slightly self-heating substances in which, in a 2.5 cm sample cube, the phenomena referred to under (b) are not observed, in the given conditions, but in which in a 10 cm sample cube at 140 °C test temperature spontaneous combustion or a rise in temperature to over 200 °C is observed within 24 hours, shall be assigned to packing group III.

Class 4 Division 4.3 Packing Group for Substances Which, in Contact with Water, Emit Flammable Gases.

Substances and articles classified under the various entries in Table A of Chapter 3.2 shall be assigned to packing groups I, II or III on the basis of test procedures of the Manual of Tests and Criteria, Part III, section 33.4, in accordance with the following criteria:  

(a) Packing group I shall be assigned to any substance which reacts vigorously with water at ambient temperature and generally demonstrates a tendency for the gas produced to ignite spontaneously, or one which reacts readily with water at ambient temperatures such that the rate of evolution of flammable gas is equal to or greater than 10 litres per kilogram of substance over any one minute period;  

(b) Packing group II shall be assigned to any substance which reacts readily with water at ambient temperature such that the maximum rate of evolution of flammable gas is equal to or greater than 20 litres per kilogram of substance per hour, and which does not meet the criteria of packing group I;  

(c) Packing group III shall be assigned to any substance which reacts slowly with water at ambient temperature such that the maximum rate of evolution of flammable gas is greater than 1 litre per kilogram of substance per hour, and which does not meet the criteria of packing groups I or II.  

Class 5 Division 5.1 Oxidizing Substances Packing Group

Oxidizing solids classified under the various entries in Table A of Chapter 3.2 shall be assigned to packing groups I, II or III on the basis of test procedures of the Manual of Tests and Criteria, Part III, sub-section 34.4.1, in accordance with the following criteria:  

(a) Packing group I: any substance which, in the 4:1 or 1:1 sample-to-cellulose ratio (by mass) tested, exhibits a mean burning time less than the mean burning time of a 3:2 mixture, by mass, of potassium bromate and cellulose;  

(b) Packing group II: any substance which, in the 4:1 or 1:1 sample-to-cellulose ratio (by mass) tested, exhibits a mean burning time equal to or less than the mean burning time of a 2:3 mixture (by mass) of potassium bromate and cellulose and the criteria for packing group I are not met;  

(c) Packing group III: any substance which, in the 4:1 or 1:1 sample-to-cellulose ratio (by mass) tested, exhibits a mean burning time equal to or less than the mean burning time of a 3:7 mixture (by mass) of potassium bromate and cellulose and the criteria for packing groups I and II are not met.  

Class 5 Division 5.2 Organic Peroxides Packing Group

All Division 5.2 materials are assigned to Packing Group II.

Know your UN packaging codes – The complete guide

Class 6 Division 6.1 Toxic Substances Packing Group

Substances of Class 6.1 shall be classified in three packing groups according to the degree of danger they present for carriage, as follows:

Packing group I: highly toxic substances

Packing group II: toxic substances

Packing group III: slightly toxic substances

To assess the degree of toxicity, account shall be taken of the human experience of instances of accidental poisoning, as well as special properties possessed by any individual substances:

liquid state, high volatility, any special likelihood of cutaneous absorption, and special biological effects.

In the absence of observations on humans, the degree of toxicity shall be assessed using then available data from animal experiments in accordance with the table below:

Substances meeting the criteria of Class 8 and with inhalation toxicity of dust and mists (LC50) leading to packing group, I shall only be accepted for an allocation to Class 6.1 if the toxicity through oral ingestion or dermal contact is at least in the range of packing groups I or II. Otherwise, an assignment to Class 8 shall be made if appropriate.

Liquids giving off toxic vapors shall be classified into the following groups where “V” is the saturated vapor concentration (in ml/m3 of air) (volatility) at 20 °C and standard atmospheric pressure:

The values calculated for LC50 (mixture) and R are then used to determine the packing group of the mixture:

Packing group, I R ≥ 10 and LC50 (mixture) ≤ 1 000 ml/m3;

Packing group II R ≥ 1 and LC50 (mixture) ≤ 3 000 ml/m3, if the mixture does not meet the criteria for packing group I;

Packing group III R ≥ 1/5 and LC50 (mixture) ≤ 5 000 ml/m3, if the mixture does not meet the criteria of packing groups I or II.

Classification of pesticides

All active pesticide substances and their preparations for which the LC50 and/or LD50 values are known and which are classified in Class 6.1 shall be classified under appropriate packing groups in accordance with the criteria given in 2.2.61.1.6 to 2.2.61.1.9. Substances and preparations which are characterized by subsidiary risks shall be classified according to the precedence of hazard Table in 2.1.3.10 with the assignment of appropriate packing groups.

The proper shipping name used in the carriage of the pesticide shall be selected on the basis of the active ingredient, the physical state of the pesticide, and any subsidiary risks it may exhibit.

Class 8 Corrosive Substances Packing Group

Substances of Class 8 shall be classified in three packing groups according to the degree of danger they present for carriage, as follows:

Packing group I: highly corrosive substances

Packing group II: corrosive substances

Packing group III: slightly corrosive substances.

Packing group, I is assigned to substances that cause full thickness destruction of intact skin tissue within an observation period up to 60 minutes starting after the exposure time of 3 minutes or less;

(b) Packing group II is assigned to substances that cause full thickness destruction of intact skin tissue within an observation period up to 14 days starting after the exposure time of more than 3 minutes but not more than 60 minutes;

(c) Packing group III is assigned to substances that:

– cause full thickness destruction of intact skin tissue within an observation period up to 14 days starting after the exposure time of more than 60 minutes but not more than 4 hours; or

– are judged not to cause full thickness destruction of intact skin tissue, but which exhibit a corrosion rate on either steel or aluminum surfaces exceeding 6.25 mm a year at a test temperature of 55 °C when tested on both materials.

For the purposes of testing steel, type S235JR+CR

Class 9 Miscellaneous Dangerous Goods Packing Group

Class 9 are assigned to one of the following packing groups according to their degree of danger:

Packing group II: substances presenting medium danger;

Packing group III: substances presenting low danger.

Data is being taken from the below Website UNECE.org