Understanding the UN-Rating System


If you are dealing in transportation or shipping of any kind of dangerous solid or liquid goods then you should know that you need to place special packaging to differentiate the dangerous goods. You also need to place ratings on the containers as per UN regulations. These ratings are known as “UN Ratings” or United Nations ratings. Let’s understand why the ratings are important and the methodology to determine the ratings.

So, how do you determine the ratings of different containers?

It is very essential to understand the rating system as it comes to the shipper to determine the right packaging and place correct ratings on it. The UN rating system is an internationally recognized system of ratings for solid as well as liquid goods.

Consider this rating: UN 1H2/X650/S.

The above rating is for solid goods represented by the ‘S’ on the end. All the other numbers and letters have their own meaning. Let us take a look at what those letters and numbers represent.

The first number from the left-hand side is ‘1’ and it represents a drum. The number for different containers are as follow:

1 – Drum

2 – Wooden barrel

3 – Jerricans

4 – Box

5 – Bag

6 – Composite Receptacle

The next is the alphabet ‘H’ and it represents the type of material the container is made of. Here, ‘H’ means plastic. Here is the alphabet code for the various container materials:

A – Steel

B — Aluminum

C — Natural Wood

D — Plywood

F — Reconstituted Wood

G — Fiberboard

H — Plastic

L — Textile

M — Paper, Multiwall

N — Metal (other)

P — Glass, Stoneware or Porcelain

The next code is a numeric ‘2’ and it means that the container is an open-head container (removable top). If the container is a closed-head type (non-removable top), the code would be 1.

The next code is ‘X’ and it represents for what packaging groups the current packaging can be used for. There are only three codes, X, Y, and Z. The packaging groups are represented as I, II, and III with I being the most hazardous and III for the least hazardous.

Packaging groups and packaging types:

X packaging includes all the packaging groups: as I, II, and III.

Y packaging includes the packaging groups II and III.

Z packaging includes the packaging group III only.

The next series of numbers together represent the maximum gross mass that the container is tested to handle. The gross weight here is the total weight of the container plus the material. Even though the container might be able to hold more weight but you should not cross the tested limit.

What are the differences between solid and liquid ratings?

If you have understood the rating system for solids then it would be a piece of cake to make sense of the rating system for liquids. Let’s take an example for liquids too and see how it differs from solids.

Liquid rating example: UN 1H1/Z1.5/80.

Here, 1 represents the drum (container type), H for plastic (container material), 1 for closed-head (non-removable top), Z for packaging type that includes the packaging group III (least hazardous), Number ‘1.5’ represents the maximum specific gravity of the liquid for which the container has been tested, and lastly, the number ‘80’ represents the maximum hydrostatic pressure the container is tested for.

It should be noted that while it is possible to pick a higher rating than what is needed but you cannot choose a rating lower than what is needed.

Also, even with these safety standards in place, accidents can happen. The responsibility for this would fall on the shipping service providers. It is important to take note of the safety measures that have been put in place by the shipping service providers such as emergency response spill kits, fire-safety mechanism, and equipment, etc.

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