It is the IMO rulebook for dangerous goods on a ship: how to class them, pack them, mark them and stow them. Each substance gets a class, a UN number and packing rules that the carrier and the terminal have to follow.
Class 5
Oxidizing Agents and Organic Peroxides
Read the divisions below as a planning note. The class name tells you the main hazard. Packing, labels and where the box may sit on the ship still come from the IMDG Code.
Oxidisers and organic peroxides, class 5
Division 5.1. Oxidiser
An oxidiser is a material that can start or speed up the burning of other materials, usually by giving off oxygen.
1. A solid is division 5.1 when, in the UN Manual of Tests and Criteria, its mean burning time is less than or equal to a 3:7 potassium bromate/cellulose mixture.
2. A liquid is division 5.1 when, in that same manual, it ignites on its own, or its mean time for a pressure rise from 690 kPa to 2070 kPa gauge is shorter than a 1:1 nitric acid (65 percent)/cellulose mixture.
Division 5.2. Organic peroxides. Most burn fast and react to impact or friction
An organic peroxide is an organic compound with oxygen in the bivalent -O-O- link. Think of hydrogen peroxide in which one or more hydrogen atoms have been swapped for organic radicals, unless one of the following applies:
1. The material meets the definition of an explosive as prescribed in subpart C of this part, in which case it must be classed as an explosive;
2. The material is forbidden from being offered for transportation according to 49CFR 172.101 of this subchapter or 49CFR 173.21;
3. The Associate Administrator for Hazardous Materials Safety has determined that the material does not present a hazard which is associated with a Division 5.2 material; or
4. The material meets one of the following conditions:
1. For materials containing no more than 1.0 percent hydrogen peroxide, the available oxygen, as calculated using the equation in paragraph (a)(4)(ii) of this section, is not more than 1.0 percent, or
2. For materials containing more than 1.0 percent but not more than 7.0 percent hydrogen peroxide
Questions
What a class does not settle
The class names the main hazard. Many goods also have a second one, such as a poisonous gas that can also burn. The papers and the placards show both, and the separation rules follow whichever hazard is stricter.
It belongs to the substance, or to a small group of similar substances, in the IMDG Dangerous Goods List. It is not one number for a whole class. Two boxes in the same class can have different numbers, packing groups and separation rules.