IATA Class 1 Thirteen Compatibility Groups

Class 1 divisions are further divided into 13 compatibility groups that identify the kinds of explosive articles and substances that are deemed to be compatible. Explosives are deemed compatible if they can be stowed together without significantly increasing either the probability of an accident or the magnitude of the effects if an accident was to occur.

The compatibility groups are designated A through S. Explosives in any one compatibility group cannot be stored or transported with explosives in any other compatibility group, unless permitted

Explosives in Compatibility Group S may be stowed with explosives in any other compatibility group. However, Division 1.4S explosives are subject to tests to verify that any hazardous effects are contained within the package. Evidence of a hazardous effect outside the package includes the following:

• Dent or perforation of the witness plate beneath the package
• Flash or flame capable of ignition
• Disruption of the package causing projection of the contents
• A projection that passes completely through the packaging

Division 1.4 articles and substances present no significant hazards. They may present a small hazard in the event of ignition or initiation during transport. The effects are largely confined to the package and no projection fragments of appreciable size are expected. An external fire would not cause instantaneous explosion. Articles and substances in this class and compatibility group S are the only Class 1 dangerous goods allowed for transport on passenger aircraft. Examples of Division 1.4 explosives include practice ammunition, signal cartridges, and consumer fireworks.

Division 1.5 articles and substances consist of very insensitive substances. They have a mass explosion hazard, but they are so insensitive that there is very little probability of initiation under normal conditions of transport. This includes explosive blasting agents, such as ammonium nitrate fuel. These types of substances are often used in mining. There are five blasting types, labeled A through E.

Division 1.6 articles and substances consist of extremely insensitive articles, which do not have a mass explosion hazard. They have a negligible probability of accidental initiation or propagation. In addition, the risk from Division 1.6 articles is limited to a single article.

An explosive, extremely insensitive (EEI) is an article that contains only extremely insensitive substances and that demonstrates a negligible probability of accidental initiation or propagation under normal conditions of transport.

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