What hazard class is assigned to materials that explode under pressure?

The hazard class assigned to materials that explode under pressure is Class 1: Explosives. This classification encompasses substances and devices that can react violently, resulting in an explosion under specific conditions. Explosives are characterized by their ability to undergo rapid chemical reactions that produce gas, heat, and pressure, leading to a potential for catastrophic events when mishandled or subjected to unfavorable conditions.

The explosive materials can be divided into subcategories based on various criteria such as their sensitivity, the type of explosive reaction, and whether they are intended to be used in a controlled manner (for example, in munitions). Recognizing this classification is crucial for safely storing, handling, and transporting these materials to prevent accidents and ensure safety for personnel and the surrounding environment.

In contrast, other hazard classes pertain to different types of hazards. Class 2 encompasses gases, which may be flammable, toxic, or corrosive, and Class 3 concerns flammable liquids that ignite easily but do not necessarily explode. Class 4 includes flammable solids, which can ignite through friction or heat but are not classified as explosives. Understanding these distinctions helps in the proper management and response to hazardous materials.