1、 Classification Description

According to the different properties of flammable and explosive substances and items, they are classified into the following categories and standards. Select and classify substances and items according to the definitions of each category.

（1） Explosive substances and items

Solid or liquid (or mixed substances) can generate gas through chemical reactions, with temperatures, pressures, and velocities high enough to cause damage to the surrounding environment.

[GB 6944-2012, Classification of Dangerous Goods 4.2.1.2]

（2） Flammable gas

A gas that meets one of the following conditions at 20 ℃ and 101.3kPa:

1. Gases with a lower explosive limit of less than or equal to 13%;

2. Regardless of its lower flammability limit, gases with an explosion limit (combustion value range) greater than or equal to 12%.

[GB 6944-2012, Classification of Dangerous Goods 4.3.2.1]

（3） Flammable liquid

Refers to flammable liquids or liquid mixtures, or liquids with solids in solution or suspension, with a closed cup test flash point not exceeding 60 ℃ or an open cup test flash point not exceeding 65 ℃.

[GB 6944-2012, Classification of Dangerous Goods 4.4.1.1]

（4） Flammable solid

Flammable solids and solids that may burn due to friction.

[GB 6944-2012, Classification of Dangerous Goods 4.5.2.1]

（5） Substances that are prone to spontaneous combustion

This item includes ignition substances and self heating substances:

1. Igneous substances: substances that burn in less than 5 minutes, even if only a small amount comes into contact with air, including mixtures and solutions (liquids or solids);

2. Self heating substance: a substance that can generate heat on its own when in contact with air, other than a combustible substance.

[GB 6944-2012, Classification of Dangerous Goods 4.5.2.2]

（6） Substances that release flammable gases when in contact with water

A substance that releases flammable gases when in contact with water and can form explosive mixtures when mixed with air.

[GB 6944-2012, Classification of Dangerous Goods 4.5.2.3]

（7） Key combustible dust

Combustible dust refers to dust, fibers, or flying fluff that can burn or stew in air and form explosive mixtures with air at room temperature and pressure.

[Catalogue of Key Combustible Dust in the Industry and Trade Sector (2015 Edition), Attachment 1]