3.1 Class 3 includes the following substances:

1. Flammable liquids
2. Liquid desensitized explosives

3.2 Flammable liquids are liquids, or mixtures of liquids, or liquids containing solids in solution or suspension (such as paints, varnishes, lacquers, etc., but not including substances which, on account of their other dangerous characteristics, have been included in other classes) which give off a flammable vapour at or below 60°C closed-cup test (corresponding to 65.6°C open- cup test), normally referred to as the "flashpoint". This also includes:

1. Liquids offered for transport at temperatures at or above their flashpoint; and
2. Substances transported or offered for transport at elevated temperatures in a liquid state, which give off a flammable vapour at temperatures equal to or below the maximum transport temperature.

3.3 However, the provisions of IMDG Code need not apply to such liquids with a flashpoint of more than 35°C which do not sustain combustion. Liquids are considered to be unable to sustain combustion for the purposes of the Code if:

1. they have passed the suitable combustibility test (see the Sustained Combustibility Test prescribed in Part III, chapter 32.5.2 of the Manual of Tests and Criteria); or
2. their fire point according to ISO 2592:1973 is greater than 100°C; or
3. they are water-miscible solutions with a water content of more than 90%, by mass.

3.4. Liquid desensitized explosives are explosive substances which are dissolved or suspended in water or other liquid substances, to form a homogeneous liquid mixture to suppress their explosive properties. Entries in the Dangerous Goods List for liquid desensitized explosives are UN 1204, UN 2059, UN 3064 UN 3343, UN3357 and UN 3379.

3.5 Hazard grouping based on flammability

Flammable liquids are grouped for packing purposes according to their flashpoint, their boiling point, and their viscosity. This table shows the relationship between two of these characteristics.