The International Maritime Dangerous Goods (IMDG) Code is the IMO's mandatory standard for classifying, packing, marking, and stowing dangerous goods carried by sea. It assigns every hazardous substance a class, a UN number, and packing requirements that carriers and terminals must follow.
IMDG · Class 3
IMO Class 3 - Flammable Liquids
Class 3 Flammable Liquids
Flammable Liquid
A flammable liquid (Class 3) means a liquid having a flash point of not more than 60.5°C (141°F), or any material in a liquid phase with a flash point at or above 37.8°C (100°F) that is intentionally heated and offered for transportation or transported at or above its flash point in a bulk packaging, with the following exceptions:
1. Any liquid meeting one of the definitions specified in 49CFR 173.115.
2. Any mixture having one or more components with a flash point of 60.5°C (141°F) or higher, that make up at least 99 percent of the total volume of the mixture, if the mixture is not offered for transportation or transported at or above its flash point.
3. Any liquid with a flash point greater than 35°C (95°F) which does not sustain combustion according to ASTM 4206 or the procedure in Appendix H of this part.
4. Any liquid with a flash point greater than 35°C (95°F) and with a fire point greater than 100°C (212°F) according to ISO 2592.
5. Any liquid with a flash point greater than 35°C (95°F) which is in a water-miscible solution with a water content of more than 90 percent by mass.
FAQ
Dangerous goods classification, explained
A substance is classed by its primary hazard, but many also carry a subsidiary risk — a toxic gas that's also flammable, for instance. The shipping documents and placarding reflect both, and segregation rules account for whichever hazard is more restrictive.
The UN number is assigned per substance (or group of similar substances) in the IMDG Code's Dangerous Goods List, not per class — two shipments in the same class can have different numbers, packing groups, and segregation requirements.
No — this is a plain-language reference for planning purposes only. Final classification, packing instructions, and stowage/segregation tables always come from the current edition of the IMDG Code and your carrier's dangerous goods desk.
Tracking a dangerous goods shipment?
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