What does this sign mean?
Class 4.3 covers materials that react with water and release flammable gas, sodium and potassium above all, plus calcium carbide and metal hydrides. The blue diamond with a flame over water drops warns that fighting this fire with water makes it worse, and that humid air or rainwater leaking into the store is enough to start the reaction.
Where does it go and when is it required?
Fixed to drums, sealed packages and containers, on the doors of dry chemical stores, in warehouses in industrial cities, on trucks carrying dangerous goods, and in laboratories that keep alkali metals under oil.
Regulation notes: GHS, the Globally Harmonized System of Classification and Labelling of Chemicals, is the classification system adopted across the Gulf, and the placard's colours, symbol and class number all derive from it. Placarding stores, containers and vehicles is the expected practice in Saudi and UAE industrial zones whenever dangerous goods are stored or moved.
- The usual placard size on trucks and containers is 250 × 250 mm; a 100 × 100 mm label is enough on a drum or single package.
- Print on a weatherproof, UV-resistant material, the placard itself usually hangs where water must never be used for cleaning.
- Keep the class number "4.3" at the bottom corner readable: it is what tells a fire crew not to bring hoses.
This sign is also known as: dangerous when wet placard, class 4.3 hazmat placard pdf, water-reactive substance sign printable, sodium potassium storage label. Informational sign not governed by a mandatory standard; designed in one consistent style for everyday use. Our own drawing, not the registered symbol from the standard.
