Class 4 - Flammable Solid / Spontaneously combustible / Dangerous when wet
Hazard labels of Class 4 are essential for the safe and legally compliant marking of substances that pose a significant fire or reaction risk during transport. Dangerous Goods Class 4 includes three very different but equally critical subclasses:
flammable solids (4.1), self‑igniting substances (4.2), and substances which, in contact with water, emit flammable gases (4.3).
These substances belong to the most demanding hazardous materials in transport, storage and handling.
With the appropriate hazard labels according to ADR, RID, IMDG and IATA, you ensure that transport personnel, emergency responders and authorities can immediately identify all relevant hazards.
flammable solids (4.1), self‑igniting substances (4.2), and substances which, in contact with water, emit flammable gases (4.3).
These substances belong to the most demanding hazardous materials in transport, storage and handling.
With the appropriate hazard labels according to ADR, RID, IMDG and IATA, you ensure that transport personnel, emergency responders and authorities can immediately identify all relevant hazards.
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The three subclasses of Dangerous Goods Class 4
- Class 4.1 – Flammable Solids (“Flammable Solid”)
Substances in Class 4.1 can ignite from sparks, friction or even short contact with ignition sources.
These include, among others, sulfur, matches, metal powders or self‑reactive compounds.
- Class 4.2 – Spontaneously Combustible Substances (“Spontaneously Combustible”)
These substances ignite upon contact with air. Pyrophoric substances can self‑ignite within minutes, while self‑heating substances may ignite in larger quantities over hours or days – without any external energy supply.
Examples: oil‑soaked fibers, certain metal powders.
- Class 4.3 – Substances which, in contact with water, emit flammable gases (“Dangerous When Wet”)
These substances react violently with water, often even with humidity in the air, releasing dangerous gases such as hydrogen – frequently explosive and highly flammable.
Typical examples include sodium, potassium, calcium carbide or aluminum phosphide.
Our Class 4 hazardous goods labels – robust, compliant with standards and reliable, specially developed for professional use.
- Class 4.1 – Flammable Solids (“Flammable Solid”)
Substances in Class 4.1 can ignite from sparks, friction or even short contact with ignition sources.
These include, among others, sulfur, matches, metal powders or self‑reactive compounds.
- Class 4.2 – Spontaneously Combustible Substances (“Spontaneously Combustible”)
These substances ignite upon contact with air. Pyrophoric substances can self‑ignite within minutes, while self‑heating substances may ignite in larger quantities over hours or days – without any external energy supply.
Examples: oil‑soaked fibers, certain metal powders.
- Class 4.3 – Substances which, in contact with water, emit flammable gases (“Dangerous When Wet”)
These substances react violently with water, often even with humidity in the air, releasing dangerous gases such as hydrogen – frequently explosive and highly flammable.
Typical examples include sodium, potassium, calcium carbide or aluminum phosphide.
Our Class 4 hazardous goods labels – robust, compliant with standards and reliable, specially developed for professional use.