DIN 6608

Standard for double-walled, horizontal steel tanks intended for the underground storage of flammable liquids.

This standard deals with the construction and security of underground steel tanks (earth tank). Liquids stored in the ground must not leak to the outside and must be stored inside the containers in such a way that they do not come into contact with the environment or experience contamination.

Underground, horizontal storage containers are hose-shaped tanks that are mostly buried in the ground, either entirely or partially, usually in a gravel bed ("earth tank"). The most commonly stored water-hazardous, flammable, and non-flammable liquids in DIN 6608 steel tanks are heating oil, gasoline, kerosene, or diesel.

In practice, these earth tanks are also used for other water-hazardous substances such as acids, alkalis, liquid and water-soluble hydrocarbons, alcohols, nitrogen and sulfur-containing organic compounds, and poisons. Due to their construction, these robust tanks are also suitable for storing firefighting water, process water, and wastewater.

Steel tanks according to DIN 6608 are available in sizes ranging from 1,000 to 100,000 liters. Newer models are typically double-walled. To prevent corrosion in the ground, the tanks are equipped with a polyurethane outer coating (according to DIN 6607).