Most warehouses have sprinkler systems. In the event of fire, the sprinklers near the fire zones start up and spray water, either containing the fire while awaiting the arrival of the fire brigade – the traditional system –, or completely extinguishing the fire – the ESFR system.   For premises where high-value goods are stored, gas extinguishers may be preferred over water, so as not to cause water damage to the stored goods. The oxygen in the air is replaced by a non-combustible gas. This system requires perfect insulation and can only be implemented over fairly small areas, generally less than 1,500 m².   For premises housing inflammable liquids or highly toxic products, water cannot be used, and the choice turns to foam – a mixture of water, emulsifier and air. In the event of fire, the premises fill with this foam and the goods are entirely covered with foam. In France, such a system is not approved by the insurers’ APSAD rules.