Fire protection for automated small parts storage facilities and vertical storage systems

Fire hazards and causes of fire in automated small parts storage

The high degree of automation technology in small parts storage facilities creates an increased risk of fire. Fires are most frequently caused by electrical components: short-circuiting pickers, overheating electrical equipment, and short circuits in electrical lines or control cabinets are all typical causes of fires in small parts storage facilities.

Small load carriers pose particularly great risks

The particular properties of the materials used in small load carriers create specific requirements when it comes to warehouse fire protection. One problem is that the small load carriers are made of highly flammable plastic: when heated, polypropylene (PP) and polyethylene (PE) behave similarly to flammable liquids. Another problem is that, when these materials catch fire, they release comparable quantities of heat to diesel or petrol. After a certain period of combustion, the material melts into burning droplets, which drip down and create a so-called pool fire underneath the storage configuration. As a result, the fire’s development is extremely dynamic.

Rack systems up to 40m in height, with very little space between them, also make it easy for the fire to spread throughout the warehouse very quickly. Another hazard is the “chimney effect”, which causes rising fire gases to ignite goods stored higher up, meaning that the fire can reach the warehouse ceiling within just a few minutes.

Fighting fires in small load carrier facilities?

The particular circumstances involved in automated small parts storage facilities makes fire suppression a rather difficult task: polypropylene and polyethylene fires are hard to extinguish using water or water fog. When these plastics catch fire, they melt and form an oily layer that water has a difficult time penetrating. The water simply pearls off of the plastics, without actually wetting them like it would (for example) cardboard. And burning droplets of the material ignite more small load carriers underneath, creating a domino effect. Conventional extinguishing systems, such as sprinkler systems, are only marginally reliable in warehouses with very high ceilings, as it takes longer to trigger them. High ceilings and goods packed densely between the pickers restrict a fire brigade’s ability to fight fires in small parts storage facilities. Limited firefighting pathways, extreme heat development, and falling parts can all complicate extinguishing work and endanger personnel. Consequences of these fires include everything from interrupting delicate operational processes to total losses and environmental damage.