Fire protection for distilled spirits in wooden barrels Distilled spirits are produced in a vast array of styles, flavours, and alcohol concentrations. Whether they are created for immediate consumption or a collector’s shelves, they are all stored in warehouses at some point. Failure to adequately protect these warehouses against fire could cost the manufacturer not just the value of the building’s contents, but customers as well. In this article John LeBlanc describes an FM Global test programme which determined adequate water-based fire protection for distilled spirits stored in wooden barrels. Storage arrangements included palletised and rack storage of wooden barrels filled with high-proof alcohol.
What is the Hazard?
When evaluating the hazard created by the storage of an ignitable liquid (e.g., alcohol), three things must be considered: 1. The fire properties of the stored liquid. Ethanol is a water miscible ignitable liquid that will burn. At near 100% concentration, it has a flash point below 38°C, which means (1) even at room temperature, a relatively weak ignition source can easily ignite a spill, and (2), once ignited, the fire will quickly spread across the entire surface of the spill. The heat release rate of a pool fire is in direct proportion to the exposed area of the pool, so a fire will keep growing as more liquid is spilled. In addition, the fire will follow the spill. Automatic sprinkler systems are not designed to fight fires that move away from operating sprinklers. If the amount of liquid released cannot be controlled, the only effective protection option is a deluge sprinkler system. Water miscible ignitable liquids can be extinguished with sprinkler water, but it takes time.
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2. The storage container. Distilled spirits are commonly stored in wooden barrels. The barrels have thick wooden walls. It actually takes quite a bit of time for fire to cause the wood to fail, but the barrels are held together with metal hoops. Unless enough water is flowed onto the hoops, the heat of the fire will cause them to expand and allow the alcohol to leak out. 3. The storage arrangement. The storage arrangement can affect fire development and the ability of a sprinkler system to get water to the fire. Barrels can be stored on-end and on-side in palletised arrays and rack arrays. Racks allow for rapid fire growth due to open flue spaces and plenty of air access. They also allow sprinkler water to quickly flow through the storage. Palletised arrays are more tightly spaced, limiting ventilation and slowing fire growth, but they also limit water flow through the array. Barrels onend act like open top containers early in a fire, collecting water in the barrel heads. Barrels on-side allow water to flow freely over the barrel.
