Cold storage warehouses, distribution centers, and storage areas have special hazards and fire protection needs not found in standard warehouses. During the years 2005 - 2009, approximately 1,310 fires ignited within warehouses in the United States (nfpa.org). Many were unprotected and were a complete financial loss.
Special Hazards in Cold Storage Warehouses
There are several special hazards that require specific fire protection solutions within cold storage warehouses. Refrigerated warehouses contain combustible attributes throughout the facility.
Refrigerated warehouses can contain a wide variety of fire hazards within the building. Flammable products are often stored within cold storage warehouses. Food coloring and other products within frozen foods are flammable, frozen foods are often classified as a class II or class III commodity. The product's cardboard storage is also combustible. The cold air within a refrigerated warehouse dries the cardboard, and the more dry the cardboard, the more flammable it becomes. Additionally, equipment needed for warehouse services are flammable such as rubber tires, rolled paper, carpet, baled fiber, lift truck batteries, and lighting. High Intensity Discharge (HID) lighting (halide lamps, mercury vapor, and high-pressure sodium lamps) are popular in modern warehouses. They are also combustible and the cause of 12% of warehouse fires. Internal temperature of this lighting can reach 1,000 degrees. If there is a sudden internal failure, the lamp can explode and spray hot fragments around the vicinity of the lamp. If the fragments fall within the storage area, it could ignite a fire.
Cold storage warehouses have unique insulation to ensure the cold air remains within the pre-established area. In order to maintain the temperature of a refrigerated warehouse, polyurethane and polystyrene foam are often used as insulators. Ammonia-based refrigeration equipment is common within a refrigerated warehouse. In concentrations of 15-28%, ammonia is flammable. All are extremely flammable and, if a fire is present, will quickly spread the fire throughout the facility. It is necessary to have sprinkler systems within the cold storage unit to contain or extinguish any fires that may occur before it can spread by means of the insulation or refrigerant.
Special hazard storage affects fire protection solutions. There are five different item configurations within a warehouse and each variation changes the way the fire sprinkler system is designed:
• Bulk Storage: piles of unpacked material in loose, free-flowing conditions. Powder would fall into this category.
• Solid Piling: Cartons, boxes, bales, or bags which are stacked on top of one another.
• Palletized Storage: Items are placed on wooden or plastic pallets.
• Shelf Storage: Solid shelves, 30 inches deep and less than two feet apart vertically.
• Rack Storage: Varied types of racks containing stored units.
The items being stored and storage configuration apparatuses have the ability to burn and are considered a fire hazard.
Fire Protection Systems and Operations
Warehouses that are refrigerated or are freezers require sprinkler systems that will not freeze the water supply in that environment. Refrigerated warehouses should use pre-action or dry sprinkler systems. Pre-action fire sprinklers are used in conjunction with a detection system, such as Protect-o-wire linear heat detection [insert link to linear heat webpage], at the roof. The pre-action systems require a detection signal and an open sprinkler, releasing pressurized air, before the sprinkler will activate. This prevents accidental sprinkler activation, which would quickly freeze within the refrigerated warehouse.
Warehouses that contain freezers should use dry-pipe deluge sprinkler systems. Both pre-action and dry pipe sprinklers will prevent the freezing of fire water supply. To ensure a quick reaction time, fire sprinkler designers must design the water supply to be close to the fire sprinkler system, but far enough away to prevent freezing.
When designing fire sprinkler systems for warehouses, distribution centers, or storage areas, storage configuration must be taken into consideration. The key to proper fire sprinkler water range is storage height versus building height. If the storage height is too close to the building height, it can inhibit the spray range of the sprinkler. If the storage height is too far from the building height, the sprinklers may not reach the fire. 18-36 inches is an ideal amount of space to be able to evenly carry the water spray.
The aisle width, which is the horizontal distance between the storage racks, should be 4-8 feet wide. This space allows ceiling sprinklers to reach the fire and diminish the chances of it spreading.
F.E. Moran Fire Protection has over forty years of experience providing fire sprinkler and detection solutions for cold storage warehouses. Their expertise in the specific fire protection needs of this distinctive market makes them uniquely qualified to provide a sound system design. Their safe installation processes have earned the company a .56 EMR, while their ability to coordinate well with on-site contractors and employees make them a simple choice.