By Dr. Randall Hanifen
Last week, a large Walmart distribution facility in Indiana burned from end to end. At first, many fire service professionals wondered how a new building that is required to be equipped with sprinklers could burn so completely.
After the radio traffic concerning the fire became public, the preliminary thought is that prematurely turning off the fire riser and opening up the building for ventilation without the fire being fully extinguished may be possible reasons for the destruction of the building. Only after a thorough investigation is completed, however, will the actual cause of the fire and contributing factors be known. Regardless of the final findings by investigators, there are ways for suburban fire departments to be better prepared for this type of fire.
Why Large Buildings Like Warehouses Are Located in Suburbs
Now that many businesses have an ecommerce department that allows customers to order online, normal retailers and online retailers such as Amazon must build a chain of warehouses to fulfill customer needs. That way, customers can find a product online at 9 a.m., place the order and see that product on their doorstep by noon.
Out of necessity, warehouses and distribution facilities must have many items under one roof. Regional distribution centers that service local distribution centers must have even more items in their buildings to ensure that they can serve local warehouses and keep customers happy with the rapid arrival of a product they order.
Placing these distribution facilities in strategic locations is key to business success. Typically, these buildings are located in outer-loop suburbs that intersect with interstates; they not only require a large workforce but also need to be one million square feet or more in size.
Often, these buildings are covered by a primarily volunteer or new career fire department that often struggles to amass the funds needed to handle these types of fires. Due to their huge size, fires that occur in buildings such as warehouses or distribution facilities present significant challenges for fire departments.
‘Horizontal High-Rises’: Another Term for Warehouses
Fire service literature has referred to the big box stores and warehouses as “horizontal high-rises.” Like a conventional high-rise building fire, a fire that occurs in a huge warehouse building can be difficult to extinguish. For instance, the distance from the exterior of the building to the seat of the fire can be thousands of feet, so firefighters require more time to build a hose line capable of extinguishing a fire.
In a typical high-rise structure, compartmentalization slows the fire’s progress and is one of the reasons there aren’t multiple floor fires in most high-rise fire events. Because it takes the fire department 10 minutes or more to arrive at a high-rise fire’s location, ascend the building to the location of the fire and build the hose lines, it is not firefighters’ quick action that holds the fire, but instead the building’s design.
Anyone who has built a 1,000-foot attack line to extinguish a fire in a horizontal building knows that setting up a hose line of that length requires at least seven to 10 minutes. In many cities, 30 firefighters can show up at a high-rise fire event in less than eight minutes, making it a little easier to extinguish the blaze.
However, the suburban location of the warehouses often means that there are only two firefighters on each fire apparatus. Consequently, it can take 20 minutes or more to amass enough firefighters to extinguish a large warehouse fire.
Relying Too Much on Built-in Fire Protection
Many fire codes have been created after tragedies, which would make you wonder why these large fires still occur. But sometimes, there is a compromise that occurs between business building construction and fire safety.
Often, that compromise involves built-in fire protection. By placing sprinklers in the building like a warehouse, you can use less sturdy building materials, open up more free space for storage and increase travel distances for occupants.
Since any fire will be held in check by a sprinkler (in theory), the builder can forego some building provisions and save money on building construction and upkeep. In addition, large warehouses can ensure everything is under one roof to speed up distribution processes. But if that if there is a miscalculation in sprinkler coverage or a system failure occurs, there is nothing to stop a fire from growing and traveling through a warehouse.
Warehouse Fire Prevention and Response
Most citizens only see fire department personnel when they are in news reports or at their house for a fire or medical emergency. The prevention aspect of firefighters’ work is often never seen by the public, but that work is responsible for the fact that there are few large warehouse fires on TV daily.
Many of the fire protection systems in large warehouse buildings are complex, especially if there is a limited water supply at the site. But to make up for a limited quantity of on-site water, risers, fire pumps and water holding tanks can be installed at a building site. Also, proper inspections and understanding of a fire suppressant system are key to ensuring it will perform properly in a warehouse fire.
After firefighters arrive at a fire scene, supplementing the pressure and volume of the sprinkler system is essential. If the building has an Early Suppression, Fast Response (ESFR) sprinkler system, this system is the equivalent of having a 1.75 attack line at each sprinkler head.
By contrast, it would take firefighters a longer amount of time to build four to five attack lines to accomplish the same water flow to extinguish the fire. Ensuring that any fire pumps are engaged and operating properly is also useful for ensuring that an uninterrupted water supply at the correct pressure will discharge from the sprinkler system.
Possibly the most important aspect of controlling warehouse fires is to continue to let the sprinkler operate, even if it seems that the fire is under control. There is a tendency among some people to quickly turn off the sprinklers.
Excuses I have heard for prematurely turning off a sprinkler system are the potential for water damage, firefighters are getting wet and low visibility due to cold smoke lying at ground level. While all of these reasons have some logic to them, it is also important to remember that:
- Whatever is in the warehouse within range of a sprinkler will inevitably become wet and damaged
- Firefighters will inevitably be wet from either sweat or water
- The advent of thermal imaging has made cold smoke less of a safety issue
When it comes to extinguishing warehouse fires, patience is necessary. The minute you have an active fire in a warehouse, it is likely a 5-hour operation or more, even if all you do is finish hitting the fire’s hot spots.
Ultimately, it is vital for fire department leaders, training officers and firefighters to adjust their mindset when they deal with large warehouse fires. It is also crucial to remember that warehouse fires present unique challenges and require significant planning to minimize human injury and building damage.