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November 2014: Detection vs. Sprinkler Protection

You might think that since you have smoke detection and/or heat detection in your building that it is almost as good as having sprinkler protection to protect your property. Is there really that much difference between a detector sounding an alarm and having the fire department come fight the fire, versus having the sprinklers operate, sound the alarm and have the fire department still come to fight the fire? Besides, won't sprinklers cause more water damage than the fire department?

Let's look at a warehouse building that has detection throughout but no sprinkler protection, and a roof supported by steel beams and columns. A fire starts involving the storage. The smoke reaches the ceiling and sounds the fire alarm. The fire department gets their gear on and starts driving to the facility. In the meantime, the fire continues to grow and the amount of heat given off continues to increase. A few minutes into the fire, the building steel is heated to the point where it begins to weaken. The fire continues to grow and the building steel starts deforming.

The building steel is weakened and portions start collapsing by the time the fire department arrives at an estimated 7 minutes into the fire. The fire department still needs to set up their hoses. They need to check to see if everyone is accounted for. If not, then they need to focus on search and rescue operations rather than focusing on fighting the fire. Assume they spend 10 minutes locating and rescuing a missing employee. It is now 17 minutes into the fire and the fire is spreading rapidly and causing more and more sections of the building to collapse. The fire department tries to fight the fire, but it has gotten too extensive to get very close and they try to wet the nearby combustibles to stop the fire from spreading. The fire department is unable to contain the fire and must retreat to walled off sections in an attempt to stop the fire from spreading further. The walled-off sections and water are able to stop the fire from spreading further. The fire department continues to spray water to keep the fire under control. They have no choice but to let the fire consume the combustibles that are well inside the fire area, and just continue to try to stop the fire from spreading further. After the fire burns for the better part of a day, the fire department is finally able to start extinguishing the fire rather than just stopping to spread. The fire department eventually extinguishes the fire. Most of the building has been destroyed.

Now let's look at this same warehouse building, but with the presence of sprinkler protection rather than smoke detectors. A fire starts involving the storage, the same as in the example above. The fire spreads and the first sprinkler operates. The alarm transmits to the fire department. The fire department gets their gear on and starts driving to the fire. A few more sprinklers operate. The water from the sprinklers wets the nearby combustibles – stopping the fire from growing. This sprinkler water also provides cooling for the building steel, and it remains strong.

The fire department arrives at an estimated 7 minutes into the fire. The fire involves just a few rack bays and the water from the sprinklers is stopping it from spreading. The fire department needs to set up their hoses and determines one employee is missing. Assume they spend 10 minutes locating and rescuing the missing employee. It is now 17 minutes into the fire. The fire department can finally start to focus on the fire. They get to fire area and see that the fire has been controlled by the sprinkler system and use their hoses to finish extinguishing the fire.

In this scenario, the sprinkler system was able to keep the size of the fire small and most of the contents and the building remain undamaged.

You may then ask about the water damage from all of the sprinklers operating when the alarm goes off, as you have seen that happen in movies. Well, Hollywood does that for effect and that is not how regular automatic sprinkler systems operate. Each sprinkler head has a fusible link that must be heated for each sprinkler to operate. Only the individual sprinklers that are heated to their operating temperate will operate – the remaining sprinklers will not operate. Since sprinklers only operate at the fire area, they actually cause less water damage than fire department hoses, as it is very difficult to only spray hoses at the fire and immediate surrounding area.

As such, sprinkler protection is generally viewed as the preferred way to protect commercial properties in the US. Risk Logic can help you determine the best way to protect your property. Please contact us for assistance.