When fire department personnel respond to a commercial kitchen range hood fire with fire possibly extending into the exhaust duct above in a high-rise building, the two primary considerations that must be determined while the fire is being brought under control are: Where does the duct terminate...
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When fire department personnel respond to a commercial kitchen range hood fire with fire possibly extending into the exhaust duct above in a high-rise building, the two primary considerations that must be determined while the fire is being brought under control are:
- Where does the duct terminate?
- Where does it penetrate the floor above if it does not discharge directly outside the building?
What is typically lacking in these fires is quick access to accurate information regarding these two concerns. Even if the chief engineer is available and not off duty, or just off premises, chances are good he will not know one or both of these answers. Drawings must be retrieved from the blueprint room and read. Unfortunately, this usually proves impractical due to not being able to find these drawings or read the blueprints (which are very difficult to read/understand). Inevitably, fire crews must search for the ductwork, which usually results in increased damage to the building. Thermal imaging cameras and a user-friendly drawing of the building ductwork can be tremendously effective tools in quickly and effectively gaining full control over the incident.
Case Study 1
The New York City Fire Department responded to a working restaurant fire where the restaurant was well-involved on arrival and fire was extending throughout the exhaust duct from built-up grease due to lack of proper and effective cleaning of the duct. The restaurant was attached to the side of a 45-story office building, extending out approximately 40 feet toward the side street. While the fire was being fought by multiple alarm companies, the incident commander accessed the building's pre-fire plan, which the owner had done voluntarily.
The ventilation diagram showed that the kitchen duct did not pass up above the restaurant and out the roof of the one-story building. It actually went up into the ceiling void space, turned 90 degrees and passed all the way through the 45-story office building into another one-story restaurant on the opposite side of the block, then turned 90 degrees again and penetrated the roof, where it terminated with an exhaust hood enclosure. Fire had raced the entire length of the duct and ignited this enclosure on the roof of the second building a block over from the initial fire building.
The incident commander noted where the duct traveled and terminated just as fire began to show from the other restaurant's roof. Crews quickly chased down and effectively extinguished all fire in the shaftway and roof enclosure while the main fire was continuing to be fought. The fire was brought under control within the hour, but the initial fire building was nearly destroyed and shortly thereafter razed. The fire never extended into the high-rise building itself, aside from the shaftway running horizontally through the first-floor ceiling void.
Case Study 2
The Chicago Fire Department responded to a report of heavy smoke showing from the roof of a 40-story twin-tower office complex which also happened to house the Chicago Mercantile Exchange. The complex was fully occupied at the time. Just as fire crews began arriving, both towers began to evacuate all floors due to the building security and engineering staff panicking a bit because of the heavy volume of smoke pushing out the roof of one of the towers.
I was in Chicago that day, meeting with the building owner representative several blocks away when an excited secretary charged into the room announcing the fire. We decided to walk down and check it out, as two alarms of equipment began arriving on scene. The crews were met with thousands of tenants streaming out of the lobby, onto the sidewalks and even the street fronting the building. The first-due chief was not happy about the buildings being dumped without his approval.