Fire Sprinkler System Saves Building Under Construction from Arson Fire

Background
Following is Chief Mikkelsen’s account of the save that occurred on December
I recently attended the Blue Card “Big Box” conference in Phoenix and learned a great deal from your (Shane Ray’s) presentation, thank you. We have been a Blue Card department for 10+ years and evidence-based decision making dictates our strategies and tactics. I remember from your presentation a request to share information from sprinkler saves in our respective areas.
Yesterday morning at approx. 04:30 we were dispatched to a possible structure fire at an apartment building four blocks from our station. Building is a medium sized four-story mixed use with a commercial occupancy on the first floor and a lobby for the three residential floors above. Building was brand new and was scheduled for the first residential tenants to move in before new year’s, occupancy was being held up by the Town due to a few outstanding items including fire door closures requiring adjustment to close fully.


Details of save
Call came in from police who had been notified by the onsite security cameras / security company that a B & E (breaking & entering) was in progress. Police found the front door open and smoke coming out of the elevator shaft in the lobby and requested the fire department. Upon our arrival we found white non-pressurized smoke (lazy) on the third and fourth floors suggesting sprinkler activation which was confirmed after making entry. Crews completed a primary search and got an all clear, only smoldering fire conditions were found in various locations but no active fire or extension. The person who did the B & E was an arsonist and had poured diesel on the stairs in both stairwells and at open doorways of numerous apartments. It appears that this individual had also propped open the stairwell doors and patio doors so there was not compartmentalization ideal for sprinkler extinguishment. However, it appeared the diesel burned very hot in the numerous locations, setting off 15+ sprinkler heads which extinguished the various fires in the stairwells and fourth floor. The fact this building was not yet occupied and there were no furnishings / contents lessening the fuel load likely contributed to the effectiveness of the sprinklers. Once we had confirmed no extension and that all the fires had been struck, we shut off the sprinkler system, the water damage will far exceed the fire damage from a cost to repair perspective.
Outcome of Event
I’m relieved that this criminal who is in custody is not terribly bright as he could have used a different accelerant, had access to the sprinkler control room, and could have disabled the sprinklers prior to lighting the fires. This building has concrete sidewalls as on sides Alpha and Delta as it was constructed “zero lot line” to two other multi-family wood frame apartment buildings. If the sprinklers had not extinguished this fire, extension to the immediately adjacent structures would have been a primary concern.

