A rapid and fast moving early morning fire in downtown Trenton, Ontario Canada resulted in the subsequent collapse of a three story mixed use commerical and apartment occupancy structure. Published media reports indicated the building was over 130 years of age and was in operation as an adult entertainment establishment on the lower level with multiple occupancy use apartments on the upper floors. The fire displaced 12 residents. The commercial portion of the building on the number one floor was not operating at the time of the alarm.
For a complete overview of the general fire, refer to the links below for the media links.
Two firefighters were nearly trapped while engaged in primary search and rescue operations as the fire conditions deteriorated and compromise and collapse conditions began to collapse the wood frame structure.
Pre-incident images clearly depict the typical building profile of a heritage type structure of the late 1880′s vintage with it’s sloping roof profile and window treatments that are evident on both the bravo and delta divisions (many with window mounted air conditioning units that constitute a collapse risk to operating companies on the ground perimeter) . As with many buildings in urban areas, the exterior envelope has been renovated in a manner that added an exterior metal clad panel system that is typically mechanically fastened directly to the facade or to a sub-assembly fastening system. This in effect covers the buildings originating facade, building materials and structural and cosmetic conditions.
Common to original building construction and layouts, the alpha division shows the manner in which the first floor wall has been modified with no indication of window locations and conditions in the upper floors. Common to this renovation technique is the placement of the metal facade directly over existing window openings and framing systems, resulting in either boarded and elimination of the window or the fames and glass still present within the interior room compartments compounding search and rescue assignments.
Sherwood Forest Inn, Image from Google Street View
The metal exterior cladding masks the ability for arriving companies to identify if the structure is wood frame Type V, ordinary Type III or Brace Frame construction. The profile and charactoristics of this building profile suggests a buidling of Type III Ordinary construction ( Brick and jost) with load bearing masony construction. This is not the case in this structure as fireground photos further depicted. The various fireground photos suggest that this was a wood frame structure with wood exterior sheathing with some brick masonry features applied to the alpha division. The building envelope is encased in a sheet metal panel cladding system attached the perimeter facade.
Delta Division, Google Street View Image
Image above shows the degree of interior fire involvement and smoke density. The sheet metal cladding that was applied to the surface facade masks the ability to monitor wall degradation and compromise, retains heat within the building envelope and has independent collapse considerations based upon the manner it is atached to the outer facade further compounding the structural integrity of the buildings wall envelope. Photo by Step Crosier.
In incidents taht have building profiles such as this, conservative risk management, establishment of primary and secondary collapse perimeters along the various divisions is imperative for firefighter safety and apparatus operabilty.
Collapse and failure of the primary structural support systems affecting both interior and exterior structural and infill systems. Photo by Marc Venema
The image above shows the extent of collapse. Look at the various construction features consisting of the original wood plank sheathing, brick facade work, wood framing system and the retrofitted metal paneling facade.
- How would you Read the Building based upon the pre incident photos shown at the being of this post?
- Would you assume the building was a type III or IV structure or a wood frame or brace frame structure?
- Does each building system have a different bearing on fireground operations, strategies, tactics and operational integrity and company and personnal safety?
- How much operatoinal time do you have for a primary search and rescue assignment or for deployment and effective location of a fire seat and application of hose streams before you developing compromising conditions with the interior compartments?
Look at the brick veneer added to the wood sheathing covered by the metal panels in this image. Photo by Steph Crosier
