Having all these areas of unprotected openings in the exterior walls should make us all think twice about the fire exposure problems and remind us of the old saying that "the chain is only as strong as its weakest link." After all, in all these cookie-cutter tract home cluster designs, the windows and vents are in close proximity even if not directly facing each other. Needless to say then, the closer they build these cluster dwellings together, the higher the chances of fire jumping from one house to the next.
In a fire scenario, especially with wind conditions, the heat from the fire in one house could definitely create fire exposure hazards for the neighboring house. The heat could begin melting the expanded foam insulation inside the exterior wall of the second house and get that one involved also. That is of course, if the fire has not already jumped right across those unprotected bedroom windows and vents to the neighboring dwelling.
I believe that in these types of situations installation of the residential fire sprinkler systems could be a great solution. Clearly, by extinguishing the fire in the incipient stage, fire sprinklers save the occupants lives. But then for most fire scenarios (other than the attic fires, since codes do not require installation of fire sprinklers in the attics of one and two family dwellings except as needed to protect fuel-fired equipment), fire sprinklers could also significantly reduce the probability of conflagration. That would then decrease the fire exposure intensity for the neighboring structure, thus reducing the probability of fire jumping from one building to the other.
In my mind, logic dictates that in one- and two-family dwellings, regardless of the fire resistive rating of the exterior walls, active fire protection provided by the residential fire sprinkler systems could provide a much higher degree of life safety for the occupants of the house involved, than the passive fire resistive rating of their exterior walls could. In reality the fire rating of the exterior wall is merely important for the fire exposures from the outside.
But then with the fires on the outside, the inside of the house would still be tenable, at least to a degree to afford the occupants of the house the chance to safely evacuate on their own will. Let's face it, if the fire in your neighbor's house is controlled by the residential fire sprinkler and contained, the fire rating of your exterior wall maybe of importance for the property protection purposes; but of less value for your life safety.
Simply stated, safety of the occupants in the residential dwellings is much higher, and they are better protected by the residential fire sprinkler systems than the fire rating of their exterior walls.
Just as important though is the safety of our own firefighters. By stopping the fire progression, fire sprinklers provide a much higher degree of safety for the firefighters. In confronting a fully involved structure, firefighters could face a higher probability of structural collapse, especially with the newer built houses that have lightweight wood trusses. And as you know, the fire service has long been concerned about the structural stability of these lightweight wood trusses under the adverse fire conditions.
As a result of these concerns, Department of Homeland Security (DHS) recently awarded Underwriters Laboratory (UL) a grant to study the structural stability and performance of the engineered lumber and lightweight wood trusses under adverse fire conditions. I believe that the results of this study will be quite valuable and could even further highlight the importance of residential fire sprinklers in protecting our own firefighters. After all, by discharging water at the earliest stages and containing the fire, structural members would not be exposed to the flames; therefore, risk of structural failure is eliminated.
Fire chiefs must also view the challenges associated with these narrow street cluster developments from yet another angle, the actual fire ground operations and tactics.
Apparatus placement is of significant importance in our fire ground operations. And the narrow streets and the long dead-ends do indeed present major challenges to our response, and further delays our fire rescue and suppression efforts.
In fighting fires, our actual battle is against the element of time. Considering that fire grows exponentially with time, the longer it takes for us to get dispatched, arrive at the scene, get set up and hooked up, and finally to get water on the fire, the much bigger fire that we have to face.