Firefighters are no longer working in structures that were built to last, like those buildings where you could simply scrape away the charring and move back in.
Many should recall in the late Francis L. Brannigan's writings that the factory buildings of earlier days were specifically constructed to sustain a fire without loss of structural integrity. Often there could be a fire and either the moderate charring that may have occurred was left in place, or scraped off. These structures were massive in size and were built to be highly resistive to fire mainly, for the economic perspective.
When sprinkler technology came along, these factory structures were even provided with scuppers to allow water to be easily removed either by natural drainage or pushed out by salvage crews. Bottom line was just that, the bottom line and it was important to get business and commerce running again. These buildings were robust and sustained, in some cases, for 100 or more years. One key feature of these structures is that after a fire they often had plenty of mass to support the designed loading of the structure.
Fast forward to our current times and look at how engineering and construction technology has allowed us to manufacture structural load-bearing components. Ones that use the least amount of material needed to carry the load, relieve the pressure on wood as a natural resource and allow for greater efficiency to the building industry in constructing buildings.
"Throw Away Homes" Are Built
The efficiency equates to profit, but the modern home has become a "throw away home." But this is not an economics paper it is about a shift that occurred about 20 years ago in the residential construction industry that we noticed and were concerned about but really have not done much to change. I am talking about the impact on firefighter safety brought on by the so-called lightweight construction.
There are really many areas of concern related to lightweight construction, but in this issue I only want to talk in a limited scope about the impact on firefighter safety and tactics of fires that can get into the structure of the building.
Going back to the example of the massiveness of timber construction I want to move you now nearly to the other end of a spectrum of construction. We'll go through this spectrum by way of where many of us cut our firefighting teeth in forgiving structures that were mostly pretty solidly built. I grew up and started as a firefighter in a suburban area that really has developed in earnest since the late 1930's common construction for that period and the next 50 years used dimensional lumber to form wood frames for the structure; or buildings of masonry walls with wood floors and roof to form what we know as ordinary construction.
Even in the smaller dimensions of the structural members you still had a measure of mass that could give you time to conduct an interior attack with less risk of structural failure. Dimensional lumber dominated construction and when combined with plaster or sheetrock compartments you were afforded considerable resistance to fire if it started in a room's contents. In these construction types floors and roofs could become (spongy) and raise caution but would not be necessarily consumed and collapse before firefighters could effectively attack and stop the destruction of the structure.
A couple years ago, there was a house in my old neighborhood that had some electrical phase problem that fedback electricity across the ground causing all wiring in the structure to glow like a bread toaster. Fire cooked this house for 20 minutes before the power company arrived to cut the current. Firefighters extinguished the fire pretty quickly. This home -- built in 1948 -- was not only still standing but was structurally in decent shape considering the insult it endured.