No one wants to be involved in a scenario like this—a building passes fire inspection, yet fire strikes and almost within minutes reduces the structure to charred rubble. People are dead. Others are left homeless.
This was the case in January 2009 when, within days of one another, fires at two separate retirement homes—one in Orillia, Ontario and the other in Saguenay, Québec—decimated the buildings and caused the deaths of several residents.
In Saguenay, seniors in bare feet and pajamas, forced out into -32°C (-26°F) temperatures (-36°C (-33°F) with the wind chill), watched as flames engulfed their home. In the words of Saguenay Mayor Jean Tremblay: “The whole building burned. The walls fell in.”
Building Codes and Fire Safety
Are building codes stringent enough? Should the use of construction materials that are not merely fire resistant but are non-combustible be mandated? Industry-standard testing allows materials such as wood frame and gypsum drywall to be rated fire resistant (the Gypsum Association in the U.S. cites fire-resistance ratings of up to four hours). After a certain amount of time, however—two-hours is a typical testing threshold—these materials will burn. Real-life experience shows they do, and typically much faster than in laboratory conditions.
Concrete block, however, is not merely fire-resistant; it’s non-combustible. When subjected to the 1,800°F (982°C) temperatures that other building materials are exposed to—and then put to the test of a fire hose gushing at a pressure of 30 pounds per square inch (PSI) (208 kPa)—the concrete block remains intact. After exposure to fire for two hours, tests have shown that the drywall is penetrated by the hose stream in just over 30 seconds. For fiber reinforced gypsum panels, the hose blasts through in a mere 10 seconds.
Here’s a real-life comparison: In recent cases of suspected arson on some Toronto area construction sites, fires all but flattened the wood-frame assemblies, in some instances leaving only the supporting masonry walls standing. The transition in recent years to objective-based building codes may be part of the problem. Previously, the codes were prescriptive, in essence describing what had to be done.
In new building codes, the objective-based format adds why to the equation, describing the desired outcome. The intent is to promote flexibility in design and construction through the use of what the Code refers to as ‘acceptable solutions’—alternatives that achieve the same desired results.
Unfortunately, these alternatives don’t always achieve the same results where fire testing is concerned. Swaps can be made that meet the letter of the code, but may more heavily favor the owner’s needs over the inhabitant’s needs.
Many locations have mandated sprinklers in multiple- unit residential dwellings over a certain height. This is a good thing. Sprinklers will no doubt help improve the fire safety of taller buildings and increase the chances that their residents will get out alive.
However, rather than simply take the reactionary approach of legislating sprinklers, why not implement building-code improvements more proactively— from the ground up? Why not legislate the use of materials that don’t burn?
A movement is underway to increase the level of fire protection in the Codes by using the balanced design approach to construction which considers three components:
- Containment with structural walls, floors and ceilings of masonry and concrete products that will not burn and will provide 2 to 4 hours of protection
- Detection with smoke detectors to alert residents to evacuate and
- Suppression using sprinklers to control the fire until the emergency responders arrive on the scene.
Detection and suppression are active systems that require a water source and a mechanical and/or electrical system that may, in some circumstances, fail. Containment with compartmentation is a passive system that does not require anything to activate.
The importance of containment with concrete based products that will never burn and will maintain their structural integrity can not be stressed enough. If a fire were to start within a given room or compartment of a building, the noncombustible walls, floor and ceiling would contain the fire and to allow time for fire fighters to arrive or for active protection such as sprinkler systems to deploy.
Currently, the Codes provide for detection and suppression but they do not require non-combustible compartmentation between dwelling units. A common argument made for not using compartmentation has been the misperception that it is cost prohibitive to the building owner.
Organizations within the building industry set out to clarify and accurately document the actual cost of constructing with non-combustible concrete based products vs. wood, gypsum and steel for interior separation walls, floors and ceilings, through a study implemented by an independent source.