Beyond Automatic Sprinkler Systems
- By Jeff Razwick
- July 1st, 2011
Automatic sprinkler systems are often considered one of the most significant components of a building’s fire protection strategy. They can activate quickly to control or extinguish flames and smoke and prevent indoor temperatures from rising to extreme levels. As such, they help buy time for building occupants to escape and for firefighters to arrive.
But what happens when automatic sprinkler systems fail to activate or water is not able to squelch the fire? The outcome often depends on whether the building also incorporates fire-rated materials such as gypsum, concrete, firestop sealants, and fire-rated glass.
Fire-resistant materials divide buildings into compartments that aid in slowing the spread of flames and smoke. Such passive systems work in conjunction with sprinklers to contain fires and, since they do not require activation, can provide buildings with around-the-clock, back-up protection if sprinklers fail. Without this ready backup, buildings are susceptible to rapid fire development. According to the National Fire Protection Association (NFPA), the quick buildup of flames, smoke, and heat has been a primary factor in numerous multiple fatality fires.
Despite the advantages of incorporating both active and passive systems, it has become increasingly common to rely largely on automatic sprinkler systems — mainly as a way to cut building costs. For the approximate 4,200 educational facilities that grant college degrees each year, this article will demonstrate the ways in which this tradeoff can shortchange life safety.
A 2010 report by the NFPA showed that between 2003 and 2007, automatic sprinkler systems operated in 93 percent of all structure fires large enough to cause activation. When activated, sprinklers were effective 97 percent of the time — for an overall performance rate of 90 percent (i.e., 97 percent multiplied by 93 percent). These are impressive statistics — until reversed. Approximately one out of ten installed sprinkler systems fails to perform adequately.
While sprinkler systems can under-perform for a number of reasons, they typically have one common denominator — human error. According to NFPA data, the top reasons sprinkler systems fail to operate are: the system was shut off before the fire started (53 percent), the system was inappropriate for the type of fire (20 percent), lack of maintenance (15 percent), and intervention that defeated the system (9 percent).
Since sprinkler failure is often the result of human error, there is little that manufacturing advances can to do reduce this failure rate. The tradeoff, then, is a one-in-ten risk that buildings without passive systems will not provide adequate protection during a fire.
The NFPA, which continually researches and conducts studies on sprinkler performance, advises against this tradeoff, emphasizing that sprinklers should not be used in isolation. An NFPA study of sprinklers underscores this point, concluding, “Even a well-maintained, complete, appropriate sprinkler system is not a magic wand. It requires the support of a well-considered, integrated design for all the other elements of the building’s fire protection.”
The Benefits of Complementary Passive Protection
By dividing buildings into contained spaces, fire-rated materials can help slow or stop flames and smoke from spreading to other parts of the building. They work in conjunction with automatic fire sprinklers — or without — to reduce the rate at which a fire progresses.
For colleges and universities, fire-rated components and systems can also help offset the quick burning rate of lightweight building materials. Advanced building designs often feature walls, floors, and ceilings that are thinner than was possible with the stone and brick commonly used in the past. These materials may be cost-affordable and aesthetic, but they do not always defend well against fires. Lightweight building materials can ignite within minutes, providing cracks, holes, or gaps through which flames and smoke can pass. Incorporating fire-rated materials — which can block flames, smoke, and, in some instances, heat transfer for a given time period — can help provide adequate compartmentalization.
Fire-rated materials’ ability to protect against fires for extended time spans can benefit colleges and universities in another way: students in study halls, classrooms, and residence halls are not always quick to exit buildings.
One key reason students may not immediately exit a school facility during a fire is failure to recognize fire alarms. A study by the Institute for Research in Construction (IRC) states that 45 percent of building occupants are not able to distinguish fire alarms from other types of alarm systems due to a lack of consistent alarm patterning. The study goes on to state that occupants exposed to more than three false alarms per year typically disregard any additional alarms as a serious indicator of danger. This is a concern for students subjected to frequent fire alarm drills or false alarms — particularly those in residence halls where pranks are common. By containing flames and smoke, fire-rated materials can provide the necessary protection until students recognize a fire and safely exit the building.
Fire-rated Doesn’t Mean Monolithic
In recent years, college and university buildings have become more open, light-filled, and energy efficient. Modern fire-rated materials do not need to be bulky or unattractive, but can incorporate seamlessly into virtually any building design. A case in point is fire-rated glazing, which can now be used in various applications that previously were required to incorporate opaque fire-rated materials such as concrete blocks and gypsum to comply with code. Imagine sequences of fire-rated glass wall panels that transfer light between interior and exterior spaces, stairwells bathed in natural light instead of being lit from artificial light sources, and fire-rated glass floor systems that draw light deep into below-ground spaces.
Such materials can help protect building users from fire while supporting daylighting goals. Beyond energy savings, daylighting can create environments in which students perform better. A study by the Heschong Mahone Group on daylighting in schools amplifies this point, stating, “There is a valid and predictable effect of daylighting on student performance.” More specifically, “Students in classrooms with the most daylight were found to have seven percent to 18 percent higher scores than those in rooms with the least.”
While one of the most significant components of a fire and a life safety protection plan may be automatic sprinkler systems, relying solely on their performance is, at best, a disguised risk. With many lives at stake, why not maximize fire and life safety by incorporating both active and passive systems?
Jeff Razwick is a vice president for Technical Glass Products (TGP, www.fireglass.com), a supplier of specialty architectural glazing products and fire-rated glass and framing systems. He writes frequently about the design and specification of glazing systems for institutional and commercial buildings. He can be reached at 800/426-0279.