By Kristopher Blume
When it comes to building construction, “newness” does not mean better or quality. Bedroom communities are popping up across the country, suffusing the market with lightweight construction, and writing checks that the fire service will have to cash in the decades to come. Keep in mind the difference between remedial and reminder. Never take for granted our understanding of construction and the threat it poses.
Modern lightweight construction, or Type 5 construction, is a popular choice for builders due to its cost-effectiveness and energy efficiency. However, this type of construction poses significant dangers to firefighters and the community in the event of a fire. The occupancies are often built with plywood, engineered wood, and plastics. These materials are lightweight and inexpensive, making them popular for construction projects. However, these materials also decay quickly under heat and release toxic gases when exposed to fire. As a result, buildings constructed with modern, lightweight materials require our professional attention.
One of the most concerning aspects of modern lightweight construction is the speed at which fire can spread. Klaene and Sanders (2005) note that the expanded use of lightweight construction materials has significantly increased the speed at which fires can spread through buildings. These materials tend to burn more quickly and with greater intensity than traditional materials such as brick and concrete, and they can fail more rapidly under fire conditions. These highly combustible materials ignite quickly, which can cause a fire to spread rapidly throughout a structure. In addition, the open spaces and voids in modern lightweight construction make it difficult for firefighters to locate and extinguish fires. This can lead to fires burning out of control, causing extensive damage to the building and putting firefighters at risk. The National Fire Protection Association (NFPA) has also recognized the dangers of lightweight construction. In its Life Safety Code (NFPA 101), the NFPA notes that lightweight construction can lead to faster fire growth and spread and earlier collapse of the building structure. These factors can increase the risk of injury or death to firefighters working in and around occupancies to extinguish the fire or rescue occupants.
Another danger of modern lightweight construction is the release of toxic gases and combustion products. When exposed to fire, these materials release harmful gases such as carbon monoxide, hydrogen cyanide, and formaldehyde. These gases can cause respiratory problems, cardiac arrest, and even death. In addition, the release of these toxic gases can also contaminate the surrounding environment, putting the community at risk. Moreover, the glues and resins used in engineered wood products can lose their bonding properties at relatively low temperatures, leading to structural failure even before the components have ignited (Babrauskas, 2003). These components are often hidden in the floors and ceilings. When they fail, they can create sudden and unexpected changes in the fire dynamics, challenging even the most experienced firefighters. Additionally, the design features that are often associated with lightweight construction, such as open floor plans and large spans without compartmentalization, contribute to faster fire spread. Without walls to contain a fire, it can quickly engulf an entire floor, cutting off escape routes and exposing residents to intense heat and toxic combustion byproducts (Hall Jr., 2010).
Back to structural collapse. Modern lightweight construction also collapses more quickly than traditional construction. These materials have a lower load-bearing capacity and can fail more quickly under stress. This poses a significant danger to firefighters inside a building when it collapses. It also increases the risk of injury or death to members of the community who may be in or around the building at the time of collapse. Spearpoint and Horn (2016) provide a detailed analysis of modern building construction and its challenges to firefighters. They note that lightweight construction materials can be more difficult to detect with thermal imaging cameras, making it harder for firefighters to locate the source of the fire. Additionally, these materials may be more prone to collapse under fire conditions, putting firefighters at risk of injury or death.
Statistically, the NFPA has documented that buildings with lightweight construction materials have a greater likelihood of structural failure when involved in a fire. This is particularly concerning for firefighters operating within or above fire-involved compartments when a collapse occurs. Between 2005 and 2009, the NFPA reported that the fireground injury rate for structure fires in buildings with lightweight construction was 8.5 injuries per 100 fires compared to 7.9 injuries per 100 fires in buildings with more traditional construction materials (Karter, M. J. (2010). U.S. Firefighter Injuries – 2009. NFPA).
In contrast, legacy construction uses traditional building materials such as masonry, concrete, and steel. These materials have been used for centuries and are known for their durability and resistance to fire. Klaene and Sanders (2005) note that traditional building materials such as brick, concrete, and steel are generally more fire-resistant than lightweight construction materials. These materials tend to burn more slowly and with less intensity, giving firefighters more time to extinguish the fire or evacuate occupants. Additionally, these materials are less likely to fail under fire conditions, which can reduce the risk of injury or death to firefighters.
The NFPA’s Life Safety Code (NFPA 101) also recognizes the safety benefits of legacy construction. The code requires that certain types of buildings, such as high-rise buildings and assembly occupancies, be constructed using noncombustible materials such as masonry, concrete, or steel. This is based on recognizing that these materials are generally more fire-resistant and can provide a safer environment for occupants and firefighters. Brannigan and Corbett (2014) provide a detailed analysis of building construction and its impact on firefighting operations. They note that traditional building materials such as masonry, concrete, and steel are generally more resistant to fire and collapse than lightweight construction materials. This can provide firefighters a safer working environment and reduce the risk of injury or death.
Numerous case studies and statistical analyses have highlighted the dangers associated with lightweight construction, particularly the increased potential for rapid structural collapse and the resulting threats to both firefighter and resident safety. One notable case study that underscores these dangers occurred on a cold night in January 2005 when a fire broke out in a residential building in New York. The building was constructed with lightweight wooden trusses, which collapsed within minutes of the firefighters’ arrival, leading to the death of a firefighter. This incident prompted an in-depth investigation and analysis, which concluded that the lightweight trusses failed prematurely due to their reduced mass and diminished fire resistance compared to traditional solid wood construction (Mahon, 2006).
In another case, in 2012, a structural collapse in a lightweight construction building in Pennsylvania resulted in the death of two firefighters. The investigation revealed that the engineered wooden I-beams used in the construction lost their load-bearing capacity within six minutes of direct flame impingement. The collapse occurred without warning, highlighting the unpredictable nature of fires involving lightweight construction materials (Fornell, 2013).
These incidents have prompted the fire service to adapt our approach to fighting fires in lightweight construction buildings. Firefighters and company officers should be trained to understand the behavior of lightweight construction materials under fire conditions and recognize the signs of impending structural failure. This knowledge is crucial for making rapid, life-saving decisions during firefighting operations (Gustin, 2011). Additionally, crews must understand their agency’s total response time for fire-related alarms. Understanding what phase of fire-growth you are most likely to encounter based on unit response time data should set the tone for your actions (likely to be) taken on the scene.
The increasing prevalence of lightweight construction in modern buildings necessitates reassessing firefighting tactics, techniques, and safety protocols. The case studies and statistical evidence present a compelling case for the fire service and building industry to work together to develop standards that ensure the safety of occupants and first responders (Meacham, et al., 2014). At the company officer and battalion chief level, officers must adapt their tactics and strategies when responding to fires in modern lightweight construction. For example, firefighters may need different approaches to locate and extinguish fires in open spaces and voids. They may also need to be more cautious when entering a modern lightweight building, as it may be more prone to collapse. In addition, crews need to be aware of the toxic gases released during a fire in modern lightweight construction and take appropriate measures to protect themselves well beyond “loss-stopped” and overhaul.
What is to be done? Let’s “sprinkle” in a little hope. In response to these dangers, fire safety organizations like the NFPA have recommended increased use of residential sprinklers, which can control the fire size and prevent structural collapse, allowing residents and firefighters more time to react safely (Corbett, 2008). Additionally, increased emphasis on rapid and effective ventilation techniques is vital for firefighters to manage the fire dynamics within lightweight structures (Meacham, 2014). The evolution of residential construction has seen a significant shift towards using lightweight materials, which, while cost-effective and efficient, present notable fire hazards. As we have illustrated, lightweight construction materials are known to fail faster under fire conditions than traditional materials, putting occupants and first responders at greater risk (International Association of Fire Chiefs [IAFC], 2023). To mitigate these risks, the IAFC has taken a strong stance, recommending that “model building and fire codes should only permit the utilization of lightweight construction in a new building, including one-and two-family detached dwelling units” to allow firefighters to manage the fire behavior within lightweight structures (Meacham, 2014).
In light of these concerns, and as we alluded to earlier, the NFPA has developed the 13D Standard, which covers automatic sprinkler systems’ design, installation, and maintenance in one- and two-family dwellings and manufactured homes (NFPA, 2023). This standard is a guideline for ensuring sprinklers are correctly implemented to safeguard against the rapid fire spread in lightweight constructions. The cost of installation, which opponents often cite as a barrier, is relatively low when integrated into the initial construction process and is offset by the potential lifesaving benefits and property protection (U.S. Fire Administration [USFA], 2023).
The installation of residential fire sprinkler systems has been shown to significantly increase residents’ safety and structures’ survivability in the event of a fire (USFA, 2023). Home fire sprinklers not only contain and may extinguish a fire before it becomes deadly, but they also provide additional time for occupants to escape and reduce the risk of injury or death. Despite their proven efficacy, NFPA reports that fire sprinklers were present in only seven percent of reported home fires from 2010-2014 (NFPA, 2023). This statistic is alarming, considering the growing prevalence of lightweight construction in residential and commercial occupancies. The argument for residential fire sprinklers in lightweight construction occupancies is about preserving property and, more importantly, saving lives. Adopting fire sprinkler requirements in building codes for lightweight constructions is critical to enhancing residential fire safety (Lightbody, 2023).
References
Babrauskas, V. (2003). Ignition Handbook. Fire Science Publishers.
Brannigan, F. L., & Corbett, G. P. (2014). Building construction for the Fire Service (4th ed.). Jones & Bartlett Publishers.
Fornell, D. (2013). “Understanding the Hazards of Lightweight Construction.” Fire Rescue Magazine.
Gustin, B. (2011). “Lightweight Construction: A Firefighter’s Perspective.” Fire Engineering.
U.S. Fire Administration. (2023). Home Fire Sprinklers.
International Association of Fire Chiefs. (2023). Firefighter Safety and Lightweight Construction.
Karter, M. J. (2010). U.S. Firefighter Injuries – 2009. NFPA.
Klaene, B. J., & Sanders, R. E. (2005). Structural Firefighting Strategy and Tactics (2nd ed.). Jones & Bartlett Publishers.
Lightbody, J. F. (2023). Fire Sprinklers: Offsetting the Dangers of Lightweight Construction.
National Fire Protection Association. (2023). “Fire sprinklers in new homes: Why should firefighters care?”
National Fire Protection Association. (2019). NFPA 101: Life safety code. National Fire Protection Association.
Spearpoint, M. J., & Horn, G. P. (2016). Understanding modern building construction. Fire Engineering Books & Videos.
Mahon, T., & Williamson, R. B. (2006). “Firefighter safety and lightweight construction.” Fire Engineering.
U.S. Fire Administration. (2023). Home Fire Sprinklers.
Kristopher T. Blume is the fire chief of the Meridian (ID) Fire Department and has more than two decades of fire service experience. He is an author, lecturer, and independent consultant. Blume is a graduate of the Executive Fire Officer (EFO) program and an instructor at the National Fire Academy. As a student of the fire service, he is focused on values-driven, mission-focused leadership for the profession.
