FEATURE: FIRE SAFETY + GREEN BUILDINGS
It Helps Reduce Your Carbon Footprint.
But Do You Know How It Behaves When Subjected To Fire?
An update on green buildings and fire safety
NFPA Journal®, November/December 2012
By Fred Durso, Jr.
Shortly before 2 a.m. on May 1, Thomas Sullivan, Jr., was startled from sleep by the yells of his father, Thomas, Sr.: “The house is on fire! Get out, get out!”
Thomas Jr., 20, opened his bedroom door and encountered heavy smoke. He began crawling along an upstairs hallway of his family’s three-story home in Carmel, New York, and tumbled down the stairway leading to the front entrance. The stained-glass windows surrounding the door were illuminated by an orange glow from outside. He grabbed the doorknob, which was searing hot and burned his palm. Retreating, he ran through the family room and the kitchen before exiting the house through the two-car garage.
When he finally got outside, though, his family wasn’t there. Sullivan could only watch as the fire intensified despite efforts by firefighters to control it. According to an investigation of the fire, the walls of the home were built with oriented strand board (OSB), a type of structural engineered wood panel that is considered a more economical and sustainable alternative to traditional plywood panels. About 30 minutes after the fire had been reported, the walls buckled and the roof came crashing down. Still inside the 3,000-square-foot property, built in 1999, was Sullivan’s father, a police captain in Larchmont, New York, along with his mother and two teenaged sisters. Their causes of death were classified as smoke inhalation. The home was unsprinklered, investigators said, adding that they were unsure if smoke detectors activated. Thomas Sullivan, Jr., told investigators that he did not recall hearing any alarms sounding during the fire.
“In my 17 years here, this was the most tragic case I’ve dealt with,” said Dan Tompkins, captain with the Putnam County Fire Investigation Team. The fire, he said, was initiated by a cigarette that Thomas Jr. had discarded in a mulch bed near the home’s front porch, which was constructed of wood, hours before a neighbor reported the fire to 911. “The home’s [lightweight] construction definitely aided the spread of this fire.”
The incident illustrates how the “green” elements in newer buildings — residential, commercial, and industrial — can also present fire and life safety challenges (see “Risk Factors” sidebar below). While many of those challenges can be addressed through detection and suppression, they also raise questions that can only be answered through further study. A new report by the Fire Protection Research Foundation, Safety Challenges of Green Buildings, released in November, identifies dozens of these concerns and how future research could pinpoint mitigation tactics specific to each potential hazard. In November, the Foundation hosted the Fire Safety Design and Sustainable Buildings Symposium in Chicago, where architects, engineers, researchers, and other stakeholders discussed the next steps for addressing the safety concerns around sustainable construction techniques.
“I’m hopeful that this new report and the symposium will ratchet up the awareness of green building design techniques and the potential hazards they can introduce,” said Robert Solomon, NFPA division manager for Building Fire Protection and Life Safety. “If you’re going to embrace these green and sustainable design approaches, all the better, and there is no reason not to. But you have to make sure you’re not trumping building and fire safety code provisions along the way.”
In recent years, just about every professional who works with the built environment — contractors, architects, engineers, building owners, manufacturers, testing laboratories — has increasingly embraced green technology. LEED, one of the most notable green building certification programs — the acronym stands for Leadership in Energy and Environmental Design — was developed by the U.S. Green Building Council and identifies and rates environmentally friendly aspects of a building’s lifecycle, from design to operation. As of October, there were more than 14,000 LEED-certified buildings worldwide and nearly 35,000 more registered for certification. Moreover, LEED-certified commercial projects worldwide have swelled from 12 in 2000 to nearly 3,700 in 2011.
Despite this growth, the U.S does not have statistics on incidents involving green buildings or green building elements, since the National Fire Incident Reporting System, the largest fire database in the U.S., does not collect this information. Researchers from Worcester Polytechnic Institute (WPI), which developed the Safety Challenges of Green Buildings (PDF 58 KB) report for the Foundation, had to base their analysis primarily on anecdotal evidence. “It seems like the move to the greening of buildings happened without in-depth investigation of potential unintended safety consequences,” said Brian Meacham, the report’s lead author and an associate professor of fire protection engineering at WPI. While isolated research has looked at some of these issues, he said, “there does not appear to have been any coordinated or comprehensive research into the breadth and depth of potential hazards, level of risk, and mitigation strategies.”
The new report outlines nearly 80 green building components — from bamboo flooring to photovoltaic roof panels to spray-applied foam insulation — and rates their “level of concern” as low, medium, or high risk, based on the possible hazards to occupants and emergency responders. Vegetative roof systems, or green roofs, for example, might contribute to the fire load or spread if not properly hydrated and are rated “moderate.” Roof-mounted photovoltaic panels that capture solar energy might impact a firefighter’s ability to vent the building during a fire and are rated “moderate.” If those systems are not properly depowered, however, they can pose the threat of electrocution, which merits a “high” rating. Lightweight, engineered lumber also received a “high” rating for its tendency to fail more quickly than traditional lumber when exposed to fire.
NFPA’s codes and standards already address some of these hazards. NFPA 70®, National Electrical Code®, has included requirements on installing solar photovoltaic systems since the 1984 edition, and NFPA 1, Fire Code, outlines system hazards and safety tactics for emergency responders and code inspectors. The 2012 edition of NFPA 101®, Life Safety Code®, includes a series of provisions that must be met for the illumination of lights controlled by automatic sensor-type lighting switches — an energy-saving feature — so occupants can find their way to exits during fire or other building emergencies. NFPA 5000®, Building Construction and Safety Code®, has contained goals and objectives on energy efficiency and the environment since the first edition was issued in 2002. The new edition of NFPA’s Fire and Life Safety Inspection Manual has a new chapter that outlines green building and sustainability trends and the potential risks that can follow.
Even if these hazards haven’t yet been fully analyzed or evaluated, it is anticipated that future changes to the codes and standards are likely to be flagged when a substantiation or justification for the change introduces the green or sustainable concept. Solomon expects to see the relevant NFPA committees becoming more aware of the evolving concerns related to green design. For instance, he points to structural insulated panels (SIPs) that sandwich foam insulation between OSB. The insulating properties of the panels make them excellent energy-saving features, but Solomon is concerned that if not properly installed, the fire protection provided by the OSB for the foam core could be compromised. “As with any construction assembly, system, or building feature, proper installation and use is crucial,” Solomon said. “We just need to make sure our eyes are wide open with regard to what is in these products.”
The research imperative
Additional research is the key to understanding these kinds of hazards, as well as how they can be mitigated, and recent studies have already highlighted potential problems with some green construction elements. Last year, the National Research Council of Canada (NRC) completed its second phase of testing on how fire impacts a single-family home constructed with lightweight, engineered assemblies, including wooden I-joists, a form of engineered lumber. Test results from Phase I indicate that the lightweight assemblies reached structural failure 35 to 60 percent faster than solid wood assemblies.
Sprinkler advocates, including the fire service, have used findings like these as part of their call for home fire sprinklers, pointing out their obvious life-saving potential for both residents as well as for firefighters. The NRC’s follow-up report, Fire Performance of Protected Floor/Ceiling Assemblies and Impact on Tenability, published last year and available online, highlights methods aimed at protecting lightweight construction assemblies. Researchers investigated the fire performance of those lightweight construction materials when they were protected with gypsum board, suspended ceilings, or home fire sprinklers. In all tests, sprinklers kept conditions tenable in the home and helped prevent structural failure or damage.
Images from a 2008 UL study of the effects of fire on lightweight construction, with two 300-pound mannequins to simulate a pair of firefighters in turnout gear. (Top) A basement fire is weakening the supporting joists below, and the floor is beginning to bow. (Bottom) The joists fail and the floor collapses. The study found that engineered wood components failed in a fraction of the time of similar systems built with dimensional lumber. (Photo: UL Laboratories)
Tompkins, of the Putnam County Fire Investigation Team in New York, said residential sprinklers would have impacted the fire that was responsible for killing four members of the Sullivan family. “Residential sprinklers make a difference,” he said. “In this case, something would have been better than nothing.”
Among the organizations researching green building materials and techniques is Underwriters Laboratories (UL), which completed a landmark study of fire and lightweight construction in 2008. (For the 2009 NFPA Journal cover story on the UL project, visit nfpa.org/lightweight. Among the findings of the UL study was that a floor system built with lightweight wooden I-beams failed after about six minutes when subjected to a fire test; a similar floor system built with dimensional lumber lasted 18 minutes. UL also received funding from the Department of Homeland Security’s Assistance to Firefighters Grant Program to examine the electrical and casualty hazards associated with fire mitigation involving photovoltaic systems, work that quantified the hazards and laid the groundwork for developing operational practices for the fire service. Chris Hasbrook, vice president of UL’s Buildings, Fire, Life Safety, and Security Industries, said finding a balance between green building design and fire safety is key, but “not to the imbalance of eliminating one or the other.”
Identifying future research needs and best practices was a component to the Fire Protection Research Foundation’s Fire Safety Design and Sustainable Buildings Symposium, an event tied to one of a series of future research recommendations listed in the Foundation’s new report. A noteworthy highlight of the symposium was a “best practices showcase” illustrating examples of how to marry fire safety with green building elements.
Meacham views the symposium and Foundation report as preliminary steps to a larger push for green building safety, consideration of construction materials, and detection and suppression methods. “Designers of green buildings and standards development organizations should consider this information so they’re aware of the potential concerns,” he said, “and seek future research to better understand and quantify the problem.”
Fred Durso, Jr. is staff writer for NFPA Journal.
Green building components and associated fire and electrical hazards
The Fire Protection Research Foundation’s report, Fire Safety Challenges of Green Buildings (PDF, 58 KB), identifies 78 green building features that fall into the following eight categories:
Solar panels on a Target store in
California. The fire service has voiced concern over fighting fires involving photovoltaic arrays on a range of buildings. (Photo: Corbis)
The grass-covered roof of YouTube’s headquarters in San Bruno, California. (Photo: Corbis)
• Structural materials and systems, such as lightweight construction and extended solar roof panels
• Exterior materials and systems, including structural integrated panels and PVC rainwater catchment
• Façade attributes, such as awnings
• Interior materials, such as wood panel walls
• Interior space attributes, including tighter construction and more enclosed space
• Building systems and issues, including high-volume, low-speed fans and refrigerant materials
• Alternative energy systems, such as wind turbines
• Site issues, such as permeable concrete systems
The report also lists the following hazard and risk attributes associated with one or more of these green features:
• Poses potential shock hazard
• Poses potential explosion hazard
• Poses potential toxicity hazard
• Readily ignitable
• Burns readily once ignited
• Contributes more fuel/increased heat-release rate
• Material affects burning characteristics
• Fast or faster fire growth rate
• Significant smoke production/hazard
• Potential for shorter time to failure
• Failure affects burning characteristics
• Failure presents smoke spread concern
• Failure presents flame spread concern
• Material presents flame spread concern
• May impact smoke/heat venting
• May impact firefighter water availability
• May impact suppression effectiveness
• May impact fire apparatus access
• May impact firefighter access and operations
• May impact containment
The following incidents illustrate some of the dangers associated with specific green building elements:
Photovoltaic array fires
A large solar power system placed atop a Target department store caught fire in April 2009 and damaged portions of a photovoltaic solar array. Firefighters were unable to disconnect and isolate the affected modules, which continued to generate electricity as a result of the sunny weather during the incident. The fire was eventually contained without any injuries or extensive damage to the structure.
Another fire at a San Diego home a year later initiated inside a converter box, which converts electricity generated from the solar panels into usable energy for the home. In spite of attempts by the San Diego Fire-Rescue Department to douse the fire, it smoldered for hours until an electrician was called in to disconnect the panels. Media accounts estimated the structure’s damage at $4,000. There were no injuries.
Electrocutions from home insulation
In 2009, the Australian government funded a rebate program to insulate the ceilings of nearly three million homes as a means to create jobs and cut home energy costs. Various types of insulation materials were used, including metal foil sheeting, which can be a fire and electrical hazard if not installed properly, according to the Australian Competition and Consumer Commission, the country’s consumer product safety group.
Following the program’s launch, a series of incidents involving metal foil insulation — more than 80 roof fires and four electrocution deaths, according to news reports — called into question the safety of the material. For instance, a 25-year-old worker was electrocuted while installing the insulation, and his 18-year-old girlfriend who was assisting him suffered severe burns. Experts attributed some of the fires and deaths to the installation of sheeting too close to electrical cables, lights, and transformers. The government halted the program in 2010 due to safety concerns and urged homeowners with foil insulation in their ceiling spaces to undergo safety inspections.
— Fred Durso, Jr.