Just minutes after lightning struck a home in the Laurels of Mount Dora subdivision in 2013, the vacant rental house was engulfed by fire.
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"We stood around and watched as flames broke through the roof of house. From there it grew and grew fast," said neighbor Ron Garmany.
The home, which had recently been remodeled, was originally built in 2004 during the housing boom and was likely constructed with newer building materials like manufactured woods, plastics, and other synthetic products. Although a lack of nearby hydrants hindered emergency crews from quickly extinguishing the fire, recent studies suggests it may have also spread rapidly due to the materials used to build the home.
Based on experiments, the safety certification company Underwriters Laboratories has found newer homes can burn eight times faster than houses built a generation earlier. The study concluded that synthetic materials used in modern homes release energy faster during a fire than natural building materials used in older homes.
"A fire is much more dangerous today and propagates much quicker than it did before," said Orange County Fire and Rescue Chief Otto Drozd. "We have less time to make an effective attack, and people trapped in these homes in fire conditions have less chance of survivability."
In one UL study, researchers built two identical rooms. They filled one room with "legacy" furniture from the mid-twentieth century that was purchased at second hand outlets. The other was furnished with modern couches, tables, chairs, and curtains. Scientists then set the rooms on fire by placing lit candles on the sofas.
During the experiments, UL scientists discovered the fire grew 700-800% faster in the rooms with modern furnishings. In one test, the room with older legacy furniture took longer than 29 minutes for flashover to occur, which is when fire suddenly consumes the room from floor to ceiling. However, in the room with new furniture, flashover occurred in just 3 minutes and 40 seconds.
In another UL experiment, researchers found that engineered (or manufactured) wood burns more quickly than solid lumber. Engineered wood, which is typically cheaper than natural wood and allowed for use in home construction under Florida building codes, is made of wood particles or fibers bonded together, often with an adhesive.
"If manufactured lumber is involved in a fire situation, it will burn through faster," said John Drengenberg, UL's Consumer Safety Director.
In recent years, homes have grown in size, often with open floor plans and taller ceilings than houses built decades ago. Those features mean there is more air volume in the home, increasing the risk for larger and faster-spreading fires, according to the UL study.
Modern homes also tend to be more insulated and energy-efficient, which presents new challenges for firefighters trying to avoid introducing more oxygen to a fire.
"In older homes, we used to have a lot of time," said Chief Drozd. "We would go into a building and get to the interior of the building and fight the fire from the inside out."
But now, as a result of the changing home designs and building materials, firefighters typically begin attacking the fire by spraying water on the exterior.
"If we hit the fire from the outside, it will keep it in that room and actually increase survivability because the temperatures will go down quickly, rather than letting air into the building," said Drozd.
Some firefighters now recommend homeowners install sprinkler systems, which cost about $2.00 per square foot of coverage, according to industry estimates.
Drozd believes the best way people can protect themselves in a newer home, or even an older home with newer furniture, is to install working smoke detectors.
"At the first sign of a fire, get out," he said.