Q. Can there be a national standard set for home separation to reduce the risk of spreading fire? — Robin (question edited for length and clarity)
A. As the price of housing has risen dramatically around the country, there has been a push from cities, states and the federal government to increase the housing supply. In January, President Donald Trump issued an executive order calling for an end to costly regulatory burdens and encouraging higher-density building to add housing quickly.
Robin’s question concerns fire safety and whether national limits on structure separation would help prevent catastrophic neighborhood destruction.
To be sure, smart planning is crucial for preventing large-scale fires, according to Faraz Hedayati, lead research engineer at the Insurance Institute for Business and Home Safety.
“Fires will happen, homes will burn down, but there is no need for ZIP code-level damage,” Hedayati told Homes.com.
However, regions and their fire risks are too different to set a single spacing standard nationally, Hedayati said.
“The fires that we get in Charlotte, North Carolina, are very different than the ones we get in Pasadena, [California],” he said. “It really depends on how people think about visually appealing homes, what are the fire resources in the area, what is the likelihood of fire.”
Downtown districts, for example, are often located away from areas with high fire risk, making it more plausible to build at higher densities, Hedayati said. “In suburban areas, you basically go live in the wildlands, so you’re exposed to fire.”
In a suburban neighborhood, Hedayati said, the rule is to keep flames from touching other structures.
“Suppression distance between homes needs to be wide enough so that if the first building ignites, and we add wind, so the flames stretch out, flames don’t touch the neighbor,” he said.
Materials make the difference
Chris Needham, a fire and explosion investigator with OCI Group, an engineering firm based in Ontario, Canada, said the nearness of buildings should matter less than how long it takes the materials to combust, also known as the fire rating.
“It should withstand a fire for a certain amount of time,” he told Homes.com.
Think of the way apartments are typically built. “You don’t want a unit on the third floor to affect the fourth, fifth and sixth,” Needham said. “It’s usually concrete [between them], which has a two-hour fire rating or more. Apartments are some of the safest places ever because the fire separation between them is so highly rated.”
What is vital in terms of spacing, according to Needham, is that firefighters have enough room to put the fires out.
“The suppression activities sometimes require space,” he said. “We might need to set up a ladder or drag a hose up that ladder to a window. That needs space.”
Adding fuel to the fire
Material considerations are a double-pronged question for Hedayati: “There are two knobs here. One is the potential fire intensity from a burning building to the neighboring structure. And the other one is the material that is receiving this heat.”
In this estimation, it is not only the material of the building that could catch, but the material of the burning building that matters.
“If a wood home is burning, it releases X amount of energy,” he said. “If the home is made of stucco or concrete, it releases less energy. The walls stay there, and the heat goes up.”
In terms of space, while it mostly cannot be increased for neighborhoods that are already built, homeowners can work to keep the space between homes free of fuel, Hedayati said.
“As a homeowner, I can decide not to add a shed to my backyard. If I do, I reduce my structure separation distance.”
Most rules are local
Part of this question concerns a national standard for fire safety. Dictating spacing requirements in codes is vital, Needham said, because developers are incentivized to put buildings as close together as possible.
“For a builder, every foot of space is money for them,” he said. “They want to use as much space as they can.”
But while some building materials, such as asbestos, are regulated by the federal government, the vast majority of building codes are written at the state and municipal levels.
Organizations such as the International Code Council and the American Society of Civil Engineers publish codes that governments and agencies can adopt, but there is no federal body capable of enforcing such codes nationwide.
And codes can vary within states. For example, California mandates fire resiliency only in areas noted as high risk, according to Hedayati. “Even in California, which is leading the nation [on fire safety building codes], just a fraction of the state is required to use resilient building materials.”
Hedayati noted that in the Los Angeles fires in January, though the placement of homes didn’t create the disaster, some of the neighborhoods had homes that were too close together for the building materials they had used.
“At the beginning, these events are wildfires,” he said, “but after the first block is burned, they become urban fires. We control the fuel, we control the structure separation, we control building materials.”