How to Build Against Wildfires
- Nov 23, 2020
The wildfire season has been tough on California in 2020. Since the beginning of the year, more than 4 million acres have burned across the state and more than 10,000 structures were damaged or destroyed, according to the California Department of Forestry and Fire Protection.
With limited availability for development in core sites, developers are moving farther from the core, often closer to forested areas more prone to wildfires, according to Nick Wilson, vice president of field operations for RAAM Construction. Based in Pasadena, Calif., RAAM Construction has vast experience in building against wildfires. In the interview below, Wilson dives into what makes Southern California’s wildfires so destructive and the techniques that can help protect multifamily properties in areas that are exposed to wildfires.
How have the wildfires impacted the multifamily sector in Southern California in particular?
Wilson: The combination of Southern California’s warm, dry climate (which is getting hotter); gusty Santa Ana winds; people living closer to forested areas; and ironically, efforts to suppress fires has created an environment in which wildfires are easily sparked. This makes developing apartment communities in greenfield areas—where construction has not been done before—more challenging when it comes to fire danger.
With infill sites for multifamily development becoming rarer, and with technology making remote work easier, many developers are moving farther out from the core to build multifamily developments. This often places them closer to forested areas that are highly prone to wildfires, and it raises the question of how to build apartment communities in a way that protects them from wildfire risk.
What are some of the construction techniques and best practices used to safeguard a building from wildfires?
Wilson: Before developing a multifamily community, it’s critical to assess a site’s wildfire risk from “fuel”—that is, chaparral, brush and dense forests that can burn and spread quickly to nearby areas. Experienced general contractors can conduct structure and landscape mitigation that help reduce wildfire damage significantly.
Bringing contractors into the development process early is also key, especially since it may be difficult to source materials and labor when wildfires are prevalent. RAAM offers developers a host of pre-construction services that are quite valuable in the early stages of development and that serve to set the stage for a smooth process throughout the construction timeline.
It’s important to note that once a wildfire begins, it is very likely to take everything in its path. Fire will compromise the structural integrity of any building, even if it has the highest fire rating and features noncombustible roofing and fire-retardant materials and finishes. Rather than trying to build as many units as possible, it’s smarter to seriously consider fire danger when doing site assessments and planning and to evaluate the risks before building.
With regard to construction techniques, the installation of fire-suppression systems is the number one defense against any type of fire and wildfire combustion. Systems such as fire sprinklers will help prevent fires from spreading throughout a building and are a standard component of the multifamily projects that RAAM constructs.
In addition, architects are constantly improving buildings’ fire ratings, and fire-rated wall assemblies will also help slow the spread of a fire from unit to unit, space to space, and floor to floor in a multifamily complex.
What are some of the construction materials that are safest to use in wildfire risk zones?
Wilson: While wood is clearly the most likely material to burn in a wildfire, concrete structures have been long thought of as the safest form of construction to withstand fires. Most of the parking structures that RAAM constructs are built of reinforcing steel, also known as rebar, and concrete. Typical concrete walls can achieve a two-hour fire rating, and some concrete floors or podiums can achieve a three-hour fire rating. It’s worth noting that even if a fire hits a concrete structure, the fire can still cause underlying issues such as the reinforcing steel weakening from excessive heat.
Another option that can be used in zones where wildfire risk is high is steel stud framing. Although this type of framing is more commonly used in midrise and high-rise construction, low-rise structures of two-to-four stories are beginning to convert from wood timber framing to all-steel stud framing in these high-risk zones.
While concrete, steel, fire-treated glazing, noncombustible roofing and fire retardants are helpful, there are only a certain number of hours that these materials will hold up during a fire and nothing is fire-proof. Also, some of these materials present added costs to development that can prevent projects from getting off the ground.
How is RAAM Construction building against wildfires? What are some common features of your wildfire-conscious projects?
Wilson: For example, Juniper Grove, one of our newest projects in Palmdale, Calif., is located in what was considered a high-fire zone; however, special requirements were made by the local fire department as part of the project’s conditions of approval. These conditions include installing two fire hydrants on the property and four fire hydrants in the public right-of-way surrounding the future property. Even though there are two existing fire hydrants located on the neighboring properties, the city of Palmdale and the city’s fire department are requesting that a total of six fire hydrants be installed to combat both any fire on the property and any wildfires that might threaten the buildings. This was all implemented as part of the finalized design, even before the Bobcat Fire in the Angeles National Forest began burning homes in Palmdale.
In addition to the above techniques, working with cities and water companies to install fire hydrants, arranging for appropriate water pressure to fight fires when needed, and installing FDC connections inside the building are key fire-safety techniques we employ in high-risk zones.
Although it can delay projects by up to eight months, we recommend that developers work with fire departments and fire authorities to have them review plans and make sure there is fire road access and that protective structures are easily accessible. Fortunately, there are already regulations in place that guide that effort in most areas.
California’s climate has always made it prone to fires, however, climate change has exacerbated this issue. How does RAAM Construction address this issue? What are some sustainability features that you are implementing in your projects?
Wilson: We have recently completed construction on Marengo Townhomes, a collection of luxury market-rate townhomes in Pasadena, Calif., featuring such amenities as Nest thermostats and increased natural light, which reduce energy use. And last year, we completed construction on Decker Court & Gill Court, a two-building community in Pasadena consisting of affordable townhomes, which included a historical relocation and preservation. This property was built to CALGreen standards, which included solar panels and electrical vehicle charging stations. These are some of the sustainability features that multifamily developers, investors and renters are demanding, and they will become more prevalent in the years to come.
Finding alternatives to concrete, which is one of the most environmentally unfriendly materials to manufacture, is another method we employ. Because of this, we work with suppliers and engineers for materials like fly ash, which, although it is not an adequate full substitution for Portland cement, is less toxic to the environment than concrete and can be added to a concrete mix design to produce a substance that is better for the environment. These days, with cement being scarce due to COVID-19 and plant shutdowns, the cost difference between fly ash and cement is minimal, therefore, fly ash is a great multifamily construction additive for sustainability and cost-effectiveness.
Lastly, LEED-certified projects, which take CALGreen building codes to a higher level, are becoming increasingly common in multifamily construction. Achieving LEED certification, while not directly correlated to wildfires, reduces projects’ carbon footprint and slows down the effects of global warming. LEED projects utilize processes such as duct leakage testing, whole-unit pressurization tests, cut-to-fit insulation, and better fire-stopping and caulking seals to reduce penetration through a fire-rated wall or floor.