Building to Weather the Storm
Building to Weather the Storm
Each season brings occurrences of extreme weather around the world: Spain paralyzed by the heaviest snowstorm in recent history; California experiencing the worst wildfires on record; the Atlantic seeing one of its most active hurricane seasons. As the severity of hurricanes, wildfires, earthquakes, and other events intensifies globally and the damage caused increases, the construction industry has begun to heighten its focus on resilience.
Defined in ASTM International’s overview, “Reducing Vulnerability: Standards and Resilience,” as the ability of structures to withstand and recover from disasters, resilience considers the long-term impact of extreme weather. For construction, this involves assessing vulnerabilities and considering where and how new buildings and infrastructure can safely be erected. When planning and designing for resilience, experts review everything from soil conditions and water systems to risk management and energy efficiency.
READ MORE: The Shape of Concrete to Come
ASTM offers many resources for a more resilient landscape. These include standards on five aspects of resilience: extreme weather protection, durability, moisture management, fire safety, and energy efficiency. Both existing and emerging committees – notably a new committee dedicated to stormwater control measures – oversee existing standards and are developing new ones. And a free webinar series was launched to share information about resilience-related topics.
The Need for Stormwater Control Measures
In 2020, ASTM organized a new committee on stormwater control measures (E64) to address the increasing demand placed on these systems. One of roughly two dozen ASTM committees formed in the 21st century, this committee focuses on test methods, specifications, practices, guides, and nomenclature for stormwater-control measures.
Committee E64 grew out of the subcommittee on precast concrete products for stormwater management (C27.70), part of the precast concrete products committee (C27). Stormwater, which is water from rain, snow, and ice melts, contributes the greatest amount of pollutants to our waterways. Because stormwater is untreated, it transports sediment, debris, garbage, metallic and organic compounds, and pathogens directly into lakes, rivers, and oceans. It erodes stream banks, causes flooding, and negatively impacts aquatic and human life. As a result, the flow, volume, and pollutants of stormwater must be managed.
At one time, stormwater was controlled with precast, concrete-based infrastructure. As stormwater systems evolved, many devices began to contain little, if any, concrete. Today they include a range of materials, including stainless steel and thermoplastic polymers, and may or may not be precast. They may also be based upon sustainable, green infrastructure, defined by Section 502 of the U.S. Clean Water Act as “the range of measures that use plant or soil systems, permeable pavement, or other permeable surfaces or substrates, stormwater harvest and reuse, or landscaping to store, infiltrate, or evapotranspirate stormwater and reduce flows to sewer systems or to surface waters.”
The stormwater control measures committee grew out of the need to develop standards for all types of stormwater management technologies. The group will initially look at manufactured stormwater quality treatment devices (MTDs) such as hydrodynamic separators and stormwater filters, and in the longer term, will coordinate with other ASTM committees to broaden the focus to flow management, runoff detention, and retention technologies, such as permeable pavements, rain gardens, and sediment basins, says Joel Sprague, technical director at TRI Environmental and chair of C27.70, which will soon become E64.
“The nexus is to reduce pollution, especially pollution associated with storm events and stormwater runoff. It’s not much of a stretch to say that this [severe weather] leads to more frequent and more severe runoff, more pollution taken into streams, rivers, and ultimately, big bodies of water. We want international uniformity on how devices are evaluated in their performance in removing pollutants,” Sprague says.
Still in its early stages, the committee has formed subcommittees on lab evaluation of devices (E64.01), field evaluation (E64.02), component evaluation (E64.03), and nonpoint control measures for agricultural runoff pollutants (E64.04). According to James Lenhart, president of Stormwater Northwest and vice chair of C27.70, developing standards to be used to establish programmatic verification requirements, maintenance procedures, laboratory quality assurance, and certification requirements will be an important part of the work of these subcommittees.
Moreover, E64 members have identified additional ASTM committees to work with. These committees include, but are not limited to, the committees on precast concrete products (C27); concrete and concrete aggregates (C09); soil and rock (D18); water (D19); environmental assessment, risk management, and corrective action (E50); and plastic piping systems (F17).
According to Seth Brown, executive director of the National Municipal Stormwater Alliance and a member of C27.70 and E64, the committee is identifying existing ASTM standards and work items that could fall under its purview. At present, the committee has singled out a number of proposed C27.70 standards that are relevant. These include terminology for standards relating to stormwater control measures (WK71442); specification for silica test sediments for the evaluation of stormwater treatment devices (WK30222); and scour testing for hydrodynamic separator devices (WK67310).
Additionally, the committee is looking at different state and jurisdictional testing protocols and determining which could be brought into a national and international program. Brown cites the states of Washington and New Jersey as having notable verification processes for manufactured stormwater treatment devices, which have become de facto verification programs for cities and states around the country.
Examples of this include the City of Indianapolis, which defers to New Jersey’s lab testing program, while the State of Minnesota defers to Washington’s field-testing program. However, because water pollution factors vary from region to region and state to state, stormwater makeup likewise differs. For instance, stormwater in cold weather climates can contain high amounts of road salts and chlorides, while in warm climates, this is far less of a water-quality issue. For this reason, a national program will need a variety of components in performance testing standards to address these differences, Brown says.
Stormwater control has become so critical to resilient construction that a new committee was recently formed.
Brown and Sprague both note that, although E64 has 108 members on its roster, more regulators, public works officials, and land developers need to become involved. At least half should be nonproducers, Brown says.
“We’re seeing a doubling of the frequency of weather events. It’s not theoretical. It’s happening today,” says Brown, who is also the overseer of the National Stormwater Testing and Evaluation for Products and Practices (STEPP). “By having a committee that can address the construction and performance of a range of stormwater products and practices, it will allow us to look at stormwater infiltration: How quickly does it happen? How does it behave? Then we can develop a better understanding of it. Performance is still a big question mark. How do we construct these structures in the right way? There is a chasm between presumed and actual performance. We are developing testing standards so that we can have greater confidence in the actual performance of stormwater infrastructure.”
Additional Standards for Resilience
ASTM International has a tremendous breadth of widely used resilience-related standards, including the standard practice for infrastructure management (E3210). Developed by the subcommittee on sustainable property management (E53.07), E3210 documents the requirements for transparency and accountability for 15 infrastructure asset systems, including potable water supply, stormwater and sewage systems, buildings, security, transit, and communication. The standard also establishes the framework for evaluating system performance, budgets,
Marty Rowland, Ph.D., chair of E53.07, professional engineer, and senior project manager for the remediation of historic landfills with the New York City Department of Parks and Recreation, anticipates an increased interest in this standard. “Cities are struggling with COVID-19. There are fewer people to pay taxes and less money coming in. I think there’s going to be a lot of interest in having a standard approach to how infrastructure is built and paid for,” says Rowland.
David Hattis, president of Building Technology Inc. (BTI) and a member of ASTM’s committee on performance of buildings (E06), points out another resilience standard relating to financial matters: the standard practice for probable maximum loss (PML) evaluations for earthquake due-diligence assessments (E2557). A standard from the subcommittee on whole buildings and facilities (E06.25), E2557 provides requirements for assessing seismic events and the resulting financial risks to properties. Currently, Hattis is also working with the subcommittee on the standard specification for flood damage-resistant materials and assemblies (E3075).
“FEMA is supporting the development of the standard [E2557], which addresses materials only and recognizes that assemblies are a bit different. You could put flood damage-resistant materials into an assembly, and it could fail because of how it was assembled,” Hattis says.
Hattis, Rowland, and others indicate that moving forward, as the need for resilience in construction grows, ASTM International will develop the standards to address the demand.
Webinar Series Supports Resilience in Construction
In 2020, ASTM began a webinar series on resilience in construction. The complimentary, on-demand sessions explore developments in construction resilience and feature such topics as windborne debris in hurricanes, wind-resistant roofing, and reducing the vulnerability of buildings to wildfires. The programs also provide attendees with the latest versions of standards from the industry leaders who helped to develop them.
ASTM kicked off the series with David Hattis’s discussion of “Standards for Windborne Debris in Hurricanes.” Hattis is also a former chair of the E06 task group that developed windborne debris standards. In the webinar, Hattis delves into the test method (E1886) and specification (E1996) for performance of exterior windows, curtain walls, doors, and impact protective systems impacted by windborne debris in hurricanes.
Although these standards focus on hurricanes as the source of flying debris, they can be applied to any windstorm. The standards aim to lessen the damage incurred by windows, doors, and the like from airborne timber and roofing gravel. Less harm to windows and doors means less risk of pressure cycling, which, in turn, may lead to building collapse.
Along with fostering a greater appreciation of E1886 and E1996 and highlighting their ongoing revisions, Hattis hopes his talk will remind participants of the importance of creating support and demand for codes and standards.
“If it’s a scientifically correct subject with a lot of industry opposition, you can overcome the opposition if you can get the industry to recognize a new, emerging market. Take impact protection as an example. The entire fenestration industry perceived impact protection as a significant market where the benefits to them persisted, and so they got onboard,” says Hattis.
In his webinar, “Sample Selection, Construction, and Testing of Wind-Resistant Roofing Products,” David Alves of FM Approvals looks at the test method for the wind resistance of steep-slope roofing products (D3161/D3161M). These products feature such materials as cedar, tin, and ceramic.
“We feel that D3161 is a more real-life test because you’re using a fan, blowing it against the shingles at a specified wind speed. It’s a hands-on test,” says Alves, who is the senior engineer at FM Approvals.
Alves adds, “It’s important to remember that shingles that are on the market are tested through industry standards. Consumers should have some confidence that the product they’re using has some performance characteristics that have met approval.”
In “Reducing the Vulnerability of Buildings to Wildfire,” Stephen Quarles, Ph.D., University of California Cooperative Extension adviser emeritus and chair of the subcommittee on fire exposure (E05.14) notes the importance of the test methods for fire tests of roof coverings (E108), referenced by California building codes. Quarles also cites a critical proposed standard, the test method for evaluating roof field vent response to wind-blown flame and burning ember exposure (WK23700).
“We cannot overlook the danger of windborne embers, or firebrands, from wildfires. Documents indicate 60–90% of home ignitions result from them. Buildings survive wildfires through a coupled approach. They depend on the things you do, from selection, location, and maintenance, which is called creating and maintaining defensible space, to vegetation, woodpiles, and other combustibles on the property. Then you have the building itself, with its construction materials and detailing and how they are put together. Homes and buildings must always be built to resist ember exposure,” Quarles says.
In addition to the standards mentioned here, Quarles cites several others that are essential to wildfire safety and resilience in construction during the event. His subcommittee on fire exposure has also drafted a work item pertaining to taller buildings: determining flammability of exterior wall assemblies for mass timber multi-story structures (WK59635). They are also considering revisions to other standards.
View the entire webinar series ON DEMAND. ■
Kathy Hunt is a U.S. East Coast-based journalist and author.