Exploring Resilient Building Design

Past experience with disasters inform current design decisions

By Peter J. Arsenault, FAIA, NCARB, LEED AP

Well-designed buildings often evoke a sense of permanence and longevity. The reality is, however, that such permanence can be routinely and sometimes dramatically challenged by natural or man-made disasters. Weather-related events such as hurricanes, tornadoes, and flooding can compromise or destroy building enclosures and structures within a matter of hours or even minutes. Seismic events can cause almost immediate destruction of entire buildings or sections of them. And in our security-conscious era, human attacks on facilities can target human lives, building structures, or both. In light of all of these conditions, architects and engineers are called upon to design buildings that can withstand these forces and situations. Some parts of the design may be mandated by regulations, others influenced by insurance requirements, and still others simply by request of the building owners. Regardless of the motivation, design teams need resources and understanding on how to address these very real situations in the interest of protecting not only the buildings we design and the contents within, but also the full health, safety, and welfare of the people who use those buildings. This course will look at some of the current thinking on these topics.

Designing in Anticipation of Disasters

The reported rise in natural and man-made disasters in recent years has focused increased attention and funding on how to prepare for and survive different types of disasters. Those engaged in this effort understand that while buildings play an important part, community resources and infrastructure are also critically important. The American Institute of Architects (AIA) has been directly involved in this area since 1972, when the role of architects was formally recognized as part of emergency response. This role became better defined in 2006 when the AIA established a Disaster Assistance Program led by a nationwide committee of architects and other stakeholders. Since then, a number of events and publications have come about, including the recent (March 2017) release of the third edition of the AIA’s Disaster Assistance Handbook (available for free download at www.aia.org/resources/71636-disaster-assistance-handbook). This informative publication provides a great overview of the topics related to resilient design (i.e., the ability to not only survive but to “bounce back” after an adverse event), some detailed information on hazard risk reduction and mitigation, and resilience planning before, during, and after an event. There are also appendices identifying AIA member groups to connect with and extensive lists of resources for more information.

The AIA website (www.aia.org/resilience) provides architects and others with additional tools and information to address the design of resilient buildings and communities. In particular, the AIA’s Understanding Resilience is a helpful primer on key terms, and Qualities of Resilience is a good jumping off point when discussing what makes a building (or community) resilient. Additional technical guidance is also available for both hazard mitigation and climate adaptation.

Using some of the AIA work as a basis, let’s turn our attention to some specific issues and how to mitigate them in the design of resilient buildings.

Floodwater Resilience

One of the most devastating and destructive environmental conditions is flooding. Whether caused by heavy rainstorms, hurricanes, or upstream conditions along rivers, buildings and people either need to be protected from floodwaters or buildings need to be designed to withstand the forces of water around the foundation and lower levels. We will look at three different design strategies for addressing flooding hazards.

Wet Flood Proofing with Operable Vents

The primary structural stresses responsible for flood damage on buildings comes from horizontal hydrostatic pressure that builds up on the outside of enclosure walls, thus pushing the walls inward. There may also be some vertical buoyancy forces on the foundation or first floor seeking to lift or float the building. This is compounded in buildings with enclosed sub-grade space, such as a finished basement, where saturated soil hydrostatic pressures and greater buoyancy forces under the basement floor can cause both lifting and collapse of a building.

Recognizing the significance of these hydrostatic forces, codes and regulations require mitigation efforts in the design and construction of buildings in flood zones. Specifically, all new construction and substantial improvements of fully enclosed areas (including crawl spaces and garages) below the lowest occupied floor that are subject to flooding must be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for both the entry and exit of floodwaters. (Note that new construction in Special Flood Hazard Areas (SFHA) designated by the Federal Emergency Management Agency [FEMA] does not allow for basements [i.e., enclosures that are below grade on all four sides]. Referred to as wet floodproofing, this strategy focuses on designing walls not to resist the hydrostatic pressure but to offset it by allowing water to flow into the enclosed space and create equalized pressure on both sides of the wall. This is a requirement whether the space is used for parking of vehicles, building access, storage, or any other function. Taken to the extreme, this approach would provide no walls at all, just “stilts” or piers that support the building and allow the water to freely pass under the first floor and around the supporting structure. While that may be appropriate for some design situations, it isn’t for all.

For enclosed areas such as crawl spaces, proper flood openings, also called flood vents, need to allow for the automatic entry and exit of floodwater without human intervention, regardless of the direction of flow of that floodwater. In the case of water entering slowly, that flow into an enclosure can cause outward pressure on an opposite or adjacent wall so water needs to flow out as easily as it flows in. Further, debris is a fact of floods, and it’s something that the design of a flood opening needs to address so the debris passes through the opening and doesn’t clog it. To be fully effective, flood vents must be installed in at least two different walls. Further, the bottom of all openings must be within 12 inches of the highest adjacent grade directly below the opening to allow no more than 1 foot of head.

FEMA’s Technical Bulletin 1 states that mass-produced, engineered flood openings must have an ICC-ES certification through the International Code Council’s Evaluation Service. Other characteristics of ICC-ES engineered flood openings are that they must mechanically open during a flood event from a latched, closed position to provide rodent resistance, and they must allow for a 3-inch-diameter sphere to be able to pass though the vent, when in the open position, to allow for flood debris flow. Full requirements can be found in the ICC-ES Acceptance Criteria for Mechanically Operated Flood Vent (AC364).

Dry Flood Proofing with Flexible Systems

Not all buildings or other structures have floor levels or conditions where wet flood proofing is appropriate (i.e., commercial space at grade level). An alternative approach is to set up a barrier around all or part of a building to protect it from rising floodwaters. Piling up sandbags is sometimes reported on the news as one way to do that, but it is time consuming and not necessarily fully effective. For new construction, this technique is not acceptable or compliant. Building walls in new construction are required to have the structural strength to withstand the flood loads. Openings in those walls, such as doors and windows, need some type of additional flood protection to maintain that structural integrity across those openings. Existing buildings can use perimeter-type systems around the whole building. For either situation, new technology allows for a grade-level floor or opening to be protected using flexible barriers that offer versatility and resiliency. This strategy allows for a flexible, high-tech fabric to serve as a flood mitigation system, with everything needed stored at the point of use at the building or the opening. Because of the flexible nature of the materials, very little space is needed, and with some simple design accommodations, it can be stored virtually unnoticed. Then when it is needed due to a flood threat, the flexible system can be deployed rapidly by building maintenance or security staff. Systems are available that are scalable for different design settings, offer robust construction, and use advanced materials.

Brian Shaw, CFM, director of sales and marketing with Smart Vent Products Inc., points out how the construction products industry has evolved in its thinking. “From recent flooding events, we’ve learned about the importance of deployment time for infrastructure flood protection systems,” he says. “The devastating damage and economic loss totals, as well as the loss of life, from Superstorm Sandy showed us that current flood proofing techniques can be useless if they are not deployed in time. The new concept of dry flood proofing using flexible soft goods stored at the point of use for rapid deployment and retraction with minimal man power addresses these issues.” Products like these support architects with flood-proofing solutions that combine aesthetics with engineered and proven performance. They can also help ensure that nonresidential structures located in flood zones are flood resilient, while also providing the lowest flood insurance premium.

Rigid Flood Barriers

Commercial and institutional buildings have often relied on rigid flood barrier systems to protect their facilities, the contents inside, and the people who work or visit there. Such systems can take the form of permanent or removable barrier walls that are constructed to be a watertight line between floodwaters and the vulnerable parts of a building. It can also take the form of doors and hatches that are specifically designed to seal openings from water and air infiltration. The technology for these systems has been traditionally based on the same techniques used for marine doors and hatches on ships. Under this approach, individual metal (i.e., aluminum or steel) components are sized to fit with others and then perimeter gaskets are engaged by mechanical or other means to create a watertight seal. Manufacturers of such systems can customize each aspect of the visible components of the design so that they are architecturally minimized from view. These rigid barriers and watertight door have been used in residences, businesses, nuclear power plants, drill rigs, and even navy vessels.

Products of this nature that are useful for flood proofing buildings can be broken down into three main categories: flood barriers, watertight and airtight doors, and watertight hatches. Each is discussed further as follows.

• Flood barriers are designed to seal an opening on three sides (along the bottom and up the sides of the frame) up to a specific height. The top is not sealed; the barrier seals to a specific height of the opening only. This height is usually based on the established flood elevation, plus at least 12 inches. By not sealing to the entire height of the opening, considerable cost savings can be achieved.
  
  A typical rigid flood barrier is made up of a series of panels that can be removable or permanently installed, and are available in single-panel or multiple-panel configurations. Flood barriers are usually manually installed and operated. As a specialty product, all types of flood barriers can be specified to meet standards of federal agencies and code requirements.
  
  Within this category of flood barrier protection, there are some specific types. Removable flood barriers are best used when flooding occurs with some advance warning. Typically, they are stored at the facility or nearby and can be moved into place and assembled by a maintenance or specialty crew in advance of a predicted flood event. A particularly cost-effective version uses stackable, modular “logs” or other components that are well suited for long perimeter protection. Permanent flood barriers can similarly take on several forms. Hinged flood barriers that act as movable portions of walls can be permanently attached to a building opening on either the side or bottom of the opening. Since everything is already in place, they can be closed with very little notice to protect the building from floodwater intrusion. Similar versions are available using panels that slide either horizontally or vertically into place from a permanent stored position. This type is particularly well suited for locations where space constraints exist. Finally, there are also systems which automatically deploy at preset water levels based on floating components that rise ahead of the water level—without any human intervention.
  
  
• Watertight and airtight doors are designed to seal all four sides of an opening. They are tested and shown to be 100 percent watertight or airtight, and can be designed for practically any size, any location, and for any pressure requirement. Both manual and power-operated doors are available, and there is now even a watertight roller curtain door that automatically deploys at a preset water level. Most of these doors can also be designed for any number of special design considerations, such as blast, ballistic, shock, vibration, radioactive, seismic, chemical, tornado, and high-pressure requirements. Both single- and double-panel doors are available for most applications.
  
  
• Watertight hatches are designed to mount horizontally in either a flush or raised configuration. Using similar technology to watertight doors, they can be designed for any size, location, or pressure requirement. Larger hatches require some type of mechanical assist for opening and closing the hatch panel, such as the use of gas springs, coil springs, counter-weights, or an electrically powered operation. Additional load factors, such as wheel loads and point loads from material-handling equipment, can be readily incorporated into custom designs. Such watertight hatches have been used, for example, as an emergency escape in subway system tunnels.

A key point for architects to be aware of is that there are companies that specialize in this type of equipment and can provide design support beginning in the very early stages of the project. Tom Themel, PE, is vice president of Walz and Krenzer Inc., a flood barrier manufacturer. He relates a very positive collaborative experience working with the Renzo Piano Building Workshop on a project in New York City at the Whitney Museum to help fortify the building’s ability to resist flooding. “Working together, we approached the specific problem with unique solutions that were custom tailored to be sensitive to the architectural design,” he says. Kevin Schorn, an associate with the Renzo Piano Building Workshop, comments, “Their ability to perform complex engineering and invent creative solutions alongside the architects made them an invaluable part of the flood mitigation design team. Their dedication to quality and precise fabrication coupled with their design and engineering skills played a crucial role in safeguarding the Whitney Museum against flooding in the future.”

Roofing Resilience

One of the most vulnerable parts of a building during a storm event is the roofing system, particularly a commercial building with a low-slope condition. Damage or failure to the roofing membrane is not only problematic in its own right, but it also exposes other parts of the building, equipment, critical building systems, and the people inside to the ravages of weather events. Consider that during severe weather, the roof could be exposed to high winds, hail, accidental puncture, unusual snow loads, or intense UV exposure from the sun, all of which could compromise the protective barrier that the roofing is meant to provide. With the short-term and long-term integrity of the building at stake, not to mention human safety, the roofing requires some special attention.

Commercial roofing systems need to address many details and conditions to be fully protective and resilient, but the fundamental decision needs to be made on what type of roofing membrane to use. One of the more popular and cost-effective systems, namely EPDM, has also been shown to be quite durable and resilient if specified and installed properly. With more than 15 billion square feet of membrane installed across the globe since the 1960s, EPDM has an impressive history of performance in the commercial roofing industry. Numerous EPDM roofs installed in the 1980s have been documented to be still performing well over 30 years later, a fact that positions EPDM as one of the strongest and most durable single-ply membranes available. While EPDM has exhibited strong physical characteristics since its inception, it has also undergone many technological advances. Some of these developments include factory-applied seam tape, providing improved seam quality and a quicker application, plus a variety of pressure-sensitive, prefabricated accessories. A particular advancement for resiliency and durability is the introduction of 90-mil membranes and 75-mil reinforced membranes in addition to the standard offerings of 45- and 60-mil membranes. All of these advances have improved the life-cycle performance, resiliency, energy savings, and installation efficiency of EPDM membranes. Manufacturers have recognized this improved performance and can now offer 30-year total system warranties on their installations as well as a 40-year nonprorated warranty option for the material alone.

Some of the defining characteristics that need to be specified for a resilient, high-performance roofing system are as follows.

• Membrane: Thicker and more durable 90-mil EPDM, 75-mil reinforced EPDM, or 145-mil EPDM with special fleece backings are available.
• Splices: Six-inch-wide splice tape for added peel, shear, and water resistance compared to the typical 3-inch splice tape. Six-inch factory-applied tape greatly exceeds the peel and shear strength of hand-applied seams while delivering a permanent, watertight bond. A seam applied in a controlled factory environment is a tremendous advantage that enhances workmanship.
• Flashings: All critical flashing details should be double wrapped with 90 mils of pressure-sensitive flashing.
• Detailing: Lap sealant needs to be applied to the exposed edge of all seams, flashings, and joints.
• Adhesives: Standard and low-VOC solvent-based bonding adhesives must be properly applied per manufacturer and industry standards.
• Cover boards: Usually a minimum ½-inch-thick rigid cover boards should be installed.
• Insulation: Coated glass facing versus standard paper faced polyiso, upgraded to 25 psi.
• Fastening density: Increased to one fastener per 2 square feet in lieu of the typical one fastener per 4 square feet.
• Insulation adhesive density: Increased to 4 inches on center in the perimeter and 6 inches on center in the field.
• Perimeter securement: Six inches on center attachment compared to the typical 12 inches on center.
• Metal edging: Engineered systems with high-performance values.

By paying attention to these details, every critical component of a 30-year EPDM roofing system is enhanced to deliver the optimum resiliency performance when the time comes that it is needed the most. Samir Ibrahim, director of design services at Carlisle SynTec, has seen first-hand the notable increase in performance of such systems. “EPDM thermoset roofing membranes feature superior UV and heat resistance along with excellent hail resistance,” he says. “Ninety-mil EPDM is thicker, more durable, and the basis of design for 30-year warranty roofing systems. The end results are that EPDM roofing systems can be designed to handle Mother Nature’s worst, whether it be 100-mph winds and driving rain, 2-inch-diameter hail, unusual snow loads, or intense UV/heat exposure.”

Seismic Resilience

While many threats to a building come from above, seismic activity in the form of an earthquake comes from the ground below. Hence, the design of a building foundation and everything around it becomes important to address resilience and safety when seismic events occur. Toward that end, an engineering technique known as base isolation has been developed and used across the Pacific Rim, including the United States. This technique recognizes that if a building is constructed in a conventional manner, its base (i.e., foundation) is directly connected to the surrounding earth. During an earthquake, that connection will cause the building to move right along with the earth and potentially sustain extensive damage as a result. The isolated base approach disconnects the transfer of seismic forces in the earth from the building by resting the foundation on flexible bearings or pads known as base isolators. The isolators work much the same way an automotive suspension system does when a car encounters a bumpy road and absorbs the shock. In the same way, the base-isolation system absorbs the earthquake movement instead of the building. That means this system can make buildings that are otherwise vulnerable to earthquake damage, such as medium-rise masonry (stone or brick) or reinforced concrete structures, safer and more capable of withstanding earthquakes. Engineers who use it do point out that it of course is not suitable for all types of structures and works best in hard, not soft, soils.

In conjunction with base isolation and other seismic mitigation measures, seismic expansion joints are also needed, particularly for larger buildings. The purpose of these joints is to separate different parts of the building from each other or to separate outdoor areas that are connected to the ground (i.e., patios, plazas, roadways, parking structures) from base-isolated buildings and structures. It is common to use expansion joints for thermal movement in buildings, and the techniques and finish options for that are well known. Seismic expansion joints pose a larger challenge in that both sides of the joint will not only be moving suddenly and dramatically, but they also need to be designed to allow a much greater moving distance. Seismic expansion joints on the order of 12 inches, 24 inches, or even 30 inches are not unusual. The design issue becomes bridging that gap to make a building or site surface usable during the majority of time that earthquake forces aren’t being imposed.

In response to this situation, manufacturers have developed some very sophisticated expansion joint cover products that can aid in the functionality of a building before, during, and after a natural disaster, such as an earthquake. The cover is basically a structural (i.e., walkable or drivable) surface that can span the gaps formed by the seismic joints. During a seismic event, some covers are designed to pop up out of the way, allow for the movement going on in the ground, and then return back into place once the seismic movement ends. That means that these covers are not intended to be sacrificial and therefore require minimal repair after a movement event. Because of the ability to return back to its resting position after an earthquake, it also eliminates the concern that the cover might block egress areas or cause tripping hazards.

Manufacturers of such expansion joint covers understand that there are many unique project situations and therefore offer a range of standard choices and will often work with architects on custom-designed solutions as well. Large joints or moat covers are available that are designed to accommodate base-isolated buildings in seismic zones. These covers surround the perimeter of the base-isolated building and, during a seismic event, they too will pop up out of the ground and return to their place after the event. Some seismic expansion joint cover systems have center pans that are strong enough to be filled with surrounding floor or wall finishes, which minimizes the cover’s sightlines for an aesthetically pleasing look. For example, a seismic moat cover system can accept concrete or terrazzo so that it blends in with the sidewalk or surfaces that typically surround a building. In other cases, expansion joint covers will span across areas where vehicular loads travel on a daily basis, imposing heavy and frequent loads. The good news here is that yes, some cover systems can handle these heavy loads, but it is important to notify the expansion joint cover manufacturer of the kind of loads that will be crossing over the cover so it can ensure that the proper heavy-duty cover is selected and installed.

Gabe Blasi, CSI, CDT, is the senior general manager with Construction Specialties. He points out that “expansion joint cover manufacturers work closely with architects, engineers, and facility owners to provide attractive, proven products that augment the seismic performance and resilience of buildings.” It behooves design teams, then, to consult with these companies to understand the options and capabilities of the available products so that the best choices can be made for specific building conditions.

Security Threat Resilience

Having looked at some environmental hazards, let’s turn our attention to the man-made hazard of security threats. It has become increasingly clear that serious security threats demand educated planning and proven protection. As radical threats have increased in both frequency and methodology to government facilities, critical infrastructure, and commercial properties, designing a resilient building now also requires designing for security. The process is similar to other resiliency design based on identifying potential risks, understanding industry standards, and providing tested solutions, all within the constraints of meeting the daily operational requirements of the facility, the construction budget, and architectural design objectives.

One of the key components of a good security design is protecting the perimeter of the property or facility. In particular, unauthorized vehicular entry has been recognized as a significant hazard with understandably high risk levels due to the potential for dramatic property damage, infrastructure disruption, or human casualties. Creating a vehicle secured perimeter includes at least two components. The first is a continuous barrier or protective device along all exposed edges of a property where a vehicle could otherwise breach the perimeter. The second component is a secure gate or entry point to allow authorized vehicles to enter but then return to a secure or closed position. We will look at each of these components separately.

Barrier Fencing

A traditional approach to protecting facility perimeters is the use of chain link or ornamental fences. These may slow or stop pedestrian attacks but are not designed to thwart vehicle attacks. Similarly, highway cable barrier systems are engineered primarily to withstand a glancing impact but not stop a direct frontal approach. The only truly effective vehicle-attack protection is to use a crash test-certified, truck-stopping barrier capable of handling a head-on impact from a vehicle traveling perpendicular to the line of the fence. Such systems are typically engineered to meet U.S. Department of State (DOS) or ASTM testing standards, while addressing common challenges associated with installation, maintenance, restrictive site conditions, and harsh environments. Whether used as a stand-alone system or in conjunction with new or existing anti-pedestrian fencing, this approach can provide anti-ram level protection to the perimeters of high-risk facilities, such as data centers, refineries, chemical plants, utility stations, military bases, and airports.

One effective but visually understated solution is to use a heavy-duty steel post-and-beam perimeter fence. The horizontal beam is kept low to the ground, just above the wheel height of a typical car or truck. The vertical posts are spaced according to the structural capabilities of the beam as required to pass crash-test certification and secured deep into the ground to provide the needed ram resistance. This type of fence is engineered to be extremely simple and efficient in terms of the materials used and the effort required for construction.

In fact, each fence section is made up of a surprisingly small number of components consisting of two posts and a beam section with a nut-and-bolt assembly to secure them together, all protected by a top cap. Reinforcing steel bars inserted into each post eliminate the need for building a foundation rebar cage, while shim plates are also used as needed to create a snug beam-to-post connection. Constructed from heavy-duty structural steel, this system utilizes a single tubular beam that allows the vertical posts to be set up to 30 feet apart and still stop a vehicle. This design feature eliminates the need for multiple intermediate posts and cable runs used in traditional anti-ram fence products. This conceptually simple post-and-beam anti-ram fence accommodates a wide range of inherent site considerations, including layout and terrain changes. It is also available with heavy-duty galvanizing or epoxy primer and polyurethane topcoat to provide a high-quality, durable finish able to withstand the elements.

Post-and-beam fencing is well suited for a variety of installations, particularly at facilities designated as high risk where the entire perimeter necessitates anti-ram defense. It is also very easy to incorporate in situations where building perimeters have minimal setbacks with immediate stopping power being critical. In urban and corporate settings, where visual appeal is an important consideration, their low profile and understated appearance help the fencing blend in while still providing the needed protection. It can also be used as an upgrade in front of chain link, ornamental, and other fencing or natural barriers to meet higher threat requirements. And of course, it’s a logical choice to use along either side of secure access control points to increase the level of protection for adjacent areas also vulnerable to vehicle impact.

Beam-Style Gates

A facility still needs to be accessed by cars and trucks to operate and allow authorized employees and visitors to enter and leave. There are many types of barriers and gates that have been used for this purpose to provide access when open and security when closed. Consistent with the post-and-beam style perimeter fence, gates with the same appearance and effectiveness are also available. This beam style of gate operates with a post on either end that houses the mechanism for the horizontal beam to lower vertically into the ground, allowing vehicle entry, and then raise back up to re-secure the perimeter. Beam-style gates are ideal for guarding access control points with wide entrances, eliminating the need to install and maintain multiple wedge barriers or bollards. And because the vertical support posts and foundations are often installed beyond the roadway margins, these barriers can reduce the risk of interference with underground utilities.

This type of rising beam gate utilizes a structural steel tube beam that travels vertically between two bollard-like posts, which permanently anchor the beam at either end. When lowered, this cross member is housed in an unobtrusive channel and shallow foundation extending across the roadway. The efficient motion of this gate design reduces the travel distance required for the barrier to open and close compared to drop-arm gates, which pivot from one end post in a long arcing motion. This feature serves to significantly decrease the cycle time required to process vehicles and eliminates potential clearance issues with overhead objects, such as trees, buildings or utilities. Normal operating time is typically accomplished in only 3–5 seconds. Because all of the operating components are installed above ground level, this barrier requires less maintenance than bollards and wedges and is easy to service.

A post-and-beam gate is ideal for a number of installations, such as wide entrances where one unit is capable of securing multiple lanes of traffic or spacious checkpoints used to process large vehicles. They can be equally effective at preventing access by two-wheeled vehicles, such as bicycles or motorcycles. They are also well suited for high-traffic areas because the beam travels a short distance, allowing the gate to process vehicles quickly. In cases where there are restrictive site conditions, such as high water tables or excessive precipitation, the post-and-beam gate avoids the negative impacts on operating components installed below ground. Since it is available with all electric operation, the post-and-beam gate is also useful where there are environmental restrictions that prohibit the use of hydraulics fluids. From a design standpoint, it works readily with minimal setbacks where critical assets or equipment are located close to entrances (such as in urban areas) and a high level of security is required regardless of potential vehicle speed. It also works well in urban and corporate settings where visual appearance and noise levels are important considerations.

When specifying post-and-beam fence and gate systems, there is an ASTM International standard that applies, namely ASTM F2656: Standard Test Method for Vehicle Crash Testing of Perimeter Barriers. Under this test, the fence and gate should meet the M50 P1 standard, which requires a vehicle barrier to stop a 15,000-pound truck traveling 50 mph with less than 3 feet (1 meter) of penetration as measured from the leading edge of the truck bed to the barrier reference point. Additionally, the DOS has specific standards for perimeter barrier testing under the Bureau of Diplomatic Security (DS), which is the department’s security and law enforcement arm. DS is a world leader in international investigations, threat analysis, cyber security, counterterrorism, security technology, and protection of people, property, and information. It is responsible for providing a safe and secure environment for the conduct of U.S. foreign policy, with every diplomatic mission in the world operating under a security program designed and maintained by DS. Its applicable standard is SD-STD-02.01 Rev A: Test Method for Vehicle Crash Testing of Perimeter Barriers and Gates.

Overall, these systems provide a reliable, efficient, and visually integrated solution for perimeter security. Scott Espensen is the perimeter security product manager with Ross Technology Corporation. He points out that “Post-and-beam fence and gate systems are crash test-certified and designed as a seamless, integrated system to avoid gaps between dissimilar solutions that were not designed to work together. They also feature wide-span post spacing and hardware to reduce material and installation costs, plus a tubular design with multiple finish options to offer enhanced architectural appeal compared to traditional cable fence systems.” It is easy to see why they are an attractive solution for incorporating effective perimeter security into a resilient building design.

Conclusion

Designing a building for resiliency requires attention to a variety of potential hazards, including floods, weather, earthquakes, and security breaches. Each specific hazard or threat needs to be assessed for the potential risk to the building, equipment, operations, or people. Based on that assessment, appropriate mitigation measures then need to be designed into the facility to assure that it will not only survive the event, but that it will be resilient enough to be able to return quickly to normal operations.

Peter J. Arsenault, FAIA, NCARB, LEED AP, is a practicing architect, green building consultant, continuing education presenter, and prolific author engaged nationwide in advancing building performance through better design. www.linkedin.com/in/pjaarch