FORTRESS Nameplate #1 is a 1200 ft² permanent demonstration and education facility for FORTRESS Protective Buildings, a company that provides multi-hazard-resistant buildings constructed from precast concrete modules. (The name FORTRESS is derived from “fragment overpressure radiation toxic resistant emergency safety shelter.”)
FORTRESS precast concrete structures offer a wide range of safety benefits in extremely hazardous settings such as industrial facilities. From the exterior, FORTRESS precast concrete modules may look familiar. However, the results from rigorous testing of the robust three-dimensional (3-D) work space show that precast concrete’s strength and noncombustible nature allow the modules to meet stringent fire codes and withstand blasts, high winds, and noxious fumes, protecting occupants’ well-being without sacrificing comfort and efficiency.
Multi-hazard-resistant buildings constructed from FORTRESS modules provide the protection required by the Occupational Safety and Health Administration’s (OSHA) facility siting regulations and the American Petroleum Institute’s recommended practice for the safe placement of permanent buildings. Furthermore, they can withstand blast, fire, and toxic events and provide fragment and severe weather protection.
Compared with structures constructed with other building materials, the precast concrete modules can withstand heavier loads with fewer materials for more environmentally friendly installations. “While the concept of precast concrete modules has been seen before in FEMA storm shelters and prison jail cells, this design goes even further. These modules are far more robust, with thicker walls and heavier and additional reinforcement, and they are purpose-built for blast resistance,” says Joel Sheets, PE, senior vice president of operations at Tindall. One major difference is that the precast concrete modules are cast as a 3-D unit and arrive on site as one piece without joints. Module sizes are selected to maximize shipping weights while reducing the number of modules and construction joints.
“There has long been a focus on the blast aspect, but as design professionals learn about other safety hazards such as fire and toxic gas, they naturally gravitate toward FORTRESS,” says Karen Vilas, president of FORTRESS Protective Buildings. “Companies are willing to invest in the safety of their people, and when they see the value in FORTRESS, they are willing to move past the slight premium in cost.”
Many companies have environmental, social, and governance goals, which, at their core, focus on both people and business risk reduction. “FORTRESS is the embodiment of that mindset, ensuring that in the event of a catastrophic event, both personnel and critical safeguards are protected and able to respond to limit the impact of the event and prevent additional asset loss,” adds Vilas.
During on-site installation, the modules are assembled to prevent harmful vapors permeating the building. While precast concrete is an impervious material, a special recess is cast in for the first stage of the module-to-module seal, and there are multiple layers at each seam. Between modules, a special patented sealant is applied for resistance to fire as well as water, smoke, and gas ingress.
A two-door vestibule system provides an additional barrier to keep gas out, and it is combined with shutdown controls upon detection of flammable or toxic gases. “Low air leakage makes FORTRESS much safer than traditional buildings,” says Vilas. “The vestibules also have the added benefit of increasing thermal protection in a fire event.”
The precast concrete modules are cast in one piece and shipped to the jobsite for rapid installation. The turnkey modules are bolted together, and for buildings smaller than 1,500 ft², they can be installed in one day, minimizing the impact to ongoing operations. The prefabrication and modularization of this system reduce on-site labor, an advantage that is critical in heavy industrial sites.
At their testing facility in La Vernia, Tex., the FORTRESS team constructed Nameplate #1 to serve as permanent demonstration and education facility. Its qualities and features highlight the differences between FORTRESS modules and steel blast-resistant modules (BRMs), which have been commonly used in the industry. “BRMs were often selected because they can be relocated, but they may not provide the protection owners and occupants believe they do,” says Thomas Mander, PE, principal engineer at BakerRisk. During a fire, the interior of the steel BRM container heats to temperatures that cannot sustain human life. Because they are lightweight and often not anchored to a foundation, steel BRMs slide during a blast, which can injure occupants. Also, given the corrosive environment at some facilities, the life-cycle costs of steel BRMs can far exceed the initial investment. “FORTRESS precast concrete modules can withstand more severe loads and have a longevity that steel BRMs cannot achieve,” Mander adds.
The design and construction of FORTRESS modules goes far beyond what we are used to seeing in general building construction. In addition to rigorous testing on the exterior, special attention is also paid to the interior. Drywall and other finishes and fixtures simulate an office setting. Unlike the more-primitive setting in a steel BRM or temporary trailer, the open concept office environment of FORTRESS Nameplate #1 features a 10-ft-high ceiling and feels roomy and comfortable.
The interior space of Nameplate #1 was partitioned to include a bathroom with a shower and a laundry room, as well as a private office with a shelter-in-place (SIP) detection control panel and an open classroom area with a kitchen. The SIP system is linked to external and internal gas detection monitors to track any toxic airborne materials and control the HVAC system and dampers.
Nameplate #1 is used as a classroom to host hazard courses where participants can witness real blast, fire, and fragment tests, and learn how precast concrete can be effectively used for their next protective building solution. This new level of multi-hazard protection demonstrates that precast concrete can be used to reach beyond industrial settings to resist terrorism, tornadoes, fires, toxic releases, blast events, and similar emergencies.