A curtain wall system is a covering of a building in which the outer walls are non-structural. These systems are typically designed with an aluminum or steel-framed wall containing infills of glass, metal panels or thin stone. Curtain wall systems do not carry any dead loads imposed from the building structure, but instead are designed to support their self-weight and transfer horizontal loads to the primary building structure. The primary functions of the curtain wall are to resist air and water infiltration and to provide a thermal barrier between inside and out.
A curtain wall system must be built to handle all loads imposed on it, including wind, seismic, snow and thermal loads, as well as the weight of the structural elements. To perform satisfactorily, a curtain wall system must control air leakage, vapor diffusion, heat loss and gain, and water penetration. If the curtain system uses glass as an infill, careful consideration should be given to allow light penetration into the building, while also reducing glare and thermal problems and, in some cases, allowing for passive solar energy gain.
There are two main methods commonly used in curtain wall framing: stick systems and unitized systems. In the stick system, the frame (mullions) and panels are installed and connected together piece by piece. Framing members may be fabricated in a shop, but all installation and glazing is typically performed at the jobsite. In the unitized system, the curtain wall is composed of large units that are assembled and glazed in the factory, shipped to the site and erected on the building.
The rainscreen principle uses various features to control entry of water, capillary action, and surface and cavity drainage. Most facades being built now make use of a pressure-equalized system to reduce water penetration.
Designs for curtain walls are almost always customized to individual project requirements. For example, when designing the aluminum handrail and laminated structural glass barrier for the outdoor Monk seal exhibit at the Waikiki Aquarium in Honolulu, Hawaii, BE Structural had to ensure that the design could withstand the force of a full-grown seal colliding with the glass.
In another project, BE Structural designed a glass and aluminum enclosed showroom, two level office area and maintenance facility for a new Volkswagon automobile dealership in York, Pennsylvania. In order to combat lateral forces, this curtain wall system consisted of a combination of steel moment frames, steel bracing and masonry shear walls.
BE Structural also took into consideration the unique demands of an indoor waterpark when analyzing and detailing the enclosure at the Spirit of the Smokies Condominium Lodge Parkway in Pigeon Forge, Tennessee. This glass enclosure was approximately 6,500 feet² with a clear span of 66 feet with aluminum rigid frames serving as mullions and support for structural glass panel walls and polycarbonate roof panels.
BE Structural is licensed to design and engineer glass enclosure and curtain wall systems in the 48 contiguous states, Hawaii, and the District of Columbia. Contact us today to discuss a customized engineering solution for your structural glass enclosure needs.