Fiberglass windows

A fairly recent addition to the window market, fiberglass framed windows consist of glass fibers and a resin that binds those fibers together. The well-known tensile strength of fiberglass gives these windows high levels of durability and impact resistance. They are better suited than vinyl to handle a wide range of temperature extremes from -40 degrees F up to 200 degrees F. The frames tend to be very energy efficient and in some cases additional insulation can be added inside the frames. Finishes are available that resist chalking, fading and chipping and are suitable for use in harsh environments.

Fiberglass windows: Durability and energy performance make these a good choice for education projects, especially in harsh climates. Building: Fred and Sara Machetanz Elementary School Location: Mat Su Borough, Alaska Architect: McCool Carlson Green Architects Photo courtesy of Pella

 

Fiberglass framed windows are mostly used in buildings where price, durability and low maintenance are important and where higher performance aluminum windows are too expensive. Common building types include dormitories, hotels, condos, apartments, low-income housing, and assisted living facilities.  They can be used in punched openings, horizontal ribbons, vertical stacks, and storefronts where extreme heat, cold, or sea air conditions are encountered.

Fiberglass Windows Case Study Fred and Sara Machetanz Elementary School Location: Mat Su Borough, Alaska Architect: McCool Carlson Green Architects

Image courtesy of Pella Fred and Sara Machetanz Elementary School is a K-5 school that opened in 2009. Located in Alaska's Matanuska Susitna Borough, the school received Silver LEED® Certification in the U.S. Green Building Council's Leadership in Energy and Environmental Design (LEED) program. It is the first LEED-certified school in Alaska, and is one of the northern-most LEED-certified projects in the United States. To help achieve this superior level of energy efficiency, McCool Carlson Green Architects chose fiberglass composite single-hung and fixed frame windows. The particular windows selected are made from a patented five-layer fiberglass composite that is virtually impervious to all weather conditions—protecting the school from harsh Alaska winters. Plus, these windows offered the energy-efficient options that meet or exceed ENERGY STAR® guidelines in all 50 states. The placement of the fiberglass windows also provide classrooms with abundant daylight—reducing the school's dependency on electric lighting and improving students' ability to focus. And the classrooms' built-in window seats serve as intimate spaces in which students can work. The manufacturer was proud to help McCool Carlson Green Architects achieve their design vision, and enhance the learning environment at Fred and Sara Machetanz Elementary School.

 

Aluminum windows

Aluminum has been a popular choice of window manufacturers for quite a while due to its light weight and superior strength. It can readily be formed into complex extruded sections that are strong and can efficiently achieve desirable weathering and operating characteristics.  These aluminum extrusions easily provide tracks, drips, baffles, and grooves for weather stripping and sealants. These pieces can then be cut and fabricated into window units of many different shapes and sizes. Further, the appearance of aluminum can be varied by selecting from a wide range of commonly available anodized and painted finishes. When complete, the final product can be decorative, strong enough to be used in large openings, and provide a low-maintenance solution. Aluminum does have a higher coefficient of expansion compared to other materials so that needs to be allowed for in the detailing. Its high rate of conductivity also makes it prone to thermal bridging and unwanted heat transfer. However, the current focus on energy efficiency has prompted manufacturers to increase the energy efficiency of aluminum frames through enhanced polyamide thermal breaks and fiberglass pressure plates to limit or reduce thermal bridging.

Aluminum windows: The products used on this school were required to meet the large missile impact test because the school is a designated hurricane shelter in Pinellas County. Building: Gibbs High School Location: Saint Petersburg, Florida Architect: Renker-Eich Parks Contractor: Ajax Building Photo courtesy of EFCO, a Pella Company

 

Buildings where added strength, durability, and design flexibility are needed are usually the most suitable application for aluminum windows. They are also popular where low maintenance is desired in moderate environments and in buildings where function and performance are important. In selecting particular aluminum windows, it should be noted that they are classified by the American Architectural Manufacturers Association (AAMA) which is a non-profit trade association of manufacturers and others in the fenestration industry. There are four AAMA performance classifications as follows:

• R class - commonly used in one- and two-family dwellings and designed to withstand pressures of at least 15 psf
• LC class - commonly used for low- and mid-rise multifamily dwellings or other buildings where larger sizes and higher loading requirements are expected and designed to withstand pressures of at least 25 psf
• CW class - commonly used in low- and mid-rise buildings where larger sizes, higher loading requirements, limits on deflection and heavier use are expected and designed to withstand pressures of at least 30 psf
• AW class - commonly used in high-rise and mid-rise buildings to meet increased loading requirements and limits on deflection and in buildings where frequent and extreme use of the fenestration products is expected and designed to withstand pressures of at least 40 psf.

Aluminum Windows Case Study Gibbs High School Location: St. Petersburg, Florida Architect: Renker-Eich Parks

Image courtesy of EFCO, a Pella Company Project Category: Schools and Colleges System Finish: Class I - Clear Anodized Aluminum Glass: 9/16" Large Missile Impact Contractor: Ajax Building Erector: Tab Glass & Window Corp. The products used on this school were required to meet the large missile impact test because the school is a designated hurricane shelter in Pinellas County. The manufacturer was able to meet the impact requirement with the fenestration systems provided.