Built-In Blinds

Integrated blinds offer controlled daylighting, occupant comfort, indoor air quality, and low maintenance
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Meanwhile, at a hospital in New Haven, Connecticut, Atelier Ten chose a fixed integrated blind system in the clerestory windows of the curtain wall.

“The fixed blinds redirect daylight into the space and prevent direct beam radiation to entering the space to protect sensitive workspaces/equipment,” explains Kienzl. “Important aspects were the fact that they were proven products, had low/no maintenance requirements and met aesthetic requirements of the architects.”

For an emergency room expansion in Roseville, California, HGA specified integral blinds in response to the owner’s goal of privacy, infection control, and low maintenance.

“By using a BBG product, the intention was to eliminate the need for a privacy curtain as well,” relates Martinez-Wyatt.

Another requirement was manual control and the ability to control blinds from both sides of the system. “Final selection was a wheel control system because it met ADA guidelines,” she adds.

In addition to health care, another prevalent application for BBG systems is K–12 and higher-education facilities where IAQ, daylighting, durability, and low maintenance are essentially required.

Overall, John Gladden, AIA, educational designer, Fanning Howey, Columbus, Ohio, points out that BBG products keep blinds out of the way of everyday activities by students and teachers and make life simpler for maintenance staff. “They can clean windows or adjust blinds without fear of damaging the product,” he explains. “In fact, the Ohio Facility Construction Commission’s school design guidelines suggest BBG for all K–12 school design projects.”

Furthermore, he says these systems give schools the freedom to control lighting levels without fear of damaging blinds. “Being able to adjust blinds is particularly important at the elementary school level, where the classroom is a students’ primary home, and different lighting levels are important for different activities. At the high school level, specialized spaces like science labs also require the flexibility of BBG products,” he adds.

Because the blinds are encased in glass, their surfaces don’t collect dust, mold, bacteria, etc., and this contributes to keeping the indoor air clean, explains Donovan. “That’s important when you consider the number of kids with asthma and other respiratory conditions or allergies,” he says.

“In terms of durability, since the blades are out of reach, they are protected from damage,” he continues. “With traditional louver systems, the blades are typically metal—and in a high-traffic location like a K–12 school, more often than not, there are a few blades with bends, dings, or creases in them, which impacts the smooth operation of the blind and is unsightly.”

With regards to maintenance, he points out that it’s far more efficient and effective to wipe down glass surfaces than it is to clean individual louvers.

“There are additional benefits to using BBGs in schools. An example: a lower run of BBG units can be closed/drawn for eye-level privacy, while an expanse of BBG units closer to ceiling height can be left open to allow natural light into the space.”

In the higher-education market, Atelier Ten specified the blinds in a punched window configuration at a University in Illinois.

Here, the architect selected manually operated interstitial blinds in operable windows as a tilt-only function for controlling daylight and glare. Thanks to extensive studies to help optimize the envelope, together with the blinds assisting with daylight distribution, overall energy use is 51 percent better than ASHRAE 90.1-1999 for this project.

Though more prevalent in Europe, office buildings are another great fit for integrated blinds.

A great example is the Parallelo headquarters building in Milan, Italy, where 400 glazed BBGs cover the southwest facade of the sprawling three-story, 14,000-square-meter elevated structure.

Photos: Courtesy of Pellini SpA/Daniele Domenicali

A total of 400 BBG units shade and insulate the sprawling Parallelo headquarters building, designed as a 14,000-square-meter elevated structure in Milan, Italy.

The project is one of the city’s first CENED A energy class commercial buildings, which means that it has achieved the highest level of energy efficiency complying with regional standards. With help from 2,500 square meters of photovoltaic rooftop panels and geothermal heat pumps, total energy costs are 26 percent less than those of a similar-sized traditional building.

Key to the design was figuring out how to shade the southwest facade. Mario Cucinella Architects originally considered brise-soleil sun shades in a metallic grid structure fixed to the building at changeable intervals. However, fixed system wouldn’t have allowed sufficient natural light to come inside, in addition to obstructing the view. Furthermore, the design would have required the creation of a structure on the wall to anchor a metal grid and add walkways to be able to periodically maintain the system. Bottom line, this original scheme was technically complicated and cost prohibitive.

The solution was an integrated blinds system in a double-glazed configuration. The panels run as high as 4.2 meters and over the entire facade, including the attic. The blinds can be rotated manually with a magnetic system or electrically via an external motor. This enables the entire system to be fixed or changed without having to touch the windows.

Debunking Stereotypes

Having established the benefits of BBG systems and its ideal applications, it’s important to address some misconceptions about the technology.

For one, there have been concerns about failure rates. While there may be a greater risk with some BBG systems, it is not an issue with higher end systems.

While Jason Thomas, president, Intigral, Walton Hills, Ohio, acknowledges that this is, in fact, an issue with some products in the marketplace, a number of manufacturers have fully addressed this issue with comprehensive testing.

Along these lines, ANSI/WCMA A100.1-2018: American National Standard for Safety of Window Covering requires that blinds are able to withstand 6,500 full raise and lower cycles in a variety of temperature and humidity conditions.

While this is an important baseline standard, it behooves designers and building owners to look for products that well exceed this standard. In fact, it is possible to find BBG systems capable of completing more than 200,000 full raise and lower cycles.

Another BBG misconception is assuming that all systems have condensation issues.

Case in point, in detailing the system for the Hadassah Medical Center’s Davidson Hospital Tower, Spector-Amisor worked closely with the project’s aluminum consultant and contractor and made sure to place the low-e coating on the glass surface 2 (i.e., the interior side of the outside pane). In addition to reducing the solar heat gain in the cavity between the panes, there have been no condensation problems.

In terms of energy efficiency, some advanced BBG systems incorporate a warm edge spacer bar, which works to insulate the edges of a sealed unit and keep the panes of glass apart. The hermetically sealed design:

  • reduces the generation of humidity on the glass perimeter;
  • improves the thermal insulation of the profile due to its low thermal conductivity;
  • ensures a lower U-value (a measure of heat flow in thermal bridges), halving heat transmission through the perimeter compared to a standard extruded aluminum spacer bar; and
  • improves the thermal transmittance value of the window, irrespective of the material used for the frame.

Some integral blind systems are also compatible with triple glazing, further reducing heat loss and rejecting unwanted heat gain and cold.

Another feature, developed in conjunction with European nanotechnology research institutes, is a coated slat which effectively enhances energy efficiencies. The slat is coated with an interference film designed to reflect the most critical solar radiation. Furthermore, the coating creates low emissivity in the slat, thereby affecting the long wave infra-red radiation characteristics.

An additional issue that may cause owners/architects to think twice about choosing BBGs is cost; however, when owners consider the no maintenance, longevity, and low probability of needing to replace the blinds, the longer-term outlook paints a different picture.

“The long-term ROI outweighs the hassle of replacing blinds outside of windows and maintenance associated with them,” confirms Martinez-Wyatt.

“The benefits of BBG systems—reduced maintenance and longer life—more than offset the potential benefits of other products,” agrees Gladden.


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Originally published in Architectural Record
Originally published in May 2019