Masonry Magazine January 1981 Page.26
GLASS BLOCK
continued from page 21
According to the International Masonry Institute, IMI's director of engineering, Robert Beiner, said, "Architects and engineers will often specify glass block to save fuel costs for heating and cooling. But they and building owners should keep in mind that glass block is extremely valuable in saving electricity for lighting purposes as well."
Using glass block to admit daylight was extremely successful for the award-winning Alfred C. Glassell School of Art in the Houston Museum of Fine Arts. (Masonry, June, 1979). In addition to administrative offices, a library and gallery, the building was to house printmaking, jewelry, ceramic and sculpture studios, so a primary goal was to have as much natural light as possible.
To provide natural light, yet keep air conditioning costs and maintenance to a minimum, the Houston architectural firm of S. I. Morris Associates selected a solar reflective glass block for the entire exterior of the two-level, 40,000 sq. ft. building. The 8"x8" block have a ribbed interior face and a highly reflective gray coating, which reduce solar heat gain while allowing natural light to enter the building.
The varieties of glass block presently manufactured by Pittsburgh Corning Corp.
While glass block was used to inhibit entry of the sun's heat in the Glassell School, another variety of glass block is sometimes used to collect solar heat in a passive solar application. In passive solar design, sunlight enters the building through large south-facing window areas. The sun's heat is stored in walls and floors made of masonry materials such as brick, stone, tile and concrete block, and at night these materials slowly radiate the heat into the living space.
If the clear, smooth variety of glass block is used as part of a passive solar design, a lot of sunlight can enter the building during the winter, and the insulating capabilities of the glass block will effectively keep the heat inside.
For example, Rosalyn Gerstein, head of a research and materials development corporation in Vermont, designed and lives in a house in which the entire south-facing wall is clear glass block. A portion of this wall forms the south face of a solarium, allowing both heat and light to enter that interior space. During the day, some of the heat is stored in the tile floor and is radiated slowly into the living area at night. In the summer months the roof overhang prevents overheating by blocking out the rays of the high summer sun.
Another portion of the glass block wall in Gerstein's house stands directly in front of a massive Trombe wall, a standard passive solar feature which stores heat during the day and radiates it into the interior living space at night. The insulating function of the glass block assures that the stored energy in the Trombe wall will heat the room rather than be lost to the outdoors.
Gerstein estimates that in the winter the passive solar glass block system keeps the house between 55 and 65 degrees; she uses a wood stove and a small amount of electricity for occasional back-up heating.
Whether it is being used to achieve privacy, energy efficiency, security, aesthetic appeal, or a combination of these effects, glass block must be skillfully assembled to achieve the best results. Louis J. Helbert, president dent of the Mason Contractors Association of America, said, "We welcome the resurgence of glass block in architectural design. It epitomizes the beauty and infinite variety of masonry as a building system."
Fred Beyer & Co. installed the glass block for this attractive lobby/reception area in a Chicago studio.