Copyright Goodheart-Willcox Co., Inc. Unit 7 Construction Materials—Types and Uses 125 • Patterned glass is flat glass with a pattern rolled into one or both sides to diffuse the light and provide privacy. • Stained glass, sometimes called art or cathedral glass, is produced by adding metallic oxides in the molten state. This glass can be used in sheets or cut into smaller pieces and made into leaded glass for windows and decorative pieces. Glass Glass is a ceramic material formed at temperatures above 2300°F (1260°C). It is made from sand (silica), soda (sodium oxide), and lime (calcium oxide). Other chemicals can be added to change its characteristics. Float glass is the most common type of glass. A continuous ribbon of molten glass flows out of a furnace and floats on a bath of molten tin. Irregularities melt out and the glass becomes flat. The ribbon of glass is fire-polished and annealed, without grinding or polishing. Over 90% of the world’s flat glass is made by the float process. Flat glass produced by the float process is commonly used for windows in thicknesses of 3/32″ (single strength, or “SS”) and 1/8″ ″ (double ″ strength, or “DS”). After the float process, other processes can further modify the properties of the glass, producing several types: • Bent glass is produced by heating annealed glass to the point where it softens so it can be pressed over a form. • Safety glass was developed to overcome the hazards of flat glass in large, exposed, or public areas. Three types of safety glass are available: tempered, laminated, and wired glass. • Tempered glass is developed by heating annealed glass to near its melting point, then chilling it rapidly. This creates high compression on the exterior surfaces and high tension internally, making the piece of glass three to five times as fi strong as annealed glass. Tempered glass can be broken, but it shatters into small, pebble-like pieces rather than sharp slivers. Tempered glass must be ordered to the exact size needed before tempering, because it cannot be cut, drilled, or ground after it has been tempered. • Laminated glass consists of a layer of vinyl between sheets of glass. The layers are bonded together with heat and pressure. This glass can be broken, but the plastic layer holds the small, sharp pieces in place. • Wired glass has a wire mesh molded into its center. Wired glass can be broken, but the wire holds the pieces together. Wired glass can be obtained with an etched fi nish, a sandblasted fi finish, or a patterned finish. fi fi • Insulating glass is a unit of two or more sheets of glass separated by an air space that is dehydrated and sealed. Insulating glass units serve as a good insulator for heat and sound transfer. A typical insulating glass installation in a window sash is shown in Figure 7-24. Marvin Windows and Doors Figure 7-24. Window with insulating glass. High-Effi ciency Windows Windo ow s and n d glass doors can leak a signific s ca nt amoun m nt of heat he in winter. Installing high-efficie en c cy , triple-glazed p d windows in cold climates s can red du ce e heat t loss by 15%–30%. Doub bl e e- glazedz win nd ows will meet weather needs and d code spe ec ifications f s in warmer, more modera at e parts of the t country.t y GREEN BUILDING