INFORMATION OBTAINED IN THIS INVESTIGATION Description of Products The imported products covered by this report are cast or rolled glass and drawn or blown (sheet) glass, in rectangles, weighing over 4 ounces per square foot; ground or polished (plate and float) glass, in rectangles; and toughened (specially tempered) glass made of flat 1/ glass. Rolled, sheet, plate, and float glass collectively will be referred to hereafter as flat glass, and toughened (specially tempered) glass, as tempered glass. Rolled glass Cast or rolled glass is flat glass that has surface irregularities impressed by the rollers used to form it. These irregularities, which make rolled glass translucent, may form either patterns or simply a rough surface texture; they may be impressed on both sides of the glass, or only on one side, the other having a smooth surface. The bulk of the rolled glass produced in the United States has a surface pattern or rough texture on only one side. A variety of patterns are impressed on rolled glass; the most common are those which have a mottled, ribbed, hammered, or fabric design. 1/ Tempered glass can be made not only from the flat glass covered by this investigation but also from flat glass that has been cut to non-rectangular shapes or that has been subject to bending, curving, beveling, edging, notching, drilling, chipping, sanding, embossing, engraving, etching, coating, staining, enamelling, painting, decora The purpose of the surface irregularities is to diffuse light and reduce glare. Rolled glass is used for decorative as well as utilitarian purposes; it is generally employed where transparency is unnecessary or objectionable but where light is needed, as in skylights, factory windows, office partitions, lavatories, and corridors. It is also used in lighting fixtures, jalousies, bath and shower enclosures, and sliding doors for closets and partitions. Some rolled glass is produced with wire netting embedded in it. The wire mesh adds strength to the glass and makes it more resistant to shock. When wire glass is broken, the mesh holds the pieces of glass together, thereby preventing injuries to persons. This type of glass is widely used where there is danger of fire or explosion; it is commonly used in terminals, power plants, factories, and subways. Wire glass is available in most of the common patterns in which plain rolled glass is furnished. The wire may be in the form of a twisted chicken wire or a welded diamond or square-shaped mesh. Rolled glass may be corrugated. In such form it is used in skylights and interior and exterior partitions. The corrugated glass used for roofs and skylights is usually wired. Colored rolled glass is known in the trade as cathedral, opalescent, opal, or ornamental glass; heat-absorbing rolled glass of colors and surface textures; it is used principally in decorative or church windows and in light fixtures. Heat-absorbing glass filters out a part of the sun's heat by reradiation, thus providing cooler interiors; it transmits that portion of the color spectrum most restful to the eyes--blue, green, and yellow. Rolled glass varies in thickness from 1/8 inch to 3/8 inch; it is regularly offered for sale in thicknesses of 1/8, 7/32, 1/4, and 3/8 inch. Wire glass is usually made 7/32-, 1/4-, and 3/8-inch thick; corrugated glass is usually 3/8-inch thick; and colored glass is usually available in thicknesses of 1/8 or 1/4 inch. A rough-surfaced flat glass--rough plate glass blanks, produced by plate glass manufacturers as an intermediate stage in the production of plate glass (except in the twin-grind method)--is sold as rolled glass without further processing. The blanks are generally used where rolled glass is customarily installed chiefly in exterior or interior partitions. The blanks are produced by a method similar to that used to produce rolled glass; the blanks, however, are available in much larger sheets than rolled glass. Sheet glass Sheet (drawn or blown) glass is a transparent flat glass. It may be either clear or colored. Its fire polished surfaces are 1/ Blown glass, which is made by hand production methods, is now virtually obsolete. smooth, which distinguishes it from rolled glass, and are not ground and polished, which distinguishes it from plate glass. Sheet glass has discernible distortion or waves, which distinguishes it from both plate glass and float glass. The great variety of uses for sheet glass require many thick- nesses and sizes. while sizes (surface area) range from less than a square inch to many square feet. For the purpose of this report, sheet glass is divided into three thickness (weight) categories: (1) Glass weighing over 4 ounces but not over 16 ounces per square foot, here- (2) Glass weighing over 16 ounces but not glass is also used in making non-automotive (3) Glass weighing over 28 ounces per square foot, Plate and float glass Plate glass is rolled glass that has been ground and polished to make the glass transparent and render its surfaces virtually plane and parallel, thereby eliminating most of the distortion found, in various degrees, in sheet glass. Float glass is transparent flat glass having plane and parallel surfaces virtually comparable to those of plate glass. The parallel surfaces of float glass are obtained by floating a layer of molten glass on molten metal rather than by grinding and polishing. Plate and float glass, which are generally interchangeable, are used principally to make laminated windshields and tempered side and rear windows of motor vehicles, to glaze large openings such as store display windows and so-called curtain walls, and to make high quality mirrors. |