Glass Types

Primary Glass Products

  1. Clear glass - is nearly colorless, and has a green or blue/green edge. It is typically made in thicknesses ranging from 3/32" to 3/4". Clear 1/4" thick glass will allow about 90% of visible light to pass through and will reflect about 8% of visible light. When looking through the glass, as the glass gets thicker the faint green color becomes more noticeable and light transmittance drops. Glass Interior

  2. Tinted glass - (heat absorbing glass) is made by adding color pigments to the raw materials in the float process. Standard colors include bronze, gray, dark gray, green, blue and blue/green. Imported glass may be in non-standard colors. The color density is a function of thickness, as the glass gets thicker the density of the color increases and the amount light transmittance decreases. Because tinted glass reduces the amount of light transmitted, it also absorbs some of that solar energy, called heat absorption. This added heat causes thermal stress which may affect the glass and can cause it to break if it is not tempered.

  3. Reflective glass - (solar control glass) is a clear or tinted glass that has a thin layer of metal oxide, approximately .000003" thick, applied to the surface of the glass. Reflective glass has aesthetic appeal because of the multitude of color choices available, but on the other hand it becomes more expensive to replace if broken. It increases energy savings by reducing solar heat gain while allowing some of the visible light to pass through.

  4. Low E glass - (low emissivity) is a type of reflective glass that appears to be clear while reflecting heat back to its source. It reduces heat loss while providing maximum light transmittance, and also helps resist UV rays. Depending on viewing angle and sunlight a slight tint can be seen. Glass from different runs or with different metal oxide coatings will exhibit differences of hue or color, making it extremely difficult to match multiple lites of Low E glass.

  5. Obscure glass (patterned glass, figured glass, decorative glass) - is typically a type of rolled glass that has a pattern embedded into the surface of the glass by the roller. The pattern diffuses the detail of objects viewed through the glass, and the degree of diffusion is a function of the pattern chosen. Some patterns can not be tempered because of the depth of the pattern or the method of manufacture. Available thicknesses depend upon the particular pattern.

  6. Stained glass (art glass, opalescent glass, cathedral glass) - is typically a type of rolled glass. It is generally manufactured in small batches and may have multiple colors in one piece of glass. Stained glass can not be tempered.

  7. Wire glass - is a type of rolled glass that has a welded wire net which is fed into the molten glass just before the glass enters the rollers. The rollers embed the wire in the glass and then both surfaces are ground and polished. Diamond shaped and square shaped patterns are typical and may also be obscure. Wired glass is commonly used in fire rated openings because the wire holds the glass in the sash if it breaks. There are limitations on the square footage of wired glass per opening based on the rating required. It is not a safety glass and can not be tempered.

Fabricated Glass Products

  1. Bent glass - is flat glass that has been heated to approximately 1,000 degrees and gravity or mechanically formed to the desired shape. Bent glass is available as annealed, heat treated, tempered, laminated, or insulated.

  2. Frosted glass - (sandblasted) is annealed glass that has a factory applied uniform density sandblasted surface. It can not be tempered unless it is sandblasted after it has been tempered. The sandblasted surface can be discolored by contact with foreign materials. Glass can be customized with etched and/or carved designs and logos. Acid etched glass is a chemical process to achieve similar properties with less potential discoloration.

  3. Insulated glass - see insulated glass

  4. Laminated glass - is typically manufactured by placing a layer of polyvinyl butyral between two or more lites of glass and then fusing it together using heat and pressure in a special oven called an autoclave. Resin laminating is a recently developed alternative process where a liquid chemical mixture is poured into the space between the two lites of glass and allowed to cure or harden. The most important characteristic of laminated glass is the ability of the interlayer to hold the glass in place when broken, providing protection against falling glass and/or penetration of the opening. The PVB layer reduces fading from UV rays and reduces sound transmission. Numerous types of glass, polycarbonate and interlayers in varying thicknesses can be used to accomplish a great variety of tasks such as bullet resistant or hurricane resistant requirements.

  5. Mirror - is annealed glass that has a silver backing applied by wet chemical deposition process and is then covered with a protective mirror backing paint. It can not be tempered. To comply with safety glazing requirements, mirror can be laminated with a PVB interlayer, or a safety backing sheet of adhesive backed polyethylene may be applied to the back of the mirror.

  6. Mirrorpane - (one way mirror, two way mirror, security mirror, first surface mirror) is actually a reflective glass coating on 1/4" gray glass, and is not a mirror because it does not have a silver backing. It is designed to allow vision from only one direction while presenting a mirror appearance from the other. The coated surface must be towards the subject side, with a recommended 10:1 light ratio. It is available for interior use only as the coating can be damaged by the weather. It can be tempered, but the process will dramatically increase visual distortion.

  7. Spandrel glass - is non-vision glass. It is typically made by fire fusing a colored ceramic frit to the inside surface of the glass, typically the #2 surface. The glass must either be heat strengthened or tempered because the color will absorb heat. Spandrel is typically used between multiple floors of a building to hide structural materials such as drop ceilings and concrete floor slabs. The inside painted surface is not suitable for use as a finished wall because daylight will show through scattered holes, it may show brush marks, and be uneven in appearance.

  8. Tempered glass - is a type of heat strengthened glass that is made by heating annealed glass and then cooling it rapidly. The rapid cooling locks the surfaces of the glass in a state of high compression and the core or interior of the glass in compensating tension. Once tempered, the glass can not be cut or drilled, so all fabrication must be completed before the tempering process. Tempered glass is approximately four (4) times stronger than annealed glass of the same size and thickness. To comply with safety glazing codes, a permanent label (logo) must be on the glass identifying the fabricator, the glass type and the safety glazing standard that it meets. All tempered glass has distortion. Bow, warp and roll distortion are inherent in tempered glass and can not be eliminated.

  9. Heat strengthened glass - is similar to tempered glass in many respects. It is approximately two (2) times as strong as annealed glass of the same size and thickness. Distortion is less evident than tempered. It does not qualify as a safety glazing material because its break pattern is like annealed glass. It does not have the tendency to break spontaneously like tempered glass. Once heat strengthened, the glass can not be cut or drilled.