Vitro PPG, AGC
1/4 Graylite 14, 1/8 Graylite 31
Pilkington, Vitro PPG, AGC
Pilkington, Vitro PPG, AGC
Solar Reflective glass has a mirror-like metallic or metallic-oxide coating that is highly reflective of solar energy. Shading coefficients of reflective glass can be as low as .14, i.e. such a coated glass will transmit only 14% as much of the solar spectrum as would clear glass in the same location.
Reflective glass offers the following attributes:
- Aesthetic appeal – metallic coatings are available on a variety of substrates to offer design flexibility
- Energy savings – through its ability to reflect, absorb, and radiate solar energy, reflective glass substantially reduces interior solar heat gain
- Occupant comfort – comfort is improved when heat gain/loss differentials between sunny and shaded elevations are reduced
Reflective products can be installed with the reflective surface facing the exterior (#1 surface) for a highly reflective look or facing the interior (#2 surface) giving a less reflective appearance and showing more of the color of the substrate. If the coating is on the #2 surface, heat strengthening the lite is required.
Low E Coatings
Low E products improve the energy performance of an insulated glass unit in terms of U value, shading coefficients, solar heat gain coefficient and relative heat gain while allowing high visible light transmittance.
Two categories of low E products are available: Pyrolitic and sputter deposition. Both products have a thin metallic coating that reflects the infrared portion of the heat spectrum back to its source. Thus, radiant heat created within a building is retained and exterior radiant heat is refused.
Sputter coatings are applied in multiple layers to glass using a vacuum chamber. The advantage of this coating is the wide selection of materials that can be sputtered. These combinations provide nearly invisible coatings with the highest level of performance possible. Sputtered coatings must be protected inside a sealed insulated glass unit.
Pyrolitic coatings, as the name implies, are applied to hot glass embedding thin layers of metal into still-soft surfaces of the material before it is cooled on the lehr line. The coating is highly durable before of this process.
Pyrolitic low E products are available from Pilkington, AFG, Visteon/PPG.
Sputter coat low E products are available from Cardinal (low E 272 and low E 366 products) and Visteon/PPG (Solarban products).
When broken, tempered glass breaks into a multitude of small fragments of somewhat cubical shape. Tempered glass meeting ANSI Z97.1 requirements is qualified as a safety glazing material.
Tempered glass is fabricated by subjecting annealed glass to a special heat-treating process. Most processes heat the glass to 1150 degrees F, then rapidly cool it by blowing air uniformly onto both surfaces simultaneously. The cooling process locks the surfaces of the glass in a state of high compression and the central core in compensating tension. The color, clarity, chemical composition, and light transmission characteristics remain unchanged. Tempered glass is approximately four times stronger than annealed glass. Heat strengthened glass is approximately twice as strong as annealed glass.
Fabrication, such as cutting, drilling, or edging is done before the tempering process.
Laminated glass can be made in many combinations of clear, tinted, low E, or solar-reflective glasses. Polyvinyl butyral (PVB), the most commonly used sheet interlayer material, is available in thicknesses from .15” to .90”, with .30” as the most common.
When laminated glass is fractured, the particles of glass tend to adhere to the plastic, affording protection against flying or falling particles. Architectural laminated glass which satisfies the safety requirements for Category II materials, is generally two lites of annealed glass with an .30” interlayer.
Burglar resisting glass covers standards for “smash and grab” type burglaries and tests only for minimal commercial security. It generally uses a special plastic interlayer which is resistant to penetration.
Bullet resisting glass usually consists of multiple lites of glass, plastic interlayers, and can include layers of polycarbonate.
Wired glass is produced by embedding wire netting into molten glass. The product is not temperable. It is considered 50% as strong as annealed glass of the same thickness. Major uses of wire glass have been in institutional buildings and fire-rated doors and windows. It is not considered a safety product.
Misco Wire Glass
Baroque Wire Glass