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1. Clear
Float Glass
Since 1959, when the float process was introduced, soda-lime
glass has been the primary type of glass used for commercial
applications. Molten glass floats onto a bath of molten tin,
where a continuous glass ribbon is formed and then cooled
through an annealing lehr before being cut. Clear float glass is
nearly colorless, with a visible light transmittance ranging
from 75% to 92%, depending on thickness. Clear glass can be the
outboard or inboard lite, or both lites, of an insulating glass
unit. Clear float glass comes in the following types:
(1) Standard Clear
Available from a variety of manufacturers, thickness available
range from 3mm(3/32”) to 19mm(3/4”).
(2) Low-Iron Glass
Iron in the glass batch ingredients is what cause the slight
green tint in standard clear float glass. By reducing the iron
content, the glass has a clearer(less green) appearance.
(3) Self-cleaning
This is a clear, coated glass that is activated by UV rays
from the sun. The photocatalytic process gradually breaks down,
loosens and dissolves dirt and other residue so that it breaks
loose from the glass. The hydrophilic action causes rain to
sheet on the glass, carrying dirt away with minimal spotting or
streaking.
(4) Standard Tints
Colorants are added to clear float glass to produce tinted float
glass with isible light transmittance of between 14% to 85%,
depending on color and thickness. When incorporated as outboard
lite of an IG unit, tinted glass will increase the thermal and
solar performance to that level achieved with monolithic glass.
Tinted heat absorbing glass often requires the heat-treatment of
the outboard lite to improve the resistance of the glass to
solar-driven thermal stress. Glass size, type and job conditions
are contributing factor. It is recommended that a thermal stress
analysis be performed on all projects.
Standard Tints are available in the following colors:
Blue
Blue-Green
Bronze
Green
Grey
(5) High Performance(Spectrally Selective) Tints
High Performance Tints offer dramatically improved benefits when
compared with standard tints. The ratio of the visible light
transmittance to the solar heat gain coefficient is referred to
as the Light to Solar Gain (LSG) Ratio. The higher the LSG
ratio, the better the glazing is at reducing unwanted solar heat
while maximizing desirable natural light transmittance. When
used as the outboard lite of an insulating glass unit, High
Performance Tinted glass often requires heat-treatment to
improve its resistance to solar-driven thermal stress breakage.
Glass size, type and job conditions are contributing factors to
thermal stress breakage. It is recommended that a thermal stress
analysis be performed on all projects.
Spectrally selective products are available in the following
colors:
Blue
Blue-Green
Green
Grey
(6) Low-Emissivity(low-E) Glass:
Low-emissivity glass may have various combinations of metal,
metal oxide and metal nitride layers of coatings that are nearly
invisible to the eye and that reflect reradiated long-wave IR
energy. The Low-E coating reduces heat lass through the glass in
winter by reflecting interior long-wave IR back into the home or
office. When incorporated into insulating glass(IG) units, Low-E
glass significantly improves the unit’s thermal performance
(lower U-Value) and can be designed to also reduce solar heat
gain.
Low-E coatings are available by the following color appearance:
Neutral
Neutral Grey
Neutral Blue
Green
Reflective
(7) Reflective Glass
Reflective glass products consists of various pyrolytic or
sputtered coatings that are applied to clear and tinted glass
substrates to product a large family of products with a wide
range of visual properties(color, transmittance, reflectance)
and performance properties (shading coefficient, U-Value).
Reflective glasses can be used in vision and/or spandrel
applications to create uniform or contrasting building
aesthetics. When used as the outboard lite of and IG unit with a
Low-E glass inboard, the lowest (best) solar heat gain
coefficient and U-Value can be achieved.
Reflective glass often requires heat treatment (tempering or
heat-strengthening) to improve the resistance of the glass to
thermal stress breakage. Many variable affect thermal stress,
including glass size, color, coating position and jib
conditions. It is recommended that a thermal stress analysis be
performed on all projects.
Reflective coatings are applied to Clear, standard Tints and
High Performance Tints, and are available in the following
colors:
Blue
Blue-Green
Bronze
Green
Grey
Silver
2. Sandblasted Decorative Glass
Sandblasting results in a “frosted” glass appearance.
Transparent float glass is transformed into a decorative,
partially or fully translucent glass, depending on the amount of
surface area that is sandblasted.
Sandblasting is produced by pressure-spraying glass with various
grit abrasives to crate a wide range of surface textures.
Sandblasting can be done to give an entire piece of glass a
uniform frosted or obscure appearance. Masking off the clear
areas with a protective film can also produce a very intricate
custom design.
Sandblasting glass obscures the view from one space to another
without blocking out natural light. Sandblasting breaks down the
glass, leaving a finely ground surface that refracts and
scatters light rays.
Heat-treated glass, both heat-strengthened and tempered, should
not be sandblasted because it will decrease the strength of the
glass. All sandblasting should be done on annealed glass, prior
to any heat-treating.
Untreated sandblasted glass can be difficult to clean and remove
fingerprints from. Surface treatments are available that can
“seal” the rough surface to make cleaning easier.
3. Insulating glass (IG):
Two or more lites of glass with a hermetically sealed airspace
between the lites. The sealed space may contain air or be filled
with an inert gas, such as argon. |
