This Online Learning Seminar is
available through a professional
courtesy provided by:
Float Glass Manufacturing
and Architectural Glass Products
Visteon Corporation
Float Glass Operations
5555 South 129th East Ave
Tulsa, OK 74133
Tel: 313-755-0088
Fax: 313-755-5986
Email: [email protected]
Web: www.visteon.com/floatglass
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© 2004 Visteon Corporation. The material contained in this course was researched, assembled, and
produced by the Visteon Corporation and remains their property. Questions or concerns about the
content of this course should be directed to the program instructor.
©2004
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Slide 1 of 79
• About the Instructor
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Architectural Glass Products
Float Glass Manufacturing and Architectural Glass Products
Presented By:
Lowell Rager
Visteon Corporation
5555 South 129th East Ave
Tulsa, OK 74133
Description:
Provides an overview of float glass manufacturing and
various architectural glass products, including clear, tinted,
and heat treated glass, as well as coated products (Low-E,
Reflective) and fabricated products (Insulated, Laminated).
AIA/CES Info:
Provider No. J624 – Course No. AEC030; LUs – 1.50
MCE Info:
Contact your respective governmental licensing and
regulatory agency. This program qualifies for HSW credit.
Expiration date:
January 31, 2006
This program is registered with AIA/CES for continuing professional registration. As such, it does not include content that may be deemed
or construed to be an approval or endorsement by the AIA or AEC Daily Corporation of any material or construction or any method or
manner of handling, using, distributing or dealing in any material or product. Questions related to specific materials, methods and
services should be directed to the program instructor.
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©2004
Slide 2 of 79
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Architectural Glass Products
How to use this Online Learning Course
•
Read and review the material contained in this seminar.
•
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comments, double-click on the
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to scroll through the text.
•
To view this presentation, use the previous/next keys on each slide or the up and
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•
Within this course is a code word that you will be required to enter in order to
proceed with the online examination. Please be sure to write down this code
word so that you have it available for the test.
•
To receive a certificate indicating course completion, refer to the instructions at
the end of the seminar.
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For additional information and post-seminar assistance, click on any of the logos
and icons within a page or any of the links at the top of each page.
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Slide 3 of 79
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Architectural Glass Products
Learning Objectives
Upon completing this course, you will have a better understanding of:
•
Terminology and concepts related to glass, solar energy, and the solar spectrum
and the various stages of soda lime float glass manufacturing and fabrication.
•
Glass performance values, such as Emissivity and Light to Solar Gain Ratios,
Shading Coefficients, U-Values and R-Values, and Solar Heat Gain Coefficients.
•
Heat treating process and characteristics of Heat Strengthened and Fully
Tempered glass.
•
Characteristics of coated glass products, such as Reflective and Low-E glass,
Fabricated glass, including Insulated, Laminated, Fire-rated, and Spandrel glass.
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Slide 4 of 79
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Architectural Glass Products
Float Glass Basics
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Slide 5 of 79
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Architectural Glass Products
Float Glass Basics
Introduction
Float glass is frequently referred to as flat glass. There are two types of flat glass
that can be used in the fabrication of architectural glass products:
•
Soda Lime Glass: Soda lime glass is the most common and least expensive type of
glass. Prime components used in the manufacturing process are silica, soda, and
lime. Other trace elements are used in the composition. This type of float glass is
used in fabricating the majority of architectural glass products.
•
Borosilicate Glass: Borosilicate glass refers to any type of silicate glass with at
least 5% boron in its composition. It is used occasionally due to its greater
resistance to very high thermal stresses. This product is available in smaller sizes,
requires special handling and is generally more expensive than soda lime glass.
The remainder of this course will focus on soda lime glass and some of the types of
architecturally fabricated glass products available on the market today.
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Slide 6 of 79
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Architectural Glass Products
Float Glass Basics
Domestic Glass Manufacturers
•
There are six Primary Glass Manufacturers (PGMs) operating soda lime float glass
plants in the United States: AFG Industries, Cardinal Glass, Guardian Industries,
Pilkington North America, PPG Industries, and Visteon Float Glass Operations.
•
Their basic products are clear and tinted glass, although some PGMs also offer
specialty products, such as online Reflective and Low-Emissivity pyrolytic coatings.
•
All PGMs manufacture their products utilizing the "float glass method".
However, because product offerings will vary between manufacturers, it is
important to research product availability and performance for each PGM.
•
Most PGMs do not fabricate glass products for the general architectural
construction market. Instead, they market their products through qualified
glass fabricators.
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Slide 7 of 79
• About the Instructor
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Architectural Glass Products
Float Glass Basics
Glass Fabricators
•
Glass fabricators assemble the float glass acquired from PGMs into finished
architectural glass products that comply with the specifications of the design
professional and conform to applicable codes.
•
Fabricators can be national, regional, or local in scope. National fabricators
typically operate facilities nationwide and market their products nationally.
Regional fabricators have one or more facilities and market their products
regionally, and local fabricators generally service a localized area.
•
The primary market for glass fabricators typically includes glass shops, glazing
contractors, and curtain wall and window fabricators. Product lines will vary
from limited to extensive. PGMs can often provide the names of fabricators
servicing specific areas.
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Slide 8 of 79
• About the Instructor
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Architectural Glass Products
Float Glass Basics
Glass Surface Designation
•
•
In order to reduce confusion, glass
surfaces are numbered sequentially
beginning with the exterior surface
(first surface) and working inwards.
For instance, the interior surface of
the exterior lite would be referred to
as the second surface, and so on.
EXTERIOR
INTERIOR
1st Surface
2nd Surface
3rd Surface
4th Surface
•
Some fabricated products may have
more than four surfaces. For instance,
some insulated glass units might be
fabricated with four or more lites,
with eight or more surfaces.
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Slide 9 of 79
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Architectural Glass Products
Float Glass Basics
Selecting Architectural Glass
•
The selection of the appropriate architectural glass products for a project
requires finding a balance between aesthetics, performance, cost (initial and
life cycle), and compliance with applicable building and energy codes.
•
Energy codes vary from state to state and, in many cases, reference the National
Fenestration Rating Council (NFRC) and EnergyStar® programs. It is important to
become familiar with applicable codes prior to selecting a glass product.
•
Because there is almost an infinite number of glass products and fabrications
available to design professionals, proper selection and installation of fabricated
architectural glass products requires a team effort and close cooperation
between architects, designers, glass manufacturers, and fabricators.
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Slide 10 of 79
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Architectural Glass Products
Float Glass Manufacturing
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Slide 11 of 79
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Architectural Glass Products
Float Glass Manufacturing
Batch Components
•
The basic components of float glass
batch are silica sand, soda ash,
dolomite, and limestone.
•
Batch may also include about 15%
to 30% cullet, which is recycled
(previously manufactured) glass that
is included to facilitate melting and
improve furnace operation.
•
Trace amounts of magnesium, iron,
aluminum, sulfur, potassium, tin, and
strontium may also be included in
batch as necessary.
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Soda Ash
Limestone
Dolomite
Silica Sand
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Slide 12 of 79
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Architectural Glass Products
Float Glass Manufacturing
Production Process
Batch House
Molten Glass
Unloading Machines
Furnace
Controlled
Atmosphere
Cutting
Defect Scanners/Markers
Molten Tin
Furnace
Tin Bath
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Annealing Lehr
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Slide 13 of 79
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Architectural Glass Products
Float Glass Manufacturing
Production Process Cont'd…
•
Batch House: Batch materials are
mixed, monitored for purity, and
digitally weighed for accuracy prior
to entering the batch house. Batch
is continuously fed into the batch
house and then into the furnace.
Batch House
Furnace
Molten
Glass
•
Furnace: Batch materials are heated
to the melting point, often reaching
temperatures as high as 2800°F. The
batch materials become a molten
homogeneous mass. The molten glass
begins to cool near the stepped area
of the furnace and pours over a gate
(tweel) onto a pool of molten tin.
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Architectural Glass Products
Float Glass Manufacturing
Production Process Cont'd…
•
Tin Bath: The molten glass flows
across a body of molten tin. Glass
thickness will depend on the speed
at which it travels over the tin bath.
A controlled atmosphere gradually
reduces the temperature, allowing
the molten glass to begin solidifying.
Long mechanized metal rods with
gear-like fittings on the end (knurls)
are in contact with the edges of the
molten glass ribbon and assist its
movement over the tin bath. The
ribbon surface in contact with the
molten tin is called the tin surface,
while the top surface is called the
atmosphere surface.
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Molten Glass
Controlled Atmosphere
Molten Tin
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Slide 15 of 79
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Architectural Glass Products
Float Glass Manufacturing
Production Process Cont'd…
•
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Glass Ribbon
Annealing Lehr: The glass ribbon
leaves the tin bath area and enters
the annealing lehr at a temperature
of over 1100°F. As the glass ribbon
passes over a series of rollers, it is
cooled under controlled conditions
in order to remove any residual
stress. At this point, the solidified
ribbon of glass (often referred to as
a super-cooled liquid) is sufficiently
cool enough for processing.
Annealing Lehr
Rollers
Next
Slide 16 of 79
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Architectural Glass Products
Float Glass Manufacturing
Production Process Cont'd…
•
Finishing: Once it leaves the
annealing lehr, the glass ribbon
passes through an inspection booth
to ensure a pristine appearance.
Defects will be marked and cut out
further down the line at the capping
(cutting) operation. Because ribbon
edges are brittle and exhibit knurl
markings, they are trimmed for later
use as cullet. The usable width of the
ribbon will vary with glass thickness.
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Unloading Machines
Cutting
Defect Scanners/Markers
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Slide 17 of 79
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Architectural Glass Products
Float Glass Manufacturing
Production Process Cont'd…
•
During capping (cutting) operations the ribbon will be cut to size for a specific
project or into larger stock sizes called lehr ends or uncuts.
•
Uncuts will have one dimension (width) spanning a large percentage of the
usable width of the ribbon, with the other dimension as ordered by the
fabricator. For 1/4" glass, the most common uncut width is 130". The second
dimension (height) is supplied in 12" multiples, from 60" to 96".
•
Jumbo uncuts are available in standard dimensions of 130" x 204". Because this
size is too large to be used on a project, it will be cut down and used by a
fabricator to produce various architectural glass products.
•
Glass can be shipped in boxes, racks or unboxed. Unboxed glass requires
specialized handling equipment.
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Slide 18 of 79
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Architectural Glass Products
Float Glass Manufacturing
Float Glass Production Cont'd…
This image illustrates the intensity of heat required at the entry to the furnace.
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Slide 19 of 79
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Architectural Glass Products
Float Glass Manufacturing
Float Glass Production Cont'd…
This shows the long mechanized metal arms with knurls extending into the float bath.
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Slide 20 of 79
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Architectural Glass Products
Float Glass Manufacturing
Float Glass Production Cont'd…
This image shows the annealing lehr where the glass ribbon is carefully cooled.
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Slide 21 of 79
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Architectural Glass Products
Float Glass Manufacturing
Float Glass Production Cont'd…
This image illustrates what the glass ribbon looks like as it exits the annealing lehr.
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Slide 22 of 79
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Architectural Glass Products
Float Glass Manufacturing
Float Glass Production Cont'd…
Here, the finished and cut glass is upended with mechanized equipment.
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Slide 23 of 79
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Architectural Glass Products
Float Glass Manufacturing
Float Glass Production Cont'd…
Upended glass is placed on racks in the wareroom until it is ready to be shipped.
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Slide 24 of 79
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Architectural Glass Products
Float Glass Manufacturing
Float Glass Production Cont'd…
Finally, upended glass is loaded onto a trailer for shipment to a glass fabricator.
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Slide 25 of 79
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Architectural Glass Products
Glass and Solar Energy
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Slide 26 of 79
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Architectural Glass Products
Glass and Solar Energy
Solar Energy
•
The most abundant natural resource
available is the short-wavelength
electromagnetic energy we receive
from the sun.
•
The solar spectrum is comprised of
three distinct bands: Ultra Violet (UV),
Visible, and (Near) Infra Red (IR).
•
All three bands produce heat. Total
solar energy is the combination of all
three bands of the solar spectrum.
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Slide 27 of 79
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Architectural Glass Products
Glass and Solar Energy
Solar Spectrum
•
The UV band makes up only 2% of
the solar spectrum, with wavelengths
ranging from 280 to 400 µm. UV rays
are primarily responsible for fading.
•
The visible band makes up about
45% of the solar spectrum and is
perceived as daylight. The visible
band ranges from 400 to 780 µm.
•
The IR band makes up the remaining
53% of the solar spectrum and is the
major heat producing band, with
wavelengths from 780 to 2,150+ µm.
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©2004
UV Visible
2% 45%
Infra Red
53%
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Slide 28 of 79
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Architectural Glass Products
Glass and Solar Energy
Reflection, Transmission and Absorption
•
Short wave electromagnetic energy
from the sun will be transmitted
through the glass, reflected by the
glass, or absorbed by the glass.
•
Absorbed energy warms the glass
and this generated heat is then
convected or conducted to the
exterior or interior of the building.
•
PGMs and fabricators have developed
a variety of products that selectively
transmit, reflect, or absorb varying
segments of the solar spectrum.
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Glass
Transmission
Reflection
Absorption
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Slide 29 of 79
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Architectural Glass Products
Glass and Solar Energy
Transmittance vs. Reflectance
•
When specifying architectural glass
products, it is important to achieve a
good balance between transmittance
and reflectance of solar energy.
•
Some projects require high light
transmittance and visibility, while
others require greater reflectance of
solar energy to the exterior in order
to reduce cooling costs.
•
In cases such as the latter, a tinted
reflective product or substrate with a
high performance low emissivity
coating is often considered.
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Slide 30 of 79
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Architectural Glass Products
Glass Performance
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Slide 31 of 79
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Architectural Glass Products
Glass Performance
Performance Values
The efficiency of architectural glass
is typically evaluated by examining a
number of performance values:
•1
Shading Coefficient
•2
Solar Heat Gain Coefficient
•3
U-Value and R-Value
•4
Emissivity
•5
Light to Solar Gain Ratio
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Slide 32 of 79
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Architectural Glass Products
Glass Performance
Shading Coefficient
•
Shading Coefficients (SCs) are a measure of how much solar heat is allowed
to transfer to a building's interior through glass. Glass with a lower Shading
Coefficient will reduce solar heat transfer.
•
Shading Coefficients are determined by calculating the ratio of solar heat gain
through a glass (or glass and shading combination) compared to the solar heat
gain of unshaded 1/8" clear float glass at normal incidence. The SC of 1/8" clear
glass is 1.0.
•
Shading Coefficients will depend upon the nature of the glass product and the
sophistication of the architectural glass assembly. For instance, thin, monolithic,
clear float glass may have an SC of 1.02, while some fabricated glass may have
an SC as low as 0.11.
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Slide 33 of 79
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Architectural Glass Products
Glass Performance
Solar Heat Gain Coefficient
•
Solar Heat Gain Coefficient (SHGC) is the fraction of incident solar radiation
admitted through a fenestration product, including directly transmitted as well
as absorbed energy that is subsequently convected or conducted inward.
•
Solar Heat Gain Coefficient contributes to approximately 86% of a fenestration
product's Shading Coefficient.
•
Solar Heat Gain Coefficients will depend upon the nature of the glass product
and sophistication of the architectural glass assembly. For instance, thin,
monolithic, clear float glass may have an SHGC of 0.88, while some fabricated
glass assemblies may have SHGCs as low as 0.09.
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Slide 34 of 79
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Architectural Glass Products
Glass Performance
U-Value and R-Value
•
U-Values are related to thermal conductance, and are a measure of the heat
gain or heat loss through glass. U-Values are typically expressed in BTUs / ft2 / °F
(or Watts / m2 / °C).
•
R-Values are related to thermal resistance, and are a measure of a material's
resistance to heat flow. R-Values are the reciprocal of U-Values (R = 1 / U).
•
Both winter nighttime and summer daytime U-Values should be considered
when evaluating the performance of a product.
•
U-Values may range from 1.15 for monolithic glass to values as low as 0.08 for
fabricated glass. U-Values will depend upon the nature of architectural glass
assembly. The lower the U-Value, the better.
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Slide 35 of 79
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Architectural Glass Products
Glass Performance
Emissivity
•
Emissivity refers to a material's ability to reflect long-wave heat energy back
toward its source. Low-emissivity (Low-E) coatings help glass reflect more longwavelength (far infrared) energy, thus helping to improve its insulating value.
•
Examples of long-wavelength energy include mechanically produced heat (e.g.
furnaces), heat from artificial lights, computers, and short-wave energy that is
absorbed by furnishings, transformed, and emitted as long-wavelength energy.
•
Emissivity is expressed as a ratio of the total radiating power of a body to that of
a perfect black body at the same temperature. The lower the emissivity ratio, the
more energy the glass will reflect.
•
For instance, the emissivity of uncoated glass is approximately 0.84. Some
reflective coatings will tend to lower this number, and specially designed Low-E
coatings will have even lower emissivities, ranging from 0.03 to 0.29.
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Slide 36 of 79
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Architectural Glass Products
Glass Performance
Light to Solar Gain Ratio
•
Light to Solar Gain Ratio (LSG) can be used to help select glass when both high
light transmittance and low solar gain are important. LSG is simply the ratio of
a glazing product's Visible Light Transmittance (VLT) to its SHGC.
•
LSG is particularly important in structures designed around daylighting concepts.
Architecturally fabricated glass products having higher LSGs are deemed to be
more efficient in these projects.
•
Architectural glass must have a minimum VLT of 40% and a minimum LSG ratio
of 1.25 to be considered a Spectrally Selective Glazing material as outlined in
Federal Technology Alert DOE/EE-0173, Federal Energy Management Program.
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Slide 37 of 79
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Architectural Glass Products
Glass Performance
Relative Heat Gain
•
RHG is not technically a performance value, but rather a method of combining
the relative heat gain values (Shading Coefficient and U-Value) of various
products under prescribed static conditions.
•
Relative Heat Gain (RHG) represents the combined heat gain transfer resulting
from a glass product's shading coefficient and U-value. RHG provides a measure
of heat transfer in BTUs / ft2 / Hr (or Watts / m2 / hr) and is used for comparative
purposes when considering vision glass options.
•
RHG is the combination of solar heat gain (transmitted energy plus that amount
of absorbed energy that is conducted or convected to the interior) and heat
transfer due to the indoor/outdoor temperature differential. Lower RHGs are
usually deemed better for climate controlled buildings, whereas higher RHGs
may be considered better for passive solar designed structures.
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Slide 38 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
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Slide 39 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
Introduction
•
•
•
All soda lime float glass is annealed
when it leaves the manufacturing
process, in order to remove residual
stresses and improve its versatility.
Sometimes, glass will be required
that is more resistant to stress or has
a different breakage pattern than
that of annealed glass.
In these cases, annealed glass can be
heat treated to produce either fully
tempered or heat strengthened glass.
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©2004
Annealed
Fully
Tempered
Heat
Strengthened
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Slide 40 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
Annealed Glass
•
Annealed glass can be cut, drilled,
laminated, insulated, bent, and
fabricated into a wide variety of
architectural glass products.
•
Annealed glass is typically very
strong in compression, however it
tends to be weak in tension.
•
If necessary, annealed glass can be
heat treated to increase its resistance
to thermal and mechanical stresses.
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Slide 41 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
Heat Treating
•
Heat treating annealed glass will increase its resistance to thermal and
mechanical stresses. Heat treating can be accomplished thermally or chemically,
and can be used to produce either heat strengthened or fully tempered glass.
•
Chemical heat treating requires specialized equipment and the maximum sizes
of glass that can be treated are relatively limited.
•
Also, the breakage pattern of chemically-tempered glass is much the same as
annealed glass. As a result, it will not comply with safety glazing codes unless it
is part of a laminated product with a minimum 0.030" innerlayer.
•
Because of the characteristics of chemical heat treating, the vast majority of
architectural glass fabricators employ thermal heat treating in their operations.
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Slide 42 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
Heat Strengthened Glass
•
Heat strengthened (HS) glass is twice as resistant to thermal and mechanical
stresses as annealed glass of the same thickness and size.
•
HS glass will withstand solar and mechanically-induced thermal stresses and
greater uniform (wind) loads than annealed glass. However, upon failure, HS
glass will break into irregular sections, or shards.
•
As a result, HS glass will not comply with safety glazing codes unless it is part of
a laminated glass product with a minimum 0.030" thick innerlayer. Most
fabricators utilize an 0.060" innerlayer thickness to ensure adequate bonding.
•
HS glass must have a surface compression between 3,500 and 10,000 PSI or edge
compression of not less than 5,500 PSI.
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Slide 43 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
Full Tempered Glass
•
Fully tempered (FT) glass is four times as resistant to thermal and mechanical
stresses as annealed glass and twice as resistant as HS glass of the same thickness
and size. FT glass must have a minimum 10,000 PSI surface compression around
its perimeter and edge compression of not less that 9,700 PSI.
•
FT glass will withstand solar and mechanically-induced thermal stresses and
greater wind loads than annealed or HS glass. Upon failure, FT glass will break
into small rock-salt-like particles that generally quickly vacate the opening.
•
Due to its breakage pattern, FT glass will comply with safety glazing codes.
However, safety glazing codes will not permit FT glass in overhead applications
unless it is part of a laminated architectural glass product.
•
Many design professionals specify laminated HS glass for overhead glazing due
to its breakage characteristics. IGUs used in overhead applications frequently
incorporate an exterior lite of FT glass and an interior lite of laminated HS glass.
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Slide 44 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
Fully Tempered Glass Cont'd…
•
•
The heat treating process places the
external layer of FT glass in a state of
compression, while the inner core is
in a state of compensating tension.
Compression Layer
Penetration of the exterior layer
of FT glass will relieve the internal
tension, resulting in immediate
fragmentation of the glass.
Tension Layer
•
This fragmentation or "spontaneous
breakage" can be caused by a variety
of occurrences.
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Slide 45 of 79
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Architectural Glass Products
Annealed and Heat Treated Glass
Heat Treating Process
•
Flat glass can be thermally heat treated via a horizontal or vertical process.
Although the vertical process was the first method introduced, there are very
few vertical heat treating lines in operation today.
•
In vertical heat treating, the lite of glass is held at the top by a series of clamps
or tongs. These tongs penetrate the glass surface when it is heated, thus leaving
indentations, or tong marks, on the glass.
•
Because the vertical process can only handle limited sizes of glass, horizontal
heat treating has essentially replaced the vertical heat treating process.
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Architectural Glass Products
Annealed and Heat Treated Glass
Horizontal Heat Treating
•
The glass is placed on a series of
horizontal, specially wrapped, steel
rollers that are revolving toward
the furnace. The glass is supported
by the rollers as it approaches the
reheat chamber.
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Architectural Glass Products
Annealed and Heat Treated Glass
Horizontal Heat Treating Cont'd…
•
Entry rollers convey the glass into
the reheat chamber where it
continues to pass over rollers as it
is heated to temperatures ranging
from 1100°F to 1500°F.
•
The glass sags slightly between the
rollers, giving the lite a characteristic
"roller hearth" pattern mark.
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Architectural Glass Products
Annealed and Heat Treated Glass
Horizontal Heat Treating Cont'd…
•
Once the glass has been reheated
to the proper level, it passes into the
"quench" area of the process. While
passing through the quench area,
cool air is simultaneously directed to
both glass surfaces.
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Architectural Glass Products
Annealed and Heat Treated Glass
Horizontal Heat Treating Cont'd…
•
The temperature and the intensity
of air flow will determine whether
the glass will be heat strengthened
or fully tempered.
•
Skilled operators ensure that the
correct temperature and air levels
are maintained in order to provide
a product that will comply with the
required specifications.
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Architectural Glass Products
Annealed and Heat Treated Glass
Characteristics of Heat Treating
•
Quench Pattern Marks: Quench pattern marks, often referred to as "strain
patterns", are markings that are centered around the air delivery system in the
quench. Air delivery may be through a series of nozzles or baffles. Quench
pattern marks are most visible under conditions of polarized light.
•
Roller Hearth Pattern Marks: Roller hearth pattern marks are imparted to a lite
of glass as it passes over ceramic rollers in the quench area of the heat treating
process. Most design professionals will specify that this pattern mark must be
parallel to the horizontal (sill) dimension in order to minimize its appearance.
•
Distorted Image Reflection: Distorted image reflection is a characteristic of
annealed and heat treated glass. Distorted images are amplified in heat treated
glass due to the irregular surfaces that are caused by the process.
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Architectural Glass Products
Annealed and Heat Treated Glass
Centerline Deflection
•
Although heat treating annealed glass will increase its resistance to thermal
and mechanical stress by two to four times, it will not affect its centerline
deflection.
•
Identical thicknesses and sizes of flat glass that are exposed to identical
conditions will deflect at the same rate whether the glass is annealed, heat
strengthened, or fully tempered.
•
Most design professionals prefer a maximum centerline deflection of about
3/4". Centerline deflections can be lowered by decreasing the size of the lites or
by increasing their thickness.
Please remember the word DEFLECTION. You will be required to enter it in order to
proceed with the online examination.
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Architectural Glass Products
Annealed and Heat Treated Glass
Standards
•
All heat treated products must conform to applicable provisions as specified by
ASTM C1048-04 "Standard Specification for Heat-Treated Flat Glass—Kind HS,
Kind FT Coated and Uncoated Glass".
•
This specification outlines requirements for flat heat-strengthened and flat fully
tempered glass coated and uncoated used in general building construction, and
supersedes Federal Specification DD-G-1403B.
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Architectural Glass Products
Clear, Tinted, and Wired Glass
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Architectural Glass Products
Clear, Tinted, and Wired Glass
Clear Float Glass
•
Clear float glass constitutes the
largest amount of float glass
manufactured in the United States.
•
It is estimated that clear glass makes
up approximately 60% to 65% of the
domestic production of float glass.
•
Clear float glass is available in a
range of thicknesses, from thin 3/32"
glass to thicker to 3/4" glass.
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Architectural Glass Products
Clear, Tinted, and Wired Glass
Tinted Glass
•
Tinted glass was developed to reduce
visible light transmittance and solar
energy transmission into a structure.
•
Tinted glass is available in a range of
colors and is typically heat absorbing
(and frequently referred to as tinted
heat absorbing).
•
The percentages of colorants such
as rouge, selenium, cobalt, and other
trace items are varied in order to
achieve specific colors and tones.
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Architectural Glass Products
Clear, Tinted, and Wired Glass
Tinted Glass Cont'd…
•
•
•
Tinted glass colors and thicknesses
vary between manufacturers. Some
proprietary products may only be
available from one manufacturer.
The performance and appearance of
"standard" tinted products (green,
bronze, grey) is often similar across
manufacturers' product lines.
Darker "non-standard" tints tend to
differ between manufacturers. It is
important to request samples in
order to ensure aesthetic integrity.
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Blue
Dark Blue
Blue Green
Green
Dark Green
Aqua
Grey
Dark Grey
Bronze
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Architectural Glass Products
Clear, Tinted, and Wired Glass
Tinted Glass Cont'd…
This chart shows the solar spectrum transmittance of several colors of tinted glass.
Some tinted products reduce transmission of total solar energy (i.e. near infrared).
90
80
% Transmittance
70
Bronze
Grey
Blue
Blue-Green
Green
60
50
40
Dark Blue
30
Dark Green
20
Dark Grey
10
0
300
500
700
900
1100
1300
1500
1700
1900
2100
2300
2500
Wavelength (µm)
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Architectural Glass Products
Clear, Tinted, and Wired Glass
Wired Glass
•
Wired glass is manufactured using the plate glass manufacturing method. As
the molten glass passes between two rollers, wire is fed between them, thus
becoming embedded in the substrate. Wired glass cannot be heat treated.
•
Polished wired glass is classified as a material that passes the 45 minute fireresistance test requirements of NFPA 80. At one point, wired glass was the only
choice for areas where fire-rated glass was required. Since then, other specialty
products with increased fire ratings have become more popular than wired glass.
•
Wire glass is available clear or tinted and can be produced with a polished or
patterned surface. Patterned glass, or rolled glass, is made using rollers with an
inscribed pattern. Patterned glass is frequently used in decorative panels.
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Architectural Glass Products
Clear, Tinted, and Wired Glass
Standards
•
All PGM products must conform to applicable provisions as specified by ASTM
C1036-01 "Standard Specification for Flat Glass". This standard supersedes
Federal Specification 451D.
•
The scope of ASTM C1036-01 "covers the requirements for annealed, monolithic
flat glass of rectangular shape supplied as cut sizes or stock sheets…" (1.1)
•
In addition, the scope of ASTM C1036-01 also "covers the quality requirements
of flat, transparent, clear and tinted glass having glossy, apparently plane and
smooth surfaces. The glass is intended to be used primarily for mirrors, coatings,
glazing, and general architectural or similar uses." (1.2)
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Architectural Glass Products
Coated Glass Products
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Architectural Glass Products
Coated Glass Products
Introduction
Coated glass products are manufactured by depositing ultra-thin layers of metal or
metallic oxides onto the surface of float glass. Coatings can be applied pyrolytically
or by an MSVD (sputter) process. There are three basic types of coated glass:
•1
Reflective: Reflective coatings function to reflect short-wavelength solar energy
to the exterior, reducing solar heat gain and cooling costs. Reflective coatings
are typically oriented toward the second glass surface. However, pyrolyticallyapplied reflective coatings may be oriented toward the first glass surface.
•2
Low-Emissivity: Low-E coatings are heat reflective and function to reflect longwavelength energy back toward its source. The amount of energy reflected
depends upon the coating and its orientation (typically second or third surface).
•3
Reflective Low-Emissivity: Combined reflective and low-E coatings reflect both
short- and long-wavelength energy, providing solar and thermal control. Some
MSVD low-emissivity coatings are formulated to reflect greater amounts of solar
energy to the exterior.
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Architectural Glass Products
Coated Glass Products
Pyrolytic Coating Process
•
Tin Bath
All pyrolytic coatings are applied
"on line" during the manufacturing
process while the glass is at a highly
elevated temperature.
Spray Booth
Lehr
•
The coating is applied to the top
surface (atmosphere surface) of the
glass via chemical vapor deposition
(CVD) in the tin bath.
•
Alternately, a metallic oxide spray is
applied just after exiting the float
bath and entering the annealing lehr.
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Architectural Glass Products
Coated Glass Products
Pyrolytic Coatings
•
•
•
The majority of pyrolytic reflective
coatings are specified as second
surface applications.
Whereas pyrolytic reflective coatings
may also be installed in first surface
applications, pyrolytic low-E coatings
should not be oriented this way.
INTERIOR
1st Surface
2nd Surface
Pyrolytic
Coating
First surface coatings will appear
silvery when viewed from outdoors
and proper cleaning programs must
be maintained.
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EXTERIOR
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Architectural Glass Products
Coated Glass Products
MSVD "Sputter" Process
•
Magnetic Sputter Vacuum Deposition
(MSVD) occurs in "off line" facilities
and can be used to apply multiple
coatings of metals or metallic oxides.
•
The glass passes under a magnetic
sputter ring in conjunction with a
plate of material to be deposited on
the glass surface (e.g. stainless steel).
•
Metal
Atoms
The negatively charged plate is
bombarded by gas ions that dislodge
molecules of the material, depositing
them onto the glass surface.
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Electromagnetic Sputter Ring
with Stainless Steel Plate
Gas
Ions
Stainless Steel Coating
over Glass Substrate
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Architectural Glass Products
Coated Glass Products
MSVD "Sputter" Coatings
•
•
•
Reflective, Low-E, and Reflective/
Low-E glass products are available
from fabricators operating MSVD
facilities.
MSVD coated products should not be
installed in first surface applications
and MSVD Low-E coatings must be
encapsulated in Insulated Glass Units.
INTERIOR
1st Surface
2nd Surface
MSVD
Coating
With a few exceptions, most MSVD
coated glass products are not postheat treatable.
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EXTERIOR
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Architectural Glass Products
Fabricated Glass Products
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Architectural Glass Products
Fabricated Glass Products
Introduction
Float glass can be fabricated into a wide
variety of architectural glass products to
meet a wide range of specifications.
•1
•2
•3
•4
Insulated Glass
Laminated Glass
Fire Rated Glass
Spandrel Glass
Heat treated glass (Heat Strengthened or
Fully Tempered), which has already been
discussed, can be used monolithically or
in the fabricated products listed above.
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Architectural Glass Products
Fabricated Glass Products
Insulated Glass
•
Sealed Insulated Glass (IG) increases
thermal efficiency and offers greater
resistance to uniform (wind) loads as
compared to monolithic glass.
EXTERIOR
1st Surface
•
•
IG can consist of two layers of glass
separated by an air space (doubleglazing) or three layers of glass and
two air spaces (triple-glazing).
Hundreds of combinations of glass
products and coatings are available,
offering a wide range of aesthetic
appearances and performance values.
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2nd Surface
Primary Seal
Desiccant
INTERIOR
A
I
R
S
P
A
C
E
Spacer
3rd Surface
4th Surface
Secondary Seal
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Architectural Glass Products
Fabricated Glass Products
Insulated Glass Components
•
Glass: Insulated Glass is composed of an exterior and interior lite of glass (in
addition to a middle lite of glass in "triple glazed" units) and can be fabricated
using a wide variety of float glass substrates and coatings. In some cases, these
lites may actually be composed of multiple lites (e.g. two lites of 1/4" float glass
laminated with an inner layer). Tinted glass is frequently used as the exterior
lite in order to reduce solar heat transfer and provide the desired aesthetic
appearance. The second glass surface can be left uncoated or have a reflective
or MSVD Low-E coating applied.
•
Air Space: Air spaces generally range from 1/4" to 5/8" in width. Air spaces of
greater widths do not increase thermal efficiency and, in fact, often result in
higher U-Values. Air spaces can be filled with air or an inert gas such as argon,
krypton or a mixture (i.e. argon/krypton) to achieve lower U-Values. The
enclosed air is desiccated by the desiccant included in the spacer (separator).
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Architectural Glass Products
Fabricated Glass Products
Insulated Glass Components Cont'd…
•
Spacer: The spacer maintains the air space and effectively separates the exterior
and interior lites of glass. Spacers are available in a variety of materials and
configurations. For example, a hollow metal tube made of zinc, steel, tin, or
composite material. The spacer is placed near the glass edge on all four sides.
The primary and secondary sealants separate the spacer from the glass. The
spacer is partially filled with a desiccant to absorb small amounts of moisture in
the Insulated Glass Unit.
•
Primary and Secondary Seal: The primary seal’s purpose is to provide a vapor
barrier to eliminate the intrusion of moisture into the air space. Primary seals
are generally made of polyisobutylene and do not have meaningful structural
properties. The secondary seal provides the structural integrity of the IGU's edge
perimeter. Secondary seals are typically polysulphide, silicone, or urethane.
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Architectural Glass Products
Fabricated Glass Products
Laminated Glass
•
Laminated glass is composed of
multiple lites of glass bonded
together by an innerlayer.
•
The innerlayer is typically polyvinyl
butyral (PVB), urethane, or resin. In
some cases, polycarbonate may also
be included in the innerlayer.
•
Differing thicknesses of float glass
and innerlayers may be used in
combination to achieve the desired
performance characteristics.
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Architectural Glass Products
Fabricated Glass Products
Laminated Glass Applications
•
Safety Glazing: Safety glazing requires a minimum 0.030 innerlayer thickness.
•
Bullet and Blast Resistance: Varying thicknesses of glass and several innerlayers.
•
Acoustical Glass: Laminated glass helps to provide sound attenuation.
•
Hurricane Glazing: Requires innerlayer thicknesses from 0.060" to 0.100".
•
Break and Entry Resistance: Helps to provide smash and rob protection.
•
UV Reduction: Helps to reduce fading of interior furnishings and materials.
•
Sloped Glazing: Required for sloped glazed areas such as skylights and canopies.
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Architectural Glass Products
Fabricated Glass Products
Spandrel Glass
•
Glass is a popular option for spandrel areas of building facades. Spandrel glass
can be used monolithically or fabricated into Insulated Glass Units or shadow
boxes. Spandrel glass should be heat treated to withstand thermal stresses.
•
With the exception of some shadow box designs, spandrel glass should have
some type of opacification to exclude vision into areas containing plenums, floor
slabs, etc. Typical opacifiers include water-based silicone coating, ceramic frit, or
polyester film. Note that polyester films should not be used on tinted glass.
•
Water-based silicone coatings are available in a wide range of colors and can be
applied to the second, third, or fourth glass surfaces. The coating should be
deleted (edge deletion) around the periphery of IGUs so as not to come in
contact with the primary or secondary seals. It can be applied to uncoated or
reflective surfaces. However, because it can be abraded, it is not recommended
for glass surfaces that are exposed to view.
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Architectural Glass Products
Fabricated Glass Products
Spandrel Glass Cont'd…
•
Ceramic frit is available in a range of standard and specialized colors and is
applied prior to heat treating. Frit can be oriented to the second, third, or fourth
glass surfaces. Because ceramic frit becomes an integral part of the glass surface
during heat treating, edge deletion is not required. Some small pinholes and
striations may be visible when viewing the coated side. As a result, it should not
be used in finished walls.
•
Polyester film can be utilized on reflective-coated glass on either the uncoated
or coated surface. The film is suspended in a roll over the glass to be opacified.
The heat treated lite and sheet of film are fed between compressing rollers
that apply the opacifier. The film can be located on the second glass surface of a
monolithic spandrel or the fourth glass surface of an IGU. Polyester films are not
recommended for use on uncoated tinted or clear glass.
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Architectural Glass Products
Fabricated Glass Products
Fire-Rated Glass
•
Wired Glass: Wired glass can be used in meeting a 45 minute fire-resistance
rating, however other specialty products with increased fire ratings have become
more popular than wired glass in recent years.
•
Laminated Glass: Layers of glass laminated with a transparent intumescent
material that foams to form an opaque protective barrier when the lite fractures
due to fire. Fire ratings for this type of material range from 45 to 120 minutes.
•
Insulated Glass: Fabricated with two or more lites of FT glass. Air spaces are
filled with a gel like substance that turns opaque when exposed to fire, thus
providing a barrier to harmful heat and radiation. Fire ratings may range from
45 to 120 minutes depending upon fabrication.
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Architectural Glass Products
Additional Information
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Architectural Glass Products
Additional Information
Trade Associations
Several trade associations provide information regarding architectural glass. The
most recognized are the Glass Association of North America (GANA), the Insulated
Glass Manufacturers Alliance (IGMA), and the National Glass Association (NGA).
GANA
2945 SW Wanamaker, Ste A
Topeka, KS 66614-5321
Tel: 785-721-0208
Web: www.glasswebsite.org
IGMA
401 North Michigan Ave
Chicago, IL 60611
Tel: 312-644-6610
Web: www.igmaonline.org
NGA
8200 Greensboro Dr, Ste 302
McLean, VA 22102
Tel: 1-866-342-5642
Web: www.glass.org
In particular, the GANA Glazing Manual contains detailed information on basic
types of flat glass, architecturally fabricated glass, and applications, as well as a list
of standards, trade association addresses, and a glossary of industry terminology.
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Architectural Glass Products
Conclusion of This Program
•
AEC Daily Corporation is a Registered provider with the
AIA Continuing Education System. Credit earned upon
completion of this program will be reported to CES
Records for AIA members.
•
If you desire AIA/CES, CSI and/or state licensing
continuing education credits, please click on the button
below to commence your online examination. Upon
successful (80% or better) completion of the exam,
please print your Certificate of Completion.
•
For additional knowledge and post-seminar assistance,
please visit the Seminar Discussion Forum (click on the
link above and bookmark it in your browser).
•
If you have colleagues that might benefit from this
seminar, please let them know. Feel free to revisit the
AEC Daily web site to download additional programs
from the Online Learning Center.
©2004 Visteon Corporation. The material
contained in this course was researched,
assembled, and produced by the Visteon
Corporation and remains their property.
Questions or concerns about this course
should be directed to the instructor.
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