Uncoated
Monolithic Heat-Processed Glass (Heat Strengthened and Tempered)
| Minimum
Size |
Maximum
Size |
| 1/4" (6mm)
|
1/4" (6mm) |
12" x 12"
(305 mm x 305 mm) |
84" x 144"
(2134 mm x 3635 mm) |
Premium over-sized maximum: 84" x 165" (2134 mm x 4191 mm) or 96" x 144" (2438 mm x 3658 mm). Premium over-sized maximum for silk-screened glass and for heat-soaked glass is 84" x 165" (2134 mm x 4191 mm). A technical review is required for all over-sized requests.
1. All Viracon heat-strengthened and tempered
glass is horizontally processed.
2. Glass cutting and fabrication is completed
prior to heat processing.
3. Viracon's two types of heat-processed glass
comply with ASTM Standard C1048. Surface compression
of heat-strengthened glass with thicknesses of
1/4" (6mm) and less is 4,000-7,000 psi. Surface
compression for 5/16" (8mm) and 3/8"
(10mm) heat-strengthened glass is 5,000-8,000
psi.* For fully-tempered glass, the minimum surface
compression is 10,000 psi. It complies with ANSI
Z97.1 and CPSC 16 CFR 1201 safety glazing standards.
*Because of reader readability and instrument
tolerances, Viracon's tolerance for heat-strengthened
glass surface compression is ±1,000 psi.
4. Heat-Treated Glass Characteristics:
• Distortion - Heat-strengthened or
fully-tempered glass that is manufactured in a
horizontal tempering furnace may contain slight
surface waves caused by contact with the rollers.
This waviness or roller wave distortion can be
detected when viewing reflected images from a
distance. Orientation of the glass in the furnace
is critical in order to minimize the appearance
of the roll wave distortion. It is recommended
that the roller wave be oriented parallel to the
horizontal glass dimension.
• Flatness - Tempered and heat-strengthened
glass products are not as flat as annealed glass
due to processes used in manufacturing. For heat-treated
glass products, the deviation for flatness is
a function of thickness, width, length and other
factors. Usually, increasing thickness yields
flatter products.
• Strain Pattern - For heat-strengthened
and fully-tempered glass, a strain pattern or
iridescence, which is not normally visible, can
become visible under certain light conditions - especially
polarized sky conditions. This is an inherent
characteristic of heat-processed glass and should
not be mistaken as discoloration or nonuniform
tint or color. Strain pattern is a result of air
quenching (cooling) of the glass and is not considered
a defect.
• Bow and Warp - Since heat-strengthened
and tempered glass are reheated to their softening
points and rapidly cooled, a certain amount of
warp and bow is associated with each glass piece
due to the resulting stress. Although warp and
bow is not generally a significant factor to the
design professional, it may appear as distorted
reflected images under certain viewing conditions.
For instance, it will be more noticeable in reflective
glass. And, it is an inherent characteristic of
heat-treated glass and is not considered a defect.
5. Viracon's sales and technical service support
staff can help you determine which type of heat-processed
glass is appropriate for your project.
Viracon offers two heavy duty choices: heat strengthened
and fully tempered. Viracon's heat-strengthened
glass provides superior resistance to thermal
stress and wind/snow loading.
Heat-strengthened glass is approximately two times
stronger than annealed glass. It is recommended
for applications requiring strengthened glass.
The exceptions are when safety glazing materials
are required or when wind/snow loading conditions
require fully-tempered glass.
Fully-tempered glass is approximately four times
stronger than annealed glass. It provides superior
resistance in high loading areas. Viracon can
supply insulating glass units with both glass
plies tempered for the following building applications:
• Fire knockout panels.
• Safety glazing for use in openings with
a walking surface on both sides, such as doors,
side glass adjacent to doors, entrances, lobbies
and balconies.
• The outboard glass ply of a sloped glazed
insulating glass unit, providing that the inboard
glass ply is a heat-strengthened laminate.
Viracon, or any other glass manufacturer, does
not warrant the glass against breakage. Although
Viracon does supply tempered glass for certain
building applications and locations to comply
with building code requirements, this should not
be construed as a recommendation for use.
The use of tempered glass in any application has
the associated risk of spontaneous breakage. Consequently,
it is the responsibility of the building owner
or design professional to consider the breakage
potential when specifying the use of tempered
glass.
Solarscreen High-Performance Reflective
Monolithic Glass
| Minimum
Size |
Maximum
Size* |
| Annealed: |
|
6" x 6"
(152 mm x 152 mm) |
84" x 144"
(2134 mm x 3658 mm) |
| Heat
processed: |
|
12" x 36"
(305 mm x 914 mm) |
84" x 144";
(2134 x 3658 mm) |
Premium over-sized maximum: 84" x 165" (2134 mm x 4191 mm) or 96" x 144" (2438 mm x 3658 mm). Premium over-sized maximum for silk-screened glass and for heat-soaked glass is 84" x 165" (2134 mm x 4191 mm). A technical review is required for all over-sized requests.
1. Solarscreen reflective glass products may require
heat processing. Refer to heat processing comments
for further product information.
2. Reflective Monolithic Glass Inspection Guidelines:
• Pinholes - Inspect glass from a distance
of 10 ft. (3m) in transmission, at a viewing angle of 90 degrees to the specimen, against a bright uniform background. If a pinhole is readily apparent, the following criteria apply: Pinholes larger than 1/16"
(1.6 mm) in diameter are not allowed
in 80 percent of the central glass area. Pinholes larger than 3/32" (2.4mm) are not allowed in the outer 20 percent of the glass area. No more than two readily apparent blemishes are allowed in a 3" (75mm) diameter circle and no more than five readily apparent blemishes are allowed in 12" (300mm) diameter circle.
• Uniformity - When viewing coated glass
from a minimum distance of 10 ft. (3 m), you may
notice some subtle variations in appearance from
glass ply to glass ply. This is not considered
a defect, but may be caused by production variations
in coating processes.
• Distortion - Various factors involved
in heat processing, insulating air spacers and
frame binding may distort reflected objects viewed
on the glass surface. These are not considered
defects of the coated glass or the final fabricated
product.
• Scratches - Inspect glass from a distance
of 10 ft. (3 m). Scratches up to 3" (76 mm)
are allowed. Scratches from 3" to 5"
(76 mm to 127 mm) are only allowed within 3"
(76 mm) from the edge of the glass. Concentrated
scratches or abraded areas are not allowed.
Solarscreen Reflective
Monolithic Spandrel Glass
| Minimum
Size |
Maximum
Size |
12" x 36"
(305 mm x 914 mm) |
83" x 144"
(2108 mm x 3658 mm) |
Premium over-sized maximum: 83" x 165" (2108 mm x 4191 mm). A technical review is required for all over-sized requests.
1. Spandrel glass with opacifier/scrim meets the
requirements of ASTM C1048 for fallout protection
if the glass breaks.
2. Viracon designs its spandrel glass for glazing
against a uniform, opaque background. It is not
recommended for use in transoms, partitions or
other areas where a dark background is unavailable.
3. Reflective Monolithic Spandrel Glass Inspection
Guidelines:
• View spandrel glass from a distance of
15 ft. (4.6 m) under daylight conditions. Color
and reflectance may vary when viewed under a uniform,
opaque background. This is not considered a defect.
• When viewing spandrel glass under similar
conditions, reflected pinholes and scratches are
not considered defects if they are unobtrusive.
Viraspan™ for Uncoated
Monolithic Glass
| Minimum
Size |
Maximum
Size |
12" x 12"
(305 mm x 305 mm) |
84" x 144"
(2134 mm x 3635 mm) |
Premium over-sized maximum: 84" x 165" (2134 mm x 4191 mm). A technical review is required for all over-sized requests.
1. Viracon designs its spandrel glass for glazing
against a uniform, opaque background. It is not
recommended for use in transoms, partitions or
other areas where a dark background is unavailable.
2. Viraspan Spandrel Glass Inspection Guidelines
• View spandrel glass from a distance of
15 ft. (4.6 m) under daylight conditions. Color
and reflectance may vary when viewed under a uniform,
opaque background. This is not considered a defect.
• When viewing spandrel glass under similar
conditions, reflected pinholes and scratches are
not considered defects if they are unobtrusive.
3. You can use Viraspan in structurally glazed
applications. However, a clear edge may be visible.
Contact Viracon’s Insides Sales Department
for more information.
4. Viracon reserves the right to change substrate
glass suppliers. As a result, this may affect
perceived colors of our Viraspan samples. Approval
of all glass colors is based on 12" x 12"
(305 mm x 305 mm) samples, which are ordered for
each project.
RECOMMENDED CLEARANCES
Note:
The maximum sizes listed are shown to illustrate
production limits. These sizes are unavailable
as finished products. Maximum piece size for annealed
glass under any condition is 50 sq. ft. (4.65
sq.m.) Maximum size for heat-treated glass under
any condition is 65 sq. ft. (6.04 sq.m.) Maximum
unit weight is 750 pounds (340 Kg).
For more information on insulating glass or additional
literature, call 800-533-2080 or
e-mail
us 
