17 Glass & Glazing
History of Glass
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
History of Glass
Early Glass Production
• Largest known piece of glass
in a public bath at Pompeii
• By 10th century A.D. the
Venetian Island of Murano
had become major center
for glassmaking
• Crown glass and cylinder
glass were produced
• Crown glass process
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–
–
–
Blowpipe on other side of punty
removed leaving a hole
Face Shield
Hand Shield
Blowing large glass sphere
Iron rod called punty used
to hold glass
Reheating sphere resulting
in crown 30”+ in diameter
Cooled and cut
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Punty
Disk or crown shaped glass
History of Glass
Early Glass Production
Swinging action resulting in cylinder
Blowing glass spheres
• Cylinder glass process
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–
–
–
–
Blowing large glass sphere
Swinging action resulted in
cylinder
Hemispherical ends were
cut
Cylinder slit lengthwise
and reheated to flatten
into rectangular sheet
Cut into panes
• Crown glass favored over
cylinder glass because of
surface quality
• Cylinder glass was more
economical
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Hemispherical ends are cut
History of Glass
From Crown to
Float Glass
• Lack of optical quality of crown
and cylinder glass gave way to
introduction of plate glass in 17th
century France
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–
–
–
Float Glass Production Process
Molten glass was cast into frames
Spread into sheets
Cooled and ground flat
Polished and cut
• Cylinder process evovled in 19th
Century
• In 20th century drawn glass was
produced
• In 1959 Pilkington started
producing float glass which is the
basis of all modern day glass
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History of Glass
Float Glass Finishing and
Cutting
• Glass is floated on molten tin and
hardens on it producing parallel
surfaces, high optical quality and
brilliant surface finish
• Automatic cutting can produce
glass to desired sizes
• Annealing Lehr gradually cools
the glass to avoid locked-in
stresses
• Glazing is the installation of glass
or the transparent material in a
glazed opening
• Installer of glass is called glazier
• Individual pieces are called lights
or lites
Float Glass Ribbon Emerging
from Annealing Lehr
Track-mounted Cutting
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Copyright © 2009 John Wiley & Sons. All rights reserved.
17 Glass & Glazing
The Material Glass
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
The Material Glass
Advanced Glazing
Systems
• Glass is the most-used cladding
material for tall buildings due to its
strength, light weight, durability, and
wide range of available optical and
thermal properties
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
The Material Glass
Advanced Glazing
Systems
• Glass has seemingly unlimited
optical and aesthetic possibilities
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Copyright © 2009 John Wiley & Sons. All rights reserved.
The Material Glass
Glass Ingredients and
Thicknesses
Tempered Glass is Used in Store Front
For Strength and Breakage Safety
• Glass is made from
–
–
–
–
–
Sand (silicone dioxide)
Soda ash (sodium hydroxide or
sodium carbonate)
Lime (calcium)
Alumina
Potassium oxide
• Glass is supercooled liquid and in
sheet form strength is impacted by
imperfections in glass
• Thicknesses range from
approximately 3/32 inch (single
strength) to 1/8 inch (double
strength) to 1 inch.
• Heat treatments such as tempering
impact glass strength and uses
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
The Material Glass
Glass Types by Heat
Treatment and Strength
Laminated Glass Used in Sloped
Glazing Provides Safety Against Falling
Shards
• Annealed glass
ˉ
Regular float glass which is cooled slowly
to reduce in built stress
• Tempered glass
ˉ
Produced by cutting annealed glass to
required size, reheating and then cooling
rapidly. Higher strength and breaks into
small shards
• Heat-strengthened glass
ˉ
Between annealed and tempered with
breakage behavior like annealed
• Laminated glass
ˉ
Sandwich of multiple layers of glass with
PVB interlayer. Suitable for security
applications as glass stays in place
• Fire-rated glass
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Copyright © 2009 John Wiley & Sons. All rights reserved.
The Material Glass
Fritted Glass Used
to Create Patterns
Glass Types by
Architectural Treatments
• Patterned glass
ˉ
Hot glass can be rolled into sheets with
many different surface textures and
patterns to obscure vision for privacy
• Fritted glass
ˉ
Pigmented glass particles called frits are
used to imprint glass. Glass is dried and
fired in tempering furnace to make it
permanent
• Spandrel glass
ˉ
Used to cover bands of floor/wall
around the floor edges. Usually
tempered or heat strengthened with
insulation behind them
Darker Colored
Spandrel Glass
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The Material Glass
Building With Reflective Coated Glass
Glass For Controlling
Solar Radiation
• Tinted Glass
–
Made by adding small amounts of
selected chemical elements to the
molten glass mixture
• Reflective Glass or Solar Control Glass
–
Thin Durable films of metal or metal
oxide are deposited on the surface of
either tinted glass or clear glass to make
the glass reflective. The film turns away
significant portion of solar radiation
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The Material Glass
Impact of Glass Type on
Control of Visible Light
and Solar Radiation
•
•
•
•
Effect of Three Different Glazing Assemblies on
Incoming Sunlight – Outside is on Left
Transmitted Radiation
Reflected Radiation
Absorbed Radiation
Re-radiation
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The Material Glass
Glass and Thermal
Considerations
•
IGU – Insulating Glass Unit
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–
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•
Two Methods of Sealing
Edge of Double Glazing
Made of multiple glass with sealed air space
reducing conductance, single glazing is single
glass, double glazing is two sheets and triple
glazing is three sheets of glass
Space filled by air or inert gas in a
hermetically sealed cavity
Different spacers used including warm-edge
spacer
Performance given in terms of U values
Low Emissivity coated glass (Low-e)
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–
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Formed with transparent metallic coating to
improve thermal performance
Located on surface 2 and sometimes on
surface 3.
Improves thermal performance
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
The Material Glass
Glass and Thermal
Considerations
•
Visible Light Transmittance - VT
–
•
Ratio of visible light passing to the
amount striking the glass
Solar Heat Gain Coefficient - SHGC
–
•
Glass Properties Impacting Thermal
Visual Performance
Ratio of heat admitted to the amount
striking the glass
Light Solar Gain Ratio – LSG
–
Ratio of VT to SHGC
1
2
Glazing Type
VT
SHGC
LSG
U
R
Single glazing, clear
0.90
0.85
1.3
1.1
6.3
0.91
0.16
Double glazing, clear
0.79
0.70
1.1
0.47
2.7
2.1
0.37
Double glazing,
medium gray tinted
0.40
0.45
0.9
0.47
2.7
2.1
0.37
Triple glazing, clear
0.53
0.52
1.0
0.34
1.9
2.9
0.52
Double glazing, clear,
low-e (low SHGC)
0.64
0.27
2.4
0.28
1.6
3.6
0.63
Double glazing, clear,
low-e (high SHGC), argon filled
0.78
0.63
1.2
0.27
1.5
3.7
0.65
1
2
o
2 o
U-Factor: Btu/ft -hr- F followed byW/m - K
2 o
2
o
R-Value: ft -hr- F/Btu followed by m - KW
2
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
The Material Glass
Glass and Thermal
Considerations
• The label on this fabricator's
glass sample indicates that this
IGU consists of
–
–
–
–
–
–
–
a ¼"-thick low-e, annealed lite
(with the trade name
Solarban 60)
a ½" spacer and
a ¼" clear annealed light.
VLT of 0.70
SC of 0.44
SHGC of 0.38
U-Value of 0.29
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
17 Glass & Glazing
Glazing
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Alternative Methods of Single Glazing
Small Lights – Outdoor Side on Left
Glazing Small Lights
• Not subject to excessive wind force or
stresses due to thermal expansion
• Glass first held in place by Glazier’s
points and then sealed on outside with
putty followed by painting
• Factory glazed units employ improved
putties or glazing compounds which stay
elastic for longer period of time
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Glaziers Install Lights of Glass that
Weigh as Much as 125 pounds (57 kg)
Glazing Large Lights
• Large lights, those over 6 ft2 (0.6 m2)
require more care in glazing due to
stresses
• Design objectives are
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–
–
–
Support weight of glass without
abnormal stress patterns
Support glass against wind pressure and
suction
Allow for expansion and contraction of
glass and frame without damage
Avoid contact of glass with any hard
material such as frame
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Alternative Methods of Single Glazing
Large Lights – Outdoor Side on Left
Glazing Large Lights
• Setting blocks are of synthetic
rubber and support weight of glass
• Bite or depth of grip on the edge
of glass of certain amount is
required to resist wind load
• Glazing components used
between frame and glass are either
wet or dry such as
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–
–
Preformed solid tape sealant
made of polybutene
Wedge or roll in gasket
Lock strip gasket
• In good design reliance for
waterproofing relies on wet and
dry seals in conjunction with
pressure equalization and drainage
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Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Lockstrip Gasket Installation in
Progress and Completed
Glazing Large Lights
• Lockstrip gasket is a dry glazing method
• It is faster, easier and less dependent on
workmanship then wet glazing method
• Wet glazing with good workmanship is
more effective
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
Mullionless Butt-Joint Glazing With
Single Glazing
• Butt-joint glazing system
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–
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Head and sill of the
glass sheets are
supported
conventionally in metal
frames, but vertical
mullions are eliminated
The vertical joints
between sheets of glass
are made by injection of
colorless silicone sealant
There is a strong effect
of unbroken horizontal
band of glass around the
building
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
Mullionless
Butt-Joint
System Seen
from the
Outside
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
•
•
Horizontal strip windows that need to
appear mullionless only from the outside
can use a mullion on the inside
Sill and head are conventionally glazed
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
Glass Mounted With Four-Side
Structural Silicone Glazing
• Structural silicone flush
glazing
–
–
–
The metal mullions lie
entirely inside the glass
with glass adhered to the
mullion by silicone
sealant
Outside skin is
completely flush
Systems with critical
silicone work done in
factory are also possible
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
Steps in assembly of a mullion for a four-side
structural silicone exterior flush glazing system
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
•
•
•
•
Structural Spacer Glazing is a proprietary
system
The glass is fastened to the mullion with an
aluminum pressure plate.
The face is then sealed
Desiccant is integrated into the system
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
Glass Suspended from Above With
Vertical Glass Stiffeners
• Suspended Glazing Systems and
Glass Mullion System
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Used primarily for high walls of
glass around building lobbies
Tempered glass sheets are
suspended from above and
stabilized by tempered glass
perpendicular stiffeners
Metal fittings are used to join
multiple sheets of glass
Stainless steel cables and fittings
are used in roof applications
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
•
•
Four point spider fitting
Adjustable vertical stainless steel rod carries
the load to the structure above
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
A suspended glazing
system with "saddle"
(anticlastic) curvature
keeps the entire wall
system in tension.
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Copyright © 2009 John Wiley & Sons. All rights reserved.
Glazing
Advanced Glazing
Systems
The spider fittings and cable
system must resist wind,
seismic, and dead loads
without inducing bending
forces in the glass or creating
stress concentrations around
the points of attachment
Fundamentals of Building Construction, Materials & Methods, 5th Edition
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Glazing
Advanced Glazing
Systems
The glass wall obtains additional
stiffness where the cable system is
tied to adjacent columns.
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Glazing
Advanced Glazing
Systems
•
•
•
•
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Insulating laminated glass
units serve as roof
Laminated glass fins
serve as beams
Vertical rods take the
load from the fins
Vertical rods transfer
load to cables which in
turn transfers it to steel
trusses
Glazing
Advanced Glazing
Systems
•
•
•
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Vertical rods take the
load from the fins
Vertical rods transfer
load to cables which in
turn transfers it to the
steel trusses
Upward arching cables
provide wind uplift
resistance
Glazing
Leaded Stained Glass
Fundamentals of Building Construction, Materials & Methods, 5th Edition
Copyright © 2009 John Wiley & Sons. All rights reserved.
17 Glass and Glazing
MasterFormat Sections For
Glass
CSI/CSC MASTERFORMAT SECTIONS
08 80 00
08 81 00
08 83 00
08 84 00
08 85 00
08 88 00
FOR
GLASS
GLAZING
Glass Glazing
Mirrors
Plastic Glazing
Glazing Accessories
Special Function Glazing
Hurricane-Resistant Glazing
Cable-Suspended Glazing
Pressure-Resistant Glazing
Radiation-Resistant Glazing
Security Glazing
Ballistics-Resistant Glazing
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