Acoustics - The science of
sound and sound control. Adhesion - The
property of a coating or sealant to bond
to the surface to which it is applied.Adhesive
Failure - Loss of bond of a coating or sealant
from the surface to which it was applied.Air
Infiltration - The amount of air leaking
in and out of a building through cracks
in walls, windows and doors.
Air Side - In reference to float glass,
the side that was up or exposed to the "air"
when it was manufactured. The bottom side
is referred to as the "tin" side
because it floated on a liquid tin bath.
Coatings are applied to the air side.
Air Spacer - An aluminum or stainless steel
frame (desiccant filled) used to separate
two lites of glass in an insulating unit.
Annealed - Raw glass with low, residual
stresses. This enables cutting and fabrication.
Annealing - In the manufacturing of float
glass, it is the process of controlled cooling
done in a lehr to prevent residual stresses
in the glass. Re-annealing is the process
of removing objectionable stresses in glass
by re-heating to a suitable temperature
followed by controlled cooling.Annealing
Lehr - An in-line, controlled heating/cooling
apparatus located after the tin bath and
before the cooling conveyor of a float glass
production line. Its purpose is to relieve
induced stress from the flat glass product
to allow normal cold end processing.Anti-Walk
Blocks - Elastomeric blocks that limits
lateral glass movement in the glazing channel,
which may result from thermal, seismic,
wind load effects, building movement, and
other forces that may apply. Argon Gas -
An invisible, non toxic gas used in insulating
units to enhance the units insulating performance
(u-value). Aspect Ratio - The quotient of
the long side of a glazing lite over the
short side of that lite.
Autoclave - A vessel that employs high pressure
and heat. In the glass industry, used to
produce a bond between glass and PVB or
urethane sheets, thus creating a laminated
glass product Backer Rod - A polyethylene
or polyurethane foam material installed
under compression and used to control sealant
joint depth, provide a surface for sealant
tooling, serve as a bond breaker to prevent
three-sided adhesion, and provide an hour-glass
contour of the finished bead.Bead - An applied
sealant in a joint irrespective of the method
of application, such as caulking bead, glazing
bead, etc. Also a molding or stop used to
hold glass or panels in position.Bent Glass
- Flat glass that has been shaped while
hot into curved shapes.Bevel of Compound
Bead - In glazing, a bead of compound applied
to provide a slanted top surface so that
water will drain away from the glass or
panel.Beveling - The process of edge finishing
flat glass to a bevel angle.Bite - The dimension
by which the framing system overlaps the
edge of the glazing infill.
Blast Resistant Glass - A laminated glazing
construction commonly specified to mitigate
injuries from flying glass resulting from
an air-blast explosive. Breather Tube Units
- An insulating glass unit with a tube and/or
hole factory-placed into the unit’s
spacer to accommodate pressure differences
encountered in shipping due to change in
elevation. The tube and/or hole are to be
properly sealed on the jobsite prior to
unit installation. Consult IG unit fabricator.Bubbles
- In laminated glass, a gas pocket in the
interlayer material or between the glass
and the interlayer. In float glass, a gaseous
inclusion greater than 1/32" (.8 mm)
in diameter.Bubbling - Open or closed pockets
in a sealant caused by release, production,
or expansion of gasses.Bulb Edge - In float
glass manufacture, the extreme lateral edge
of the ribbon as drawn. Bullet Resistant
Glass - A multiple lamination of glass or
glass and plastic that is designed to resist
penetration from medium-to-super-power small
arms and high-power rifles. Buttering -
Application of sealant or compound to the
flat surface of some member before placing
the member in position, such as the buttering
of a removable stop before fastening the
stop in place. Butt Glazed - The installation
of glass products where the vertical glass
edges are without structural supporting
mullions.
Butyl - Shortened term for polyisobutylene.
The primary seal of an insulating unit and
key component in restricting moisture vapor
transmission. Capillary Tube - A small tube
factory-placed into the air spacer of an
insulating unit used for balancing interior
and exterior pressures during transportation
over higher elevations, i.e. mountain ranges
or air transport. Caulk - (v) The application
of a sealant to a joint, crack or crevice.
(n) A compound used for sealing that has
minimum joint movement capability; sometimes
called low performance sealant.
Ceramic Frit - A ceramic frit enamel applied
to glass for decorative/aesthetic appearances.
Applied with a large roller for full coverage
applications or through a screen for silkscreening
applications. Channel Glazing - The installation
of glass products into U-shaped glazing
channels. The channels may have fixed stops;
however, at least one glazing stop on one
edge must be removable.Channel Width - The
distance between opposing glazing stops.Checks
- Very small cracks in flat glass, usually
at the edge. Chemically Strengthened Glass
- Glass that has been strengthened by ion-exchange
to produce a compressive stress layer at
the treated surface.Chipped Edge - An imperfection
due to breakage of a small fragment from
the cut edge of the glass. Generally this
is not serious except in heat absorbing
glass.Clips - Wire spring devices used to
hold glass in rabbeted sash, without stops,
and face glazed. Coated Glass - A general
reference to any glass incorporting a reflective
or low-e coating.Cohesive Failure - Internal
splitting of a compound resulting from over-stressing
of the compound.Consistency - Degree of
softness or firmness of a compound as supplied
in the container and varying according to
method of application, such as gun, knife,
tool, etc.Compound - A chemical formulation
of ingredients used to produce a caulking,
elastomeric joint sealant, etc. Condensation
- The appearance of moisture (water vapor)
on the surface of an object caused by warm
moist air coming into contact with a colder
object.
Conventionally Glazed - A framing system
that captures the glazing component in the
glazing channel. Crush - A lightly pitted
area on glass resulting in a dull gray appearance.Cullet
- Broken glass, excess glass from a previous
melt or edges trimmed off when cutting glass
to size. Cullet is an essential ingredient
in the raw batch in glass-making because
it facilitates melting.Cut Sizes - Glass
cut to specified width and length.Deflection
(framing member) The amount of bending movement
of any part of a structural member perpendicular
to the axis of the member under an applied
load.Deflection (center of glass) - The
amount of bending movement of the center
of a glass lite perpendicular to the plane
of the glass surface under an applied load.Delamination
- An unbonded area in laminated glass between
glass and PVB. Design Pressure - Specified
pressure a product is designed to withstand.Diffusing
- Scattering, dispersing, as the tendency
to eliminate a direct beam of light.Digs
- Deep, short scratches. Desiccant - Small,
extremely porous beads used to absorb moisture
in the sealed air spacer of an insulating
unit.
Distortion - General areas of optical deviation
or image deformation as seen looking at
the glass. Double Glazing - In general,
any use of two lites of glass, separated
by an air space, within an opening, to improve
insulation against heat transfer and/or
sound transmission. In insulating glass
units the air between the glass sheets is
thoroughly dried and the space is sealed,
eliminating possible condensation and providing
superior insulating properties.Dry Glazing
- Also called compression glazing, a term
used to describe various means of sealing
monolithic and insulating glass in the supporting
framing system with synthetic rubber and
other elastomeric gasket materials.Dry Seal
- Accomplishment of weather seal between
glass and sash by use of strips or gaskets
of Neoprene, EPDM, silicone or other flexible
material. A dry seal may not be completely
watertight. Double Laminated Insulating
Glass - An insulating glass unit in which
both the interior and exterior components
are a laminated glass.
Double Strength - Refers to clear 1/8"
(3mm) thick float glass.
Dual Seal - Refers to an insulating unit
with a primary seal of polyisobutylene (butyl)
and a secondary seal of silicone. Durometer
- The measurement of hardness of a material.
A gauge to measure the hardness of an elastomeric
material.Edge Clearance - Nominal spacing
between the edge of the glass product and
the bottom of the glazing pocket (channel).Edging
- Grinding the edge of flat glass to a desired
shape or finish.Elastomer - An elastic,
rubber-like substance, such as natural or
synthetic rubber.Elastomeric - (adj) Having
the property of returning to its original
shape and position after removal of load.
(n) An elastic rubber like substance. Emissivity
- The measure of a surface's ability to
emit long-wave infrared radiation.
Etch - To alter the surface of glass with
hydrofluoric acid or other caustic agents.
Permanent etching of glass may occur from
alkali and other runoff from surrounding
building materials.
European U-Value (formerly K-Value) - Based
on ISO-DP10292 draft standard conditions.
It is based on an outdoor temperature of
5.5°C, and indoor temperature of 20.5°C
and a 4.8 m/s outdoor air velocity Exterior
Glazed - Glazing infills set from the exterior
of the building.Exterior Stop - The molding
or bead that holds the lite or panel in
place when it is on the exterior side of
the lite or panel.Facade (face) - The whole
exterior side of a building that can be
seen at one view; strictly speaking, the
principal front. Commonly used as reference
to the exterior skin of a building.Face
Glazing - A system having a triangular bead
of compound applied with a putty knife,
after bedding, setting and clipping the
glazing infill in place on a rabbetted sash.Fenestration
- Any glazed panel, window, door, curtain
wall or skylight unit on the exterior of
a building.Fillet Bead - Caulking or sealant
placed in such a manner that it forms an
angle between the materials being caulked.Fire
Polish - To make glass smooth or glossy
by the action of fire or intense heat.Fire
Protection Rating - The period of time that
an opening protective assembly will maintain
the ability to confine a fire as determined
by tests – NFPA 252/ NFPA 257/UL 9/UL
10c/ASTM E 2010/ASTM E 2074.Fire Resistance
- That property of materials or their assemblies
that prevents or retards the passage of
excessive heat, hot gases or flames under
conditions of use.Fire Resistance Rating
- The period of time a building element,
component or assembly maintains the ability
to confine a fire, continues to perform
a given structural function, or both, as
determined by tests – NFPA 251/ASTM
E 119/UL 263 (wall assemblies).Flare - A
protrusion on the edge of a lite of glass.Flat
Glass - A general term that describes float
glass, sheet glass, plate glass and rolled
glass. Float Glass - Raw glass, float refers
to the process in which the glass was made.
Flush Glazing (Pocket Glazing) - The setting
of a lite of glass or panel into a four-sided
sash or frame opening containing a recessed
"U" shaped channel without removable
stop on three sides of the sash or frame
and one channel with a removable stop along
the fourth side.Frosted Finish - A surface
treatment for glass, consisting of an acid
etching of one or both surfaces that diffuses
transmitted light and reduces glare. Fully
Tempered Glass (FT) - Glass that has been
heat-treated to have either a minimum surface
compression of 10,000 psi or an edge compression
not less than 9,700 psi in accordance with
the requirements of ASTM C 1048, kind FT
or meet the requirements of ANSI Z97.1 or
CPSC 16 CFR 1201 safety glazing standards.
Tempered glass is 4-5 times stronger than
annealed glass, and when broken, breaks
into small, relatively harmless, pieces.
Flush Glazing (Pocket Glazing) - The setting
of a lite of glass or panel into a four-sided
sash or frame opening containing a recessed
"U" shaped channel without removable
stop on three sides of the sash or frame
and one channel with a removable stop along
the fourth side.Frosted Finish - A surface
treatment for glass, consisting of an acid
etching of one or both surfaces that diffuses
transmitted light and reduces glare.Gas-Filled
Units - Insulating glass units with a gas
other than air in the air space to decrease
the unit’s thermal conductivity (U-value)
or to increase the unit’s sound insulating
value.Gaskets - Pre-formed shapes, such
as strips, grommets, etc., of rubber or
rubber-like composition, used to fill and
seal a joint or opening either alone or
in conjunction with a supplemental application
of a sealant.Girth - In bent glass, the
distance around the concave or convex surface
measured perpendicular to the height, including
any flats.Glass - A hard brittle substance,
usually transparent, made by fusing silicates,
under high temperatures, with soda, lime,
etc. Glass Clad Polycarbonate (GCP) - One
or more lites of flat glass bonded with
an aliphatic urethane interlayer to one
or more sheets of extruded polycarbonate
in a pressure/temperatuer/vacuum laminating
process. Glass Fines - Minute glass particles
typically resulting from glass fabrication
processes (i.e. cutting, grinding, polishing,
drilling, edging, etc.)Glass Quality (Flat)
- Defined by ASTM C 1036 on the basis of
end use and allowable blemishes. Glazing
- (n) A generic term used to describe an
infill material such as glass. (v) The process
of installing an infill material into a
prepared opening in windows, door panels,
partitions, etc. Glazing Bead - A strip
surrounding the edge of the glass in a window
or door, which holds the glass in place.Glazing
Channel - A three-sided, U-shaped sash detail
into which a glass product is installed
and retained. Ground Edge - A special fabrication
done to the edge of a piece of glass. Makes
the edge smooth and gives it a whitish/gray
appearance. Gun Consistency - Sealant formulated
in a degree of viscosity suitable for application
through the nozzle of a caulking gun.Heat-Absorbing
Glass - Glass that absorbs an appreciable
amount of solar energy.Heat Resisting Glass
- Glass able to withstand high thermal shock,
generally because of a low coefficient of
expansion.Heat Soak - A process of heating
glass to a specific temperature for a specified
time in a special oven in an attempt to
find any impurities in the glass known as
"nickel sulfide inclusions".
Heat Strengthened Glass (HS) - Flat or bent
glass that has been heat-treated to have
a surface compression between 3,500 and
7,500 psi (24 to 52 MPa) and meet the requirements
of ASTM C 1048, kind HS. Heat-strengthened
glass is not a safety glazing material and
will not meet the requirements of ANSI Z97.1
or CPSC 16 CFR 1201.
Heat Transfer Methods - Heat transfers from
one place to another via convection, conduction
or radiation. Convection occurs from the
upward movement of warm, light air currents.
Conduction occurs when energy passes from
one object to another. Radiation occurs
when heat is sent through space and is capable
of traveling to a distant object where it
can be reflected, absorbed or transmitted.
Heat Treated - Term used for both fully
tempered glass and heat-strengthened glass.
Heel Bead - Sealant applied at the base
of a channel, after setting the lite or
panel and before the removable stop is installed;
one of its purposes being to prevent leakage
past the stop.High-Transmission Glass -
Glass, which transmits an exceptionally
high percentage of visible light.
Hurricane / cyclic wind-resistant glass
- Laminated glazing tested to one or more
test protocols for high velocity hurricane
winds and windborne debris. Infrared (IR)
- IR is part of the solar spectrum, or sunlight,
that is invisible to the human eye. It has
a wavelength range of ~790-3000 nanometers
and has a penetrating heat effect. Short-wave
IR converts to heat when it is absorbed
by an object.
Insulating Glass (IG) - Two glass components
separated by an air spacer and hermetically
sealed. Inherently, insulating glass increases
a window's thermal performance. Insulating
Laminated Glass - An insulating glass unit
inwhich the exterior component is a monolithic
glass ply and the interior component is
a laminated glass . Interior Glazed - Glazing
infills set from the interior of the building.Interior
Stop - The removable molding or bead that
holds the lite in place when it is on the
interior side of the lite. Interlayer -
Refers to the plastic or vinyl in a laminated
unit. Examples are PVB, SentryGlas Plus,
Saflex HP, Vanceva Storm, etc.
Iridescence - Also called strain pattern
or Q-lines. It is a pattern in heat treated
glass not normally visible except under
certain lighting conditions. It is especially
visible with the use of a polarized lens.
Iridescence is an inherent characteristic
of heat treated glass. Jambs - The vertical
frame members at the perimeter of the opening.Joint
- The space or opening between two or more
adjoining surfaces.Kink - An abrupt deviation
from a flat plane or the normal contours
of bow and warp, and most commonly found
near the edge of a piece of heat-treated
glass.Knocked Down (KD) - Fabricated framing
components shipped loose for assembly at
another location.Laminated Glass -Two or
more pieces of glass bonded together by
a piece of plastic/vinyl called polyvinyl
butyral (PVB.) A minimum interlayer thickness
of .030 (.76mm) meets the requirements of
ANSI Z97.1 or CPSC 16 CFR 1201 safetly glazing
standards.
Laminated Insulating Glass - An insulating
glass unit in which the exterior component
is a laminated glass and the interior component
is a monolithic glass ply.Laminated Plastics
(Plastic Laminates) - Two or more lites
(or sheets) of polycarbonate (or acrylic)
with an aliphatic urethane interlayer between
polycarbonate or acrylic bonded together
under heat and pressure.
Light to Solar Gain Ratio (LSG) - The ratio
is equal to the Visible Light Transmittance
divided by the Solar Heat Gain Coefficient.
The Department of Energy's Federal Technology
Alert publication of the Federal Energy
Management Program (FEMP) views and LSG
of 1.25 or greater to be Green Glazing/Spectrally
Selective Glazing.Lehr - A long, tunnel-shaped
oven for annealing glass, usually by a continuous
process. Lite -Another term for a pane of
glass. Sometimes spelled "light"
in industry literature.Live Load - Loads
produced by the use and occupancy of the
building or other structure and do not include
construction or environmental loads such
as wind load, snow load, ice load, rain
load, seismic load or dead load.
Low-E -An abbreviation for Low Emissivity
coatings. They are applied to glass to reflect
invisible long-wave infrared or heat. They
reduce heat gain or loss in a building by
redirecting the heat. In addition, they
typically provide greater light transmission,
low reflection and reduce heat transfer.
Lucor -A powder used to separate lites of
glass to prevent damage from scratching
or rubbing. Luminous Efficacy (Light-to-Solar
Gain Ratio) - The visible transmittance
of a glazing system divided by the solar
heat gain coefficient (or shading coefficient).
This ratio is helpful in selecting glazing
products for different climates in terms
of those that transmit more heat than light
and those that transmit more light than
heat.Mastic - Descriptive of heavy-consistency
compounds that may remain adhesive and pliable
with age.Mock-Up - A full size sample or
model of a unit normally used to judge appearance
and performance. Modulus - Stress at a given
strain. Also tensile strength at a given
elongation.
Monolithic - Refers to a single lite of
glass as a finished product.
Mullion - A vertical framing member separating
fixed lites of glass, operating sash, or
door openings. Multiple-Glazed Units - Insulating
glass units with three or more lites of
glass.Muntins - Horizontal or vertical bars
that divide the sash frame into smaller
lites of glass. Muntins are smaller in dimensions
and weight than mullions. Negative Air -
Refers to an insulating unit wherein the
two lites of glass are closer together in
the center of the unit than they are at
the edge. This gives the unit the appearance
of being "bowed in".
Nickel Sulfide - an inclusion in float glass
that can cause spontaneous breakage in fully
tempered glass. Offset - Either a laminated
or insulating unit wherein the two edges
don't match up.
OITC Rating - An abbreviatoin for Outside-Inside
Transmission Class Rating. This rating is
used to classify the performance of glazing
in exterior applications. It is based on
ASTM E-1332 Standard Classification for
the Determination of Outdoor-Indoor Transmission
Class. While STC rating is based on a "White'
noise spectrum, this standard utilizes a
source noise spectrum that combines Aircraft/Rail/Truck
traffic and is weighted more to lower frequencies.
Opacifier Film - An adhesive film applied
to glass for spandrel applications.Organic
- Any compound which consists of carbon
and hydrogen with a restricted number of
other elements, such as oxygen, nitrogen,
sulphur, phosphorous, chlorine, etc.
Patterned Glass - One type of rolled glass
having a pattern impressed on one or both
sides. Used extensively for light control,
bath enclosures and decorative glazing.
Sometimes called "rolled," "figured"
or "obscure" glass.Permanent Set
- The amount by which a material fails to
return to its original dimensions after
being deformed by an applied force or load.Pocket
(Channel) - A three-sided, U-shaped opening
in a sash or frame to receive glazing infill.
Contrasted to a rabbet, which is a two-sided,
L-shaped section, as with face glazed window
sash.Pocket (Channel) Depth - The inside
dimension from the bottom of the pocket
to the top. Pocket depth equals the bite
plus the edge clearance.Pocket (Channel)
Width - The measurement between stationary
stops (or stationary stop and removable
stop) in a U-shaped channel.Points - Thin,
flat, triangular or diamond shaped pieces
of zinc used to hold glass in wood sash
by driving them into the wood.Polariscope
- A device for examining the degree of strain
in a sample of glass. Polished Edge - A
special fabrication done to the edge of
a piece of glass. Makes the edge smooth
and gives it an extremely shiny or polished
appearance. Polished Wired Glass - Wired
glass that has been ground and polished
on both surfaces.
Polycarbonate - Extruded plastic sheet that
can be glazed singly or as a component of
a laminated glazing product.
Polyisobutylene (PIB) - The primary seal
of an insulating unit and the key component
in restricting moisture vapor transmission.
Polymer - A chemical structure consisting
of long chains of molecular units.Polysulfide
Sealant - Polysulfide liquid polymer sealant,
which are mercaptan terminated, long chain
aliphatic polymers containing disulfide
linkages. They can be converted to rubbers
at room temperature without shrinkage upon
addition of a curing agent.
Polyurethane - Also commonly called urethane.
Used by some insulating fabricators for
a secondary sealant. It is also an interlayer
used in polycarbonate security products.
Polyurethane Sealant - An organic compound
formed by the reaction of a glycol with
an isocyanate.
Polyvinyl Butyral (PVB) - The plastic or
vinyl used in the makeup of a laminated
unit, the vinyl is what holds that unit
together. Polyvinyl Chloride (PVC) - Polymer
formed by polymerization of vinyl chloride
monomer. Sometimes called vinyl.Pot Life
- The time interval following the addition
of an accelerator before a chemically curing
material will become too viscous to apply
satisfactorily. Positive Air - The opposite
of negative air. In an insulating unit,
where the center of the unit is farther
apart than around the air spacer, these
units have a bowed out appearance. Pre-Shimmed
Tape Sealant - A sealant having a pre-formed
shape containing solids or discrete particles
that limit its deformation under compression.Primer
- A coating specifically designed to enhance
the adhesion of sealant systems to certain
surfaces, to form a barrier to prevent migration
of components, or to seal a porous substrate.Priming
- Sealing of a porous surface so that compound
will not stain, lose elasticity, shrink
excessively, etc., because of loss of oil
or vehicle into the surround. A sealant
primer or surface conditioner may be used
to promote adhesion of a curing type sealant
to certain surfaces. Pyrolytic Deposition
- A process of applying a thin metallic
coating to the surface of flat glass during
the float glass manufacturing process. R-Value
- Thermal resistance is expressed in ft^2/hr/°F/BTU.
It is the reciprocal of U-value. The higher
the R-value, the less heat is transmitted
through the glazing material. Rabbet - An
"L" shaped section, which can
be face glazed or receive a removable glazing
bead to hold the lite of glass in place.Racking
- A movement or distortion of sash or frames
causing a change in angularity of corners.
RAT Equation - The RAT equation accounts
for 100 percent of solar energy, which is
equal to the sum of solar reflectance, absorption
and transmittance. For example, with a single
pane of 1/8" (3mm) clear glass, 83
percent of solar energy is transmitted,
8 percent is reflected and 9 percent is
absorbed by the glass. Of the solar energy
absorbed, portions are emitted back towards
the exterior and towards the building interior.
Reflective Glass - Glass with a metallic
coating to reduce solar heat gain.
Relative Heat Gain - The amount of heat
gain through a glass product taking into
consideration the effects of solar heat
gain (shading coefficient) and conductive
heat gain (U-value). The value is expressed
in Btu/hr/ft2 (W/m2). The relative heat
gain is calculated as RHG = (Summer U-value
x 14oF) + (Shading Coefficient x 200). The
lower the relative heat gain, the more the
glass product restricts heat gain.Removable
Double Glazing (RDG) - A removable glazed
panel or sash on the inside or outside of
an existing sash or window, such as a storm
panel, used for additional insulation and
protection against the elements.Roll (or
Roller) Distortion - Waviness imparted to
horizontal heat-treated glass while the
glass is transported through the furnace
on a roller conveyor. The waves produce
a distortion when the glass is viewed in
reflection.Roll Impressions - Indentations
in the surface of rolled glass that are
caused by contact of the glass with the
rolls and/or displaced roll disks while
the glass surface is in a plastic state.Roll
Marks (also Roll Scratches) - A series of
the fine parallel scratches or tears on
the surface of rolled glass in the direction
of draw. They are 1/8" (3 mm) long
or smaller, but usually so fine and so close
together that they appear to be a series
of incipient checks rather than scratches.
They are caused by a difference in velocity
between rolls and the sheet of glass.Rolled
Glass - Glass formed by rolling, including
patterned and wired glass.
Roller Wave - The appearance of waviness
sometimes seen in heat treated glass caused
by the glass moving over rollers in the
tempering furnace. Rough Opening - The opening
in a wall into which a door or window is
to be installed.Rub - A series of small
scratches in glass generally caused during
transport by a chip lodged between two lites.R-Value
- The thermal resistance of a glazing system
expressed ft2/hr/oF/Btu (m2/W/oC). The R-value
is the reciprocal of the U-value. The higher
the R-value, the less heat is transmitted
throughout the glazing material.
Sandblasted Finish - A surface treatment
for flat glass obtained by spraying the
glass with hard particles to roughen the
surface. The method restricts vision while
maintaining a level of light transmission.
Sash - The window frame, including muntin
bars if used, to receive the glazing infill.Score
- To penetrate the surface of a lite of
glass by means of a cutting device, e.g.
a glass cutter, along a predetermined line
in order to produce a lite of glass of a
specific size and/or shape.Scratches - Any
marking or tearing of the surface appearing
as though it had been done by either a sharp
or rough instrument.Screw-On Bead (or Applied
Stop) - Stop, molding or bead fastened by
screws as compared with those that snap
into position without additional fastening.Sealant
- An elastomeric material with adhesive
qualities, applied between components of
a similar or dissimilar nature to provide
an effective barrier against the passage
of the elements.Seam (verb) - To grind,
usually with an abrasive belt, wet or dry,
the sharp edges of a piece of glass.Seeds
- Minute bubbles in float glass less than
1/32" (.8 mm) in diameter. SentryGlas®
Plus (SGP) - A laminate that incorporates
an ionoplast interlayer which is bonded
directly between two layers of glass. The
product was originally marketed for hurricane
protection but is also used for blast mitigating
applications. Setting - Placement of lites
or panels in sash or frames. Also action
of a compound as it becomes more firm after
application.
Setting Blocks - Small pieces of neoprene
or other material which are placed under
the lower edge of a lite of glass to support
it within a frame.
Shading Coefficient - Shading coefficient
is the ratio of solar heat gain through
a specific type of glass that is relative
to the solar heat gain through a 1/8"
(3mm) ply of clear glass under identical
conditions. As the shading coefficient number
decreases, heat gain is reduced, which means
a better performing product. Shadowgraph
- A device for inspecting glass with respect
to distortion and other defects.Shelf Life
- Used in the glazing and sealant business
to refer to the length of time a product
may be stored before beginning to lose its
effectiveness. Manufacturers usually state
the shelf life and the necessary storage
conditions on the package.Shore "A"
Hardness - Measure of firmness of a compound
by means of a Durometer Hardness Gauge (Shore
A hardness range of 20-25 is about the firmness
of an art gum eraser. A hardness of 90 is
about the firmness of a rubber heel).Sight
Line - The line along perimeter of glazing
infills corresponding to the top edge of
stationary and removable stops. The line
to which sealants contacting the glazing
infill are sometimes finished off.Silicone
Sealant - A sealant having as its chemical
composition a backbone consisting of alternating
silicon-oxygen atoms. Silkscreen - A process
of applying a specific design or pattern
to glass. The design is made by placing
a screen over a piece of glass and then
pressing ceramic frit, by means of a large
squeegee, through the pores of the screen.
After the frit is applied, the glass goes
through an infra-red oven to dry the frit
and then through a tempering furnace to
fire (bond) the frit to the glass permanently.
Skylight - A window glazed in a roof or
ceiling of a building.
Sloped Glazing - Glass units that are glazed
more than 15° off vertical.
Solar Control Glass - Tinted and/or coated
glass that reduces the amount of solar heat
gain transmitted through a glazing product.
Smoke - Streaked areas appearing as slight
discoloration on glass.Solar Control Glass
- Tinted and/or coated glass that reduces
the amount of solar heat gain transmitted
through a glazed product.
Solar Energy - The sum total of the solar
spectrum. Solar Energy Reflectance - In
the solar spectrum, the percentage of solar
energy that is reflected from the glass
surface(s).
Solar Energy Transmittance - The percentage
of ultraviolet, visible and near infrared
energy within the solar spectrum (300 to
2100 nanometers) that is transmitted through
the glass. Solar Heat Gain Coefficient (SHGC)
- The portion of directly transmitted and
absorbed solar energy that enters into the
building's interior. The higher the SHGC,
the higher the heat gain.
Solar Reflectance - The percentage of solar
energy that is reflected from the glass
surface(s)
Solar Reflective Coatings - Coatings that
reduce heat gain through higher solar reflection.
Solar Spectrum - The solar spectrum, commonly
referred to as sunlight, consists of ultraviolet
light, (UV), visible light and infrared
(IR). The energy distribution within the
solar spectrum is approximately 2 percent
UV, 47 percent visible light and 51 percent
IR. One aspect of the solar spectrum is
its wavelength in which nanometer (nm) is
the unit of length [1 nm+10^-9 m].
Solar Transmittance - The percentage of
ultraviolet, visible and near infrared energy
(300 - 3000 nanometers) that is transmitted
through the glass.Solarization - Change
in transmission, and sometimes color, of
plastics as a result of exposure to sunlight
or other radiation.
Spacers (Shims) - Small blocks of neoprene,
EPDM, silicone or other suitable material,
placed on each side of the glass product
to provide glass centering, maintain uniform
width of sealant bead and prevent excessive
sealant distortion. Spandrel - The panel(s)
of a wall located between vision areas of
windows, which conceal structural columns
floors and shear walls. Glass panels incorporate
either a ceramic frit, opacifier film, or
are installed into a shadow box application.
Spectrally Selective Glass - Tinted and/or
coated flat glass that reduces the amount
of solar heat gain transmitted through a
glazed product. STC (Sound Transmission
Class) - A single number rating derived
from individual transmission losses at specified
test frequencies (for more information see
ASTM E 90 and ASTM E 413). It is used for
interior walls, ceilings and floors and
in the past was also used for preliminary
comparison of the performance of various
glazing materials.STL (Sound Transmission
Loss) - The reduction of the amount of sound
energy passing through a wall, floor, roof,
etc. It is related to the specific frequency
(Hz) at which it is measured and it is expressed
in decibels (dB). Also called "Transmission
Loss (TL)." STC Rating - Abbreviation
for Sound Transmission Class Rating. When
glass is used on the building interior,
the sound transmission classification (STC)
value can be used to categorize the glass
performance. The STC rating is a single-number
rating system for interior building partitions
and viewing windows. The STC rating is derived
by testing in accordance with ASTM E90,
'Laboratory Measurement of Airborne sound
Transmission of Building Partitions".
The STC value is achieved by applying the
Transmission loss (TL) values to the STC
reference contour of ASTM E413, "Determination
of Sound Transmission Class". The STC
rating is a basis for glass selection. Its
original intent was to quantify interiro
building partitions, not exterior wall components.
As a result, it is not recommended for glass
selection of exterior wall applications,
since the single-number rating was achieved
under a specific set of laboratory conditions.
Stones - Any crystalline inclusion imbedded
in the glass.Stop - Either the stationary
lip or the removable molding of the rabbet,
serving to hold the glazing infill in the
sash or frame, with the help of spacers.Storm
Door - A panel or sash door placed on the
outside of an existing door to provide additional
protection from the elements.Storm Window
- A glazed panel or sash placed on the inside
or outside of an existing sash or window
as additional protection against the elements.Stain
- Discoloration of either a glass or finished
aluminum surface caused by alkalis that
leach from surrounding materials such as
pre-cast or cast-in-place concrete or from
sealants, pollutants or other contaminants.
Strain - The percentage of elongation or
compression of a material or portion of
a material caused by an applied force.Strain
Pattern - A specific geometric pattern of
iridescence or darkish shadows that may
appear under certain lighting conditions,
particularly in the presence of polarized
light (also called quench marks). The phenomenon
is caused by the localized stresses imparted
by the rapid air cooling of the tempering
operation. Strain pattern is characteristic
of heat-treated glass.Stress (Residual)
- Any condition of tension or compression
existing within the glass, particularly
due to incomplete annealing, temperature
gradient, or inhomogeneity.Striking Off
- The operation of smoothing off excess
compound or sealant at sight line when applying
same around lites or panels.Structural Glazing
Gaskets - Cured elastomeric channel-shaped
extrusions used in place of a conventional
sash to install glass products onto structurally
supporting sub-frames, with the pressure
of sealing exerted by the insertion of separate
lockstrip wedging splines.Structural Silicone
Glazing - The use of a silicone sealant
for the structural trnsfer of loads from
the glass to its perimeter support system
and retention of the glass in the opening.
Substrate - The raw glass or base material
to which other materials or fabrication
procedures are applied.
Tape Sealant - A sealant having a pre-formed
shape, and intended to be used in a joint
under compression.Thermal Endurance - The
relative ability of glass to withstand thermal
shock.Tin Side - The bottom side of float
glass as it was manufactured. Called "tin
side" because float glass rides on
a bath of liquid tin while it is being cooled.
Tinted Glass - Glass with colorants added
to the basic glass batch that give the glass
color, as well as, light and heat-reducing
capabilities. The color extends throughout
the thickness of the glass. Typical colors
include bronze, gray, dark gray, aquamarine,
green, deep green, blue and black.Toe Bead
- Sealant applied at the intersection of
the outboard glazing stop and the bottom
of the glazing channel; must be sized to
also provide a seal to the edge of the glass.Tong
Marks - Small, surface indentations near
and parallel to one edge of vertically-tempered
or vertically heat-strengthened glass resulting
from the tongs used to suspend the glass
during the heat treating process.Tooling
- The operation of pressing in and striking
a sealant in a joint, to press the sealant
against the sides of a joint and secure
good adhesion; the finishing off of the
surface of a sealant in a joint so that
it is flush with the surface.Toughened Glass
- International terminology for fully tempered
glass. (See Fully Tempered Glass)Transmittance
- The ability of the glass to pass light
and/or heat, usually expressed in percentages
(visible transmittance, thermal transmittance,
etc.).Two-Part (Multi-Component) Sealant
- A product comprised of a base and curing
agent or accelerator, necessarily packaged
in two separate containers, which are uniformly
mixed just prior to use.U-Value - A measure
of heat gain or heat loss through glass
due to the differences between indoor and
outdoor temperatures. These are center pane
values based on NFRC standard winter nighttime
and summer daytime conditions. U-values
are given in BTU/hr/ft^2/°F for the
English system. Metric U-values are given
in W/m^2/°C. NFRC winter nighttime U-values
are based on an outdoor temperature of 0°F
(-17.8°C), an indoor temperature of
70°F (21°C) and a 12.3 mph (19.8
km/h) outdoor air velocity. NFRC summer
daytime U-values are based on an outdoor
temperature of 89°F (32°C), an indoor
temperature of 75°F (24°C), a 6.2
mph (10.1 km/h) outdoor air velocity and
a solar intensity of 248 BTU/hr/ft^2/°F
(782 W/m^2).
Ultraviolet Light (UV) - The name of the
invisible portion of the light spectrum
with wavelengths shorter than 390 nanometers.
The damaging effects on long-term UV exposure
results in fabric fading and plastic deterioration.
Unit - Term normally used to refer to one
single assembly of insulating glass.United
Inches - Total of one width and one height
of a lite of glass in inches.Vacuum (Sputtering)
Deposition - Process for applying multiple
layers of metallic coatings to the surface
of flast glass in a vacuum chamber.
Vinyl Glazing - Holding glass in place with
extruded vinyl channel or roll-in type.Visible
Light Reflectance - The percentage of visible
light (390 to 770 nanometers) within the
solar spectrum that is reflected from the
glass surface. Visible Light Transmittance
- The percentage of visible light (380 -
780 nanometers) that is transmitted through
the glass. (Visible light is the only portion
of the solar spectrum visible to the human
eye.) Wave - An optical effect in flat glass
due to irregularities in the surface of
the glass that make objects viewed at various
angles appear wavy or bent.Weathering (also
Stain) - Attack of a glass surface by atmospheric
elements.Weather-stripping - A material
or device used to seal the opening between
sash and/or sash and frame.Weeps (or Weep
Holes) - Drain holes or slots in the sash
or framing member to prevent accumulation
of condensation and water.Wet Seal - Application
of an elastomeric sealant between the glass
and sash to form a weather-tight seal.Window
- An opening constructed in a wall or roof
and functioning to admit light or air to
an enclosure, usually framed and spanned
with glass mounted to permit opening and
closing. Wired Glass - Rolled glass having
a layer of meshed or stranded wire completely
imbedded as nearly as possible to the center
of thickness of the lite. This glass is
available as polished glass (one or both
surfaces) and patterned glass. Approved
polished wired glass is used as transparent
or translucent fire protection rated glazing.
Patterned wired glass is sometimes used
as decorative glass. It breaks more easily
than unwired glass of the same thickness,
but the wire restrains the fragments from
falling out of the frame when broken.Work
Life - The time during which a curing sealant
(usually two compounds) remains suitable
for use after being mixed with a catalyst.Zebra
Board - A board with alternating black and
white diagonal lines used to observe optical
transmission and reflection qualities in
coated and uncoated glass. |
