Glossary

 
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A

Abrasion
A method of shallow, decoration grinding using a diamond wheel. The decorated areas are then left unpolished.
Acid Etching
A process, manly used for glass decoration, where the glass surface is treated with hydrofluoric acid. Acid-etched glass has a distinctive, uniformly smooth and satin-like appearance.
Annealed Glass
During the float glass process, the hot glass is gently cooled in the \"annealing lehr\", which releases any internal stresses from the glass to enable the cutting and further processing of the glass post manufacture.
Antique glass
A general term describing a very old piece of glass, perhaps even several centuries old. Glass with an uneven surface texture and bubbles inside, produced using antique methods in order to obtain the appearance of glass made before the development of industrial processes.
Antique mirror
Is a decorative silvered glass mostly used for interiors. They may be available in a variety of colors and design.
Anti-reflective glass
Anti-reflective glass is float glass with a specially-designed coating which reflects a very low % of light. It offers maximum transparency and optical clarity, allowing optimum viewing through the glass at all times.
Armor Plate Glass
Laminated glass, resistant to mechanical shock, composed of at least four panes of glass and usually at least 25 mm thick.

B

Bevel
A decorative form of edge working.
Beveling
The production, by abrasion, of a sloping edge on the glass sheet. Commonly used on mirror glass.
Bulletproof Glass
Designed and produced to resist penetration by bullets. Armor plate glass which is more than 60 mm thick and which resists penetration by bullets.

C

Carving
The removal of glass from the surface of an object by means of hand-held tools.
Cavity
The cavity formed by the spacer bar between the two panes of glass in double-glazed units. It is generally filled with air.
Clear Glass
Mostly composed of soda, lime and silica to obtain a very clear type of glass.
Coating
A thin layer or covering which changes the basic composition of glass.
Cutting
A process in which glass is trimmed, also for decorative purposes.

D

Diamond Tool
Natural and synthetic diamonds are used on drills, saws, cutting wheels, abrasive discs and belts. The higher cutting rates achievable than with previous tools have stimulated the development of very precise, high-speed machinery. A constant flow of coolant is required to avoid the diamonds burning out and to wash away glass particles which build up on the working surface of the tool.
Diamond Wheels
Abrasive tools coated with diamond powder, used for a range of operations including grinding, milling, sawing, drilling, edging and polishing.

E

Edge-polished
A glass finishing process of polishing edges.
Edgework
A process consisting of polishing or abrading-scraping the edge of the glazing surface.
Emissivity
Is the relative ability of a surface to absorb and emit energy in the form of radiation.
Engraved or Engraving
The process of cutting a design, etc. on an annealed glass.
Etching
A process of acid etching one side of float glass to obtain a distinctive, uniformly smooth and satin-like appearance.

F

Fire-resistant glass
Special type of glass designed to contains flames and inflammable gas for a longer period. Contains flames and inflammable gas for a short period of time, but does not prevent the transmission of heat to the other side of the glazing(example: wired glass, reinforced laminated glass).
Flat Glass
All types of glass (rolled, float, plate, etc.) produced in a flat form, regardless of the method of production.
Float Glass
A term for perfectly flat, clear glass (basic product). The term \"float\" glass derives from the production method, introduced in the UK by Sir Alastair Pilkington in the late 1950\'s, by which 90% of today\'s flat glass is manufactured.
Fogging
A reaction caused by glass condensation.
Frame
The basic rigid supporting structure of a window, building, etc.
Frosting
The process of giving a glass surface a matt finish, thus reducing transparency. Frosting may be by means of acid treatment (pouring hydrofluoric acid onto the glass), sandblasting, special glue application and subsequent removal, or mechanical etching with a grinding wheel.

G

Glass Staining
Staining is caused by a chemical change or degradation of the glass surface.
Glass
A homogeneous material with a random, liquidlike (non-crystalline) molecular structure. The manufacturing process requires that the raw materials be heated to a temperature sufficient to produce a completely used melt, which, when cooled rapidly, becomes rigid without crystallizing.
Glazing
Glass used as a covering.
Glue Chipping
A texture created on the surface of cold glass by applying hot animal glue and allowing it to dry under controlled temperature and humidity conditions. As the glue dries and contracts, it chips the glass surface in a natural and attractive pattern, likened to frost on a window pane.
Grinding
The removal of glass with abrasives or abrasive (grinding) wheels in order to shape, polish or otherwise finish both flat and hollow glass. Grinding processes include milling, sawing, edging and drilling.

H

Heat resistant Glass
Glass which has a low coefficient of expansion and which is therefore less liable to thermal shock. Borosilicate glass is the most common type of heat resistant glass.

I

Infiltration
Amount of air leakage into a building.
Inner pane
The pane of a double-glazed unit which faces the interior of a building.
Insulating glass
Insulating glass is a multi-glass combination consisting of two or more panes enclosing a hermetically-sealed air space. Insulating glass is a multi-glass combination consisting of two or more panes enclosing a hermetically-sealed air space.
Insulating Strip
A material used to protect the edges of the glass from rigid contact with non-resilient material.
Insulating Glazing Unit (IGU)
American terminology for Insulating glass.
Interior Glazes
Glass used inside buildings.
Interlayer
The term applied to the material used in laminated glass to bond the glass leaves together.

L

Laminated (or compound) glass
consists of two or more sheets of glass with one or more viscous plastic layers \"sandwiched\" between the glass panes. The solid joining of the glasses takes place in a pressurized vessel called an autoclave (similar to an oven). In the autoclave, under simultaneous heating of the already processed layers of glass and special plastic, lamination occurs. When laminated safety glass breaks, the pieces remain attached to the internal plastic layer and the glass remains transparent.
Laminated glass
Laminated glass is a combination of two or more glass sheets with one or more interlayer\'s of plastic (PVB) or resin. In case of breakage, the interlayer holds the fragments together and continues to provide resistance to the passage of persons or objects.
Light-to-solar-gain ratio
The ability of glass to permit sunlight to pass without excessive solar heat gain.
Liquid crystal glazing
This is laminated glass, with a minimum of two clear or colored sheets of glass and a liquid crystal film, assembled between at least two plastic interlayer\'s. In the OFF state, the liquid crystals are not aligned, which prevents vision, yet allows light to pass through the glass. When is it switched ON, the liquid crystals align, turning the glass transparent and allowing vision through the glass.
Lite of glass
A single piece of glass, regardless of thickness.
Low Emissivity Glass
Commonly known as "low-E" glass and often used in double and triple glazing units, this window glass has a special thin-film metallic or oxide coating which allows the passage of short-wave solar energy into a building but prevents long-wave energy produced by heating systems and lighting from escaping outside. Low-E glass thus allows light to enter while also providing thermal insulation.
Low-emittance (low-E) coating-Microscopically
thin coating of metal oxide, which allows the sun\'s heat and light to pass trough the glass into the building. At the same time it blocks heat from leaving the room, reducing heat loss considerably.

M

Milk Glass
Milk colored glass.
Mirror
Mirrors are commonly made using glass with a smooth, polished surface that forms images through the reflection of rays and light.
Mirror Silvering
A chemical process used in the manufacture of mirrors, whereby a coating of metal, mostly silver, is deposit on the surface of clear or body-tinted glass.
Mullion
A vertical framing section between glass panes.

O

Obscure Glass
Any type of glass with uneven surfaces which offers light diffusion and privacy.
Opacified
Glass which has been fully enameled or painted on one side to make it non-transparent.
Outer pane
The pane of double-glazed unit which faces the exterior of a building.

P

Pane
A lite/sheet of glass.
Patterned glass
Patterned glass presents uneven surfaces with different impressed patterns.
Peg
A metal tool to hold glass in a frame.
Plate Glass
Used in the past to produce higher quality glass, this technology was completely outperformed by the float glass process.
Plate Glass
Flat glass made by the casting or rolling of molten glass which is then mechanically ground and polished to produce a smooth and transparent sheet.
Polishing
Smoothing the surface of an object when it is cold by holding it against a rotating wheel fed with a fine abrasive. Glass can also be polished with hand-held tools.
Primary seal
A butyl-based sealant applied to the edges of the space bar during assembly into double-glazed units, to ensure a watertight and airtight seal around the perimeter of the unit.
PVB
The plastic interlayer incorporated into laminated glass in order to ensure good adhesion and the mechanical and safety breakage characteristic of the glass.

R

Re-silvering
a processes for restoring mirrors which involves stripping the back paint from the mirror, then removing the deteriorated silver with an acid. The glass is now polished and rinsed. It is now ready for silvering.
Resin laminate
Two or more sheets of glass assembled with one or more resin interlayer\'s.
Resin Stained glass
Process of applying resin to the outer layer of glass to create a coloured image on the glass.

S

Safety Glass
Glass which must have passed an impact test and either must not break or must break safely.
Safety Glass
Glass which does not disintegrate into sharp and potentially dangerous splinters when it is broken. Safety glass may be produced by laminating (see \"laminated glass\") or by tempering (see \"tempering\").
Sand-blasted glass
This type of glass is produced by spraying sand at high velocities over the surface of the glass.
Sandblasting
A method for giving glass surfaces a matt finish either for decoration or to reduce transparency. Compressed air forces the abrasive material through the nozzle of a sandblasting gun and onto the glass surface. The glass is normally placed inside a special cabinet with arm holes, a viewing window and dust extraction facilities. A special glass treatment in which sand is sprayed at high velocities over the surface of the glass.
Screen printed glass
Screen printed glass is tempered or heat-strengthened glass, one face of which is covered, either partially or totally, with mineral pigments.
Sealant
A flexible material for sealing.
Sealed Double Glazed Unit
A combination consisting of two glass panes enclosing a hermetically-sealed air space.
Sealer
A substance applied to glass and frame surfaces that guarantees consistent adhesion.
Secondary seal
A sealant applied to the edges of double-glazed units after the primary seal, to provide effective and durable adhesion between the glass components and spacer bar.
Self cleaning glass
This type of glass is covered by a special coating which literally cleans itself.
Sheet Glass
A lite of glass.
Sight size
The actual size of the opening that admits daylight.
Silicone
A polymeric organic compound offering excellent resistance to cold, heat and water.
Silicone
used principally as adhesives and setting materials, particularly where plasticity or water-repellent characteristics are required.
Silvering
is the chemical process of coating glass with a reflective substance to create a mirror. When this substance is applied to the glass a chemical reaction takes places, bonding the silver to the glass. The mirror is dried and coated with a special back paint.
Single glazing
Window or door with a single glass lite.
Single-strength glass
A term used to describe glass with a defined thickness (2.16-2.57 mm).
Snow load
An imposed load exerted onto a structure by formation of snow.
Space bar
Generally an aluminum bar along all edges of a double-glazed unit, filled with desiccant, which separates the two panes of glass and creates a cavity.
Spacer
A metal bar or strip, generally of aluminum, which is bent into a frame to separate the two panes of glass in an insulating glass (I.G.) unit.
Spall
Small fragments of glass that are ejected from the surface of a laminated glass sheet when the opposite surface is impacted.
Sputtering
Is a method better known as \"vacuuming\" to apply coating on the glass.
Structural sealant glazing
An external glazing system where the glass is bonded to a carrier frame without mechanical means.
Surface Coatings
A thin layer or covering which changes the basic composition of glass.

T

Tempered glass
Tempered (toughened) glass is two or more times stronger than annealed glass. When broken, it shatters into many small fragments, thus preventing major injuries.
Tempering
Special process of solidification of a glass sheet in order to make it particularly resistant to breakages. The result is a sheet of glass which is two or three times stronger than un-tempered glass and which, upon breakage, shatters into tiny pieces with blunt edges (the most common applications are for automotive glass).
Thermal break
A type of metal frame that incorporates an insolating material of low thermal conductivity located between the inner and outer parts of the frame in order to reduce the rate of heat loss.
Thermal expansion
Change of material size as a result of temperature change.
Thermal mass
A special mass in a structure which is used to absorb solar heat during the day and then release the heat in the evening.
Thermal shock
When glass is exposed to high temperatures, it absorbs heat and expands. At the same time, its edges remain cooler, causing thermal stress.
Thermally insulting glazing
Double-glazed units provide thermal insulation.
Tight size
The actual size of an opening into which glass is to be glazed and is measured from the rebate platform.
Tinted interlayer
A colored plastic or resin sheet between two or more panes of glass.
Toughened Glass
(tempered glass) Toughened glass is two or more times stronger than annealed glass. When broken, it shatters into many small fragments which prevent major injuries.
Translucent
Allowing light to pass through diffusely.
Transmittance
Ratio of light or heat that can pass through the glazing surface.
Transom
A horizontal framing bar between glass panes.
Transparent
Clear, permitting vision.
Triple glazing
Three panes of glass enclosing two hermetically-sealed air spaces.

U

UDL
Stands for uniformly distributed load.
U-factor (U-value)
This is a measure of the rate of heat loss of a building component. It is expressed as watts per square meter, per degree Kelvin, W/m2K.
ULTRA-violet (UV absorbing glass}
Ultra-violet radiation is absorbed by normal glass. Where ultra-violet transmission is required, quartz glass is used
UV transmittance
Determines the percentage of solar energy in the form of ultra-violet radiation transmitted by glazing.
U-value - A measure of the rate of heat loss of a building component.

V

Visible light
spectrum part of the electromagnetic spectrum, that produces light, to which the human eye is sensitive.
Visible transmittance (VT)
The percentage or fraction of light that is transmitted through the glazing surface.
V-Grooving
Process of engraving a groove into the surface of the glass.

W

Warm edge spacers
Insulating spacers used to seal Insulating glass. Since they do not contain aluminum, they are less conductive, thereby improving the U-value of the window, and reducing condensation.
Waterjet cutting technology
This system consists of high pressure (60.000 psi) water, mixed with abrasives, that passes through a gauge orifice at three times the speed of sound. Such pressure produces a pure working power able to cut any shape of glass or other materials.
Weathering
The action of water on exposed materials - glass.
Weather-strip
A piece of material used on windows or doors to reduce leaks and prevent rain and wind from entering the structure.
Weather tight
Hermetically-sealed to prevent entry of water and air into the structure.
Wheel Engraving
A process by which the glass surface is decorated using grinding wheels.
Wind load
The pressure acting on an external surface of a building caused by the direct action of the wind.
Wind Pressure
The amount of pressure produced by wind velocity on the glazing surface.
Wired glass
A product in which a wire mesh has been inserted during production. It has an impact resistance similar to that of normal glass, but in case of breakage, the mesh retains the pieces of glass.
Wired Glass
Flat rolled glass reinforced with wire mesh and used especially for glass doors and roofing to prevent objects from smashing through the glass and also to hold pieces of broken glass together. By holding the glass together, it can also protect against break-in and the spreading of fire. Wired glass is produced by continuously feeding wire mesh from a roller into the molten glass ribbon just before it undergoes cooling. (See also "Boudin process", "Pilkington double-pass wired glass process").