Glass jargon: a glossary of glass industry terms

Do you know your desiccants from your DGUs?

The world of glass can be confusing if you don't know the lingo. That's why we've put together this glass jargon glossary to help you out.

Acid etching

An etching technique that uses hydrofluoric acid to create detailed pictures or wording on glass.

Acoustic glass

Glass designed with acoustic interlayers that help prevent sound ingress or egress.

Airspace

The space (cavity) between two panes of glass. It's generally not filled with air – more commonly, an inert gas like argon is used for improved thermal insulation.

Annealing

A process to help glass cool evenly and become more stable. Under natural conditions, glass can cool unevenly, which could cause it to crack, shatter, or explode at some point – especially if you will be cutting it or working with it. 

Annealed glass

The most common type of affordable glass for doors and windows. See annealing above.

Annealing lehr

A special cooling oven used in the annealing process to keep the glass at the annealing point for a specific length of time. This allows stress in the glass to dissipate, leaving it ready to be worked on.

Anti-reflective glass

Glass with a surface coating that minimises light reflection.

Arrising

Glass edge working performed with abrasive belts to remove sharp or imperfect edges from cut panes of glass.

Autoclave

A vessel used to heat polyvinyl butyral (PVB) laminated glass and subject it to high pressure to bond the layers.

Balustrade

A waist-height barrier, sometimes made of glass, to prevent people from falling from a height. Balustrades are often found on balconies and stairs.

Base glass

Glass before it has a process applied to it (for instance, sandblasting or digital printing).

Body-tinted glass

Transparent float glass with a consistent colour throughout to protect from things like light and solar radiation.

Bow window

A type of bay window that creates a curved alcove within the inner room, often installed to add character or to allow for panoramic views.

Bullet-resistant glass

Also known (misleadingly) as bullet-proof glass, this type of glass is made up of layers of glass laminate, making it very strong. It's known for its resistance to bullets and other projectiles.

Blast-resistant glass

A type of flexible glass designed to withstand explosions by absorbing the force of blasts.

Cavity

See airspace.

Coloured glass interlayers

A glass product made by sandwiching a coloured interlayer between glass panes. You can also experiment with different light transmission designs and opacity.

Containment

How well glass can withstand specified loads in guarding situations to stop people from falling through it.

Cut sizes

Cut panes of glass that are ready to be glazed.

Desiccant

A drying agent placed in the cavity-spaced bar of insulated windows to remove any moisture or organic vapours inside.

Distortion

An altered image or reflection caused by glass that isn't flat or homogeneous.

Double glazing unit (DGU)

A name for two panes of glass with an insulation cavity.

Double window

A window with two panes of glass – glazed separately – that share the same vision area. Some people also call this "secondary sash glazing".

Edge-deletion

The process of removing a coating from the surface of glass, often to reseal it with a better coating.

Edging (edgework)

Treatments applied to glass edges to strengthen them and make them look as good as possible. The three most popular types of edging are ground, polished, and arrised.

External condensation

Condensation that forms on the outside of windows.

Face

The name given to glass surfaces when put in numerical order from the exterior to the interior. For example, the outside pane of glass in a window is always face one. Then, if a window is double-glazed, face two would be the surface of the outer pane that's facing into the window cavity. And so on, until you get to the innermost pane.

Fabric laminated glass

Also known as fabric interlayer glass, fabric laminated glass is made by sandwiching fabrics between layers of glass laminate. It's designed to showcase the colour, texture and beauty of fabrics.

Fire-rated glass

Glass that has been through a specialised procedure to make it more able to withstand fire, smoke and heat, helping people exit safely in the case of a fire.

Frame

Material surrounding a window or door that helps hold it in place.

Glare

A shine from the sun or electric light that is particularly strong or dazzling and makes it hard to see.

Glass fines

Tiny particles of glass that form from drilling, cutting, grinding and edging techniques.

Glazing

This has two meanings:

1. The frame, glass and glazing materials as one complete object.
2. The process of installing the glass product.

Hard coating

A name for durable glass coatings that help defend against abrasion damage.

Heat-strengthened glass

Glass that has been treated with heating and cooling, making it up to twice as strong. Heat-strengthened glass is weaker than toughened glass but breaks in a more controlled fashion and is less prone to roller wave distortion.

Horizontal line load 

A load that is distributed horizontally and uniformly at a certain height above floor level.

Inclusion

A visual imperfection or localised impurity in glass.

Inner glass/pane/leaf

The innermost pane of glazing facing the interior of the building.

Interlayer

The name for the material used to bond glass panes together for laminated glass. Glass processors tend to use polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), cast-in-place resin, intumescent or ionoplast interlayers.

Internal glass applications

Glass or glazing installations that will not be exposed to natural weather, like wind or rain.

Laminated glass

A type of glass that consists of two or more glass layers bonded together with an interlayer material (see interlayer above).

Leaf

Another name for a piece of glass – usually used when the glass has been cut and is ready to be glazed.

Low emissivity or Low-E glass

An energy-efficient type of glass designed to stop heat from escaping out of a structure through the windows.

Mesh laminated glass

A form of decorative glass made by sandwiching a wire mesh interlayer between glass sheets. Mesh laminated glass is distinct from wired glass: a form of fire-resistant glass that incorporates a metal mesh directly within the glass panels. 

Mirror glass

Glass that has been treated with a metallic substance to make it reflective.

Polished edge

A glass edge that has been ground, smoothed and then polished until it shines.

Quench

The part of the tempering process when glass is cooled very quickly – usually with high-pressure cold air being blasted at it.

Sandblasting

A process that gives a polished glass surface a matt finish. It is performed by blasting a fine grit (like sand) at the glass and can be used to add a frosted effect or create stencilled designs.

Switch glass

Glass that can change its opacity on demand. You may also hear it referred to as "smart glass".

Toughened glass

Also known as tempered glass, toughened glass is a safety glass made by treating annealed glass with thermal or chemical treatments to make it stronger and more resilient. 

Translucent glass

Glass that blocks some amount of light, making it difficult to see through in detail.

Triple glazing

Three panes of glass making up an insulated glass unit.

Uniformly distributed load (UDL)

Pressure spread out uniformly over a pane of glass.

Visible Light Reflectance Outdoors/Indoor (Rv out/in%)

The percentage of incident visible light reflected directly by the glass.

Visible Light Transmittance (Tv%)

The percentage of incident light transmitted by glass that falls into the wavelength range of 380 to 780nm.

Walk-on glass

Glass that has been treated to be strong enough for people to walk over.

Warm edge

The result of replacing conventional aluminium cavity spacer bars with low heat-conductive thermally insulating cavity spacers to reduce the thermal bridging effect around double-glazed windows.

Zebra board

A board with white and black diagonal stripes used to compare the flatness of processed glass.

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