Glassary - G

G0:
see bullet resistance.

G1:
see bullet resistance.

G1/S:
obsolete British Standard Specification for bullet resistance.

G2:
see bullet resistance.

G3:
obsolete British Standard Specification for bullet resistance.

Galleria™:
Pilkington Galleria™ is our brand name for a rolled glass, which is designed for picture framing. The rolled surface diffuses the reflections from the surface of the glass and so enhances the visibility of the picture.

Gaskets:
solid, preformed glazing materials used to separate glass from other parts of the fixing or frame.

Georgian Bar:
a grid of bars fixed inside an insulating glass unit in order to make it appear from a distance as though the insulating glass unit is composed of smaller panes. Bar are usually white though Gold and other colours are available.

Georgian Wired:
the old generic name for the Pilkington Pyroshield™ range, see also Pyroshield™.

Georgian Wired Cast:
the old generic name for Pilkington Pyroshield™ Textured.

Georgian Wired Polished:
the old Generic for Pilkington Pyroshield™ Clear.

Glare:
excessive illumination or excessive contrast between lit and unlit areas, which causes difficulty with vision.

Glare reduction:
the ability to reduce glare problems, either by reducing the overall illumination or by diffusing direct light or a combination of both.

Glass:
Glass is a liquid that has cooled to a rigid state without crystallising. It is sometimes described as a supercooled liquid, which it is not. A supercooled liquid is still a liquid at a temperature below that at which is would normally solidify. Glass is actually a solid with an amorphous random or non-crystalline structure. The use of the term supercooled liquid suggests the idea of flow, but in fact glass is too rigid to flow at normal temperatures however long a force is applied to it. Glass consists of a network of silicon-oxygen-silicon bonds. These are randomly modified by the presence of calcium and sodium. This arrangement is completely random as it would be a liquid, it is not orderly or regular like the molecules in a crystal of sugar or ice. Because of this random network glass is non-ductile (it cannot be beaten or worked like say copper) and it is this that sets it apart from most other materials. The raw materials we use to make glass are Sand (SiO2) 72.6%. The sand we use at St. Helens is dug from the Cheshire countryside near Sandbach. Soda Ash (Na2CO3) 13%, Limestone (CaCO3) 8.4%, Dolomite (MgCa(CO3)2) 4%, Salt Cake (Na2CO3) 1%. We like to mix as much clean cullet as we can with these raw materials because we use 50% less energy to melt cullet than we do raw materials.

Glass fin:
another name for a glass mullion.

Glass mullion:
a mullion support for glass panes made entirely from glass or from glass beams splice jointed with metal connectors. Usually fixed at a 900 angle as a brace and support. Also know as a fin.

Glazing:
depending on the context it is either:

• The complete element of construction comprising the glass, the glazing materials and the fixing or frame or
• The glass or glass product itself, or
• The act of installing the glass or glass product.

Glazing attenuation:
see attenuation.

Glazing bead:
the common mechanism used to retain glass in a frame.

Glazing compound:
a glazing material, which is soft and pliable, such as putty or silicone sealant and can be used as a gap filler.

Glazing factors:
another term for radiometric properties, i.e. solar properties and optical properties.

Glazing fin:
another name for a glass mullion.

Glazing materials:
the gaskets, glazing tapes, glazing compounds, bushes, sealants and other items required for the purpose of glazing a glass product.

Glazing platform:
the horizontal leg of the rebate in a frame, upon which the glass sits (on setting blocks) when it is glazed.

Glazing seal:
another term for glazing compound or sealant.

Glazing spacer:
a small separator placed between the glass and frame. See also location blocks and setting blocks.

Glazing system:
the frame and the design or method of fixing the glass into the frame.

Gothic:
Competitor textured glass pattern, Pilkington Warwick™ should be offered as a substitute.

Greenhouse effect:
the retaining of solar heat by glass, for two reasons. Firstly, the presence of the glass prevents the wind removing the heat rapidly. Secondly, the glass lets through the short wavelength radiation direct from the sun, but is opaque to the long wavelength radiation emitted by the warmed items inside the greenhouse, so the heat takes a lot longer to escape than it does to enter the greenhouse, resulting in the greenhouse getting warm inside. (See also effective U value).

Guarding:
the prevention of persons falling, by means of barriers and balustrades. Any glass glazed into or forming such a barrier or balustrade is required to give containment. See also Technical Bulletins Glass and Glass and Building Regulations — Stairs, Ramps and Barriers.

G.W.C.:
stands for Georgian Wired Cast, the old name for Pilkington Pyroshield™ Textured and Pilkington Pyroshield™ Safety Textured.

G.W.P.P.:
stands for Georgian Wired Polished Plate, the old name for Pyroshield™ Clear and Pyroshield™ Safety Clear.