Satin-like, translucent glass manufactured by acid-etching one surface of the glass.

Beading is the part of the frame that holds the glass in place, it is usually in the form of a plastic strip at the edge of the glass which snaps securely into the recess. It can, however, be removed with careful prising, which is why beading on the inside of the frame (ie, "internally-beaded") is obviously much better for security. Safestyle's Diamond Windows come internally-beaded as standard.

Codes of Practice offering guidance and recommendations on what is considered current best practice. Applicable to the whole of the UK and in most cases adopted by the Republic of Ireland.

The British Standards Institution.

Building Control legislation laid down by Acts of Parliament.

The cavity formed by the spacer bar between the two panes of glass in double-glazed units, is generally filled with air. The air can be replaced with argon for example, for enhanced thermal insulation.

Approved Document L of the Building Regulations for England and Wales relates to the conservation of fuel and power.

Glazing comprising two panes of glass for acoustic or thermal insulation.

Two panes of glass, separated by a cavity and hermetically sealed in a factory, to provide thermal insulation.

Emissivity is a surface characteristic of a material. It is the relative ability of a surface to absorb and emit energy in the form of radiation. Low-emissivity (Low-E) coatings reduce the normally relatively high surface emissivity of the glass. The coatings are mainly transparent over the visible wavelengths but reflect long wave infra-red radiation towards the interior of the building.

Conventional double glazing provides thermal insulation. Double glazing comprising a low-emissivity glass provides enhanced thermal insulation.

The term used to describe the surfaces of the glass in numerical order from the exterior to the interior. The exterior surface is always referred to as face 1. For a double-glazed unit, the surface of the outer pane facing into the cavity is face 2, the surface of the inner pane facing into the cavity is face 3 and the internal surface of the inner pane is face 4.

The Fenestration Self-Assessment Scheme, set up by the Glass and Glazing Federation (GGF), at the request of the Office of the Deputy Prime Minister in response to the current Building Regulations for England and Wales. See Document L.

High quality, transparent flat glass manufactured by means of the float tank procedure that is floating molten glass on a "tin-bath" at extremely high temperature.

The proportion of the visible light spectrum that is transmitted through the glass.

See "emissivity"

See "Document L"

Translucent patterned glass, manufactured by rolling heat-softened glass between embossed cylinders.

Identified by BS 6262 part 4 and defined as glazed sections of a door, wall or other part of a building most likely to be subject to accidental human impact.

The percentage of total solar radiant heat energy transmitted through glazing (the sum of energy transmitted directly and energy absorbed and re-emitted to the interior).

Generally an aluminium bar along all edges of a double-glazed unit, filled with desiccant, which separates the two panes of glass and creates a cavity.

Double-glazed units provide thermal insulation. See also "enhanced thermal insulation" and "Document L".

Glass that has been subjected to a controlled heating and cooling process in order to significantly increase its resistance to mechanical and thermal stress. Through the thermal toughening process, the glass attains its safe-breakage characteristics.

This is a measure of the rate of heat loss of a building component. It is expressed as Watts per square metre, per degree Kelvin, W/m2K.