either cracking without producing large openings or separate large sharp edged pieces (i.e. in a manner similar to laminated glass), or cracking into many small fragments (i.e. in a manner similar to toughened glass). Safe breakage is precisely defined in BS 6206. Depending on the context, this may be either:
- the ability of glass to reduce the possibility of piercing and cutting injuries when subjected to accidental human impact, or
- the reduction of hazard from breakage of glass in overhead glazing, or
- fire protection.
an alternative term for safety film usually used in connection with mirrors.
a plastics film adhered to one surface of the glass with the intention of holding it together after fracture, so that the glass can be classified as a safety glass.
a glass or glazing product, which conforms to BS 6206, which classifies the product as giving no break or safe breakage when the glass is tested. The glass is classified as Class C, Class B, or Class A (or Class Co, Class Bo or Class Ao, if the test is from one side only of an asymmetric product) according to the drop height achieved in the test.
the classification achieved for a safety glass to BS 6206.
technique for bending glass. Glass is heated over a mould till it becomes soft and sags into the shape of the mould. It is then allowed to cool slowly for annealed glass or can be cooled rapidly to make toughened glass. See also curved glass.
a process whereby the polished surface of glass is etched by exposure to high-pressure air blown sand or grit. The process is done primarily for decorative effect.
stands for Standard Assessment Procedure. It is the Government approved method of determining the energy efficiency of a dwelling. It is measured on a scale of 0–100 with 100 being the most efficient. From 1st January 2001 it is a legal requirement that house builders display the SAP rating in all new dwellings.
Pilkington Optifloat™ Satin is the old brand name for a translucent decorative rolled glass that has been specially processed to give it the appearance of having been grinded. It has been replaced by Pilkington Optifloat™ Opal - translucent acid etched glass.
Screen printed glass:
glass which has been given a specific decorative surface finish of either ceramic ink (a type of enamel) which is subsequently fired onto the glass, or epoxy based ink. This product can be used for decorative effect or as a means of glare reduction or solar control.
a glazing compound, which sets after application into a rubbery consistency.
another name for insulating glass units.
see secondary sash glazing.
subsequent processing of glass after initial manufacture, e.g. manufacture into laminated glass, toughened glass, insulating glass units or decorative processing.
Secondary sash glazing:
a double window.
see dual seal system.
depending on the context this means either:
- the ability of glass to withstand manual attack or armed attack, or
- blast resistance, or
- electromagnetic shielding, or
- one-way vision.
a glass, which assists in giving security.
a glazing system including security glass, which assists in giving security.
The old brand name for Pilkington Glass System for Observation. This product consists of a polyurethane frame available in six standard colours containing two panes of Pilkington Toughened Safety Glass with applied stripes and one internal louvered glass. By moving one pane relative to the others, vision through the panel can be allowed or prevented.
a small bubble trapped within a piece of glass.
small packers, usually of hardwood, hard rubber or plastics, placed under the bottom edge of the glass to support it off the glazing platform and allow clearance for drainage and ventilation.
the total shading coefficient is a measure of the total amount of heat passing through the glazing (known as the total solar heat transmittance) compared with that through a single clear glass. Glass lets heat through in two ways; a proportion of the short wavelength radiation is transmitted straight through, while some is absorbed by the glass and re-radiated as long wavelength radiation.
The total shading coefficient is split into two parts relating to the proportions of the total solar heat transmittance, which are:
- the short wavelength - the short wave shading coefficient, and
- the long wavelength - the long wave shading coefficient.
old brand name for 9% light transmission tinted interlayer.
an old brand name for Pilkington Glass System for Shopfronts. This system involves bonding laminated glass into a special reinforced frame, to prevent the glass being removed from the frame.
an old brand name used by Pilkington Leeds to describe laminated glass manufacture in a range of thicknesses between 7.5 mm – 13.5 mm in sizes of 3210 x 2000 and larger.
Short wavelength energy:
an alternative term for short wavelength radiation.
Short wavelength radiation:
that part of electromagnetic radiation (i.e. from 280 to 2500 nm wavelength), which is radiated by the sun. The main components of glass are transparent to the majority of this short wave radiation.
Short wave shading coefficient:
see shading coefficients.
a chemical often used as a desiccant or molecular sieve.
a type of glazing compound made from silicone material which is gunned into position and cures into an elastic solid. The product is more resistant to UV light and so is used in roof glazing and structural glazing situations where the sealant could be degraded due to exposure to UV light.
see screen printed glass.
depositing silver on glass to form a mirror. The layer of silver is then protected by a copper backing, which is then protected by a lead based backing paint.
fitted with only one pane of glass, neither an insulating glass unit nor a double window.
usually used to describe an insulating glass unit that only has one seal. All Pilkington Insulight™ units are dual sealed.
an alternative name for inclined glazing.
Soda lime silicate glass:
ordinary window glass, including float glass, patterned glass and wired glass and any products made of these.
the effectiveness of glass is limiting solar heat gain. Solar control can be described in terms of the total shading coefficient of the glass, as being low (shading coefficient > 50%), medium (35% < shading coefficient < = 50%), or high (shading coefficient < = 35%).
Solar direct transmittance:
the proportion of incidence solar radiation, which passes straight through the glass, expressed as a fraction. (See solar properties).
an alternative term for solar radiation.
Solar gain factors:
numbers related to and derived from shading coefficients, which also describe the ability of the glazing to reduce solar heat gain.
Solar heat gain:
the amount of heat from the sun, which passes through the glass into a building.
These fall into two main types, Photovoltaic which convert sunlight to electricity and panels designed to use the sun's solar radiant heat properties to warm water.
these properties of glass related to solar radiation, i.e. reflectance, absorptance, solar direct transmittance, total solar heat transmittance, shading coefficients and solar gain factors. The term is also used occasionally to include emissivities and optical properties.
Solar radiant heat properties:
see solar properties.
the heat, light and UV light emitted by the sun as received at the surface of the earth.
the electromagnetic radiation emitted by the sun and its variation with the wavelength of the radiation. The solar spectrum effectively has a range of wavelengths from 280 to 2500 nm, with the largest proportion present as visible light.
see acoustic properties.
depending on context can be:
- an alternative term for spacer bar, or
- a glazing spacer.
the preformed section, usually aluminium or steel, which spaces apart the panes of an insulating glass unit in order to form the cavity. The spacer bar also usually acts as a container for the desiccant in the insulating unit. They are available in a variety of widths usually acts as a container for the desiccant in the insulating unit. They are available in a variety of widths usually 6, 12, 16 and 20 mm. They are also available in a variety of colours, silver, black, white, bronze and gold.
the pieces of glass ejected from one face of a pane of glass when it is impacted from the opposite face. This term is commonly used in connection with bullet resistance, where a requirement fro reduced spall may be part of the classification system.
a glass panel, commonly used in a curtain wall, which is made of an enamelled glass or an opacified glass in order to hide parts of a building structure, such as the edge of floor slabs. This product is known as Pilkington Spandrel Glass.
the proportion of different wavelengths of a spectrum.
the wavelengths contained within a particular type of electromagnetic radiation, such as the solar spectrum.
holes drilled or sand blasted into a cashier screen to allow cashier and public to hear each other.
an alternative term for spontaneous fracture.
the breakage of glass for no immediately obvious reason. The term is more often associated with fracture of toughened glass than any other type, because the mode of fracture of toughened glass tends to disguise the cause. See also nickel sulphide inclusion.
Spread of flame:
See reaction to fire.
solar radiant heat transmission another name for total solar heat transmittance.
Standard stock size, our range of smaller glass sizes. Usually refers to 2500 x 1605 and smaller.
depending on the context, this may mean:
- a traditional leaded light made with glass of different colours to form a picture or decorative pattern, or
- a pane of glass with coloured applied film and applied leading which looks like a traditional leaded light,
- a piece of glass of the type used in the leaded light.
under constant conditions. This is usually associated with environmental properties. Since the environment (temperature, wind and sun) is in a constant state of flux, this makes calculations of the glass performance very difficult. The solar properties and Ug value of the glass are therefore calculated with a steady state set of conditions.
an insulating glass unit with one pane larger than the other. The unit may be stepped on only one edge (often used on the bottom edge of roof glazing) or it may be stepped on more than one edge.
a packaging method for transporting and sorting glass. See also rack and pallet.
Pilkington Stippolyte™ is the brand name for one of the Pilkington Texture Glass range of patterned glass. Pilkington Stippolyte™ has an obscuration level of 5.
an alternative term for stock sizes.
the glass as manufactured and stored ready for cutting down to cut sizes.
a foreign body in the surface of a piece of glass.
the effect seen on toughened glass when it is viewed under polarized light or through a polarizing filter, which shows a patterning of spots or bars due to slight non-uniformity of the surface compressive stress in the glass.
glass used in a manner where it may be supporting other building components (e.g. glass mullions) or where it performs a semi-structural role (e.g. free standing glass protective barriers). The term may also be used for glass fixed using bolted connections (frameless glazing), even if it performs no structural function.
Pilkington Suncool™ is the global product name for a range of off-line coated, high performance solar control glass. The products combine both solar control and Low Emissivity into one product.
the surface of the glass exposed to the weather.
the room side surface of single glazing, or the cavity surface of the outer glass in an insulating glass unit.
the cavity surface of the inner glass in an insulating glass unit.
the room side surface of double-glazing.
Surface coated glass:
see coated glass.
Surface comprehensive stress:
see toughened glass.
the inverse of the heat transfer coefficients at a surface.
Surface spread of flame:
see reaction to fire.
an old brand name for Pilkington Mirropane™ our one way vision mirror.
short wave shading coefficient.
Pilkington Sycamore™ is the brand name for one of the Pilkington Texture Glass range of patterned glass. Pilkington Sycamore™ has an obscuration level of 3.