glass and glazing information


		INFORMATION

	Double glazed sealed units


	The purpose is to join two panes of Glass with an aluminium spacer in between. The spacer contains a Hygroscopic material which absorbs water vapour in the air, thus creating dry air in between. The Glass can either be Laminated, Toughened or ordinary, depending on the application.


	Spacer bar

		Seal


Dessicant

(Hygroscopic material)

The first function of insulating glazing is to reduce the thermal exchange between the two environments, which it separates, this brings many advantages:

* Reduction of installation cost for air-conditioning and/or heating.

* Lower energy consumption.

* Better comfort through reduction of disagreeable drafts near the windows.

* Perfect transparency by reducing the incidence of condensation {or even icing}on the hot air side.

* Possibility of using bigger glazed areas for a given room temperature without increasing the energy consumption.

Its K Value or U Value gives the insulating power of a wall, ie the quantity of energy, which passes through it under well defined conditions.

A normal single glazing of whatever thickness, has a U or K value in the order of 5.8 W/Sqm.K, whereas an insulating glazing composed of the same glass with an airspace of 12mm has a U or K value of around 2.8 W/Sqm.K, which means that in the last case the heat loss is less than half.

There are means to further improve the insulating power or to add other functions to the insulating units such as solar protection & safety consideration.

Acoustic insulation

Unwanted noise is another feature of modern life that correct window design can remedy. Noise from cars, railways and aircraft; noise from heavy industry, noise from power tools and high fidelity sound equipment - all have to be taken into account in designing and building.

Sometimes it may be enough just to specify a thicker glass - e.g. 12mm instead of the normal 4mm, 5mm, or 6mm. In serious cases, double-glazing with a wide airspace is the best solution


	Cristal Glass stock the following spacer bar colours & sizes:

	Silver, Bronze, Gold & White. 6mm, 8mm, 10mm, 12mm, 14mm, 16mm, 18mm & 20mm.

		Critical locations for safety glass


	Shaded areas must be fitted with safety glass. This is now a legal requirement !


		Door Panes

Doors and all glazing in windows where the glass is within 2ft 7in - or 800mm, of the floor or ground, where particularly toddlers and the elderly are most at risk.

Door panels under 1500mm from floor or ground level must be fitted with safety glass.

Panels within 300mm either side of a door and under 1500mm from floor or ground level must also be safety glass.

All installed safety glass should be clearly marked with the British Standard test referenceBS6206.

Safety Glass types :- Toughened, Laminated & Georgian Wired ( cast or polished )


	Door panes under 250mm must be 6mm glass. Door panes over 250mm Must be 4mm or 6mm safety ( toughened, laminated or wired ) glass.


	Pilkington "k" glass


		K glass which usually forms the inner pane of a double glazing unit, allows less heat to escape through your windows than ordinary glass - thanks to a special energy saving coating which lets the suns rays through, but reflects heat from fires and radiators back into your home. Heat which ordinary double glazing allows to escape. K glass also reduces internal condensation by making the surface of the glass warmer.

Typical sem-detatched house costs	Annual heating costs	Annual savings compared to single glazing
Single glazing	£194
Conventional double glazing	£152	£42
Double glazing with Low-E glass	£126	£68


	Laminated Glass


	Laminated glass is made up of two sheets of standard glass with a plastic membrane called polyvinyl butyrain (pvb) sandwiched between. When broken, the glass will stick firmly to the membrane and not allow shards or splinters to fly off.


	Cristal Glass stock the following thicknesses of Laminated glass: 4.4mm, 6.4mm, 6.8mm (obscure), 7.5mm, 8.8mm, 9.5mm, 10.8mm & 11.5mm.


	Toughened Glass

Toughened or tempered glass is four to five times harder to break than ordinary annealed glass. If toughened glass does break it does so safely by shattering into thousands of very small chunks with blunt edges (like a car windscreen). It is now a legal requirement to replace any glass in critical safety areaswith safety glass such as toughened or laminated. Toughened glass is available in thicknesses from 4mm to 19mm.

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INFORMATION