Material Group Research: Glass

Research Credited to: 

• Rachel Cross 
• Xavier Ellah 
• Madison Duxfield
 
• Brad Mancer 
• Natalie Harris 
• Steph O'Shea

Material: Glass

List the main manufacturing brands of this material in the New Zealand construction sector:

• Kelly Glass and Mirror:
• http://kellyglassandmirror.co.nz
• Viridian ( New Zealand) Limited
• http://www.chrissmithglass.co.nz/pilkingt ons.asp
• NZ GLASS
• http://www.nzglass.co.nz/services
• Pacific Glass
• http://pacificglass.co.nz/glass- exportsimports/

List the main uses/forms of this material in building construction:
Windows & Doors
Bench tops & Splash Backs Pool fencing/ Balustrades Showers
Office Partitions
Celling
Green Houses & Conservatories Insulation
Communications

Of what and/or how is it made in it's general use/form?
Glass is made from sand, pure silica which has a melting point of 2000 C and soda (sodium carbonate) or potash which is used to lower the melting point to about 1000C. Lime (calcium oxide) is added to restore insolubility.

Where does it come from?
Silica Sand appropriate for making new glass is mined in New Zealand at: 

• Pakiri Beach (North Auckland)
• Te Arai Point (North Auckland)
• Mangawhai (Northland)

“Silica sand of Quaternary age is found in dune, beach and shallow offshore marine sand deposits along the present day coastline. The principal localities are all in Northland, at Parengarenga Harbour on the east coast and around Kaipara Harbour on the west coast. These deposits have been derived from intense chemical weathering of sedimentary rocks.”

Limestones in Canterbury, and marble from west Nelson are used by the major producer Omya (NZ) Limited for manufacture of industrial grade lime, by thermal decomposition of the Limestone in a lime kiln, where it is heated to above 825 °C.

Potash is imported.

What is it ‘good’ for?
Lets light in which heats interior spaces
Allows natural light – connects inside with outside – indoor-outdoor flow
Division of spaces
Allowing transparency, openness
Modulates sunlight – takes out harmful UV rays
Double glazing is a useful insulator
Meditative quality – ‘nature’
Can be angled or tilted in variety of ways for desired effect – eg. skylight vs. vertical window panes
When used in windows and doors – important ventilators
Good for establishing various levels of public and private (eg. reflective glass vs. completely transparent glass, tints, opacities...)
Liberates space, makes it feel bigger, stops from feeling claustrophobic
It can be recycled
Technological advances with tinted windows, you can screen print onto glass

What is it ‘bad’ for?
Earthquakes
Cleaned on a regular bases, but can be semi low maintenance
Not very strong
Requires a framing structure to hold it all together, add steel etc
It can cause excessive heat gain from sunlight & rapid cooling if not double glazed. - it uses quite a lot of energy in production

Diagram the ‘normal’ lifecycle of 3 uses of this material.

• Glass is first manufactured by melting sand, soda ash, dolomite and limestone together at temperature of 1700 degrees Celsius. It is then cooled into a form that can be cut.
• It is then distributed and formed into various products of use: plate glass in windows; food packing; computer equipment; automotive glass; in solar panels etc.
• Flat glass from windows is regularly sent to landfill as there are few places that recycle glass windows and they are not well known.
• Glass that has been laminated (automotive glass) or had high-tech films (eg. Colour filters for high-rise buildings) are more difficult to recycle because of the mix of material.
• Broken and ground-up glass is inert (ie okay) in the landfill, but some resins and plastics applied to the surface of the glass are not okay.
• Broken & recycled glass can be embedded in a resin to create an aesthetic surface.
• Other forms of glass include ‘fiber glass’ [when used in conjunction with expoxy-resins – to become a very strong but lightweight material eg. Used to form the hulls of boats and compound curve canopies (for cars)] and ‘glass wool’ [Pink Bat insulation].

What could be used as an alternative in these 3 instances?
In most instances plastics are an alternative to glass

• In food packaging glass is considered dangerous because of breakage and heavy to transport, so plastic is often preferred. Plastic is not as ‘safe’ for health reasons, as it leaches many toxic compounds into the food/water.
• Acrylic (trade name ‘Perspex’) is sometimes used instead of glass for windows however is is easily scratched and becomes increasingly brittle over time. (ie it breaks)
• In traditional houses in Japan, oiled or waxed paper is used in windows. This permits light to enter but does not permit views through.
• The glass in ‘fiber glass’ is now often replaced with ‘carbon fiber’ for an even stronger structure.
• The glass in ‘glass wool’ can be replaced with animal wool, polyester wool, or shredded paper/timber fibers.

Discuss recent innovations to improve the environmental rating of this material?
Recent innovations, such as high-tech cameras for detecting faults in products and virtual sampling facilities that allow the machines to check themselves for faults, have contributed to making the process as efficient as possible and minimising unnecessary rejections of finished products.

Techniques for integrating ‘smart films’ for opacity switching and photovoltaic electricity generation are making glass a ‘value added’ building material.

Though fiber-optic glass is not new, there are increasing options for its use in a range of building systems eg. ‘transparent concrete’