Explain glass speaks to what is glass and why use glass.
The fact is that the major ingredient of glass is sand also known as silicon dioxide.
Sand is mixed with soda ash, which is is either sodium hydroxide or sodium carbonate, lime and mall amounts of alumina, potassium oxide and various elements to control colour and then heated to make glass. The finished material while seeming to be crystalline and for the most part solid, is actually a super cooled liquid, for it has no fixed melting point and has an open, noncrystalline microstructure.
When drawn into small fibers, glass is stronger than steel, though not nearly as stiff. In larger pieces, the microscopic imperfections that are an inherent characteristic of glass reduce its useful strength to significantly lower levels, particularly in tension.
When a surface of a sheet of glass is placed in sufficient tension, as happens when an object strikes the glass, cracks propagate from an imperfection near the point of maximum tension and the glass shatters.
Production of Glass
The major raw materials for glass, sand, limestone and sodium carbonate are finite but abundant materials.
Newer technologies are allowing for the manufacture of glass using much less energy, by as much as 30 to 65 percent.
Some glass production involves the generation of potentially unhealthy or pollution causing waste materials. Traditional mirror glass manufacturing, for example, generates an acidic waste effluent with high concentrations of copper or lead. However, recently mirror glass manufactured with environment friendly production techniques are now available.
Although glass bottles and containers are recycled into new containers at a high rate, there is still little recycling of flat glass at the present time. Most old glass goes to land fills.
Efforts are underway to find new uses for waste glass. Now it is possible that vitrified glass aggregate which is glass that has melted and rapidly quenched to trap heavy metals and other contaminants can be reused in asphalt, concrete, construction backfill, roofing shingles and ceramic tiles.
Use of Gas
If it is not broken glass lasts for a very long time with little degradation of quality, often much longer than other building materials.
Glass is inert and does not affect indoor air quality and it is easily kept clean and free of molds and material..
The impact of glass on energy consumption can be very detrimental, very beneficial or anything in between depending on how intelligently it is used.
If badly used, glass can contribute to summertime overheating from unwanted solar gain, excessive wintertime heat losses due to inherently low R values, visual glare, wintertime discomfort caused by radiant heat loss from the body to cold glass surfaces and condensation of moisture that can damage other building components.
Well used, glass can bring solar heat into a building in winter and exclude it in summer with attendant savings in heating and cooling energy. It can bring daylight into a building without glare, reducing both the use of electricity for lighting and the cooling load produced by that lighting.
These benefits accrue over the entire life of the building and payoffs can be huge. Thus’ glass is a key component of every energy efficient building and a chief accomplice of the ill informed designer in most energy wasted buildings.