A snapshot of how glass is made and why window cleaning can ensure your windows value.
Clean windows are not only pleasing to the eye, it is part of normal building maintenance that over time will save thousands of dollars and ensure your buildings value. Glass is a very porous material and not removing dirt and grime will obscure glass visibility and the dirt will permanently be etched into the glass.
Glass is made up of 5 ingredients:
The process begins in a batch house, where the above raw materials are put into silos. Each material, from the silo, is proportionally mixed, weighed and conveyed to the charging area and melting furnace of the plant.
A glass melting furnace is a large brick structure similar to an old fashion brick baking oven. In this oven, the materials are melted to form liquid glass. Sand, which is the major ingredient in glass, has a typical melting point of 3000 degrees Fahrenheit. However, when sand is mixed with the other ingredients its melting point declines.
The Melting Process: As the materials enter the furnace, pre-heated air is forced into chamber by large fans and is combined with jet streams of natural gas to produce torch flames which causes the materials to melt in a manner of just minutes.
Once all the materials have melted, the Fining Process begins. This process allows all the air bubbles, which formed during the melting process, to escape into the surrounding chamber atmosphere. Once Fining is complete, the melted glass is pushed into the Forming Chamber through a connecting canal.
The Forming Chamber is also referred to as the Bath. As the glass is cooling & forming, the glass rise to the top of the liquid bath of tin. The glass is then put through the stretching process which alters the glass thickness and width. The stretching process encompasses fine tooth wheels that pull the cooling glass through the chamber. There are also other heating elements on top of the bath that controls the glass thickness and width as it passes through the chamber.
The temperature of the glass after the Bath is around 1000 degrees Fahrenheit. Once the Bath process is complete, the glass goes through a series of cooling water baths by conveyor. The cooling process is done at a controlled rate to ensure that the proper stresses are put into the glass so the glass can cut & snap well. Once the cooling method is complete the glass comes out at around 350 degrees Fahrenheit. At this point the glass is moved through another cooling area and inspected. Then the glass passes under a machine that adds a special powder. This powder adds a separation medium between each sheet of glass; similar to adding flour to the cutting board when rolling a pie crust.
The glass is then moved to the cutting stage in which the glass is cut and snapped on a series on conveyers. Once the glass is cut to the right dimensions, the glass goes through a final stage called MSVD: Magnetic Sputter Vacuum Deposition. This is where proprietary high performance coatings, also known as low-e coatings, are applied to the glass. The glass is passed by conveyers through vacuum chambers where small microscopic pieces of metals are bonded to the glass surface. The metals added are primarily silver.
Glass in its final stage can be compared to a sponge and will soak up whatever is left on it over time. Weather it is dirt, tree sap, or rain water, over time these materials will become etched into the glass if not cleaned regularly. The dirt and grime can also damage the low-e coatings and negate the effectiveness of the glass. To ensure your windows lifespan and value, proper window cleaning and washing is the simple answer.