Polyvinyl chloride, the very versatile compound of which vinyl windows are built, is generally referred to as PVC or simply vinyl. Essentially, PVC is made of a combination of salt and petroleum. It is similar in nature to plastics, which are made from hydrocarbon-based raw materials such as petroleum, natural gas, and coal.
The process that manufactures PVC is essentially one that continually breaks down and combines salt and petroleum. First, petroleum is heated and filtered in a process called “cracking” which breaks it into its core component, ethylene. At the same time as that is occurring, salt and water are mixed, and in a process called electrolysis they form chlorine. The ethylene and chlorine are mixed and together, resulting in ethylene dichloride (EDC. They undergo the cracking process, and vinyl chloride monomer is produced. It is immediately fed into another tank to undergo a process known as polymerization. When it is produced, vinyl chloride monomer is a gas. Polymerization causes vinyl polymer to form from vinyl chloride monomer as a solid, powdery substance. This powder can then be easily transformed into vinyl resin.
Extrusion is the process by which vinyl resin is molded and shaped into vinyl window frames. First, vinyl resin is mixed with any number of substances to change some of its properties. This can be to make the vinyl more resistant to heat, cold or the sun’s rays. It could also make the vinyl structurally stronger or simply change the overall color. Next, the vinyl mixture is superheated until it is a viscous semi-liquid. It is then squeezed into molds which will shape the frames and sashes of the windows. The resulting shapes are placed into vacuum chambers which are carefully calibrated to cool the vinyl without warping or damaging the shape. The product at this step is a number of long pieces called lineals.
The lineals are cut into pieces of various lengths, depending on what part of the window frame they will become. Minor details are also cut at this point, such as making holes for hardware fixtures like locks to screw into. After cutting into pieces for the sill, header, sash and jambs of the window, the pieces are welded together. This is part of one of the many benefits of vinyl windows. Because the frame is one solid piece, cold air and water cannot penetrate the window as easily. The parts that were welded together with heat are trimmed to remove the excess vinyl that results (called the weldseam). Finally, parts of the window are glazed and operating hardware, such as handles are installed.
Impact on the Environment
While wood or even aluminum might seem like the most environmentally-friendly substances with which to construct replacement windows, it is the production of vinyl and its specific properties that make it ecologically safe. Vinyl is cited by LEED (Leadership in Energy and Environmental Design) as very energy efficient for use in buildings. This reduces overall energy consumption, which the attributes of vinyl contribute to. Vinyl also uses less energy to make, and requires less gas emissions in its production. Vinyl can also be recycled and re-used for many different things.
Certified Quality Construction
If you purchase vinyl replacement windows, you will want to be sure that they have been constructed with the highest level of quality. Certified windows will have a label on the window glass proving that they have been tested to withstand sun, wind, and other weather. Accreditation is garnered by achieving standards set by the American Architectural Manufacturer’s Association and the Window and Door Manufacturer’s Association. Make sure to check for the gold label on your windows that signifies they were manufacturer certified with vinyl extensions and tested for stability and color fastness in an independent laboratory.