What is PVC (uPVC)

Polyvinyl chloride (/ˌpɒlivaɪnəl ˈklɔːraɪd/;[5] colloquialpolyvinylvinyl[6]; abbreviated: PVC) is the world’s third-most widely produced synthetic plastic polymer, after polyethylene and polypropylene.[7] About 40 million tonnes are produced per year.

PVC comes in two basic forms: rigid (sometimes abbreviated as RPVC) and flexible. The rigid form of PVC is used in construction for pipe and in profile applications such as doors and windows. It is also used in making bottles, non-food packaging, and cards (such as bank or membership cards). It can be made softer and more flexible by the addition of plasticizers, the most widely used being phthalates. In this form, it is also used in plumbing, electrical cable insulation, imitation leather, flooring, signage, phonograph records,[8] inflatable products, and many applications where it replaces rubber.[9] With cotton or linen, it is used to make canvas.

Pure polyvinyl chloride is a white, brittle solid. It is insoluble in alcohol but slightly soluble in tetrahydrofuran.

PVC has high hardness and mechanical properties. The mechanical properties enhance with the molecular weight increasing but decrease with the temperature increasing. The mechanical properties of rigid PVC (uPVC) are very good; the elastic modulus can reach 1500-3,000 MPa. The soft PVC (flexible PVC) elastic limit is 1.5–15 MPa.

Sash Windows

What is Double Glazing ?

Insulating glass (IG), more commonly known as double glazing (or double-pane, and increasingly triple glazing/pane), consists of two or three glass window panes separated by a vacuum or gas filled space to reduce heat transfer across a part of the building envelope.

Insulating glass units (IGUs) are manufactured with glass in range of thickness from 3 to 10 mm (1/8″ to 3/8″) or more in special applications. Laminated or tempered glass may also be used as part of the construction. Most units are produced with the same thickness of glass used on both panes[citation needed] but special applications such as acoustic attenuation or security may require wide ranges of thicknesses to be incorporated in the same unit.

Insulating glass is an evolution from older technologies known as double-hung windows and storm windows. Traditional double-hung windows used a single pane of glass to separate the interior and exterior spaces.

In the summer, a window screen would be installed on the exterior over the double-hung window to keep out animals and insects.
In the winter, the screen was removed and replaced with a storm window, which created a two-layer separation between the interior and exterior spaces, increasing window insulation in cold winter months. To permit ventilation the storm window may be hung from removable hinge loops and swung open using folding metal arms. No screening was usually possible with open storm windows, though in the winter, insects typically are not active.
Traditional storm windows and screens are relatively time consuming and labor-intensive, requiring removal and storage of the storm windows in the spring, and reinstallation in the fall and storage of the screens. The weight of the large storm window frame and glass makes replacement on upper-stories of tall buildings a difficult task requiring repeatedly climbing a ladder with each window and trying to hold the window in place while securing retaining clips around the edges. However, current reproductions of these old-style storm windows can be made with detachable glass in the bottom pane that can be replaced with a detachable screen when desired. This eliminates the need for changing the entire storm window according to the seasons.

Insulated glazing forms a very compact multi-layer sandwich of air and glass, which eliminates the need for storm windows. Screens may also be left installed year-round with insulated glazing, and can be installed in a manner that permits installation and removal from inside the building, eliminating the requirement to climb up the exterior of the house hto service the windows. It is possible to retrofit insulated glazing into traditional double-hung frames, though this would require significant modification to the wood framed due to the increased thickness of the IG assembly.

Modern window units with IG typically completely replace the older double-hung unit, and include other improvements such as better sealing between the upper and lower windows, and spring-operated weight balancing that removes the need for large hanging weights inside the wall next to the windows, allowing for more insulation around the window and reducing air leakage, provides robust protection against the sun and will keep the house cool in the hot summer and warm in winter. These spring-operated balancing mechanisms also typically permit the top of the windows to swing inward, permitting cleaning of the exterior of the IG window from inside the building.