For purposes of this discussion glass constructions are divided into four major groups: monolithic, insulating, laminated, and miscellaneous as defined below.
Monolithic glass is the primary glass product that is produced. It consists simply of a flat piece of glass of constant thickness. In the past monolithic glass was produced using either sheet or plate glass processes. However, virtually all monolithic glass produced in the world today is produced using the float glass process. Monolithic float glass can be annealed or heat-treated as described in the glass type section.
Laminated glass is manufactured by bonding multiple layers of glass together through the use of layer(s) of polyvinyl butyral (PVB) or in some cases the use of liquid resins. Usually, laminated glass involves two pieces of glass of the same thickness and a single interlayer as shown below. The primary function of the interlayer is to securely fasten the layers of glass together. When laminated glass is broken, the interlayer helps to hold broken pieces of glass together.
Insulating Glass is manufactured by enclosing a sealed gas space between two or more pieces of glass which are separated by spaces of constant thickness. The seal between the glass plates is accomplished through the use of variety of different types of materials and sealants. In addition, a desiccant is incorporated into the edge seal technology to adsorb water vapor that migrates across the seal. The concept of IG seal failure is fully discussed in the Insulating Glass Seal Failure section.
While no amount of effort can assure the production of a trouble-free IG unit, there are certain IG manufacturers who participate in insulating glass certification programs to assure the production of a quality product. These certification programs administer independent testing of IG units based on ASTM standards to assure that the IG units produced meet performance test requirements and review quality control standards of the fabricators. The filming of certified IG units should be less of a risk than that of filming uncertified IG units.
There are a number of different miscellaneous types of glass that may be encountered in the marketplace including wired, textured, and patterned glass. The manufacturing processes associated with these types of glass typically introduce surface and edge flaws which make the filming of these products risky.
Back To Guide Topics