Types of Glass Used in Construction
In the construction industry, various types of glass are used for a wide range of purposes. Beyond its most obvious function (windows), glass is routinely used in staircases, doors, skylights, translucent roofs, interior curtain walls and more.
The type of glass used depends on the specific needs of each project, and advances in technology have expanded the possibilities almost beyond imagining. The basic components (primarily silica, lime, and soda) can be combined with various additives to achieve different qualities according to the function.
Here’s a brief overview of the various types of glass used in construction today
Most windows nowadays are made of float glass. In this process, the essential components are melted and floated onto a bed of molten tin. The material solidifies gradually into the uniform sheets we’re all familiar with. It is then annealed, or heat treated, to remove stresses and increase stability.
But that’s just the beginning. Additional processes and materials provide the versatility that makes glass so useful in an array of settings:
Also known as hardened glass, tempered glass is made by rapidly heating the molten material to more than 1,000 degrees Fahrenheit, then cooling it quickly to room temperature. The resulting product is up to four times stronger than regular annealed glass.
Another benefit is that when it does break, tempered glass separates into small, granular pieces rather than dangerous sharp-edged shards. This is one reason it’s used for the side windows and rear windshields in cars. The unique chemical properties of tempered glass also make it easy to shape into various forms. The tempering process does produce optical distortion, so tempered glass is not preferable when clarity and transparency are important.
The process for making heat-strengthened glass is similar to that of tempered glass, except it is cooled much more slowly. The resulting product is about twice as strong as regular annealed glass. It has some of the strength of tempered glass, but without the optical distortion. This makes heat-strengthened glass the best choice for windows in high-rise buildings, which must be able to resist high winds, while still providing optical clarity.
To make glass nearly impervious to breakage, a plastic resin called polyvinyl butyral (PVB) is added during the manufacturing process. This makes the material much tougher without compromising aesthetics, since it is visually indistinguishable from normal glass. Its strength makes it desirable for floors, staircases, railings, skylights and windows.
An obvious way to increase the strength of glass is to fuse two layers together. This is what is done with laminated glass. The process also involves PVB—the same resin used in the production of shatterproof glass. In this case, a layer of PVB is sandwiched between the two glass lites (sections). The composite unit is heated and pressurized to create a product of exceptional strength.
Various types of glass (heat-strengthened, tempered, clear, tinted, reflective, etc.) can be laminated to achieve different objectives. And by varying the thickness and color of the PVB layer, the glass can reduce glare or screen out ultraviolet radiation. When laminated glass breaks, the particles tend to adhere to the PVB rather than falling or flying. These unique qualities make laminated glass ideal for certain uses. For instance, car windshields are made of laminated glass. It is also used for skylights, sloped glazing, burglar-proofing, and soundproofing (as in music studios). Bullet-resistant glass is simply several thick layers of glass with a laminate of polycarbonate that can absorb the energy of a bullet.
And Much More …
There are, of course, many other uses for glass in today’s construction industry.
- Glass wool is one of the most effective and widely used insulation materials available today. It is available in rolls and can also be sprayed or applied in place.
- Glass block (or glass brick) is now used in much contemporary architectural design, sometimes to stunning effect. Its popularity has revived after a conspicuous debut in the art deco era.
- Tinted glass can offer pleasing esthetic effects without compromising glass’s other important qualities. The resulting product is especially useful for reducing the transmission of light and heat.
- Extra clear glass transmits 92% of sunlight without distortion, making it ideal for displays, museum cases, picture windows and other instances where clarity and true color transmission are important.
Since glass is an integral part of virtually all construction projects, it helps to know the different varieties and their uses.