Types and Properties of Structural Glass in Architecture - Term Paper Example

TYPES AND PROPERTIES OF STRUCTURAL GLASS IN ARCHITECTURE due Glass can be defined as a hard and breakable substance which is mostly transparent allowing one practically, to see through it or translucent, allowing only a little light to pass. Glass is made from a fusion of sand or silica with other elements like lime, Potash, soda and sometimes additional components depending on the intended purpose of the final product. Uses of glass vary from construction of structures and structure components, to manufacture of common objects like drinking bottles, food plates, television screens and spectacles among many other items. The main focus of this paper will be on the architectural use of glass in construction of structures and components of structures. Glass comes in various forms and types. They vary from look, weight, texture and color among other aspects and in this paper we will look deeper and further into the types of glasses and their properties focusing mainly on three types of glass namely; float glass, tempered glass and laminated glass. The paper will also look to discover the implications of each and every type of glass, mentioned above with relation to its structure of design in an architectural point of view. Characteristics and behavior of each type of glass will also be evaluated, and its effects in construction discussed1. Float Glass Float glass is a type of glass that is forged or made by floating liquid form glass on molten metal still in its liquid form specifically the tin metal which is mostly used, and then allowing the glass to cool and harden. Tin is normally chosen because of its chemical ability to withhold molten glass in its liquid form and allows it to cool where it maintains the smooth liquid surface of the glass, after its hardening and leaves no space for a coarse feeling when the glass dries. Traditionally, glass was made by blowing molten glass or the liquid form of glass and then laying it on a flat surface when still hot and liquid before it has reached the cooling temperature. This has since changed, and the process has become much easier compared to the traditional one. From the floating process, the result is a flat, smooth and an even sheet of glass which can be made into thick or thin flat sheets and also in different sizes, which can be, further resized into small panes depending on the purpose for which the glass was formed to serve. Float glass is commonly made from a fusion of lime and soda, and the process for making this type of glass is also known as the Pilkington process. This type of glass is mostly used for making window panes, a vital substance in architecture, and also in the making of mirrors. Both of the uses mentioned above may also be of an ornamental nature where the glass panes are colored differently or even shaped into various forms, to provide a shiny finish to, for example, in the construction of a building or a monumental structure. The general appearance of an architectural structure will be substantially improved if colored float glass is used in its finishing since this type of glass gives the impression of a smooth and soft environment. This can be seen in architectural cities like Dubai where we have most of the sky scrapers finished in glass. Since this type of glass is mostly made from a fusion of soda and lime with no extra component or process, the glass is generally weak and breaks easily. This limits its uses in architecture as it cannot be used for a protective purpose or even in a place that has harsh conditions. Thick sheets of pane glass, however, can be used to make floors due to their compactness and smooth surface nature, even though this increases the weight of the structure which is appropriate2. Float glass utilization, in addition, poses a threat to, human’s well-being as it postures a risk where it is used for window panes in sky scrapers. Flying glasses has been a common cause of death across ages and places where shattered glass pieces get lethal to the persons around in case of a blast emergency. The risk has been countered, however, by improvement in the glass making processes and safe approaches in architecture. Float glass is technically referred to as the standard glass due to its manufacture process and components3. Tempered Glass Another beneficial type of glass in architecture is the tempered glass. This is a type of glass made by further processing of the standard glass by way of thermal treatment, also heat treatment, or chemical treatment, which makes the glass tougher and stronger through a process known as tempering thus the name tempered glass. This type of glass is also referred to as toughened glass. The process of tempering makes the glass, in an event of breaking, to fragment into small grain like pieces instead of the sharp and splintering pieces that one would get, for example, in a broken window pane. This type of glass was developed to add a precautionary characteristic to the standard glass which was a more likely source of bodily harm. Since it proves to be a strong glass, it has seen its way into the creation of bullet proof glasses because of its impenetrability4. In addition, tempered glass is commonly used to make passenger bus window glasses, glassware coffee tables, and master bedroom shower doors among other uses including fridge shelves. Most of kitchen ware such as glass dishes, glass plates and glass pots will also be made using tempered glass, which in addition to its toughness, has, a capability to withstand heat. In buildings, this type of glass makes frameless doors and other architecturally loaded structures to withstand human impact. In the food industry, this glass type is used on rim-tempered wine glasses where the rim of a drinking glass is tempered to avoid chipping. Accordingly, the safety characteristic of tempered glass has led to the formulation of federal safety laws of the United States. Some of these federal laws linked to tempered glass include, regulating cafeteria buildings by ensuring that glass within eighteen inches of the floor with a top edge higher the thirty six inches from the floor, is tempered so long as it has an area of nine square feet and above and is closer to a walking space than thirty six inches. In architecture, this type of glass is hard to work with since it requires shaping from the manufacturer or maker. Tempered glass is toughened by imputing stress on the glass surface during manufacturing where shrinkage of the inside layer prompts compressive strains on the glass surface which in turn, gets balanced by the stretchable pressures in the glass body. For this reason, cutting or grinding the glass to shape it has to be done before the tempering. When done after the tempering process, it results to fracturing the glass. This makes its utilizable factor diminish and get limited as it cannot be used in an architectural field where certainties of sizes and shape are yet to be determined5. The known advantages of the tempered glass would be its capability to withstand heat where it can range from four to six times that of standard glass. It also has an advantage where pressure is an issue since it is much stronger compared to the standard glass. However, the required shape or size of this type of glass must and have to be done before the actual toughening or the tempering. Tempered glass is held by balanced pressures and trimming or cutting will affect the edges, where the tensile stress is greatest and bending will be impossible due to the stiff character of a glass. Hard impact to the glass in the middle will also cause shattering when it is done by a sharp object. This makes the glass unsuitable for constructions of structures where sharp impact is frequent. Constructions of canopies where the glass is exposed to falling objects are not recommended as one runs a risk of shattering the glass completely if an object falls on to it. Tempered glasses also contains surface wave as a result of their nature and manufacturing process which makes the glass unsuitable for the making of thin glass films as in solar cells. Though the glass, withstands impacts fro6m large articles like rocks, it breaks easily when a sharp object is used to break it Laminated Glass Another type of glass mostly used in construction is the laminated glass. This type of glass is made by bonding or combining two or more layers of glass, using a chemical component known as PVB in between the layers. Heat is also used when combining the layers making this type of glass much stronger compared to the other two afore mentioned types. Laminated glass has various sub categories as different glass characteristics will be achieved when different types of glass are bound together using the PVB. The manufacturing of the laminated glass determines the breaking pattern of the glass in case of an impact. Laminated glass can be sub divided in to three categories. These are; laminated annealed glass; heat strengthened laminated glass and the tempered laminated glass. Laminated annealed glass is formed by using a simple process of bonding two or more glass panes with PVB. Here, there is no extra treatment to strengthen the glass further. It is this kind of glass that one can see on automobile windscreens. In the event that the glass breaks, the PVB layer or layers in between the glass layers keeps the glass together. This gives the glass a spider web breaking pattern. In architecture, this type of glass will be more popular in the making of canopies and skylights where only slight impact is expected, but tempering is not a choice7. The other type of laminated glass is the heat treated laminated glass. The manufactured type of glass involves joining two or more planes of glass and then subjecting the glass to high levels of heat and cooling. This makes this type of laminated glass stronger than the annealed glass since an extra process to strengthen the glass has been undergone. When any glass is given a thermal strengthening process or a heat treatment, it gets the capability to hold its shape hence it can withstand more pressure as compared to glasses that have not undergone the same process. For this reason, Heat treated laminated glass has the ability to hold much more weight and for a much longer period compared to other types of glass. The other type is the tempered laminated glass. Glass panes will undergo the process of tempering and then combined to form a single glass with many layers of tempered glass. This type of glass breaks into ultra-small pieces which creates a wet blanket effect when the impact is heavy. The glass is almost free of harm since, by its design, the exceedingly small shattered particles will be held together by the PVB making the glass fall off its place rather than injure persons around. In essence, the three types of laminated glasses have a general purpose of maintaining safety in constructions and can be used in those places where people frequent and the dangers are present. Tempered laminated glass is the safest because of its wet blanket effect during an impact. However, it cannot be used in constructions where pressure is frequent, for example, in floor making. The right type of glass for floors would be the heat strengthened laminated glass since it is able to hold high pressure for longer. Laminated annealed glass is useful since it is cheaper to produce and it does not compromise on the safety nature of laminated glass. This type of glass is also used where sound insulation is needed. Laminated glass also acts as a sound insulator and the insulation deepens depending on the number of layers that the glass contains. Advantages and Disadvantages of the Types of Glass All types of glass highlighted in this discussion have their pros and cons and not a single type of glass has been found fit to accomplish every purpose for which glass is meant to serve. Though some of the glasses have proved to be tougher from their manufacture processes, they have shown their short coming both in the cost of production and in their utilization, in structures. Window panes need to be clear and smooth, and the float glass has proved to be a vital part in construction of structures. The smooth surface of float glass has also influenced its being largely used in wall finishing in large structures and also since it can be made into ultra-thin films; it conquers the weight difficulty where weight is of concern in a construction. Tempered glass has accomplished its purpose in making normal or standard glass stronger without affecting the general look or appearance of the glass. It can be used in the making windows, in sky scrapers where impact by birds is expected. Laminated glass brings safety into architecture. The presence of an element bonding two or more glass sheets makes it less dangerous in case of an impact thus making construction of people related structures safer using glass8. Indeed, the see through characteristic of glass, or the ability to allow light to pass through, makes glass a highly valued building material. Not only is glass appealing to the eye, but it also serves an extremely vital purpose of allowing people to see through a hard and safe object. Windows would be totally different were it, not for the invention of glass. Telephone booths would be a disaster if not for glass where people would be colliding while banks would be riskier since each customer would have to be attended by the tellers on a one on one basis without a safety glass in between them. Glasses have been used to make quarantine structures in the event that a patient with an unknown or a highly contagious disease will be watched by doctors through a glass, making the remain safe while still observing the patient9. Future of Glass in the Construction Industry Glass is and has been an essential component in the construction of structures. This has led to builders heavily depending on glass in construction. Accordingly, for safety purposes, governments have even regulated the use of glass. Citing an example of the United States, glass used to construct cafeterias was required to be tempered so long as it is close to where people walk. Standard and provisions for minimum design in structural glass has been set in the United States which is being applied in most jurisdictions of the country. Another law has been passed still in the United States where specific requirements and conditions have been set for structural and non-structural components including those for structural glass. Glass has undergone a significant evolution in its manufacturing process since when it was being made as a basic sheet or plane of glass by blowing it from a pipe to now where it is much easier. Regardless of the type of glass, there still remains the need to have a substitute type where one type does not fit. This means that in a complex construction, people currently have to buy various types of glass to finish a particular task or purpose. The rate at which glass making has changed and continues to change shows that, in the near future, there might be manufacturing of glasses that serve all the key requirements and needs in a glass. Presence of a single type of glass that is light, smooth, strong and safe is highly likely in the future. There has been a tremendous dependence on glass in constructions. It has been growing since its invention and continues to grow to date. There has been no single element present today that has threatened the dependency on glass as an architectural component. Glass has a future since it is recyclable and it is cheap to produce. Moreover, glass is available in different sizes and types hat come in many colors. This has made it to be accepted worldwide as a construction and preservative good. In addition, glass does not affect the environment like plastic would. Therefore, it is good to note that glass will be very much sustainable and has a very bright and promising future10. This paper has discussed types of glasses namely the float glass, tempered glass and also the three types of laminated glass. The paper has also briefly discussed the processes involved in their manufacture and it has also shown their application in architecture with regard to their properties. Works cited Elkadi, Hisham. Cultures of Glass Architecture. Farnham: Ashgate Publishing, Ltd, 2006. Architects, The American Institute of. Architectural Graphic Standards. Hoboken, New Jersey: John Wiley & Sons, 2007. glasstec. "Sustainable future for the construction industry." Glass on Web, 2010: n.p. Source Wikipedia, Books Llc. Glass Types: Glass, Smart Glass, Hebron Glass, Heatable Glass, Fused Quartz, Pyrex, Porous Glass, Carnival Glass, Tiffany Glass, Silica Gel. Memphis, Tennessee: General Books LLC, 2010. Read More