Today, improvements in glass processing technology have made it possible to render specific and effective solutions for a wide range of architectural projects. In fact, there are so many options available that it’s almost necessary to research different products and their properties, and how this will impact, for example, the windows and doors that you are designing.
What variables should be considered – and prioritized – when choosing the glass used in a project? How can aesthetics coincide with function and efficiency? We sat down with the experts at Cristales Dialum to delve into the complex world of glass and to better understand the hows and whys of choosing the best type of glass for your projects and ensuring the best results for your clients.
The Basics: Dimensions and Types of Glass
Glass panels are normally sold at a standard size of 2.5 x 3.6 meters. Starting at this size, the glass is cut to meet a project’s specific needs. The glass can be basic and colorless or include elements that improve their thermal, visual, and acoustic qualities, as well as many others.
Although less-used, Jumbo glass panels, measuring approximately 5.0 x 3.0 meters, are also an option. At Dialum’s processing plant in Santiago, Chile, one of the 10 most important plants in the world and one of the 5 most modernized in the Americas, they can produce panels measuring up to 6.0 x 3.3 meters, reaching almost 19 square meters and close to a ton of glass.
The panels surpassing 4.5 meters wide and 2.5 high could go so far as to be considered monumental glass.
Mainly used in first floors, reception areas, or Lobbies, Dialum’s Monumental Panels produce impeccably seamless results thanks to their great size. To achieve this subtlety, it’s essential to choose frames that can withstand the weight of the panels without dominating the structure. Aluminum is the most widely used in constructing frameworks thanks to its economical cost; however, for projects with glass panels measuring more than 6 meters high, the aluminum should be reinforced with steel, which adds to the size of the framework.
What material allows for slimmer frameworks while also being sturdy enough to withstand the weight of larger glass panels? Steel.
Wood was the first material used in carpentry. At the beginning of the 20th century, around the same time when industrialization and Rationalism began to shape architecture, steel became the go-to material for the construction of doors and windows, before being replaced by the emergence of new technologies like PVC and aluminum. Today, steel is back on top, having evolved to minimize its dimensions without losing its strength and durability.
Three times stronger than aluminum, Jansen’s steel frameworks integrate classic aethetics and modern style that work in sync with the specifications of good glass work. To achieve larger glass fixtures, like the Glass Monuments, aluminum frameworks should be reinforced, resulting in a more complex and voluminous structure. Steel frameworks work well with larger glass fixtures while maintaining their clean and simple form.
Furthermore, the welding capacity of steel takes away the need for jointed unions, eliminating problems like bending and shifting. This enables us to undertake more complex designs with less effort.
How to choose the most efficient glass fixtures for every project
First, you need to understand the realistic needs of the project. You can add every available characteristic and property to your windows, but this usually turns out to be an exaggerated – and costly – move that won’t benefit the final product in any significant way. In fact, you could choose different types of glass for every specific surface, but the project might end up being more complicated than necessary.
So we recommend looking for an integrated solution that addresses the predominant environmental conditions, for example, intense sun exposure or harsh cold.
The Importance of Double-Paned Glass in Every Project
Before seeking out more specific results, it’s important to understand that double-paned windows are a minimum requirement to ensure the efficiency of glass fixtures in a project, especially in terms of the thermal transmittance and sun protection required by the structure based on its location and orientation. In special applications, you can use monolithic glass fixtures but they should be thermally treated.
Solar rays emit both heat and light energy. In areas with stronger sun exposure, it’s important to avoid the overheating of the structure while at the same time allowing light to enter.
For this, you should research glass selectivity, choosing a glass fixture that filters and “selects” the specific percentages of light and heat that will enter the interior space. The more selective a glass, the more light and less heat that it will let pass through. It’s three times more expensive to cool than to heat a space, making solar protection an essential factor to consider when choosing glass fixtures.
In cold climates, a space’s ability to retain heat is a key factor to address when designing and executing a project. The flow of heat passes from the warmest to the coolest areas of the structure, and if there is a window, heat escapes through it. How much heat is lost? That depends on how well your windows work.
If you choose a monolithic (or single-paned) glass, you are losing a certain number of Watts per every square meter of window. This number can be cut in half if we install a basic double-paned window, saving you almost 50% in energy costs; however, with an even more advanced window fixture, like Low-E, which have low emissivity, you can save up to 80% on energy costs.
In noisy areas, double-paned glass is effective against high-frequency sounds and they can be even more effective with acoustic Polyvinyl panes, which protect against low-frequency noises as well (constant buzzing sounds that can be harder to detect but very irritating).
In extreme cases, such as airports, this solution could be even more effective by widening the space between the panes, which would significantly lower outside noise by decibels.
Anti-Theft Protection and Security
Laminate, made up of two glass panels with a plastic film between them, offers more protection against vandalism. To break through, you would have to break the first glass panel, then the plastic film, and then the second panel. This feature is especially important for skylights or other windows on the roof if you want to guarantee the security of the building’s inhabitants.
Glass floors require many layers of laminate to support the weight of the people walking on them.
Mechanical Resistance and Reheating
This glass is heavy but fragile. Thermal treatments like tempering or heat-strengthening increase glass’ mechanical resistance up to 5 times that of non-treated glass. This is an excellent option for glass doors which have to withstand constant force when being opened or closed.
In buildings with high sun exposure and heat intake, there is a greater risk for breaks in their surfaces thanks to overheating. Tempered glass gives increased resistance to heat damage and high temperatures.
Solar Control and Design
Screen Printing / Digital Printing
Surface printing, or digital printing, consists of applying a layer of paint that permeates the glass through heating. You can choose based on the look of the glass, like adding images, or the function, like solar performance. For example, if you add white points on the glass, this will create shade spots in the interior space.
In the case of light shafts, you can use the double point technique, painting dots over a certain percentage of the glass (for example, 50% of the surface). White dots are painted on the exterior and reflect the sunlight and prevent it from passing through while black dots painted on the interior, while blocking the sun, still allow you to see everything outside the window.
Analyzing the particulars of every project will allow you to get the most effective results from the fixtures you choose to build with. In high towers, for example, many builders opt for a mix of the previously mentioned solutions, combining Double-paned, laminated, and tempered glass.
There are two types of this glass. First, you have fire resistant glass that stops the fire and the toxic gases (the principal cause of death during a fire) and then the fire wall which stops the fire, the toxic gases, and the increase in temperature. The latter acts as a barrier that absorbs the necessary percentage of heat that prevents the fire from spreading for a given amount of time (F30, F60, F90, F120).
The Importance of Norms and Regulations
Regulations provide guidelines for executing processes correctly, be it manufacturing a product or designing and constructing and building, and eliminate the possibility of arbitrary decisions.
In Argentina, IRAM is the regulatory body, while in Chile it’s the NCH, in Europe the EN, in the US the ASTM, and so on and so forth in every country in the world. Within every regulation, there are specifications that dictate every facet of design and construction and there are even certifications for products according to international testing, such as the ANSI SGCC (for laminated glass) and IGCC (for double-paned glass).
If you are unsure of the regulations that correspond with your project, it’s possible to refer to the current regulations found in Europe or the United States as a way to ensure the efficacy of the solutions you have chosen for your project. In any case, it’s essential to review the technical specifications of the products you have chosen and to ensure the support of the specialists from your supply companies.
Key Recommendations for Design
- Trust in the specialists’ assessment: As architects, we’re not necessarily experts in glass, nor do we have reason to be. Choosing the wrong solution could have grave long-term consequences, such as excessive air conditioning costs.
- Understand the project and the characteristics of the glass: Location, orientation, function, and specific hours of use, among other variables.
- The bigger the glass, the wider it should be: Or, at least, it should come with the necessary treatments to ensure its mechanical resistance.
- When looking at the glass’ appearance, verify that the appearance won’t change once it is installed: Certain conditions can alter the appearance and behavior of glass.