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Tempered glass is significantly stronger and better than standard annealed glass. There are plenty of reasons why even the average consumer should be drawn to tempered glass products.
This article will include references to several studies confirming the strength of tempered glass. There are plenty of consumer-friendly products making use of this technology. There are also many ways to overcome any losses in energy efficiency by combining the safety features of tempered glass with the energy efficiency ratings of insulating glass.
Tempered Glass is a Type of Heat-Treated Glass
You may have heard of both impact-resistant glass and tempered glass. These are actually different types of glass. Tempered glass is heated so that the center of the glass remains relatively hot compared to the surface of the glass.
While the center of the glass cools, the surface and edges are compressed. Safety is ensured in the early stages of the tempering process. The glass is prepared for the process by first being cut into the desired size. After this, the glass is thoroughly inspected for imperfections. Otherwise, breakage could occur at some point during the tempering process.
Sharp edges are removed during the tempering process via the use of an abrasive such as sandpaper. These safety procedures ensure that the tempered glass does not unexpectedly break into shards that would defeat the purpose of having the glass tempered in the first place.
Tempered glass is designed to maximize safety as many building codes require the installation of tempered glass, specifically due to safety concerns. You are always encouraged to consult local building codes to find out if tempered glass is required. As you will learn here, tempered glass is always a practical alternative to standard glass, even if you are not required by code to install this type of glass.
Four Times Stronger than Annealed Glass
Tempered glass is approximately 4 times stronger than standard annealed glass. The strength of glass is measured by tensile strength, defined as the maximum load that the glass can take while being stretched. Tempered glass has a tensile strength of 10,000 pounds per square inch (psi). Standard glass has a tensile strength of approximately 1,000 psi.
While tensile strength isn’t the only measure of strength, it is one of the most critical measures of strength when judging a material. The key takeaway here is that it is significantly harder to break tempered glass than it is to break standard annealed glass.
This fact makes tempered glass a popular choice among those seeking out glass products that are both strong and economical. In many situations, tempered glass will be required by local building codes.
Even if tempered glass is not required by building construction codes, there are many reasons why the average consumer should take the increased strength of tempered glass into account when searching for glass products.
- Reduced Likelihood of injury
- Heightened security
- Resistance to storm damage
- Reduced likelihood to be damaged from scratching
- Economic feasibility (may only cost 15% more than standard glass)
Tempered glass has started to become more popular for the average consumer, thanks to the innovation of products that balance both safety and economic feasibility. One such product is a square window that will be referenced later in this article. Other such products include skylights that are still practical in regions receiving frequent hail storms and aesthetically-pleasing fireplace screens.
Tempered Glass Reduces the Risk of Injury
Tempered glass reduces the risk of injury when it is broken, relative to standard annealed glass. The way that tempered glass breaks is referred to as “dicing.” When it is broken, tempered glass breaks into small and relatively harmless fragments.
Local building codes may require safety glazing materials like tempered glass in areas where human-related impact damage is likely to occur. This can include door assemblies, bathtubs, hot tub enclosures, and glass located near stairways. If the glass is somehow broken, then cutting and piercing injuries will be less likely.
Other safety applications for tempered glass include:
- Side and rear windows in vehicles
- Racquetball furniture
- Microwave ovens
- Patio furniture
Tempered Glass is Often Used as a Screen Protector
Tempered glass is often used as a screen protector for phones. Take, for example, this tempered screen protector for the iPhone 11. The tempered glass is a quality protective layer for cell phones, which hold a reputation for being quite easy to drop and break.
Tempered glass is also more difficult to scuff up and scratch than other types of glass, as will be discussed in further detail later in this article. Even if you are generally careful with your electronic devices, you could easily crack your screen with one simple misstep or drop.
Tempered glass screens are among the most popular options for cell phone cases. For one thing, they are generally lightweight. This removes the need to carry around a bulky screen protector. They also are relatively affordable, especially when compared to the cost of having to repair a broken cell phone screen or having to replace a broken cell phone entirely in the worst-case scenario.
Tempered Glass is Useful for Greenhouses
Glass, in general, is one of the preferable choices for materials to use for greenhouses. There’s a reason that high-end garden retail centers use glass, according to Washington State University. Glass is much more aesthetically-pleasing in greenhouses than plastic or structured polycarbonates. Glass is also superior to alternative options when it comes to allowing direct radiation to be transmitted through the material.
Glass also comes with the highest life expectancy compared to other materials used to make greenhouses. The glass used in greenhouses is anticipated to last 25+ years. Local municipalities will often require greenhouse owners to install safety glass, such as tempered glass.
The tempered glass used for greenhouse construction often comes in large sizes, such as 39” by 65”. Tempered glass is a popular option in glass greenhouse kits such as this Palmetto Aluminum & Glass Greenhouse Kit.
Tempered Glass is Used for Skylights
Tempered glass is commonly used for skylights. Local building codes may require that the skylight be made of tempered glass even if the local building codes do not require tempered glass for skylights. There are numerous advantages to having a tempered glass skylight. One of the most popular models on the market is the Velux FCM Skylight.
Tempered glass allows you to enjoy all the benefits of having a skylight, even if you live in a region where hail damage is a frequent problem. Tempered glass is often used on solar collectors because it is resistant to hail damage. This also makes tempered glass well-suited for skylights. Skylights can frequently be subject to hail storms, depending upon the specific region of residence.
In addition to being impact-resistant, tempered glass is also heat resistant. The high heat resistance of tempered glass makes it a popular choice for cookware. Tempered glass is an advantageous option for cooking because it is less likely to shatter in the event that the cooking method involves rapid heating and cooling. These are conditions that normally cause glass to shatter.
Even if the tempered glass does shatter, it will shatter in such a way that broken pieces will not have the sharp edges typically associated with broken glassware. Popular tempered glass cooking items include cookware sets with tempered glass lids.
These heat resistant properties also make tempered glass advantageous in the realm of building and construction. Tempered glass is frequently used to construct glass structures near fireplaces because of the heat that the glass will be exposed to. Take, for example, this Design Specialties Glass Free-Standing Screen For Fireplaces that is made out of tempered glass for maximum safety.
The thermal strength of tempered glass is statistically significant. Tempered glass offers increased resistance to breakage in temperature differentials up to 250 deg C (482 deg F). Standard annealed glass can only withstand temperature differentials up to 40 deg C (104 deg F). You can easily see why tempered glass is a must in areas where rapid temperature changes are anticipated.
The heat resistant properties of tempered glass also make it an attractive option for the construction of structures associated with the food services industry. Tempered glass products are often used in restaurants, hotels, and bars.
Protection From Scratches
Tempered glass is a popular choice in both residential and commercial applications thanks to its heightened ability to resist scratching. Doors and windows, particularly frameless doors, often contain tempered glass for safety reasons and for the reason that tempered glass is less likely than standard glass to accumulate unsightly scratches.
A good example of a tempered glass door is the ODL Exterior Entry Door. Doors like these are popular among families because they are more resistant to scratching than other types of doors. A home improvement expert with the SF Gate recommends placing a layer of tempered glass over your wood tabletop in order to help stave off unappealing scratches on the surface.
Tempered glass may not be completely resistant to scratching, but it is significantly less likely to accumulate scratches then standard annealed glass. This characteristic makes tempered glass an attractive option in both commercial and residential installations.
The usefulness of tempered glass extends to glass countertops where scratching is a concern. Furthermore, tempered glass is a safety feature because it will not break into pieces with razor-sharp edges, as is the case with standard glass.
Tempered Glass Can Be Combined With Energy-Efficient Products
Window replacement companies often claim that using tempered glass will also lead to energy savings. They assert that tempered glass windows are better than standard glass windows at maintaining the desired interior temperature, in addition to being able to keep the home dry and comfortable. While tempered glass alone is not known for its energy efficiency, it can be combined with products that will lead to energy savings.
The U-Value of Tempered Glass
A material’s U-value is defined as a measurement of the material to transfer heat. A lower U-value means that the material is more energy-efficient. The U-value of fully- tempered glass is between 5.7 and 6.4 W/sq.m.K depending upon the thickness of the glass. The goal of energy-efficient construction is to install glass with a lower U-value, getting as close to 0 as is possible.
Concerns regarding the energy efficiency of tempered glass have been addressed by companies such as Guardian Glass. The company has designed windows that meet safety codes while still offering energy savings compared to tempered glass products that are traditionally perceived as products that have poor U-factors.
Combining Safety and Energy Efficiency
Tempered glass and insulating glass features are often combined in the same products in order to achieve a balance of safety and energy efficiency. These features can be observed in double pane Low-E tempered glass windows, such as the one found here. This square window contains a triple-silver MSVD Low-E coating.
A Low-E coating is a coating put in windows that reduces the amount of radiant heat transfer through the window. This means that the window will be able to act in the same way that you would expect a quality thermos to behave. During the summer, less of the cooled air in the interior of the building will be allowed to escape. During the winter, less of the heated air will be allowed to escape through the tempered window.
If your building codes require you to use tempered glass, then you do not have much of a choice. However, if you are on the fence about using tempered windows or doors, you should be aware that there are products such as the square window linked above that seek to combine the safety features of tempered glass with the insulating characteristics of a Low-E glass.
Being tasked with having to install tempered glass should not have to lead to sacrifices regarding the energy efficiency of a residence or building. Through time, increasingly efficient tempered glass products are being developed.
Ideal For Fire Safety
Tempered glass windows with Low E coatings are ideal for fire safety, particularly in the event of wildfires. This is because tempered windows are resistant to both high impact and high heat. The Low E layer helps to stop the flow of radiant heat beyond the exterior of the house.
Those who live in wildfire-prone areas, such as many of the areas of the American West, are encouraged to look into outfitting at least portions of their home with Low E tempered glass to hold back the transfer of radiant heat during wildfire events.
Radiant heat is dangerous during such fire events because radiant heat alone can contribute to the interior of the home catching fire. Glass often breaks due to extreme temperature differential during wildfire events. A study on the damage of California wildfires on homes in the area has confirmed that tempered glass windows are less likely to be damaged by radiant heat exposure from nearby fires.
The fire safety characteristics of tempered do not solely benefit those who live in areas that are prone to wildfires. The results showing that tempered windows are safer during wildfires also further confirms the feasibility of using tempered glass in front of fireplaces.
If you install a tempered glass barrier of some kind in front of your fireplace, then you will have a barrier that could be more aesthetically-pleasing then some type of metal cage. You will not have to worry about tempered glass breaking during times of increased temperature differential, either.
Tempered glass may be required by some local building codes that apply to commercial storefronts. Even if tempered glass is not required by building code, such as probably the case for residential installations, you are still encouraged to at least explore the option of installing tempered glass.
Tempered glass is an excellent option in circumstances where security demands have been heightened. This is because tempered glass is significantly more resistant to impact than standard annealed glass, which can usually be broken with relative ease. Tempered glass is even twice as strong as double-pane standard glass.
There are so many reasons why tempered glass is stronger and better than standard annealed glass. Tempered glass is commonly used in situations where injuries would be minimal even if the glass were to break. Tempered glass can also withstand dramatic temperature changes.
There are many reasons that the average consumer can find tempered glass appealing. One of the most attractive features of this type of glass is the fact that it is less dangerous when it does shatter. It can also withstand dramatic temperature changes of up to 482 degrees Fahrenheit. This makes tempered glass one of the most aesthetically-pleasing candidates for a fireplace screen.
Tempered glass is also less prone to scratching than other types of glass. For this reason, it is widely used as a material for cell phone screen protectors. It’s also economically feasible since it is quite durable. Any excessive upfront costs should be offset by the fact this type of glass can even last through severe weather events such as hail storms.