Is glass temperature safe?

08 Apr.,2024

 

What Is Borosilicate Glass And Why Is It Better Than Regular Glass?



What is borosilicate glass?

Borosilicate glass is a type of glass that contains boron trioxide which allows for a very low coefficient of thermal expansion. This means it will not crack under extreme temperature changes like regular glass. Its durability has made it the glass of choice for high-end restaurants, laboratories and wineries.

What most people don't realize is that not all glass is created equally. Take our high-grade borosilicate Kablo bottles for example.

Borosilicate glass is made up of about 15% boron trioxide, which is that magical ingredient that completely changes the behavior of glass and makes it thermal shock resistant. This allows the glass to resist extreme changes in temperature and is measured by the “Coefficient of Thermal Expansion,” the rate at which the glass expands when it is exposed to heat. Thanks to this, borosilicate glass has the ability to go straight from a freezer to an oven rack without cracking. For you, this means you can pour boiling hot water into borosilicate glass if you wanted to say, steep tea or coffee, without worrying about shattering or cracking the glass.

What’s the difference between borosilicate glass and soda-lime glass?

Many companies choose to use soda-lime glass for their glass products because it is less expensive and readily available. It accounts for 90% of manufactured glass worldwide and is used for items like furniture, vases, beverage glasses and windows. Soda lime glass is susceptible to shock and does not handle extreme changes in heat. It’s chemical composition is 69% silica (silicone dioxide), 15% soda (sodium oxide) and 9% lime (calcium oxide). This is where the name soda-lime glass comes from. It is relatively durable at only normal temperatures.

Borosilicate glass is superior

The coefficient of soda-lime glass is more than double that of borosilicate glass, meaning it expands more than twice as fast when exposed to heat and will break very quickly. Borosilicate glass has a much higher proportion of silicon dioxide in comparison to regular soda lime glass (80% vs. 69%), which makes it even less susceptible to fractures.

In terms of temperature, the maximum thermal shock range (the difference in temperatures it can withstand) of borosilicate glass is 170°C, which is about 340° Fahrenheit. This is why you can take borosilicate glass (and some bakeware like Pyrex—more on this below) out from the oven and run cold water over it without shattering the glass.

*Fun fact, borosilicate glass is so resistant to chemicals, that it is even used to store nuclear waste. The boron in the glass makes it less soluble, preventing any unwanted materials from leaching into the glass, or the other way around. In terms of overall performance, borosilicate glass is far superior to regular glass.

Is Pyrex the same as borosilicate glass?

If you have a kitchen, you’ve probably heard of the brand name ‘Pyrex’ at least once. However, borosilicate glass is not the same as Pyrex. When Pyrex first hit the market in 1915, it was initially made from borosilicate glass. Invented in the late 1800s by German glassmaker Otto Schott, he introduced the world to borosilicate glass in 1893 under the brand name Duran. In 1915, Corning Glass Works brought it to the U.S. market under the name Pyrex. Since then, borosilicate glass and Pyrex have been used interchangeably in the English-speaking language. Because Pyrex glass bakeware was initially made of borosilicate glass, it was able to withstand extreme temperatures making it the perfect kitchen staple and oven companion, contributing to its huge popularity over the years.


Today, not all Pyrex is made of borosilicate glass. Some years ago, Corning switched the material in their products from borosilicate glass to soda-lime glass, because it was more cost-effective. So we can’t really be sure what is actually borosilicate and what is not in Pyrex's bakeware product line. 

What is borosilicate glass used for?

Because of its durability and resistance to chemical changes, borosilicate glass has traditionally been used in chemistry labs and industrial settings, as well as for kitchenware and premium wine glasses. Because of its superior quality, it is often priced higher than soda-lime glass.

Should I switch to a borosilicate glass bottle? Is it worth my money?

Great improvements can be made with small changes to our everyday habits. In this era, buying disposable plastic water bottles is just plain silly considering all the alternative options available. If you are thinking about buying a reusable water bottle, that's a great first step in making a positive lifestyle change. It's easy to settle for an average product that is inexpensive and does the job, but that's the wrong mindset if you are looking to improve your personal health and make positive lifestyle changes. Our philosophy is quality over quantity, and purchasing long-lasting products is money well-spent. Here are some of the benefits of investing in a premium reusable borosilicate glass bottle.

It’s better for you. Since borosilicate glass resists chemicals and acid degradation, you don’t need to worry about stuff seeping into your water. It's always safe to drink from. You can put it in the dishwasher, put it in the microwave, use it to store hot liquids or leave it out in the sun. You won’t have to concern yourself with the bottle heating up and releasing harmful toxins into the liquid you are drinking, something very common in plastic water bottles or less expensive stainless steel alternatives.

It’s better for the environment. Plastic water bottles are terrible for the environment. They are made from petroleum, and they almost always end up in either a landfill, lake or ocean. Only 9% of all plastic gets recycled. Even then, often times the process of breaking down and reusing plastics leaves a heavy carbon footprint. Since borosilicate glass is made from naturally abundant materials that are more easily acquired than oil, the environmental impact is also smaller. If handled with care, borosilicate glass will last a lifetime.

It makes things taste better. Have you ever drank from plastic or stainless steel bottles and tasted the plastic or metallic flavor from which you are drinking? This occurs because it is actually seeping into your water due to the solubility of the plastic and steel. This is both harmful to your health and unpleasant. When using borosilicate glass the liquid inside remains pure, and because borosilicate glass has low solubility, it keeps your beverage free from contamination.

Glass is not just glass

While the different variations may look similar, they are not the same. Borosilicate glass is a significant upgrade from traditional glass, and these differences can make a big impact on both your personal health and the environment when compounded over time.

We’ve designed Kablo bottles so that you can maximize the health benefits of drinking water. A wide mouth provides ample room for ice cubes, fruit or herb infusions, and you may use your Kablo bottle to steep your favorite tea or coffee (safely). It saves time and money because you can prepare and enjoy your own beverages in advance, instead of buying pre-bottled health tonics and pressed juices in plastic disposable containers. It takes time to transition to a greener, more conscious lifestyle. But with the right mindset and concentrated effort, we can all get there. An eco-friendly water bottle is just one step we can take towards a smarter, more sustainable lifestyle.

 

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When thinking of some of the world’s most dramatic, visually breathtaking buildings, they most likely involve large expanses of glass. Before these architectural masterpieces can be created, the glass may need to be heat-treated for durability and/or safety reasons. The type of processing required—heat-strengthening or tempering—depends on the glass’ specific application.

There are two different types of heat-treated glasses, heat-strengthened and tempered. The similarities between the two include:

  • Production using the same processing equipment
  • Heating the glass to approximately 1,200 degrees Fahrenheit, then force-cooling it to create surface and edge compression

The differences between the two glasses are as follows:

  • With tempered glass, the cooling process is accelerated to create higher surface compression (the dimension of force or energy per unit area) and/or edge compression in the glass. It is the air-quench temperature, volume and other variables that create a surface compression of at least 10,000 pounds per square inch (psi). This is the process that makes the glass four to five times stronger and safer than annealed or untreated glass. As a result, tempered glass is less likely to experience a thermal break.
  • With heat-strengthened glass, the cooling process is slower, which means the compression strength is lower. In the end, heat-strengthened glass is approximately twice as strong as annealed, or untreated, glass.

The industry standard specification requirements for heat-treated or tempered glasses are ASTM C1048. For heat-strengthened glass, the requirement is a surface compression of 3,500 to 7,500 psi with no requirement for edge compression. Fully tempered glass will have either a minimum surface compression of 69 MPa (10,000 psi), or an edge compression of not less than 67 MPa (9,700 psi).

Safety glazings are typically specified to provide security or to keep occupants safe wherever there is the potential for broken glass to hurt people if it becomes a projectile, such as in a fire, explosion, tornado or hurricane.

Heat-strengthened glass is typically specified when additional strength is needed to resist wind pressure, thermal stress or both, and the additional strength or safety break pattern of fully tempered glass is not required. Another advantage of heat-strengthened glass is that when broken, the glass fragments are more similar in size and shape to annealed glass fragments and thus tend to stay in the opening longer than fully tempered glass particles. Although heat-strengthened glass is NOT a safety glazing by building code, this breakage pattern prevents the glass from falling and injuring someone.

Safety glazing is fully-tempered glass that meets the requirements of the safety glazing standard CPSC 16 CFR 1201 or ANSI Z97.1, or both. Safety glazing, when broken, fractures into relatively small pieces, thereby greatly reducing the likelihood of serious cutting or piercing injuries in comparison to ordinary annealed glass. For some applications, such as glass in doors, tub and shower enclosures and fixed glass in close proximity to a walking surface, fully-tempered safety glass is required by building codes and ordinances. Fully-tempered safety glass is often used for other applications where its strength and/or safety characteristic are desirable, such as table tops, counter tops, showcase enclosures, refrigeration and food service equipment, furniture and similar applications. Fully-tempered glass also is used in applications when significant additional strength is needed to resist wind pressure, thermal stress or both.

However, because of this break pattern, tempered glass is much more likely to fall from the glazing system immediately upon breakage. It’s essential for design professionals to consider this when selecting a safety glass. If it’s important for the glass to stay anchored in the glazing system, another form of safety glass, such as laminated glass, should be considered.

With both heat-strengthening and tempering, distortion is a possibility. Optical image distortion occurs in glass for many reasons, including glazing pressure, wind load, temperature and barometric pressure changes, or even changes in altitude between where a glass is made and where it is installed. Because of its fluidity at higher temperatures, glass also is inherently susceptible to roller wave, bow and warp while it is being heat-treated.

That’s why doing full-scale mock-ups under job-site conditions are recommended to evaluate the optical aesthetics of a specific heat-treating process. In addition, the following tips are suggested in order to minimize the potential impact of glass distortion that is inherent with heat-treating processes:

  • Produce all heat-treated glass for a given project on the same equipment, using the same processing parameters
  • Glass distortion may also occur due to strain patterns in heat-treated glass or interference fringe patterns in the fabrication of insulating glass units
  • Use thicker glass, as it is less prone to distortion
  • Orient heat-treated glass so that roller wave (the periodic wave imparted to glass during heat-treatment, measured by the peak-to-valley distance) is parallel to the window sill/header

While there is no industry standard to quantify permissible heat-treated glass roller wave, a tolerance of 0.005 inches is often specified. Vitro Architectural Glass (formerly PPG glass) recommends using a millidiopter specification instead, if it is available.

Safety is a prime consideration when determining the type of heat-treating process necessary for a project. Deciding whether to use heat-strengthened or tempered glass depends on the specific application. For example, heat-strengthened glass can be selected for applications that do not specifically require a safety glass product; and tempered glass should be used wherever safety glass is a requirement.

For complete technical information about using heat-treated vs. heat-strengthened glass, read Vitro Architecutral Glass Technical Document TD-138. For any other glass questions, please contact Vitro glass or call 1-855-VTRO-GLS (1-855-887-6457).

Is glass temperature safe?

Heat Strengthened vs. Tempered Glass