Tempered Glass is one of the most widely used types of safety glass in the construction and interior decoration industry. This glass is favored by designers and contractors due to its high strength, beautiful appearance, and safety standards. However, many people encounter various names when purchasing and may become confused in their choice.
In this article, we will fully explain what tempered glass is, how it is produced, and by what names it is known in the market.
Tempered Glass is a type of strengthened glass that, through a process of heating and rapid cooling, achieves a strength four to five times greater than ordinary glass. An important feature of this glass is that when broken, it shatters into small, non-sharp particles, reducing the risk of cuts or serious injury. For this reason, it is classified as safety glass.
The production process of tempered glass involves the following steps:
The production process of tempered glass begins with ordinary glass; glass that must first be cut precisely and without the slightest error. The reason this cutting stage is so critical is that after tempering, the glass can no longer be cut, drilled, or modified in any way. For this reason, all details including hinge positions, locks, handles, and even small cutouts must be specified and applied to the raw glass from the start. After the cutting stage, the glass enters the washing stage. This stage is very important because any dust, stains, or grease on the glass can affect the final quality and even cause microscopic cracks that will cause problems later.
After washing, the glass is completely dried and enters the tempering furnace. This furnace is the heart of the tempered glass production process. Inside the furnace, the glass is heated to approximately 650 to 700°C; a temperature at which the glass reaches a near-softening state but still maintains its shape. The most important part of this stage is uniform heating. If heat is not evenly distributed, the glass will end up wavy, warped, or with thermal spots. For this reason, standard furnaces use advanced systems for precise temperature control.
When the glass reaches the required temperature, it immediately enters the rapid cooling or quenching stage. In this stage, very strong and controlled streams of cold air at high pressure strike both surfaces of the glass. This sudden cooling causes the outer layers of the glass to freeze and harden quickly, while the inner part of the glass is still hotter and cools at a slower rate. This difference in cooling speed creates permanent compressive stresses on the glass surface and tensile stresses inside it. These stresses are what make the glass 4 to 5 times stronger than ordinary glass.
Finally, the glass is removed from the furnace and slowly cooled to stabilize the stresses. It is then inspected by factory quality experts. They check the glass for flatness, absence of waviness, absence of warping, possible micro-cracks, and uniformity of firing. Only glass that passes these standards enters the market as standard tempered glass.
The result of this process is glass that is very strong, transparent, safe, and durable, with completely different performance against impact, thermal shock, and pressure compared to ordinary glass, and it breaks into small, harmless particles if shattered.
Tempered glass is approximately 4 to 5 times stronger than ordinary glass.
This high strength is due to the compressive stresses created on the glass surface during the tempering process.
For this reason:
It breaks later
It is resistant to sudden impacts
It is considered an excellent choice for places where security is important
such as storefront doors, office partitions, and display cases.
One of the most important advantages of tempered glass is its safe behavior when broken.
When this glass breaks:
It breaks into small, cube-shaped particles
It has no sharp edges
The risk of cuts and serious injury is greatly reduced
For this reason, it is used in high-traffic areas such as commercial centers, halls, glass elevators, and more.
Tempered glass can withstand temperature differences of up to 200°C.
While ordinary glass may crack even with a temperature difference of 70°C.
This feature makes it:
Used in glass facades, balcony glass, partition glass, and shower cabins
Easy to use in direct sunlight and steam without being damaged.
Due to its thermal and mechanical resistance, tempered glass has no installation limitations.
This glass is very suitable for:
Interior spaces (doors, partitions, shower cabins, tables)
Exterior spaces (balconies, terraces, building facades, parapets)
Moisture, heat, and cold have no effect on its quality.
Tempered glass is not only clear.
It is produced in various types:
Clear
Gray
Bronze
Satin (matte)
Acid-etched matte
Printed
Patterned
Colored
This variety makes it a professional and attractive option in interior design and decoration.
Due to its compact surface structure, tempered glass can withstand greater pressure.
On glass tables
Glass flooring
Storefront display glass
Sliding and hinged door glass
All these applications require load-bearing capacity, and tempered glass is ideal for them.
Tempered glass is resistant to:
Color change
Surface scratches (in some models)
Warping
Waviness
It has good resistance.
If produced in a standard furnace, it will remain without quality loss for years.
Tempered glass is compatible with various fittings:
Hinges
Clamps
Locks
Rails
Patch fittings
This makes installation easy and quick, and highly practical for modern decoration.
Tempered glass can be combined with the following:
Due to its strong and stable structure, tempered glass has the ability to be combined with various technologies and offer completely different performance. One of the most common combinations is tempered laminated glass. In this case, two or more layers of tempered glass are bonded together with an intermediate layer of PVB or SGP. The result is glass that is much stronger than regular tempered glass; glass that, even if broken, does not allow the glass pieces to separate due to the intermediate layer. This feature makes it much safer for use in glass flooring, parapets, railings, and elevated spaces.
Another type of combination is smart or switchable tempered glass. In this technology, a smart film layer (PDLC) is placed on the tempered glass. When electricity is applied, the glass becomes transparent, and when the power is cut, it becomes opaque. This type of glass is widely used in executive offices, meeting rooms, bathrooms, and modern spaces. The reason this system is applied to tempered glass is the high resistance of tempered glass to pressure and temperature; because the smart film is very sensitive and requires a surface with high stability.
Another combination that is less known but very practical is digital printing on tempered glass. In this method, a design or image is digitally printed on the glass surface, and then the glass enters the tempering furnace to fix the printing ink onto the glass surface and make it fully resistant. The result is glass whose design does not fade, does not lose color, and has high scratch resistance. This technology is widely used in building facades, office partitions, and decorative glass.
Tempered glass can also be used in manufacturing double-glazed glass. In this case, one or both layers of the double-glazed unit use tempered glass, so the glass not only provides insulation but also offers higher strength. This combination is very suitable for large windows, frameless facades, building display cases, and high-risk spaces; because if one layer is damaged, the double-glazed unit still maintains its structure.
The combination of tempered glass with modern aluminum, steel, and UPVC frames is also widely used. These frames enhance insulation, aesthetics, and structural strength. Since tempered glass has good resistance to heat and pressure, it is considered the best choice for these systems.
In summary, the ability to combine tempered glass with various technologies has made this glass not just a simple product, but a completely versatile option adaptable to today’s needs; whether in special and decorative designs, or in cases where safety and technology are of high importance.
In the Iranian market, tempered glass is known by various names. Some of these names are technical, while others are common terms used among sellers and installers.
This is the most common commercial name for tempered glass in Iran. Many customers refer to any heat-treated glass as “Miraleh glass.”
The technical name for this product in the glass industry.
The international name for tempered glass, also heard in the market.
When discussing its use in sensitive spaces such as bathrooms, balconies, or partitions, it is often referred to as safety glass.
Although scientifically it is not completely “unbreakable,” due to its high strength, this name has become popular among customers.
Sometimes the combination of laminated glass and tempered glass is also called “tempered laminated.” This product consists of two layers of tempered glass with a PVB layer between them.
Tempered glass is used in various parts of a building due to its numerous advantages:
Glass doors (offices, stores, buildings)
Office partitions
Shower cabins and bathrooms
Balcony and terrace glass
Building facades (frameless, spider)
Glass tables and decorative glass
Storefront display cases
Parapets and glass railings
Cooktop glass, household and industrial appliances
| Feature | Ordinary Glass | Tempered Glass |
|---|---|---|
| Impact Resistance | Low | Very High |
| Thermal Shock | Sensitive | Resistant |
| Breakage Pattern | Sharp and Dangerous | Small, Harmless Particles |
| Cutting Capability | Possible | Impossible After Tempering |
| Safety | Low | High |
When you intend to buy tempered glass, the first thing you should pay attention to is glass production quality. The quality of tempered glass directly depends on the type of furnace and factory standards. Glass produced in old or non-standard furnaces typically has waviness, warping, or tiny thermal spots. These issues may not be very noticeable at first glance, but after installation, especially in spaces with direct light, they become clearly visible and ruin the appearance. Therefore, it is important to choose glass that has uniform firing, no waviness, and no spots.
Check the quality of fittings (hinges, locks, clamps).
Tempered glass fittings are crucial. No matter how good the glass quality is, if low-quality fittings are used, both safety and the glass’s useful life are reduced. Hinges, locks, clamps, rails, and patch fittings must be made of strong materials and from reputable brands. Many sudden breakages of tempered glass occur due to improper fittings or non-standard installation. So when buying, it’s not just the glass that matters; standard fittings must also be part of your decision.
Choose the appropriate glass thickness for the application (10mm and 8mm are the most common).
Appropriate glass thickness is essential. The choice of thickness depends on the installation location and type of use. For example, glass used for storefront doors is typically 10mm because it needs to have greater resistance to pressure and impact. But shower cabin glass or lighter partitions can be 8mm. If glass thinner than the standard is chosen, the risk of breakage increases, and if it is thicker than needed, the extra weight puts pressure on the fittings and increases costs. Therefore, the best approach is to choose the thickness according to the standard recommended by the installer or specialist.
Do not underestimate the frame and professional installation; safety is very important.
One important point that is often overlooked is that tempered glass can no longer be cut or drilled after production. For this reason, all measurements must be precise. The slightest measurement error can render the glass completely unusable and require reordering. So before production, measurements must be taken by a professional installer. Also, if lock, hinge, or handle positions are to be created on the glass, they must be specified and executed by the factory before the tempering process.
In addition to these, the type of glass usage is also determining. For example, glass installed for a storefront display case must have very high strength, because it has more contact surface and is more likely to be impacted. But shower cabin glass needs resistance to moisture and temperature differences. For balcony glass, resistance to wind, pressure, and temperature changes is more important. Therefore, before selection, the exact application of the glass must be determined to choose the appropriate type.
Another essential point is the color and type of tempered glass. Some glass is clear, some gray, bronze, matte, or satin. Color choice is not just aesthetic; in some spaces like offices, reduced visibility may be needed, making matte glass more suitable. Or for building facades, colored or reflective glass might be better. Therefore, color and model selection should be based on ambient light, interior design, and the purpose of use.
Finally, tempered glass installation plays a very important role in its safety and durability. Even if you buy the best type of glass, non-standard installation can cause sudden breakage, loose doors, or the glass coming out of place. A professional installer must place the glass without extra pressure, observe standard frame gaps, and avoid impact to the glass edges; because the edge of tempered glass is its most sensitive part, and the slightest impact can shatter it.
In summary, when buying tempered glass, you should pay full attention to production quality, standard thickness, proper fittings, precise measurement, type of application, glass color, and professional installation. Observing these points will ensure you have durable, safe, and trouble-free glass and prevent additional costs.
Tempered glass is one of the best options for increasing safety, beauty, and durability in construction and interior decoration projects. This glass is known in the market by names such as Miraleh, Tempered, Heat-Treated, Safety, and Unbreakable, and is available in various designs and thicknesses depending on the application.
greenbrick, as a reference for building material sales, provides technical and economic consultation for choosing the best type of glass and materials compatible with Iran’s climate.
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[accordion title=”FAQs”]
[accordion-item title=”1. What is tempered glass and how is it different from ordinary glass?”]
Tempered glass is a type of heat-treated glass that is 4 to 5 times stronger than ordinary glass. If broken, it shatters into small, non-sharp particles, which is why it is classified as safety glass.
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[accordion-item title=”2. By what names is tempered glass known in the market?”]
In the Iranian market, tempered glass is known by names such as Miraleh Glass, Unbreakable Glass, Tempered Glass, Heat-Treated Glass, and Safety Glass. All these refer to the same type of glass.
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[accordion-item title=”3. Is tempered glass really unbreakable?”]
No, the term “unbreakable” is not accurate. Tempered glass does break, but much more pressure or impact is required to break it, and when it breaks, it does not become sharp or dangerous.
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[accordion-item title=”4. Can tempered glass be cut or drilled after production?”]
No. After the heat treatment process, tempered glass can no longer be cut, drilled, or resized. All dimensions and hinge and lock positions must be specified before tempering.
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[accordion-item title=”5. Where is tempered glass commonly used?”]
This glass is used in storefront glass doors, office partitions, shower cabins, railings and parapets, balcony glass, building facades, storefront display cases, glass tables, and many interior and exterior spaces.
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[accordion-item title=”6. Why is tempered glass not dangerous when broken?”]
Due to the internal stresses created during the production process, when broken it shatters into very small, cube-shaped particles that have no sharp or cutting edges; therefore, the risk of injury is very low.
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[accordion-item title=”7. In what thicknesses is tempered glass produced?”]
The most commonly used thicknesses are 8mm and 10mm, but depending on the application, it is also produced in thicknesses of 4, 6, 12, and even 15mm.
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[accordion-item title=”8. What is the difference between tempered glass and laminated glass?”]
Tempered glass has very high strength but if broken, it shatters into powder. Laminated glass is made of two or more layers of glass with a PVB layer, and if it cracks, the pieces do not fall. In many cases, for greater safety, tempered and laminated glass are combined.
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