Tempered Vacuum Glass: A Comprehensive Guide to Performance Advantages and Maintenance
In the field of modern architecture and home decoration, glass, as a crucial decorative and functional material, has always seen its performance upgrading as a focus of the industry. Tempered Vacuum Glass, a core product of glass technology iteration, has gradually replaced traditional insulated glass and single-pane glass with its outstanding safety performance, energy-saving effect, and durability, becoming the first choice for high-end buildings, passive houses, and high-quality homes. However, even with excellent performance, the use and maintenance of Tempered Vacuum Glass still need to follow scientific methods, among which "keeping away from acid and alkaline substances" is a key principle to prolong its service life. This article will comprehensively analyze the characteristics of Tempered Vacuum Glass from two dimensions: usage precautions and core advantages, providing professional references for users.
I. Core Usage Precaution: Why Keep Away from Acid and Alkaline Substances?
Although Tempered Vacuum Glass is far superior to ordinary glass in performance, its core component is the same as that of ordinary glass, with silicon dioxide as the main raw material. This chemical property determines its "sensitivity" to acid and alkaline substances - long-term or direct contact with specific acid and alkaline substances will cause irreversible chemical reactions, thereby damaging the glass structure and affecting its performance and service life.
From the perspective of chemical principles, silicon dioxide, as an acidic oxide, will undergo a double decomposition reaction with alkaline substances. Strong alkaline substances such as sodium hydroxide (caustic soda) and potassium hydroxide commonly found in daily life and industrial scenarios, if accidentally in contact with the surface of Tempered Vacuum Glass, will gradually corrode the glass surface layer and generate soluble substances such as sodium silicate. In the early stage, it may manifest as foggy turbidity and decreased gloss on the glass surface; in the later stage, it will lead to the peeling of the surface layer, reduced structural strength, and even cracks. For example, if a cleaning agent containing strong alkaline components (such as some industrial degreasers) is mistakenly used for cleaning and not rinsed thoroughly in time, damage to the glass surface may be observed in a short period.
What is more alarming is the special acidic substance like hydrofluoric acid. Different from ordinary acids (such as hydrochloric acid and sulfuric acid), hydrofluoric acid can directly react with silicon dioxide (chemical equation: SiO₂ + 4HF = SiF₄↑ + 2H₂O), generating volatile silicon tetrafluoride gas and water. This reaction is "penetrating" - it not only corrodes the glass surface but also may penetrate into the interior to damage the sealing layer of Tempered Vacuum Glass, leading to the leakage of the vacuum cavity and directly losing core functions such as heat preservation and noise reduction. Hydrofluoric acid is widely used in industrial fields such as glass engraving and semiconductor processing. Although it is not common in daily scenarios, it is necessary to be alert to its residues or accidental contact - once in contact, it may cause permanent damage to the glass within just a few minutes, and the repair difficulty is extremely high.
In addition, even weak acid and alkaline substances (such as accumulated rainwater and cleaning agents containing acidic components) will produce a "cumulative effect" if they adhere for a long time. For example, if the Tempered Vacuum Glass on the outer wall of a building is exposed to an acid rain environment for a long time, acidic substances such as sulfur dioxide and nitrogen oxides in the rain will slowly erode the glass surface and accelerate aging. Therefore, in daily use, it is necessary to achieve "two avoidances and two protections": avoid using cleaning agents containing acid and alkaline components, and avoid using Tempered Vacuum Glass in scenarios where it is in direct contact with acid and alkaline solutions (such as laboratory operation table glass); choose neutral cleaning agents (such as special glass water) for daily cleaning, and wipe dry with a dry cloth in time after cleaning; if it accidentally comes into contact with acid and alkaline substances, rinse immediately with a large amount of water, and then wipe with a neutral cleaning agent.
In essence, although tempered glass has improved toughness (its impact resistance is 3-5 times that of ordinary glass), reduced flexibility through high-temperature quenching process, and broken into granular shapes without sharp corners, greatly improving safety performance, the "tempering" process only changes the physical structure, not the chemical properties. Therefore, following the maintenance principle of "keeping away from acids and alkalis" is the basis for ensuring that Tempered Vacuum Glass can exert its performance stably for a long time.
II. Seven Core Advantages of Tempered Vacuum Glass: Redefining the Performance Standards of Glass
The wide application of Tempered Vacuum Glass stems not only from the convenience of its maintenance but also from its "breakthrough advantages" in terms of safety, energy saving, and service life. Compared with traditional insulated glass and single-pane glass, it has achieved a comprehensive performance upgrade through the combination of "high vacuum cavity + low-temperature sealing technology + high-performance Low-E glass". Specifically, it can be summarized into seven advantages:
1. Tempered Safety: Fully Retaining Tempered Properties, Meeting Standards Without Composite Processing
Safety is the primary consideration for glass materials, and Tempered Vacuum Glass has achieved a "technological breakthrough" in this dimension. In the production process of traditional vacuum glass, the high-temperature sealing process (temperature exceeding 600℃) is often adopted, which will cause the "annealing phenomenon" of tempered glass - that is, the internal stress formed during the tempering process is released, losing the core characteristics of impact resistance and wind pressure resistance, and finally becoming "ordinary vacuum glass". To make up for this defect, some products need to improve safety through composite processes such as lamination, which not only increases costs but also affects light transmittance.
However, high-quality Tempered Vacuum Glass adopts the unique low-temperature sealing technology (sealing temperature below 300℃), which fundamentally avoids the damage of high temperature to the tempered structure and fully retains the physical properties of tempered glass: its impact resistance can reach more than 150kg/cm², which can resist external impacts such as hail and strong winds; its wind pressure resistance meets the needs of high-rise buildings, and it can withstand the pressure caused by strong winds even when installed on the outer wall of buildings above 30 floors. More importantly, Tempered Vacuum Glass does not need to be additionally combined with other materials, and can meet all the standards for safety glass in the national "Regulations on the Management of Building Safety Glass" when used alone. It is suitable for various scenarios such as doors, windows, curtain walls, and sunrooms, taking into account both safety and aesthetics.
2. True Energy Saving: Heat Transfer Coefficient as Low as 0.4W/(m²·K), the First Choice for Passive Houses
Driven by the "dual carbon" goal and the concept of green buildings, energy saving has become a core indicator of building materials, and the energy-saving performance of Tempered Vacuum Glass can be called the "industry benchmark". Its energy-saving advantage comes from two core designs: high vacuum cavity and high-performance Low-E glass.
The high vacuum cavity is the key to blocking heat transfer. The cavity of traditional insulated glass is filled with air or inert gas, and the thermal movement of gas molecules will still cause heat transfer; while the vacuum degree of the cavity of Tempered Vacuum Glass can reach below 10⁻³Pa, with very few gas molecules, so gas heat transfer is almost negligible. At the same time, the application of high-performance Low-E glass (low-emissivity glass) can greatly "alleviate radiant heat transfer" - the special metal coating on its surface can reflect more than 90% of far-infrared rays, reducing the heat exchange between indoor and outdoor. Combined, these two factors make the heat transfer coefficient (U-value) of Tempered Vacuum Glass as low as 0.4W/(m²·K), which is far superior to that of insulated glass (usually 1.8-3.0W/(m²·K)) and single-pane glass (about 5.8W/(m²·K)).
Specifically, the thermal insulation performance of Tempered Vacuum Glass is 2-4 times that of insulated glass and 6-10 times that of single-pane glass. This performance makes it the ideal choice for "passive houses" - as the highest standard of energy-saving buildings, passive houses have extremely strict requirements on the heat transfer coefficient of doors and windows (usually requiring U-value ≤ 0.8W/(m²·K)), and Tempered Vacuum Glass can fully meet this requirement when used alone without additional insulation layers. In practical applications, buildings installed with Tempered Vacuum Glass can reduce heating energy consumption by 30%-50% in winter and reduce air conditioning load by more than 40% in summer, which can save users a lot of energy costs in the long run.
3. Long Service Life: Expected Service Life of More Than 25 Years, Stable Performance for a Long Time
Due to the limitations of sealing technology, the gas in the cavity of traditional insulated glass is prone to leakage. Usually, problems such as fogging and condensation will occur after 8-12 years of use, the thermal insulation performance will decrease significantly, and replacement and maintenance are required. However, relying on advanced sealing technology and structural design, Tempered Vacuum Glass extends its expected service life to more than 25 years, which is almost the same as the service life of the main building structure, greatly reducing the later maintenance costs.
The secret of its long service life also depends on the high vacuum cavity and low-temperature sealing technology: on the one hand, the high vacuum environment reduces the erosion of the sealing layer by gas molecules, avoiding the aging of the sealant; on the other hand, the low-temperature sealing technology ensures that the combination of the sealing layer and the glass is tighter, and cracks and leaks are not easy to occur. At the same time, the coating layer of high-performance Low-E glass has undergone special treatment, with excellent aging resistance, and there will be no problems such as coating peeling and decreased light transmittance during long-term use.
According to tests by third-party testing institutions, after Tempered Vacuum Glass operates continuously for 5000 hours in a simulated extreme environment (cycling between -40℃ and 80℃, humidity above 95%), the change rate of the heat transfer coefficient (U-value) is only 2.3%, which is far lower than the maximum allowable change rate of 15% for insulated glass. This means that Tempered Vacuum Glass can maintain stable performance for a long time even in cold northern regions, humid southern regions, or high-altitude areas, without frequent maintenance.
4. Light and Thin Structure: Thinner and Lighter, Balancing Light Transmittance and Space Adaptability
To improve energy-saving performance, traditional glass often adopts multi-layer structures such as "triple glazing with two cavities", resulting in increased thickness (usually 24-30mm) and weight (about 35kg per square meter). This not only affects the lightness of the building's appearance but also places higher requirements on the load-bearing capacity of the door and window frames. However, while upgrading its performance, Tempered Vacuum Glass has achieved a "structural weight and thickness reduction".
Under the premise that the heat transfer coefficient (U-value) is far superior to that of "triple glazing with two cavities" insulated glass, the thickness of Tempered Vacuum Glass is only 4-5mm, which is equivalent to one-sixth of that of traditional insulated glass; in terms of weight, each square meter of Tempered Vacuum Glass weighs less than 25kg, which is 10kg less than that of "triple glazing with two cavities" insulated glass. This advantage makes it suitable for various architectural scenarios: when installed on curtain walls, it can reduce the overall load-bearing of the building and lower the structural design cost; when used for indoor partitions, it can enhance the transparency of the space and avoid a sense of depression; even for the door and window renovation of old buildings, there is no need to replace the frames with weak load-bearing capacity, reducing the renovation difficulty and cost.
In addition, Tempered Vacuum Glass uses fewer Low-E glass panels (usually a single panel), which reduces the reflection and absorption of light by the coating layer. Its light transmittance can reach more than 80%, which is far higher than that of "triple glazing with two cavities" insulated glass (about 65%). While ensuring energy saving, it can introduce more natural light into the room and improve the comfort of living and office environments.
5. Anti-Condensation: Fundamentally Eliminating Internal Condensation, Adapting to Extreme Low Temperatures
Condensation is a common problem of traditional glass - when the temperature difference between indoor and outdoor is large in winter, water vapor in the air will condense into water droplets on the inner surface of the glass, which not only affects the line of sight but also may cause the window frame to get damp and the wall to become moldy. However, relying on the design of the high vacuum cavity, Tempered Vacuum Glass fundamentally solves this problem.
The cavity of traditional insulated glass contains air or inert gas. When the indoor temperature is higher than the outdoor temperature, the temperature of the inner surface of the glass will drop with the outdoor temperature. If it is lower than the dew point temperature, water vapor will condense into dew. However, the high vacuum environment of Tempered Vacuum Glass almost blocks heat transfer, so the temperature of the inner surface of the glass can always be close to the indoor temperature. Even if the outdoor temperature drops to -40℃ (such as in extremely cold areas in Northeast and Northwest China), the temperature of the inner surface of the glass can still be maintained above 10℃, which is far higher than the dew point temperature (usually 5℃-8℃), so there will be no internal condensation.
At the same time, the outer surface of Tempered Vacuum Glass has undergone special treatment, with a certain anti-fogging performance, which can reduce fogging on the outer surface even in an environment with high outdoor humidity. This advantage enables it to be used stably in humid southern areas, bathrooms with high humidity, and extremely cold northern areas, avoiding equipment damage and environmental problems caused by condensation.
6. Effective Noise Reduction: Significant Sound Insulation for Medium and Low-Frequency Noise, Creating a Quiet Space
Noise pollution is one of the main troubles in modern urban life. Medium and low-frequency noises (with a frequency of 200-1000Hz) such as traffic noise (such as car engine sound and tire friction sound), construction noise, and neighborhood noise have strong penetration and are difficult to be effectively blocked by traditional insulated glass. However, the high vacuum cavity of Tempered Vacuum Glass can block sound from the transmission path, especially having a significant sound insulation effect on medium and low-frequency noise.
The transmission of sound requires a medium (solid, liquid, gas), but there are almost no gas molecules in the high vacuum cavity, so sound cannot be transmitted through gas; at the same time, the sealing layer and support structure of Tempered Vacuum Glass are made of damping materials, which can reduce solid-borne sound transmission. From the perspective of data, the human ear is extremely sensitive to noise - for every 5-decibel difference, the auditory perception differs by 3-4 times. According to the weighted sound insulation quantity (RW) standard test, for outdoor noise of 75 decibels (equivalent to traffic noise on busy roads), after being blocked by Tempered Vacuum Glass, the indoor noise can be reduced to below 39 decibels (equivalent to the quietness of a library), while the sound insulation quantity of traditional insulated glass is usually only 29 decibels (equivalent to the sound of normal indoor conversation).
In practical applications, residences installed with Tempered Vacuum Glass can effectively isolate noises such as car horns and engine roars even if they are adjacent to the street; when used in offices, it can reduce external interference and improve work efficiency; when used in places sensitive to noise such as hospitals and schools, it can provide a quiet environment for patients and students.
7. Versatile Environmental Adaptability: Unaffected by Region, Altitude, and Installation Angle, with Strong Adaptability
Due to the gas in the cavity, traditional insulated glass is prone to performance fluctuations in different environments: in high-altitude areas (such as Tibet and Qinghai), due to low air pressure, the cavity of insulated glass may expand and deform; when installed at an incline (such as sloped roofs and curtain wall corners), gas convection will cause the heat transfer coefficient to increase, affecting the energy-saving effect. However, the high vacuum cavity of Tempered Vacuum Glass is completely unaffected by external air pressure and installation angle, with strong adaptability.
In terms of regions, whether in low-altitude coastal areas (such as Shanghai and Guangzhou) or high-altitude plateau areas (such as Lhasa and Xining), the cavity of Tempered Vacuum Glass will not expand or contract, and its performance is stable. In terms of installation angle, whether it is installed horizontally (such as doors and windows), obliquely (such as sloped roof skylights), or vertically (such as curtain walls), its heat transfer coefficient can remain constant and will not change due to gas convection. This advantage makes it suitable for various climate zones and building types across the country, without the need to adjust the design according to regions, reducing the application threshold.
III. Conclusion: The Value and Maintenance of Tempered Vacuum Glass
As a high-end product of glass technology, Tempered Vacuum Glass has redefined the performance standards of glass with its seven advantages of "tempered safety, true energy saving, long service life, light and thin structure, anti-condensation, effective noise reduction, and versatile environmental adaptability", providing an ideal material for green buildings and high-quality homes. However, the sensitivity of its core component silicon dioxide to acid and alkaline substances determines that "keeping away from acids and alkalis" is the key to maintenance - avoiding contact with substances such as sodium hydroxide (caustic soda) and hydrofluoric acid and choosing neutral cleaning agents can effectively prolong its service life and ensure stable performance for more than 25 years.
In the future, with the advancement of passive house construction and the improvement of consumers' requirements for living quality, Tempered Vacuum Glass will become the mainstream choice of building materials. Mastering its performance advantages and maintenance methods can not only help users better exert its value but also provide guarantees for the energy saving and safety of buildings, realizing the living goal of "green, comfortable, and long-lasting".
