LOW-E glass, also known as low-e glass, is a kind of energy-saving glass. Because of its superior energy-saving and colorful colors, it has become a beautiful landscape in public buildings and high-end residential buildings. Common LOW-E glass colors include blue, gray, colorless, etc. These mainstream colors are durable and durable, and are the mainstream exterior colors of urban architecture. There are also some more distinctive colors, such as gold, silver, and silver. Blue wait.
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As we all know, we use glass as a curtain wall for the following reasons: adopting natural light, reducing energy consumption, and being beautiful. The color of glass is like a person’s clothes. The right color can make people look bright, and the inappropriate color can make people look uncomfortable. So how do we choose the right color? Let’s discuss the following aspects: Light transmittance, outdoor reflection color, reflection color and transmission color of the film surface, original film and structure, and the influence of interference color during the sample viewing process.
01、Proper light transmittance
According to the “General Principles of Civil Architecture Design” GB50352-2005, civil buildings are divided into two categories according to their use functions: public buildings and residential buildings.
Mandatory provisions: “Code for Energy-saving Design of Public Buildings” GB50189-2015 for Class A public buildings: when the area ratio of single facade window to wall is less than 0.4, the light transmittance of glass should not be less than 0.60; single facade window to wall area ratio ≥ 0.4 At this time, the light transmittance of the glass should not be less than 0.40.
Implicit regulations: “Code for Energy Efficiency Design of Public Buildings” GB50189-2015, “Design Standards for Energy Efficiency of Residential Buildings in Severe Cold and Cold Areas” JGJ26-2010, “Design Standards for Energy Efficiency of Residential Buildings in Hot Summer and Cold Winter Areas” JGJ134-2010, “Hot Summer and Winter In the “Energy-saving Design Standard for Residential Buildings in Warm Areas” JGJ 75-2012, for building facades, glass materials with different window-to-wall ratios have specific parameter limits for shading coefficient Sc or solar heat gain coefficient SHGC, while shading coefficient and light transmittance Rates are closely related. When we choose glass, we need to refer to specific performance parameters.
Other principles: building use (such as housing needs better daylighting), owner’s preferences, local solar radiation illuminance factors, other relevant national and local energy-saving standards, etc.
02, suitable outdoor color
1) Appropriate outdoor reflectance:
Outdoor reflectance is a color factor that is easily overlooked by everyone. In fact, it is not just specific red, green, yellow, blue and other color values. The reflectance of glass is also closely related to its color expression.
The outdoor reflectivity of hollow LOW-E glass is generally between 10%-30% (national regulations, the external reflection of LOW-E glass is not more than 30%),
①10%-15%: It can be called low-reflectivity. The low-reflective glass color is less irritating to human eyes, not very deep color, and will not give people very vivid color characteristics;
②15%-25% reflectivity: it can be called mid-reflection. The color expression of mid-reflection glass is the best, and it is easy to highlight the color of the film. For example, blue glass has reflectivity in this section. , The color will be blue and very gorgeous, for the same reason, other colors will be the same;
③25%-30%: It can be called high reflection. High reflection glass has too strong reflectivity and is very irritating to the pupils of human eyes. The pupils will shrink adaptively to reduce the amount of light incident. Therefore, we look at high reflectivity. The color of the glass will be distorted to a certain extent, and the color looks like a piece of white. This color is generally called silver, such as silver white, silver blue and so on.
Glass with high reflectivity will cause certain light pollution and safety hazards under certain conditions. For example, in the “Optical Performance of Glass Curtain Walls” GB/T 18091-2000, it is proposed that the reflectance of glass curtain walls installed on both sides of urban arterial roads, overpasses, and elevated roads is less than 20m, and the other road sections less than 10m. The reflectance should be controlled below 0.16 ; Glass curtain walls should be restricted in residential areas (for safety and daylighting, try to choose glass with lower reflectivity). ·
2) Appropriate color value:
The color is like the coat of a building. We need to choose the right color according to the customer’s preference and usage function. Featured item color recommendation:
Traditional banking, finance, and high-end consumer places need to create a magnificent feeling. At this time, if you choose pure color and high-reflectivity gold-based glass, you can set off a good atmosphere.
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libraries, exhibition halls and other projects, you can choose high-transmittance and low-reflection colorless glass, without visual obstacles, no sense of restraint, and can provide people with a relaxed reading environment.
Commemorative public construction projects such as museums and martyrs’ cemeteries need to give people a sense of solemnity. We can choose Chinese anti-gray glass.
In general residential projects, in order to take into account the characteristics of safety, lighting, comfort and other aspects, you can choose colorless, blue-gray, gray and other colors of glass with medium and high transparency.
03, the influence of transmission color and film surface color
Generally speaking, we pay more attention to the outdoor reflection color, but less to the transmission color and the reflection color outside the film surface.
If we stick LOW-E glass on a piece of white paper, or look at the outdoor scenery through the window, what affects our vision is the through color. Outdoors, we look up at the glass of the tall building, and the glass on the low floor will Seeing through the interior and high-rise glass, because the angle between the viewing angle and the vertical glass is very small, what we see is the color reflected by the glass.
Because the film surface of LOW-E glass faces indoors, if you look at the glass indoors, it is difficult to see the reflection color of the film surface due to the light intensity and angle. Generally, we see the transparent color. , When the outdoor is dark, turn on the light indoors, and the color of the film can be seen clearly at a specific angle.
In the national standard, only the chromatic aberration range of the outdoor reflected color of the glass is specified, and there are no specific restrictions on the transmission color and the surface color of the film.
Only low-rise buildings and indoors can see the transmittance color, and the range of the transmittance color is very small. The transmittance color of the conventional film system is generally within the acceptable range; the color of the surface color of some films is heavier, but only Indoors at night can only be seen under certain conditions. Therefore, as long as the transparent color and the surface color of the film are within a reasonable range, it is acceptable.
04, the effect of different original films and glass structures on color
Sometimes, when choosing the color, we choose the color of a certain 6+12A+6 conventional LOW-E glass. If the original film and structure change, after the wall is installed, the color and selection of the glass may be found There is a big difference from time to time for the following reasons:
1) Ultra-white glass: Because the iron ions in the glass are removed, the color will not show green. The color of conventional hollow LOW-E glass is adjusted based on ordinary white glass, and the structure will be 6+12A+6. The white glass is adjusted to a more suitable color. If the film is coated on the ultra-white substrate, some colors may have a certain degree of redness. The thicker the glass, the greater the color difference between normal white and ultra-white.
2) Thick glass: The same is true. The thicker the glass, the greener the glass. The thickness of the single piece of insulating glass increases. The use of laminated insulating glass makes the color greener.
3) Colored glass. Common colored glass includes green glass, gray glass, tea glass, etc. These original films have heavy colors. After coating, the color of the original film will cover the color of the film. The main function of the film is heat. Performance.
Therefore, when choosing LOW-E glass, we must not only consider the color of the standard structure, but also comprehensively consider the glass substrate and structure.
05. Eliminate the interference color in the process of glass hanging sample
Before LOW-E glass is mounted on the wall in large quantities, a small batch of wall color comparison is a necessary process, but there will be more interference items during outdoor color comparison, such as the intensity of sunlight and the angle of sunlight on the day , The color contrast between different LOW-E glasses, etc., the first two can be observed through different time periods and different angles, but the color contrast between different colors of glass can sometimes cause us trouble .
In the coating process control coordinate system L*a*b*, we use digital methods to accurately control the color, L* represents the brightness value; a* represents red and green, a* is a positive value, showing red, a* is Negative value means green, a* is 0, which means colorless; b* means yellow and blue, b* means positive value, means yellow, b* means negative value, means green, b* means 0, means colorless.
For example, in the color of glass, red tone is a color that we are very taboo. The reason is that the human eye is very sensitive to red (the warning color in many occasions, such as traffic lights and factory warning signs are red), for LOW- The color of E glass, even a very light red can be detected by our naked eyes. But when two films with the same green tone (or a green and a gray) are put together and compared, the glass with a* biased (large) will appear red. In summary, it means “no contrast.” , There will be no harm”, put it together, the small difference between the two will be detected by our eyes, in fact, if this piece of “red” glass is taken out alone for observation, it may not be red. It may even be a very attractive color; if we want to reduce the impact of chromatic aberration caused by this color, we can appropriately increase the distance between the two, or set a transition color of the same hue between the two .
Most of the time, we are not only taboo red, but the human eye has a certain range of adaptability to various colors. If we cannot eliminate the influence of interference colors in time during the color matching process, we may choose the wrong color. Color, you will regret it after the products are put on the wall in large quantities.
