How to choose suitable glass curtain wall materials?

Here are some factors to consider when choosing suitable glass curtain wall materials:

1、 Glass material

1. Transparency

If the building has high requirements for indoor lighting, such as commercial centers, offices, etc., it is necessary to choose glass with high transmittance. For example, white glass (colorless transparent glass) has a relatively high light transmittance, usually around 80% -90%, which can allow a large amount of natural light to enter the room and create a bright spatial environment.

For places with special privacy requirements or a need for light control, such as residential buildings, hotel rooms, etc., low transmittance glass such as frosted glass can be considered. The transmittance of frosted glass is around 60% -70%, which allows light to pass through but also blocks the line of sight, ensuring both natural lighting and privacy.

2. Thermal insulation

In cold regions, in order to reduce indoor heat loss, glass with good insulation properties should be selected. Low-E coated glass is a good choice. This type of glass has a special coating on its surface that can reflect heat, and its insulation performance is much better than ordinary glass. It can block the outward radiation of indoor heat, maintain indoor warmth in winter, and reduce heating energy consumption.

For hot areas, insulated glass can prevent outdoor heat from entering indoors. In addition to Low-E glass, hollow glass structures can also be used. The air layer inside the insulated glass (or filled with inert gas) can effectively insulate heat, and its insulation performance is better than single-layer glass, which can reduce the frequency of indoor air conditioning use and lower cooling costs.

3. Sunshade performance

In areas with abundant sunlight or parts of building facades that are heavily exposed to sunlight, the shading performance of glass needs to be considered. The shading coefficient is an important indicator for measuring the shading performance of glass, which represents the proportion of solar radiation allowed to pass through the glass. Glass with low shading coefficient can better block solar radiation heat.

For example, glass with a shading coefficient of 0.3 has better shading effect than glass with a shading coefficient of 0.6. Some coated glass can reduce shading coefficient while maintaining good visible light transmittance by adjusting the composition and structure of the coating.

4. Ultraviolet transmittance

To protect indoor furniture, decorations, carpets, and other items from UV damage, glass with low UV transmittance should be selected. Because ultraviolet radiation can cause items to fade and age. Ordinary glass has a certain absorption and reflection effect on ultraviolet rays, but the effect is limited. And some special coated glass (such as sunscreen coated glass) can effectively block ultraviolet rays, and its ultraviolet transmittance can be reduced to below 50%.

5. Mechanical strength

Glass curtain walls need to withstand external forces such as wind loads and earthquakes, so the mechanical strength of glass is very important. Tempered glass is a common high-strength glass material. It increases the strength of glass by 3-5 times compared to ordinary glass through a special heat treatment process. Tempered glass will form obtuse angle particles when broken, which is not easy to harm people and has high safety. It is suitable for curtain walls in high-rise buildings.

Laminated glass is also a choice with good mechanical strength. It is composed of two or more pieces of glass sandwiching one or more layers of organic polymer intermediate film. This structure enables laminated glass to have high resistance to penetration when impacted. Even if the glass breaks, fragments will be stuck by the intermediate film, maintaining the integrity of the glass and reducing the risk of injury to personnel. It is particularly suitable for use in high safety areas such as skylights and entrances in buildings.

2、 Aluminum profiles (curtain wall frame material)

1. Material and strength

The quality of aluminum profiles is crucial for the structural safety of glass curtain walls. Usually, aluminum profiles for construction are mainly made of aluminum alloys such as 6063-T5. This aluminum alloy has good strength and toughness, and can withstand external forces such as the self weight and wind load of glass curtain walls.

Pay attention to the wall thickness of aluminum profiles, as a thin wall thickness can lead to insufficient frame strength. The minimum wall thickness of general curtain wall aluminum profiles is around 3.0mm, and thicker wall thicknesses may be required for areas with special load-bearing requirements.

2. Surface treatment

Anodizing is a common surface treatment method for aluminum profiles. It forms a dense oxide film on the surface of aluminum profiles through electrolysis, which can improve the corrosion resistance and wear resistance of aluminum profiles. The thickness of the oxide film generally varies from 10 μ m to 15 μ m, and the greater the thickness, the better the corrosion resistance and wear resistance.

Electrophoretic coating is also a good surface treatment process. It is based on anodizing, in which organic pigments and resin components are attached to the surface of the oxide film through electric field action, making the surface of aluminum profiles not only have good corrosion resistance, but also rich color choices, which can enhance the aesthetic appearance of buildings.

Powder spraying technology can achieve various colors and textures of effects. Powder coatings have good adhesion and weather resistance, which can maintain the integrity and aesthetics of aluminum profiles for a long time. However, their corrosion resistance may not be as good as aluminum profiles after anodizing treatment.

3. Connection performance

The connection method of aluminum profiles should be reliable, generally using bolt connections, plug-in connections, and other methods. When selecting aluminum profiles, it is necessary to consider whether the design of their connection parts is reasonable and whether the firmness and sealing of the connection can be guaranteed. For example, aluminum profiles connected by bolts need to have suitable bolt hole positions and sizes, with high machining accuracy to ensure that the bolts can be tightly connected and prevent the frame from loosening under wind loads.

3、 Hardware accessories

1. Material and strength

Hardware accessories (such as glass claws, connectors, etc.) should be made of corrosion-resistant and high-strength materials. Stainless steel is one of the commonly used materials, among which 304 stainless steel and 316 stainless steel are relatively common. 316 stainless steel has better corrosion resistance than 304 stainless steel, especially in air environments containing salt (such as seaside buildings), and is less prone to rusting.

For some hardware accessories with high stress, such as supports for curtain walls, connectors for beams and columns, their specifications and dimensions should be determined based on calculations to ensure that they can withstand the corresponding loads.

2. Accuracy and adaptability

The processing accuracy of hardware accessories should be high, and the connection parts with materials such as aluminum profiles and glass should be well matched. For example, the contact part between the glass claw and the glass needs to be finely processed to ensure uniform clamping of the glass, while preventing the glass from being subjected to excessive local stress during installation and use and breaking.

3. Durability

Consider the durability of hardware accessories during long-term use. Some inferior hardware accessories may fail due to factors such as material aging and fatigue. When selecting, you can view the product's quality certification and testing reports, and choose products with good durability.

4、 Sealing material

1. Sealing performance

Sealing glue is a key material for sealing glass curtain walls. Silicone sealant is one of the common types of curtain wall sealant. It has good elasticity and sealing properties, which can effectively prevent the leakage of air and rainwater. High quality silicone sealant can maintain good sealing performance during the service life of buildings, and its tensile strength and elastic modulus meet relevant national standards.

Sealing strips (such as EPDM rubber strips) are also important sealing materials. EPDM rubber strips have good weather resistance and ozone resistance, and can maintain elasticity in long-term outdoor environments, playing a good sealing role. When selecting sealing strips, attention should be paid to their compatibility with aluminum profiles and glass to ensure a tight fit.

2. Weather resistance

The sealing material should be able to adapt to different climatic conditions, including temperature changes, ultraviolet radiation, etc. In cold winters and hot summers, sealing materials should not exhibit brittle cracking, aging, or other phenomena. Silicone sealant and EPDM rubber strips have good weather resistance, but the weather resistance of products of different brands and qualities may vary, and suitable products need to be selected according to specific engineering requirements.