Analysis of the advantages and disadvantages of glass curtain walls, worth a look

1. Regarding glass curtain walls

The glass curtain walls in modern architecture incorporate insulating glass, which consists of a combination of mirrored glass and ordinary glass, with a layer of dry air or inert gas trapped between them. Insulating glass can be divided into two-layer and three-layer types. Two-layer insulating glass consists of two layers of glass with a sealing frame, forming a laminated space; three-layer glass consists of three layers of glass, creating two laminated spaces. Insulating glass has advantages such as sound insulation, heat insulation, frost resistance, moisture resistance, increased light transmittance, and high wind pressure resistance. However, it also faces issues such as light pollution and high energy consumption.

1. Analysis of advantages and disadvantages

(1) Advantages

Glass curtain wall is a new type of contemporary wall, which bestows upon buildings the most prominent feature of organically integrating architectural aesthetics, architectural function, architectural energy efficiency, and architectural structure. The building exhibits different hues from different angles, presenting a dynamic beauty that changes with the sunshine, moonlight, and lighting.

The reflective insulating glass is 6mm thick, with a self-weight of approximately 50kg/㎡ on the wall. It boasts advantages such as being lightweight and aesthetically pleasing, resistant to stains, and energy-efficient. By incorporating trace metal elements into the float glass composition and tempering it into a transparent plate-like glass, it can absorb infrared rays, reduce solar radiation entering the room, and lower indoor temperatures. It can reflect light like a mirror and transmit light like glass. The inner side of the outer layer of the curtain wall glass is coated with a colored metal film. From the outside, the entire exterior wall appears like a mirror. With the reflection of light, the interior is shielded from direct sunlight, providing a soft visual experience.

(2) Disadvantages

Glass curtain walls also have some limitations, such as light pollution and high energy consumption. Coated glass or coated glass is used on the curtain walls of buildings. When direct sunlight and skylight are shone on the glass surface, reflective glare is generated due to the specular reflection (i.e., regular reflection) of the glass. However, with the development of glass curtain wall technology and the continuous emergence of new material technologies, the materials used in glass curtain walls in buildings can now better address the issues of light pollution and energy consumption.

II. Basic classification

1. Visible frame glass curtain wall

The visible frame glass curtain wall is a glass curtain wall where the metal frame components are exposed on the outer surface. It utilizes aluminum alloy profiles with special cross-sections as the frame, and the glass panels are fully embedded into the grooves of the profiles. Its characteristic lies in the aluminum alloy profiles themselves, which serve as both the structural framework and the means to secure the glass. The visible frame glass curtain wall is the most traditional form, widely used, and reliable in performance. Compared to the hidden frame glass curtain wall, it is easier to meet the requirements of construction technology levels.

2. Hidden frame glass curtain wall

The metal frame of the hidden frame glass curtain wall is concealed on the back of the glass, and the metal frame is not visible from the outside. The hidden frame glass curtain wall can be further divided into two types: fully hidden frame glass curtain wall and semi-hidden frame glass curtain wall. The semi-hidden frame glass curtain wall can be either horizontally exposed and vertically hidden, or vertically exposed and horizontally hidden. The structural characteristics of the hidden frame glass curtain wall are: the glass is on the outside of the aluminum frame, and the glass is bonded to the aluminum frame with silicone structural sealant. The load of the curtain wall is mainly borne by the sealant.

3. Point-supported glass curtain wall (metal-supported point-supported glass curtain wall)

The point-supported glass curtain wall is a glass curtain wall composed of glass panels, point support devices, and supporting structures. It combines the stability of steel structures, the lightness of glass, and the precision of machinery.

The glass of the point-supported glass curtain wall is reliably fixed by stainless steel claw pieces penetrating through pre-drilled holes in the glass. Generally, glass curtain walls are fixed to the frame using structural adhesive. For its surface glass, holes are drilled at the corners and connected to the supporting structure's full glass curtain wall using metal connectors. Generally, glass curtain walls are mostly of a flat frame-type, vertical rod-bearing system structure. Compared to general glass curtain walls, the load-bearing system of point-supported glass curtain walls is not in the frame, but in the supporting system.

The glass panels on the point-supported glass curtain wall are connected to the supporting structure only through a few points, resulting in almost no obstruction and maximized visibility. The transparency of the glass is utilized to the fullest extent. Therefore, in the use of glass, light-pollution-free white glass, ultra-white glass, low-emissivity glass, etc. are often chosen, especially the use of insulating glass, which has a more pronounced energy-saving effect. However, this type of glass curtain wall does not have operable windows.

III. Technical Requirements

1. Sealing material

Weather-resistant silicone sealant is used between glass panes, while structural silicone adhesive is employed to bond glass to metal structures. In the technology of point-supported glass facades, sealant solely serves as a sealing component, and its strength does not require calculation. Prior to use, compatibility tests must be conducted between the sealant and the contact materials. The sealant must pass performance tests, be used within its shelf life, and strictly adhere to operational procedures to ensure construction quality.

2. Glass

Glass curtain walls should use curtain wall glass with a reflectance ratio of no more than 0.30. For glass curtain walls with lighting requirements, the lighting reduction coefficient should not be lower than 0.20. Frame-supported glass curtain walls should preferably use safety glass (film-coated glass, tempered glass, laminated glass, etc.); panel glass for point-supported glass curtain walls should use tempered glass.

3. Metal

The surface of steel should undergo anti-corrosion treatment. When hot-dip galvanizing is used, the film thickness should be greater than 45μm; when electrostatic spraying is employed, the film thickness should be greater than 40μm. Insulation measures should be taken between different metal materials to prevent electrochemical corrosion between dissimilar metals.

IV. Common problems of glass curtain walls

1. Poor fire prevention capability

Glass curtain walls are non-combustible materials, but they can melt or soften in the face of intense heat. Glass breakage can occur in a very short period of time in a fire. Therefore, fire protection requirements must be fully considered in architectural design.

2. Structural adhesive failure

Due to the long-term exposure to adverse factors in the natural environment, structural adhesives in curtain walls are prone to aging and failure, leading to the fall of glass curtain walls. Therefore, in design, it is advisable to use visible or semi-hidden frame glass curtain walls as much as possible, because even if the structural adhesive fails, the support and restraint provided by the frame will greatly reduce the likelihood of glass falling.

3. Thermal stress causes glass breakage

Glass expands when heated. If the heating is uneven, tensile stress will be generated inside the glass. When there are small cracks on the edge of the glass, these small imperfections are easily affected by thermal stress, ultimately leading to glass breakage. Therefore, when installing glass, the edges of the glass should be carefully processed to reduce the occurrence of cracks.

4. Water seepage

There are many reasons for water seepage in glass curtain walls, but the main ones are related to construction and sealing materials. Therefore, it is important to select experienced construction companies and materials that meet national standards to minimize water seepage.

V. Summary

Most of the information about the advantages and disadvantages of glass curtain walls is here. Did it help or inspire you after reading? There may be many inadequacies, so if there are any aspects about the advantages and disadvantages of glass curtain walls that are not mentioned here but you happen to know about, please leave a message in the comment section and tell me. Let's discuss and supplement together! I'm waiting for you in the comment section!!

Behind every completed project, there are many unknown difficulties and people who constantly strive to innovate to overcome these difficulties. From time to time, our editor will sort out some projects, not only to let everyone know about some new skills, but also to hope that everyone can learn more about and understand the people who have worked hard behind these buildings. Because of everyone's understanding, there is more motivation to complete better projects.

Just like all the employees at Carteron Curtain Wall, we are always ready to provide you with high-quality and reliable services throughout the entire lifecycle of building curtain walls. We rigorously control every aspect, from curtain wall design and construction to maintenance, all with the aim of achieving excellence and satisfying you. Therefore, we hope you will understand and consider Carteron Curtain Wall whenever you have relevant needs!