How to improve the durability of glass curtain walls

Glass curtain walls, as a widely used enclosure structure in modern architecture, come in various classifications, which can be divided based on dimensions such as structural form, construction method, support system, opening method, and functional characteristics. The following is a detailed classification system and example explanation:

1. Classification by structural form

Framed glass curtain wall (component-based curtain wall)

Definition: A frame structure consisting of beams and columns supports the glass panel, with the glass being fixed to the frame using structural adhesive or mechanical connectors.

Features:

Flexible installation, adaptable to complex architectural designs;

The framework is exposed on the facade, creating a sense of linearity;

The construction period is relatively long, requiring on-site installation layer by layer.

Example: The external curtain wall of the Shanghai center building adopts a unitized frame structure, which improves installation efficiency through standardized modules.

Unitized glass curtain wall

Definition: In the factory, glass, frames, sealing materials, etc. are pre-assembled into independent unit panels, which are directly lifted and assembled on site.

Features:

High degree of industrialization, fast construction speed;

Excellent sealing performance, with water and air tightness reaching the highest level of national standards;

The cost is relatively high, requiring large-scale transportation and lifting equipment.

Example: Guangzhou Tower (Xiaomanwaist) adopts triangular unitized curtain walls, achieving curved surface modeling through parametric design.

Point-supported glass curtain wall (full glass curtain wall)

Definition: The glass panel is directly fixed to the supporting structure (such as steel trusses, cable nets) through stainless steel claw pieces or metal connectors, without an explicit frame.

Features:

Excellent light transmittance, visually transparent;

Suitable for large-span and large-grid spaces;

It requires high-precision machining and installation, resulting in high costs.

Example: The external curtain wall of the Beijing National Grand Theatre adopts a point-supported glass curtain wall, complemented by titanium metal plates, creating an effect akin to a "pearl on water".

Full glass curtain wall

Definition: It consists of glass ribs and glass panels, with the glass ribs serving as the supporting structure arranged vertically or horizontally.

Features:

Ultimate transparency, with no obstruction from metal components;

Tempered laminated glass is required, with high safety requirements;

Suitable for atria, exhibition halls, and other spaces in public buildings.

Example: The Shanghai Apple flagship store features a fully glazed curtain wall, achieving a column-free space through 12-meter-high glass ribs.

II. Classification by construction method

Visible frame glass curtain wall

Definition: The frame components (such as aluminum profiles) are exposed on the outside of the glass, forming decorative lines.

Features:

The structure is safe and reliable, and easy to maintain;

It has a strong decorative appeal and can achieve diverse appearances through profile design;

The light transmittance is slightly lower than that of the hidden frame curtain wall.

Example: The external curtain wall of the Shenzhen Ping An Financial Center adopts an exposed frame design, with the aluminum profiles being anodized and forming a contrast with the glass.

Hidden frame glass curtain wall

Definition: The glass is adhered to the aluminum frame using structural adhesive, with the frame concealed on the inside of the glass, resulting in a sleek appearance.

Features:

High light transmittance and flat facade;

The performance requirements for structural adhesives are extremely high, necessitating regular testing;

Suitable for modern minimalist style architecture.

Example: The Guangzhou Chow Tai Fook Financial Center adopts a hidden-frame curtain wall, achieving high light transmittance and energy efficiency through ultra-clear glass and low-emissivity coating.

Semi-hidden frame glass curtain wall

Definition: One side of the glass is adhered to the frame with structural adhesive, while the other side is fixed through mechanical connection (such as pressing plate), forming a horizontal or vertical hidden frame effect.

Features:

Combining the advantages of both visible and hidden frames, while considering both safety and aesthetics;

The construction process is complex, requiring precise control of the glue joint width.

Example: The Raffles City Hangzhou adopts a vertical semi-hidden frame design, enhancing the wind pressure resistance of glass through aluminum pressure plates.

III. Classification by support system

Modular supporting curtain wall

Definition: A supporting system composed of linear components such as columns and beams, with glass fixed onto the components.

Features:

Strong adaptability, capable of meeting the needs of complex surfaces;

On-site welding or bolt connection is required, with high requirements for construction accuracy.

Example: The terminal building of Beijing Daxing International Airport adopts a curved component-style curtain wall, achieving a streamlined appearance through parametric design.

Cable net supporting curtain wall

Definition: A structure supported by a prestressed steel cable net, with glass fixed to the net via claw components.

Features:

Lightweight and high-strength, suitable for large-span spaces;

High-precision tensioning construction is required, which incurs high costs.

Example: The Allianz Arena in Munich, Germany, utilizes a retractable cable net curtain wall that can be quickly opened and closed via a hydraulic system.

Single-layer cable net curtain wall

Definition: A flexible structure formed by supporting a glass panel solely with a single steel cable (horizontal or vertical).

Features:

Minimalist aesthetics, with strong visual impact;

It needs to be used in conjunction with heavy-duty glass (such as laminated glass), and has high safety requirements.

Example: The "Gherkin" building (30 St Mary Axe) in London, UK, adopts a single-layer cable-supported curtain wall, which resists wind loads through the collaborative work of steel cables and glass.

IV. Classification by opening method

Fixed glass curtain wall

Definition: The glass panel is non-openable and fully enclosed.

Features:

Optimal airtightness and water tightness;

It needs to be used in conjunction with a mechanical ventilation or air conditioning system.

Example: The observation deck of the Shanghai Center Tower adopts a fixed curtain wall, achieving energy conservation through a double-layer breathing structure.

Openable glass curtain wall

Definition: The glass panel can be opened through devices such as hinges and sliding rails to achieve natural ventilation.

Classification:

Top-hung window: The window sash opens upwards, providing good rain-proof performance;

Sliding window: The window sash slides horizontally, providing a large ventilation area;

Centre-hung window: The sash rotates around the central axis and can be opened in both directions.

Example: Shenzhen Vanke Cloud City adopts a horizontally sliding curtain wall system, which achieves intelligent ventilation through an electric control system.

V. Classification by functional characteristics

Energy-saving glass curtain wall

Definition: Reducing energy consumption through materials such as Low-E coated glass, insulating glass, and thermal break profiles.

Features:

Heat transfer coefficient (K value) ≤ 1.5 W/(m²·K);

The shading coefficient (SC) is adjustable to adapt to different climatic zones.

Example: The headquarters of the Passive House Institute in Germany adopts triple-silver Low-E insulating glass curtain walls, reducing annual energy consumption by 90% compared to traditional buildings.

Fire-resistant glass curtain wall

Definition: Utilizing single-piece cesium potassium fire-resistant glass or composite fire-resistant glass to meet the requirements for fire integrity.

Classification:

Insulation type (Type A): Fire resistance limit ≥1.0h, temperature on the unexposed surface ≤140℃;

Non-insulated type (Type C): Fire resistance limit ≥ 0.5h, only meeting integrity requirements.

Example: The Hong Kong International Finance Centre Tower 2 adopts Class A fire-resistant glass curtain walls at the fire escape routes, with a fire endurance of up to 1.5 hours.

Explosion-proof glass curtain wall

Definition: Resistance to explosive impact through laminated glass (PVB or SGP film) or bullet-proof glass.

Features:

The impact resistance meets the GA 667-2006 standard;

Suitable for use in places with high security requirements, such as banks and embassies.

Example: The US Embassy in London adopts explosion-proof glass curtain walls, which can withstand the impact of an explosion with a TNT equivalent of 15kg.

Photovoltaic glass curtain wall

Definition: Integrating photovoltaic cells into glass to achieve the integration of power generation and enclosure functions.

Classification:

Crystalline silicon type: high power generation efficiency (15%-20%), but low light transmittance;

Thin-film type: high light transmittance (50%-70%), but low power generation efficiency (8%-12%).

Example: The Dubai Solar Vertical Village adopts thin-film photovoltaic glass curtain walls, with an annual power generation capacity of 2.3 GWh.

VI. Classification by building location

External wall curtain wall

Definition: It covers the exterior walls of buildings and serves as a protective enclosure, provides decoration, and contributes to energy efficiency.

Example: The Shanghai World Financial Center utilizes an exterior curtain wall, achieving natural ventilation through a double-layer glass curtain wall.

Roof curtain wall

Definition: Used for building roofs, it must meet the requirements of waterproofing, wind pressure resistance, and snow load resistance.

Example: The Flower Dome at Gardens by the Bay in Singapore adopts a roof curtain wall, achieving lightweight and translucency through an ETFE (Ethylene Tetrafluoroethylene) cushion structure.

Skylight curtain wall

Definition: Located in the atrium or on the top of a building, with the primary function of lighting.

Example: The National Library of China in Beijing adopts a skylight curtain wall, achieving a large-span column-free space through a point-supported structure.

Classification summary and application suggestions

Super high-rise buildings: Unitized or frame-type curtain walls are preferred, combined with energy-saving glass (such as triple-silver Low-E) to reduce energy consumption.

Cultural buildings: Point-supported or full glass curtain walls can be adopted to highlight transparency and artistic sense.

Safety-sensitive locations: Fire-resistant and explosion-proof glass curtain walls must be used and comply with relevant regulatory requirements.

Green building: It is recommended to use photovoltaic glass curtain walls or double-skin facades to achieve energy self-sufficiency and passive energy conservation.

Through reasonable classification and selection, glass curtain walls can balance functionality, aesthetics, and sustainability, providing long-term value to buildings.