Glass Curtain Wall Installation Standards

Glass curtain walls represent a modern, innovative type of building envelope. Their defining characteristic is the organic integration of architectural aesthetics, functionality, energy efficiency, and structural integrity. Viewed from different angles, the building reveals varying color tones; as sunlight, moonlight, and artificial lighting shift, the structure conveys a sense of dynamic beauty.

A glass curtain wall (also known as a reflective glass curtain wall) refers to an external building enclosure or decorative structure supported by a structural system that allows for a certain degree of relative displacement independent of the main building structure, and which does not bear any of the structural loads acting upon the main building. These walls are available in two configurations: single-layer and double-layer glass. Glass curtain walls constitute an aesthetically pleasing and novel method of exterior wall decoration, serving as a distinctive hallmark of the era of modernist high-rise architecture.

Glass curtain walls in modern high-rise buildings typically utilize insulated glass units (IGUs), which consist of a combination of reflective glass and standard glass, with the intervening space filled with dry air or an inert gas. Insulated glass units are classified into two-layer and three-layer varieties: a two-layer unit comprises two panes of glass separated by a sealed frame, creating a single interlayer space; a three-layer unit consists of three panes of glass, creating two separate interlayer spaces. Insulated glass offers numerous advantages, including sound insulation, thermal insulation, resistance to frost and moisture, and high resistance to wind pressure. Measurements indicate that when the outdoor temperature is -10°C, the temperature immediately in front of a single-pane window is -2°C; in contrast, the indoor temperature within a room utilizing three-layer insulated glass remains a comfortable 13°C. Conversely, during the hot summer months, double-layer insulated glass can block up to 90% of incoming solar radiant heat. Sunlight continues to pass through the glass curtain wall, yet the heat felt on one's body is significantly reduced. Rooms featuring insulated glass curtain walls thus remain warm in winter and cool in summer, thereby vastly improving the living environment.

1. Sealing Materials
Weather-resistant silicone sealant is used to seal the joints between adjacent glass panes, while structural silicone adhesive is used to bond the glass to the metal support structure. In the context of point-supported glass curtain wall systems, the sealant serves a purely sealing function and does not require structural strength calculations. Before use, compatibility testing between the sealant and the contact materials must be conducted. The sealant must pass performance verification tests, be used within its valid shelf life, and be applied in strict compliance with operational procedures to ensure construction quality.

2. Support Materials
The thickness of the primary load-bearing sections of the mullions shall comply with the following requirements:
1) For aluminum profiles, the thickness of open sections shall not be less than 3.0 mm, and the thickness of closed sections shall not be less than 2.5 mm. In instances where a direct threaded connection is utilized to transfer load between the profile hole wall and a screw, the local thickness at the connection point shall not be less than the nominal diameter of the screw.
2) For steel profiles, the thickness of the primary load-bearing sections shall not be less than 3.0 mm.
3) For mullions subjected to eccentric compression, the width-to-thickness ratio of the cross-section shall comply with the relevant provisions of Article 6.2.1 of JGJ102-2003, *Technical Code for Glass Curtain Wall Engineering*. Glass Requirements

1. Glass curtain walls shall utilize curtain wall glass with a reflectance not exceeding 0.30. For glass curtain walls with specific daylighting requirements, the daylighting reduction coefficient shall not be lower than 0.20.

2. Framed glass curtain walls should utilize safety glass.

3. The glass panels for point-supported glass curtain walls shall consist of tempered glass.

4. For point-supported glass curtain walls utilizing glass fins as supports, the glass fins shall consist of tempered laminated glass.