Point-fixed spider glass curtain wall is a system for point-supported vertical glazing in which thermally toughened (Tempered) glass sheets are used, in single glazing or in insulated glass. Laminated safety glass (tempered laminated glass) is preferable to be used in single glazing or as the outer sheet of the insulating glass units. 

This system consists of a number of accessories with metal arms. At the end of each arm, a sheet of glass is fixed by the corners with a special screw. The vacuum between these sheets is filled up with insulators to overcome mechanical pressure and weather conditions.

Specifications:

Point Fixed Glass System Curtain Walls are used most frequently in structural glass curtain walls to create transparency and depth of vision for the occupants.

The glass panes are either bolted or clamped with components providing attachment to the structural system. The most common system type is often referred to as a “spider” system. The metallic fingers that support the glass façades allow the designer to increase transparency by minimizing the structural framing.

A four- armed fitting, usually of cast stainless steel, supports four glass panes at adjacent corners on the glazing grid and ties back to the structural system. The spider fitting is designed to provide for glazing system movement under environmental loading, as well as to accommodate specified field tolerance during assembly. A variety of spider systems are available from the suppliers of cable and rod rigging systems.

Cast stainless components can be quite expensive, especially if large, customs spiders are required, as they often are in large glass grids. Alternatively simple stainless spring plates have been used in place of a cast fitting with excellent results.

Features:
1. Engineers and modern architects have designed this system with a main objective of getting the most possible transparency and thus the clearest vision which is normally hindered by using the various constructing elements. 
2. The spider system offers practical solutions to glass assembly that no other system can provide. 
3. To fix the glass up at the edges of the facade, one or two arms-accessories can be used.  In special applications, the number of arms might be more than two and the sheet of glass can be fixed by one arm at each corner. 
4. The used accessories can be mounted against metal frames or against glass fins and tension rods are used to pull these accessories together. 
5. Single, Insulating and laminated glass can be used with the spider system.  The thickness of the glass depends on the specifications of the project; therefore a special study is performed for each project. 
6. When the spider system is chosen, halls will be applied to glass before being assembled. Therefore, tempered glass should be used.

Advantages:

(1) Good permeability: The glass panel is only connected to the supporting structure through a few points, almost without obstruction, the line of sight through the glass is the best, the field of view is maximized, and the transparency of the glass is applied to the limit.

(2) Good flexibility: In the design of metal fasteners and metal connectors, in order to reduce and eliminate the stress concentration on the edge of the glass plate, the glass plate and the connector are in a hinged state, so that each connection on the glass plate The points can be rotated freely, and a small amount of translation is allowed to compensate for the errors in the installation and construction, so the glass of the point-supported glass curtain wall generally does not produce installation stress, and can comply with the load generated by the supporting structure Deformation, so that the glass does not produce excessive stress concentration. At the same time, the use of point-supported glass curtain wall technology can meet the needs of architectural modeling to the greatest extent.

(3) Good safety: Because the glass used in the point-supported glass curtain wall is all toughened, it is safety glass, and metal fasteners and metal connectors are used to connect with the supporting structure. The weather-resistant sealant only serves as a seal and does not bear Under load, even if the glass is accidentally damaged, the toughened glass will break into pieces, forming the so-called “glass rain”, and there will be no serious injury accidents of the whole glass falling.

(4) Good sense of craftsmanship: The support structure of the point-supported glass curtain wall has many forms. The support members are processed finely, the surface is smooth, and they have a good sense of craftsmanship and art. Therefore, many architects like to use them.

(5) Good environmental protection and energy saving: One of the characteristics of the point-supported glass curtain wall is its good permeability. Therefore, in the use of glass, white glass, ultra-white glass and low-e glass with no light pollution are used, and the energy-saving effect is more obvious.