Analysis of deepening design points of glass curtain wall

When glass curtain wall is used in the building facade, the fire protection, energy saving, green building, smoke and smoke performance requirements of the windows in the building construction drawings should be realized through the secondary design of the glass curtain wall. At the same time, the glass light roof, the glass railing in the air space is also often designed by the glass curtain wall company for the second time, the fire prevention, waterproofing, drainage and smoke evacuation performance requirements of the glass light roof, and the safety and protection requirements of the glass railing in the air space also need to be realized through the second design of the glass curtain wall company.

First,fire protection design requirements for glass curtain wall

The secondary design of the glass curtain wall needs to implement the building construction drawings about the vertical and horizontal direction of the glass curtain wall fire requirements, fire rescue window setup requirements.

1.Vertical fire protection requirements for glass curtain wall

(1) Vertical fire blocking of glass curtain wall

According to the “building fire blocking application technical standards” GB/T51410-2020 Article 4.0.3, the glass curtain wall layer fire blocking structure should be set up above and below the two channels, the thickness of each channel structure should not be less than 200mm, and the spacing between the two channels should not be less than 1.20m, with automatic fire extinguishing system should not be less than 0.80m.

(2) The original building fireproof glass wall instead of the solid wall between the layers, should meet the provisions of Article 6.2.5 of the Building Regulations, high-rise building fireproof glass wall fire-resistant integrity should not be less than 1.00h, multi-storey building fire-resistant glass wall fire-resistant integrity should not be less than 0.50h, and the integrity of its fire-resistant in accordance with the national standards in the “fire-resistant test method of the glass components” GB/T 12513 in the non-insulated glass components. The fire-resistant integrity is determined in accordance with the test method and judgment standard for non-insulating glass components of GB/T 12513 of the current national standard “Fire-resistant test method for glass components”. The height of fireproof glass wall should not be less than 1.20m, and should not be less than 0.80m when setting up automatic fire extinguishing system.

2.Horizontal fireproof requirement of glass curtain wall

Transparent glass curtain wall is located in the firewall on both sides of the nearest edge of the horizontal distance of 2.0m range or located in the firewall corner on both sides of the nearest edge of the horizontal distance of 4.0m range, it should meet the “Building Regulations”, Article 6.1.3, 6.1.4 of the provisions. That is to say, fixed or self-closing Class B fireproof window should be set up in case of fire, and its fire-resistant insulation and fire-resistant integrity should not be less than 1.0h, and its fire-resistant performance should be measured by adopting the national standard of “fire-resistant test methods for glass components” GB/T 12513 in the experimental methods and judgment standards for heat-insulating glass components.

3.Fire rescue window setup requirements

The location and size of the fire rescue window of the secondary design construction drawings of the glass curtain wall should be consistent with the original building construction drawings, and the net size of the fire rescue window should not be less than 1.0mx1.0m, and it should be noted that the glass should be easy to break.

 

Second, the energy-saving design requirements of the glass curtain wall

The secondary design of glass curtain wall needs to implement the building construction drawings about the glass curtain wall heat transfer coefficient, solar heat gain coefficient, airtightness, visible light transmittance ratio, can be opened than the area ratio, thermal bridge insulation construction practices and other building energy-saving requirements.

 

Third, the green building design requirements of the glass curtain wall

The secondary design of the glass curtain wall needs to implement the green building design requirements for the visible light reflection ratio of the glass curtain wall in the building construction drawings.

 

Fourth, the glass curtain wall smoke and smoke exhaust design requirements

The secondary design of glass curtain wall needs to implement the building construction drawings about the glass curtain wall smoke, smoke requirements.

1.Natural ventilation requirements.

Using natural ventilation of closed stairwells, smoke-proof stairwells, should be set in the highest part of the area of not less than 1.0m 2 of the openable windows; when the building height is greater than 10m, should also be set in the stairwells of the external wall of every 5 layers of a total area of not less than 2.0m 2 of the openable windows, and the arrangement of intervals of not more than 3 floors; the use of natural ventilation of the independent anterior room, the front of the fire elevator room can be opened to the external window area should not be less than 2.0m 2, and the area should not be less than 2.0m 2. The area of the openable external windows of the independent front room and the front room of the fire elevator using natural ventilation should not be less than 2.0m 2 , and the area of the common front room and the shared front room should not be less than 3.0m 2 ; the refuge floors (rooms) using natural ventilation should be equipped with openable external windows of different directions, and their effective area should not be less than 2% of the floor area of the refuge floors (rooms), and the area of each direction should not be less than 2.0m 2 .

2.Requirements for natural smoke evacuation

If the ventilation specialty adopts natural smoke exhaust, the effective opening area of the smoke exhaust window within the height range of the smoke storage compartment shall meet the requirements of the ventilation specialty, and the effective smoke exhaust area shall be calculated according to Article 4.3.5 of the Technical Standard for Smoke and Smoke Exhaust System of Buildings (GB51251-2017). Note that when the external windows adopt hanging windows, the opening angle of the hanging windows shall be indicated in the elevation drawings.

 

Fifth, the glass curtain wall of the airspace safety protection requirements

The secondary design of the glass curtain wall needs to implement the building construction drawings about the safety protection of glass railing panels in the airspace, the fixed fan instead of the low bay window guard railing design requirements.

1.For the roof, porch, balcony, open balcony and other airside safety protection glass railing, its effective net height should meet the original building construction drawings and the requirements of the relevant provisions of the standard. The glass of balustrade plate shall meet the provisions of Article 7.2.5 of JGJ 113-2015, Technical Regulations for the Application of Architectural Glass.

2.When the fixed fan of glass curtain wall is used instead of window guard railing, the following requirements shall be implemented:

(1) The transverse keel of the glass curtain wall shall be 800mm high from the floor, and the size, wall thickness, and fixing measures between the keel of the glass curtain wall and the main body of the building shall be indicated, and the calculation book reviewed and approved by the structural profession shall be provided, or the test report meeting the requirements of the load specification on the prevention of impingement shall be provided.

(2) Fixed fan glass shall meet the provisions of Article 7.2.5 of JGJ 113-2015, Technical Regulations for the Application of Architectural Glass. The minimum requirement of insulating glass of a layer of glass should be 6.38 thick laminated glass (note that the construction practice of the fixed fan should also meet the energy-saving requirements).

 

Six, glass ceiling design requirements

The secondary design of the glass ceiling needs to implement the building construction drawings about the glass ceiling fire, water, drainage, smoke requirements.

1.The fire resistance level of the load-bearing components of the glass ceiling is determined according to the original building requirements. When the fire resistance level of the building is one, the fire resistance limit should not be less than 1.50h; when the fire resistance level is two, the fire resistance limit should not be less than 1.00h.

2.The waterproof grade of glass light roof is determined according to the original building requirements. It should not be lower than grade I or II.

3.The construction practice of glass roof should meet the original building energy-saving requirements (including heat transfer coefficient and solar heat gain coefficient).

4.The roof glass must use laminated insulating glass, and its film thickness should not be less than 0.76mm to meet the provisions of Article 8.2.2 of JGJ 113-2015 of the Regulations for the Application of Architectural Glass.

5.When the atrium adopts mechanical smoke evacuation: the roof should be equipped with temperature control function to open the openable fan, and not less than 5% of the floor area of the atrium. To meet the provisions of Article 4.4.15 of the Technical Standard for Building Smoke Prevention and Exhaust System GB51251-2017. (Note that according to the specification requirements, the roof should be made of laminated glass, which can’t be broken and can’t be used for fixed windows).

6.When the atrium adopts natural smoke exhaust: when the atrium adopts natural smoke exhaust system, the effective window area should be calculated by ventilation professional according to the provisions of Article 4.6.5 of “Technical Standard for Building Smoke and Smoke Exhaust System” GB51251-2017, and check the original building construction drawings.

7.The drainage slope of glass light roof shall not be less than 5%.

 

Conclusion

When reviewing the building construction drawings, the elevation should be required to express the location, size and opening mode of the glass curtain wall opening fan, the location and size of the fire rescue window, and the part of the fire-resistant glass wall, etc., so as to ensure that the glass curtain wall company can be put into practice in the secondary design.