ABOUT USCompany Profile Course of Development Honors And Qualifications Research Team Quality Management Company Culture Video Center
Curtain wall contamination problem - how to solve vertical flow pollution
In the previous Baiyun online article, we introduced the permeation pollution, prevention and solutions of the curtain wall. In addition to seepage pollution, the curtain wall pollution manifestation is vertical pollution. In this issue of Baiyun Online, we focused on the vertical flow pollution of the curtain wall.
1, the form of vertical flow pollution
Most of the curtain wall panels have “flow mark” pollution phenomenon, that is, pollutants appear vertical flow pollution on the curtain wall panel under the effect of rain. The “flow mark” can be observed both above and below the glue seam. This is the vertical flow pollution. The difference with osmotic contamination is that vertical flow contamination can be cleaned. The vertical flow pollution not only appears in exposed outdoor stone curtain walls, aluminum curtain walls, but also in glass curtain walls. Under the premise that the curtain wall is not cleaned, the vertical flow pollution will gradually increase with time and the accumulation of pollutants will gradually become apparent. Under the general use environment, we found that there was a vertical flow pollution phenomenon in the curtain wall for about 3 months. After the occurrence of vertical flow pollution, the performance of light-colored stone and aluminum curtain walls is particularly evident, which has a greater impact on the overall aesthetics of the curtain wall.
Figure 1 Vertical flow pollution of aluminum curtain wall
Figure 2 Vertical flow pollution of stone curtain wall
Figure 3 Vertical flow pollution of glass curtain wall
Fig. 1 and Fig. 2 show the phenomenon of significant vertical flow pollution in an aluminum panel curtain wall project and a stone curtain wall project, respectively. Figure 3 shows the phenomenon of vertical flow pollution of the glass curtain wall. Observing the vertical flow pollution of the glass curtain wall may not be as obvious as the stone curtain wall and the aluminum curtain wall. However, a certain observation angle is taken from the inside of the building to see the flow marks of the vertical flow pollution of the glass curtain wall. Sometimes it's more obvious.
2. Analysis of causes of vertical flow pollution
The production of vertical flow pollution is mainly due to the low surface energy of silicone rubber, which can easily absorb the dust in the air. The dust accumulates on the surface of the glue seam and forms a “pollution source”. When it rains, the dust adsorbed on the surface of the glue joint is washed by rain, and the surface of the substrate near the glue seam and under the horizontal glue seam is contaminated. Because the vertical flow pollution is caused by the adsorption of dust on the surface of the glue seam, the vertical flow pollution occurs not only in exposed stone curtain walls but also in metal sheet curtain walls, glass curtain walls, and the like.
Figure 4 Schematic of vertical flow pollution
Another cause of vertical flow pollution is the improper design of the platform or slope. Dust can accumulate on the platform or slope for a long period of time to form a “pollution source.” At the same time, the platform or slope is improperly designed to form an outward drainage method. The accumulated dust is thus Rain washed down will form a dirty flow mark on the lower panel, causing pollution, see Figure 5.
Figure 5: The windowsill accumulates dust on the lower panel
3, vertical flow pollution prevention, solution
1) Regular cleaning
The vertical flow pollution can be removed by cleaning the surface of the curtain wall. At present, most users adopt regular cleaning methods to maintain the clean and beautiful appearance of the curtain wall; however, cleaning takes time and effort, especially in the high-rise and super high-rise curtain walls, the cleaning of the curtain wall plate is more difficult and costly. Higher, and there is a hidden danger of high-altitude operations, as shown in Figure 6. For example, in April of this year, the CCTV building was cleaned with a "big pants" outer wall. The media reported that the cost of cleaning was 500,000 yuan, which took 40 days. After the vertical flow cleaning, the curtain wall can be kept clean and beautiful for a certain period of time, and it must be cleaned again after a certain period of time. In case of relatively bad weather, such as sandstorms in the north, it is possible that the pollution will soon appear again and need to be cleaned again.
Figure 6 High-altitude operations for curtain wall cleaning
2) Design prevention
When designing, avoid as much as possible that the ash platform or the escaping rainwater flows directly to the curtain wall. If reasonable drainage measures are designed or rain measures are properly adopted, the water flow formed on the curtain wall will be minimized, resulting in dirty flow marks. The provocative design of Figure 7 reduces the flow of water on the facade wall when it rains.
Figure 7 Provocative Design of Stone Curtain Wall
3) Use anti-pollution weathering sealant
a) Polyurethane sealant and Japanese MS glue
Both types of adhesives can be used to seal joints in building curtain walls. The surface does not absorb dust, but their aging resistance is inferior to that of silicone rubber. The surface is susceptible to aging and cracks. The adhesive surface of the glass and the glass is irradiated with ultraviolet rays. There will be degumming, so these two sealants can not be used for glass curtain walls, foreign countries have only a certain application in the stone curtain wall project, and after a certain number of years to consider the need for regular renovation.
b) Anti-pollution silicone weatherproof sealant
The user is recommended to use this kind of sealant product, which still uses silicone polymer as the main raw material, and has the excellent anti-aging performance of silicone sealant. At the same time, the formulation of the silicone sealant has been improved to make it oil-proof and non-ash-removing. Not only does it not cause osmotic contamination of porous materials such as stone, but it also has excellent anti-sag flow pollution properties. At present, there are Baiyun brand SS818 anti-pollution silicone weatherproof sealants on the market.
The two Baiyun online articles introduced the pollution problems and prevention and solutions for the curtain walls. I believe that everyone has a certain understanding of the problem of pollution and the prevention of the curtain walls. We work together to make the curtain walls cleaner and more beautiful. The next issue will introduce the construction process of weatherproof sealant, so stay tuned!