The primary function of the chimney is to exhaust smoke and gases, improving combustion conditions. In high-rise buildings, various vertical shafts such as stairwells, ventilation ducts, air supply ducts, exhaust ducts, elevator shafts, and pipe shafts are typically installed at different numbers. When the indoor temperature is higher than the outdoor temperature, the lighter hot air rises naturally through these vertical channels. It escapes through gaps in doors and windows and various openings from the upper floors. Cold air from outside, being denser, enters from the lower levels to compensate, creating the chimney effect. The chimney effect is the result of the combined action of thermal pressure due to the indoor-outdoor temperature difference and wind pressure outside, with the former usually being predominant. The thermal pressure is proportional to the air density difference caused by the indoor-outdoor temperature difference and the height difference between the intake and exhaust openings. This indicates that the higher the indoor temperature is above the outdoor temperature and the taller the building, the more pronounced the chimney effect becomes. It also suggests that the chimney effect in residential buildings generally occurs only during winter. Theoretically, the midpoint of the building's height is considered the neutral zone, where rooms below this level are assumed to be infiltrated with outdoor air, and rooms above this level are assumed to be exhausted with indoor air.
Several points to note in the construction of chimney anticorrosion:
1. Construction sites must be clean and well-ventilated, with harmful gas levels not exceeding specified requirements. Flammable materials, except for paints used in chimney anti-corrosion, are strictly prohibited from being stored on the job site. That is to say, pay attention to environmental safety and keep the site clean.
2. Smoking is prohibited on-site. Welding or open flame activities are not allowed within a 10-meter radius. Explosion-proof lighting equipment must be used during construction. Workers should wear necessary protective gear, work in containers in shifts, and ensure good ventilation. Anti-slip measures must be in place, and workers must wear safety belts.
3. Chimney anticorrosion work completed. When cleaning tools and containers containing waste solvents, do not pour them carelessly and dispose of them properly. In case of any accidents, place them in designated areas.
