The primary function of a chimney is to draw fire and smoke out, expelling fumes, and improving combustion conditions. In high-rise buildings, vertical shafts such as stairwells, ventilation ducts, air supply ducts, exhaust ducts, elevator shafts, and pipe shafts are typically installed in varying numbers. When the indoor temperature is higher than the outdoor temperature, the lighter hot air inside naturally rises through these vertical channels. It escapes through gaps in doors and windows and various openings from the upper part of the building. The denser cold air outside then infiltrates from the lower levels to compensate, creating the chimney effect. The chimney effect is the result of the combined action of the thermal pressure caused by the indoor-outdoor temperature difference and the 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 typically occurs only during winter. Theoretically, the midpoint of the building's height is considered the neutral zone, where rooms below it are believed to infiltrate air from outside, and rooms above it to expel air from inside.

Key points to note during the construction of chimney corrosion prevention:

1. The construction site must be clean and tidy, with adequate ventilation and harmful gas levels not exceeding the specified requirements. Flammable materials, except for those used in the anti-corrosion paint for chimneys, are strictly prohibited from being stored on the construction site. In other words, pay attention to environmental safety and keep the site clean.

2. Smoking is prohibited on-site. Welding or open flame operations are not allowed within a 10-meter radius. Explosion-proof lighting equipment must be used during construction. Workers should wear necessary protective gear, operate in containers in shifts, and ensure good ventilation. Anti-slip measures must be in place, and workers must wear safety belts.

3. The chimney anti-corrosion construction is completed. When cleaning tools and containers containing waste solvents, do not pour them at will and should be disposed of properly. In case of any accidents, place them in designated areas.