The fresh air required by buildings is generally calculated according to the "building volume" and "indoor number", and the fresh air system takes a larger value. An example is easy to understand:

1) For example, if there is a building with a building area of 30m2 and a floor height of 3m, according to the formula "building volume = room area x clear height x ventilation times" (the national standard ventilation times is 0.5), the required fresh air volume of the building is 45m. /HP;

2) What if it is more than 30m? There are three people living in the building. Under normal circumstances, the fresh air required for each person is 30m. /hp, so the fresh air required for the building is 90m? /HP;

3) In order to ensure sufficient fresh air volume, the building needs 90m fresh air volume? /hp standard selects fresh air system.