The number of air changes is a parameter in a thousand level purification workshop. The so-called number of air changes actually refers to the amount of clean air in a room that is equivalent to a multiple of the room volume, and its unit is times per hour. If the amount of air passing through people within an hour is the same as the volume of the room, the number of air changes is 1 per hour, and so on. The number of air changes is the most important parameter determining the level of cleanliness in a turbulent clean room. So, do you know how to calculate the number of air changes in a thousand level purification workshop?

The "Code for Design of Clean Buildings" (GB 50073-2001) in China clearly specifies the experience air exchange times required for calculating the clean air supply volume of non unidirectional flow clean rooms of different levels, as shown in the table below:

The number of air changes varies depending on the cleanliness of the room. The capacity of dust particles varies depending on the number of air changes, resulting in different filtration of dust particles. The air volume, equipment, and cost are also different.

Therefore, the calculation method for the number of air changes in a thousand level purification workshop can be based on the air cleanliness level of the thousand level in the table above, combined with the indoor number of people, room area, other indoor dust emissions, and fresh air ratio through formulas. Especially under dynamic conditions, it is more necessary to calculate according to specific conditions.

However, when calculating the ventilation frequency of a thousand level purification workshop, it should be noted that the air volume should not be blindly designed based on the ventilation frequency, and comprehensive consideration should also be given to room and process waste heat and humidity. Otherwise, the initial air volume may meet the temperature and humidity requirements, and the system may not work as well after running for a period of time.