How to control differential pressure in purification workshop? Method of positive pressure control in purification workshop

In order to ensure that the purification workshop is in normal operation or the air balance is temporarily damaged, such as when opening or closing the door, the air flow can gradually flow from the area of high air cleanliness to the area of low air cleanliness, so that the indoor cleanliness will not be interfered with the polluted air, so it is necessary to adhere to a certain positive pressure in the purification workshop. Positive pressure value should be selected appropriately. If too small, the positive pressure of the purification workshop is simply damaged, affecting the indoor cleanliness; If too large, the air conditioning purification system increases the air volume, air conditioning load is added, and the service life of the filter is shortened, so it is not economic. In addition, when the positive pressure value is higher than 50Pa, it is very difficult to open the door of the purification workshop.

 

The positive pressure value of the purification workshop

 

Relevant standards at home and abroad have made rules for the positive pressure value of the purification workshop. For example, the federal standard FS-209b states that the minimum positive pressure difference between the purification plant and any adjacent low-cleanliness area is 13Pa (0.05in water column), and the NASA standard NASA NHB 5340.2 has the same rule value as FS-209b. The rules are as follows:

 

Different levels of purification workshop minimum pressure difference of 5Pa; The minimum pressure difference between the purification workshop and the quasi-purification workshop is 10Pa; The minimum pressure difference between the purification workshop and the general room is 15Pa. Rule 5.2.1 of our "Purification Workshop Design Standard" (GBJ 73-84) "It is necessary to adhere to a certain positive pressure in the purification workshop. The static pressure difference between different grades of purification workshop and dust-free area and non-dust-free area should not be less than 5Pa, and the static pressure difference between dust-free area and outdoor should not be less than 10Pa ". The new standard GB 50073-2001 Rules on differential pressure (Section 6.22) are in common with the above rules.