The fresh air volume in the clean room plays an irreplaceable role in supplementing the exhaust system, ensuring the indoor air quality,?maintaining the health of operators,?ensuring production safety, etc.

Calculation of fresh air volume in clean rooms

Fresh air volume that meets hygiene standards

The fresh air volume that meets the hygiene standards is divided into two situations:

1) For the general situation where there is no obvious harmful gas in the room, according to p style="margin-top:0;margin-right:0;margin-bottom:0;margin-left:0;padding:0 0 0 0 ">  

2）For the situation where harmful gases occur indoors, the fresh air volume for diluting the indoor harmful gases shall be calculated according to the allowable concentration of the indoor harmful gases.

Compared with the fresh air volume calculated above,

Compensate for the indoor exhaust volume and maintain the indoor positive pressure value of the fresh air volume

In order to prevent the external environment air (outdoor or adjacent rooms with lower cleanliness requirements) from penetrating into the clean room, interfering with the indoor temperature and humidity, and destroying the indoor cleanliness, it is necessary to use a certain amount of fresh air in the air conditioning system to maintain the positive pressure of the room.

Under normal circumstances, the indoor positive pressure of 5~10Pacan meet the requirements. Excessive positive pressure is not only unnecessary, but also reduces the economic efficiency of system operation.

Due to factors such as the net height of the clean room and the different values ​​of the ventilation frequency, the total air supply volume varies greatly. Therefore, GB 50073-2013 "Clean Room Design Code" stipulates that the amount of fresh air should be the maximum value between meeting the hygiene requirements and ensuring the positive pressure in the room (while ensuring local exhaust).

Calculation of clean room air supply volume

The calculation of air supply volume in a clean room is different from that in a general air-conditioned room. Because the clean air sent into the clean room after filtration not only has to bear the air supply volume required to ensure the indoor temperature and humidity, but also has to remove and dilute indoor pollutants to maintain the indoor air cleanliness.

So the air supply volume of the clean room should be taken from the following three air supply volumesMaximum：

(1)Air supply volume that meets the air cleanliness level requirements

(2)Air supply volume determined by cold, hot and wet load calculation

(3)Fresh air volume supplied to the clean room

The final determination of the clean room air supply volume needs to comprehensively meet the air volume required for clean room temperature and humidity requirements and the supplementary air volume required to eliminate indoor toxic and harmful substances.