How to determine the fresh air volume in a clean room?

Suzhou Pharma has nearly 20 years of experience in the cleanroom industry. Based on hundreds of cleanroom workshop, biological laboratory, medical pharmaceutical factory cases, we have summarized how to determine the fresh air volume in a cleanroom.

1. Fresh air volume that meets health standards

(1)Workshop no harmful gas emission:

When there is no significant harmful gas generation inside the workshop, the purification workshop must ensure that the amount of fresh air supplied to the clean room can reach no less than 40 cubic meters/person/hour standards.

(2)Workshop have harmful gas emission:

When harmful gases are emitted in the workshop, the calculation method of fresh air volume needs to be accurately determined based on the allowable concentration of harmful gases present in the workshop,determine the amount of fresh air required to effectively dilute indoor harmful gases and reduce their concentration to a safe range.

2. The amount of fresh air required to compensate for indoor exhaust air and maintain positive indoor pressure

(1)Standard basis and value principles:

The final value of the fresh air volume should be the maximum value that meets the hygienic requirements and maintains indoor positive pressure (while ensuring the smooth progress of local exhaust).

• The principle and significance of positive pressure:

In order to prevent harmful gases from the outside from penetrating into the clean room, it is extremely necessary to use the air conditioning system to introduce an appropriate amount of fresh air and maintain positive pressure inside the workshop. Under normal circumstances, the positive pressure in the control room is within the range of 5~10 Pa, which can fully meet the actual production needs.

(3). Fresh air compensation for local exhaust air:

During the actual implementation of the purification workshop project, in order to effectively avoid negative pressure conditions in the clean room, the air conditioner must be installed The system is configured with correspondingly sufficient fresh air volume, always maintain positive pressure state.

3. Air supply volume to ensure air cleanliness level

(1). Calculation of air supply volume based on heat and moisture loads:

First of all, it is necessary to use professional thermal calculation formulas to conduct in-depth analysis and accurate calculations based on the heat and humidity loads inside the workshop, so as to determine the air supply volume value that can meet the temperature and humidity control needs of the workshop.

(2). Additional fresh air supply:

At the same time, full consideration must be given to the continuous and stable supply of fresh air to the clean room to further optimize indoor air quality and improve the overall environmental quality.

The final air supply volume of the clean room should be selected to meet the above-mentioned fresh air volume that meets the hygienic standards, the fresh air volume required to compensate for indoor exhaust air and maintain indoor positive pressure, and to ensure the air The maximum value among the three air supply volumes of the cleanliness level.

Suzhou Pharma Machinery Co.,Ltd.

2025/07/28

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