Personnel entry and exit may affect gaseous pollution control through opening doors for ventilation, pressure differential fluctuations, and carrying materials, but the degree of impact depends on the adjacent air and system status. The need for additional chemical filters cannot be judged simply by the large number of people. A place with many people may not have excessive gas, and a place with few people may not be safe.

Three paths for people to influence gaseous pollution

The impact of personnel entry and exit on gaseous pollution occurs roughly through three paths. The first is to open the door for ventilation : when the door is opened, indoor and outdoor air are exchanged driven by the pressure difference and the passage of people, and gas from adjacent areas may enter. The second one is the fluctuation of pressure difference : Frequently opening the door will disturb the pressure difference in the door area, and the instantaneous pressure difference drop may allow air that should be blocked to enter. The third article is carried release : people's clothing, shoe soles, materials or packaging may bring external pollutants into the room, or slowly release them indoors. The three paths have different influences. When making a judgment, you should not just look at the number of people, but also the door area conditions and adjacent air conditions.

The effect of opening the door for ventilation depends on the adjacent air

The impact of people entering and exiting depends largely on what is in the air outside the door. If the adjacent area is a low-pollution buffer zone or corridor, the pollution input when opening the door for ventilation is relatively limited; if the adjacent area is close to cleaning, coating or other release sources, the gas introduced when the door is opened may be more obvious. Therefore, when assessing the impact on personnel, one should first understand the air conditions on both sides of the door area, and then make judgments based on the frequency of entry and exit and the duration of the door opening. To directly equate 'many people' with 'heavy pollution' ignores the key variable of adjacent air.

Door area structure and pressure difference management are more important than the number of people

The buffer room setting, door opening direction, pressure difference stability and door seal status often have a more direct impact on gaseous pollution control than the number of people. In a door area with a buffer section and a stable pressure difference, the instantaneous exchange volume can be controlled even if people come in and out frequently; in a door area with insufficient buffering or unstable pressure difference, backflow may occur even if there are not many people. During the inspection, attention should be paid to the change in pressure difference in the door area at the moment of opening and closing the door, whether the door seal is intact, and whether there is independent air supply and exhaust in the buffer room. Regarding the problem that the pressure difference is qualified but external gas still enters, please refer toIf the clean room pressure difference is qualified, why can external gas still enter?。

Release of personnel carry needs to be seen separately

The organic matter released from people's clothing and carrying materials belongs to indoor sources and is different from opening the door for ventilation. This type of release is usually small but sustained, has limited impact on the general area, and may require concern for highly sensitive processes. If the test finds that the concentration of indoor organic matter is related to the period of human activity, the investigation can be carried out based on the changing procedures, clothing materials and management of carried materials. The chemical filtration section has a certain treatment effect on this type of indoor release, but the premise is that the airflow passes through the filtration section and covers the area where people move.

Aili industrial supporting equipment

When people enter and exit items that affect gaseous pollution, we usually recommend that customers record the pressure difference in the door area and the concentration changes during the door opening and closing periods, and then determine whether the main cause is opening the door for ventilation, pressure difference fluctuations, or carrying release, rather than adding a filter element directly. Aili Industry can provide selection packages for box-type, flat-plate and V-type chemical filtration products. For box-type MAU packages, please refer toMAU box type chemical filter , product series can be viewedChemical filter product range . Device-side applications can useChemical filter FFU type, integrated chemical adsorption layer withHEPA/ULPA filter particle filtration, near the door area or circulation section can be configured according to the actual air flow organization. The manufacturing end covers independent R&D and production of motors and fans, control systems, sheet metal and complete machine assembly. The pressure difference in the door area, circulating air volume and filter section position can be checked in the same package, and non-standard air paths can be adjusted according to on-site conditions. The specific gas effect, applicable environment and replacement cycle still need to be verified based on the corresponding configuration data and on-site working conditions. The actual results are subject to on-site leak detection and gas detection results.

Related questions and answers

With frequent personnel coming in and out, is it necessary to add a chemical filter?
uncertain. First look at the adjacent air, door area structure and pressure difference status. If the main cause is opening the door for ventilation or pressure difference fluctuations, improving door area management may be more direct than adding a filter element.

Why did the gas concentration not drop after the number of people decreased?
It shows that the main cause of pollution may not be human activities, but external input, process release or return air accumulation. The source should be re-judged based on time period and location data.

Can Aili Industrial help check the pollution control in the door area?
It can be combined with door area pressure difference, adjacent air and circulation filtration configuration to help determine the main cause and the direction of measures. The specific plan needs to be confirmed based on product data and on-site working conditions.

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Key points for selection and acceptance inspection