How to test and verify the dust removal rate of air shower room?
Publish Time: 2025-03-25
As a key equipment for cleanroom personnel purification, the dust removal efficiency of air shower room directly affects the air quality of clean environment. How to accurately test and verify the dust removal rate of air shower room is the core link to ensure that its performance meets the standard. This process requires not only rigorous testing methods, but also simulation of real usage scenarios to evaluate the actual effect of the equipment with scientific data.
The preparation work before the test determines the reliability of the data. First of all, it is necessary to ensure that the air shower room is in a stable operating state, and the fan, filtration system and control system are working properly. The test environment should simulate the actual use conditions, including temperature and humidity control (usually 22±2℃, humidity 55±5%) and background cleanliness (at least one level lower than the cleanliness of the outlet of the tested air shower room). Testers need to wear standard clean clothes to avoid becoming a source of pollution. International standards such as ISO 14644-3 and GB/T 25915.3 provide a basic framework for testing, but the specific methods need to be adjusted according to the application scenarios of air shower rooms.
Particle counting method is the most direct way to verify the dust removal rate. During the test, a laser particle counter is used to sample at the entrance and exit of the air shower room at the same time to compare the changes in particle concentration. Particles with a particle size of 0.3μm, 0.5μm and 5.0μm are usually detected, which cover most of the particles carried by the human body. The sampling point should be arranged at a height of 1.2 meters above the ground (simulating the breathing zone of personnel) and evenly distributed at multiple points in the air shower room to evaluate the uniformity of air flow. The test needs to be repeated many times and the average value is taken to reduce accidental errors. For example, the test data of an electronics factory shows that the removal rate of 0.5μm particles in a qualified air shower room should be ≥99%.
Human simulation test is closer to actual working conditions. Professional testers wear clean clothes with specific pollution loads (such as applying standard dust) and enter the air shower room for showering. Before and after showering, use a contact plate or a sticky stick to take samples on the surface of the clothing, and culture and calculate the number of colonies or particle residues. This method can intuitively reflect the air shower room's ability to remove pollutants actually carried by personnel, and is particularly suitable for pharmaceutical and biological laboratories. However, it should be noted that the standardization of the tester's actions (such as rotation and raising hands) will affect the reproducibility of the results, so strict operating procedures need to be formulated.
Airflow visualization technology provides a basis for optimized design. Through a smoke generator or atomized oil mist, combined with high-speed video, the airflow organization in the air shower room can be visually observed. The ideal airflow should cover the whole body, without dead corners and turbulence. Computational fluid dynamics (CFD) simulation can further predict the particle movement trajectory under different nozzle angles and wind speeds, and assist in improving the design. A case study of a medical equipment factory showed that the dust removal rate was increased by 12% through airflow optimization, while the shower time was shortened.
Long-term performance monitoring is also important. The dust removal rate is not constant, and the decline in filter efficiency, fan performance attenuation or seal aging will affect the effect. Therefore, regular testing (such as once a quarter) is essential. Smart air shower rooms can integrate online particle monitoring systems to record data in real time and warn of performance degradation. Historical data comparison and analysis can also predict the filter material replacement cycle to avoid sudden failure.
The verification report needs to integrate multiple indicators. Although dust removal rate is a core parameter, it also needs to be comprehensively evaluated in combination with data such as wind speed uniformity, noise level, and door sealing. For example, the acceptance criteria of a semiconductor factory require: 0.5μm particle dust removal rate ≥ 99%, wind speed deviation at each point ≤ 15%, and door gap leakage rate < 0.01%. Only multi-dimensional testing can ensure that the air shower room can stably play a barrier role in long-term use.
With the advancement of detection technology, new methods such as fluorescent particle tracking and electrostatic particle adsorption detection are gradually applied. These technologies can more accurately locate the location of residual pollution. But no matter what means are used, scientific testing processes and rigorous data analysis are always the cornerstones of verifying the performance of air shower rooms, and are also an important line of defense for ensuring the quality of clean environments.
