Latest company case about Guangzhou Cleanroom Construction Co., Ltd. Certifications

In modern industrial production, the importance of cleanrooms is beyond question. For industries with exceptionally stringent environmental requirements — such as semiconductor manufacturing, biomedical research and production, and precision optical instrument processing — even microscopic particle contamination can seriously impact product quality, production efficiency, and equipment lifespan. However, building a high-standard cleanroom is only the first step. How to scientifically evaluate its purification effect is a core competency that every cleanroom engineering professional must master.

This article systematically outlines the key technical dimensions for evaluating cleanroom purification performance, offered as a reference for industry practitioners.

1. Air Filtration System Performance Evaluation — The Core Defense Line

The air filtration system is central to controlling particle contamination in cleanrooms. Evaluation should cover all three filtration levels: pre-filters, medium-efficiency filters, and high-efficiency filters.

• Pre-filters: Designed to intercept large particles such as dust and hair with diameters greater than 5 microns. The standard benchmark for filtration efficiency is no less than 80%.
• Medium-efficiency filters: Targeting particles with diameters between 1 and 5 microns, these filters should achieve a filtration efficiency of 70%–90%.
• HEPA filters: Must exceed 99.97% efficiency for particles ≥0.3 microns. The higher-grade ULPA filters must achieve 99.999% or above for particles ≥0.12 microns.

Evaluations should include regular differential pressure testing and leak scanning tests (DOP/PAO method) to confirm that filters are free from damage and bypass leakage, thereby safeguarding air quality at the source.

2. Airflow Organization Assessment — Precise Guidance of Airflow

Well-designed airflow organization is essential for maintaining a clean environment. The key evaluation focus is whether the airflow pattern matches the required cleanliness level.

• Unidirectional flow (laminar flow): Air moves in uniform, stable parallel streamlines, rapidly sweeping particles out of the clean zone. This is suited for ultra-high-cleanliness areas such as lithography process workshops in chip manufacturing. Evaluation metrics include cross-sectional airflow velocity uniformity (typically ≥0.45 m/s) and airflow parallelism.
• Non-unidirectional flow (turbulent flow): Clean air dilutes and mixes with contaminated room air to reduce particle concentration. Used in general-cleanliness environments. Evaluation focuses on whether air change rates meet standards and on indoor concentration recovery time.

Additionally, the effectiveness of air curtains and air showers should be assessed by measuring outlet air velocity and shower duration to verify their ability to block external contaminated air and remove particles carried by personnel.

3. Electrostatic Adsorption Device Performance Evaluation — Efficient Capture of Sub-Micron Particles

Electrostatic adsorption technology charges airborne particles using a high-voltage electrostatic field, then captures them on oppositely charged collector plates. This approach offers outstanding advantages for removing sub-micron particles that are difficult to eliminate through conventional filtration. Key evaluation indicators include:

• Capture efficiency: With particular attention to the removal rate of particles smaller than 0.1 microns;
• Operating resistance: Compared to traditional HEPA filters, electrostatic devices have lower airflow resistance and energy consumption, which should be factored into energy-efficiency assessments;
• Combined performance: In localized high-requirement areas — such as sample preparation zones in electron microscopy laboratories — the overall purification effect of electrostatic adsorption devices used in conjunction with traditional filtration systems should be evaluated holistically.

4. Surface Cleanliness Evaluation — Eliminating Secondary Contamination Sources

Equipment surfaces, walls, and floors that are not sufficiently smooth can easily become secondary particle release sources. Surface cleanliness evaluation should cover the following:

• Material suitability verification: Review whether interior finishing materials are smooth, dust-resistant, and anti-static;
• Surface particle residue testing: Use methods such as RODAC contact plates, swab sampling, or optical particle scanning to regularly detect particle adhesion on surfaces;
• Cleaning procedure effectiveness review: Assess whether professional cleaning tools, agents, and operating procedures can consistently maintain surface particle levels within specified limits. For high-cleanliness areas such as aseptic drug filling workshops, the coverage completeness and cleaning effectiveness of automated cleaning robots should also be evaluated.

5. Personnel and Material Management Compliance Evaluation — Contamination Control at the Source

Personnel represent one of the largest contamination sources in cleanrooms, generating particles such as skin flakes, hair, and fibers through their activities. Management compliance evaluation should encompass:

• Personnel behavioral compliance: Verify that all staff entering the cleanroom are properly equipped with cleanroom garments, masks, caps, shoe covers, and other required protective gear, and have completed purification procedures such as air showering;
• Personnel density and movement management: Assess whether staff numbers and movement ranges comply with cleanroom personnel management regulations;
• Material control effectiveness: Verify that all materials entering the cleanroom have undergone proper cleaning, disinfection, and packaging, and that dust-proof and anti-contamination measures are in place during transportation and storage.

Conclusion

Evaluating cleanroom purification performance is a systematic undertaking that requires comprehensive control across five dimensions: air filtration, airflow organization, electrostatic adsorption, surface cleanliness, and personnel and material management. A lapse in any single area can compromise overall purification levels and affect product quality and production stability.

With extensive engineering experience and a specialized technical team, a professional cleanroom construction company can provide end-to-end services — from solution design and construction to purification performance testing and verification — helping enterprises across industries achieve efficient, stable operations under demanding environmental requirements.