Cleanroom technology employs comprehensive strategies to control contamination in controlled microenvironments and achieve target air cleanliness levels. Key technical measures include:
① Using compliant materials for cleanroom construction
② Selecting equipment meeting cleanroom standards
③ Implementing containment, isolation, or dust removal to control pollutant dispersion
④ Applying pressure differential controls
⑤ Designing rational personnel/material decontamination protocols
⑥ Adopting airflow organization patterns aligned with cleanliness requirements
1. Cleanroom Construction Materials
Contamination control in cleanrooms requires systematic coordination of multiple measures to maximize efficiency at minimal cost. Walls, floors, and ceilings must:
- Generate minimal dust
- Resist particle accumulation and bacterial growth
- Feature seamless or tightly sealed joints
Recommended materials:
- Walls/Ceilings: Color steel sandwich panels, antibacterial-coated electrolytic steel plates, artificial stone panels
- Floors: Epoxy resin self-leveling surfaces, anti-static PVC flooring, premium terrazzo
2. Equipment Selection & Adaptation
Process engineers must verify equipment compatibility. Current challenges include:
- Many industrial devices have uneven surfaces prone to dust retention
- Post-installation solution: Clad non-compliant surfaces with stainless steel plates (without affecting functionality) to ensure smooth, clean finishes
Pressure differential strategy:
- Airflow direction: From high-cleanliness to low-cleanliness zones
- Polluted cleanrooms: Maintain negative pressure to prevent cross-contamination
3. Personnel/Material Flow Design
Decontamination protocols:
- Multi-stage changing rooms (primary → secondary → tertiary)
- Air showers to remove particles from cleanroom garments
Material transfer controls:
- Dedicated pass-through windows/channels
- External packaging vacuuming and removal before entry
- Clean zone pressurization: Maintain +15Pa vs. non-clean areas
4. Airflow Organization Patterns
Non-unidirectional flow systems:
- Strategically position supply/return vents
- Dilute contaminants through diffusion and exhaust
Unidirectional flow systems (“piston effect”):
- Push contaminants directly toward return vents
(Detailed methodologies covered in Chapter 4)
Molecular Contamination Control
For precision manufacturing requiring both particle and molecular contamination control (e.g., semiconductors, advanced optics), integrate these into HVAC systems:
- Chemical filters
- Adsorption filters
- Gas scrubbers
