Industrial gas source cleanliness requirements

In the field of industrial production, air source cleanliness is a core factor in ensuring product quality, production safety and stable operation of equipment. The following systematically describes the key requirements for industrial gas source cleanliness from four dimensions: technical standards, industry applications, implementation paths and operation and maintenance management:

1. Cleanliness technical standard system

The ISO 14644 standard formulated by the International Organization for Standardization (ISO) divides the air cleanliness of clean rooms into 9 levels (ISO levels 1-9), using the number of particles of different particle sizes per cubic meter of air as a quantitative indicator. For example:

• ISO Level 1: Allow ≤10 particles with a diameter ≥0.1μm, suitable for precision fields such as semiconductor chip manufacturing.
• ISO Class 5: ≤100 particles with a diameter ≥0.5μm are allowed, which is the benchmark standard for the production of sterile preparations in the pharmaceutical industry.
• ISO Class 8: ≤3,520,000 particles with a diameter ≥0.5μm are allowed, which are common in general electronic assembly workshops.

The domestic standard GB/T 16292-2010 adopts a similar grading system, but some industries have special specifications. For example, the food industry requires the oil content of compressed air to be ≤0.01mg/m³, and the microbial indicators must meet the GB 4789.2-2016 Food Microbiological Inspection standards.

2. The core impact of cleanliness on industrial production

1. product quality assurance
   • In semiconductor manufacturing, particles with a diameter of ≥0.1μm may cause short circuits in integrated circuits and reduce yields.
   • If the production of sterile preparations in the pharmaceutical industry is exposed to environments below ISO level 5, the risk of microbial contamination will increase.
2. Equipment operating stability
   • Precision instruments (such as mass spectrometers and laser cutting machines) require air source cleanliness to reach ISO 3-4. Particulate matter pollution will cause wear of optical lenses and increase maintenance costs.
3. regulatory compliance
   • Good Manufacturing Practice (GMP) clearly requires that the production of sterile drugs must be carried out in a Class A clean area in an ISO 5 background.
   • Compressed air used in contact with food must comply with GB 4806.7-2016 National Food Safety Standards to avoid oil stains and odors contaminating products.

3. Path to achieve high cleanliness air source

1. Air purification system design
   • multi-stage filtration: Using three-stage filtration of primary effect (G4), intermediate effect (F8), and high efficiency (HEPA), the filtration efficiency of particulate matter with a diameter of ≥0.3μm reaches 99.97%.
   • Air flow organization optimization: Ensure that clean air evenly covers the production area through vertical one-way flow or turbulent air flow patterns and avoid pollution in the vortex area.
2. Environmental control system integration
   • temperature and humidity control: Maintain the temperature of 18-26℃ and the humidity of 45%-65% to inhibit microbial reproduction and static electricity generation.
   • Pressure gradient management: The clean room needs to maintain a positive pressure of ≥10Pa to prevent the intrusion of external polluted air.
3. Special process guarantee
   • nitrogen protection: In the production of easily oxidizable products, a nitrogen environment with a purity of ≥99.999% is provided through liquid nitrogen vaporization.
   • oil mist separator: Use a coalescing filter to control the oil content of the compressed air below 0.001mg/m³.

4. Cleanliness maintenance and verification system

1. daily monitoring
   • particle count: Use a laser particle counter to regularly detect critical control points in accordance with ISO 14644-1 requirements.
   • microbiological monitoring: Measure the concentration of microorganisms in the air through a plankton sampler (such as the Anderson impactor sampler).
2. filter management
   • differential pressure alarm: When the filter pressure difference exceeds 150% of the initial value, the replacement process needs to be started.
   • integrity test: Use the DOP/PAO aerosol method to verify that the HEPA filter leakage rate is ≤0.01%.
3. Personnel and material control
   • gowning procedure: Operators need to go through the air shower to remove dust and wear one-piece cleaning clothes, gloves and masks.
   • material purification: Through the transfer window or airlock, clean and disinfect the external packaging before entering the clean area.
4. Incident Response Service Mechanism
   • Handling of uncontrolled differential pressure: If the pressure difference in the clean room is less than 5Pa, the backup fan needs to be started immediately and the leak point should be checked.
   • Disposal of excessive particulate matter: Pause production, start deep cleaning procedures, and conduct environmental verification again.

5. Comparison of cleanliness requirements in typical industries

Through strict technical standard implementation, systematic environmental control and standardized operation and maintenance management, the cleanliness of industrial gas sources can be ensured to meet high-precision manufacturing needs and provide basic guarantee for product quality and production safety.