What indicators are usually used to measure the cleanliness performance of clean room automatic sliding doors?

The cleanliness performance of Automatic Sliding Doors in cleanrooms is a critical factor in ensuring the stability of the cleanroom environment and maintaining the required cleanliness level. It is typically assessed through a series of comprehensive indicators that are interrelated and collectively ensure the reliable operation of the door in a cleanroom setting.

1. Airtightness

· Indicator Description: Airtightness measures the ability of the door to prevent air leakage when closed, which directly affects the pressure differential control within the cleanroom, the prevention of external contaminated air ingress, and the maintenance of internal cleanliness. Poor airtightness can lead to pressure imbalance in the cleanroom, allowing external contaminants to enter and disrupt the clean environment.

· Testing Method: Pressure decay tests are conducted by applying a certain pressure inside the cleanroom after the door is closed and monitoring the pressure change over time to calculate the pressure decay rate. Alternatively, smoke tests can be used by releasing smoke near the door seal and observing whether it leaks into or out of the cleanroom.

· Standard Requirements: Typically, compliance with ISO 14644 or relevant industry standards (such as Chinese GB standards) is required. For cleanrooms of different cleanliness levels, there are specific leakage rate limits. For example, in high-grade cleanrooms, the leakage rate must be below a very low value to ensure stable indoor air quality.

2. Surface Cleanliness

· Indicator Description: The door surface should be smooth, seamless, and easy to clean to prevent the adhesion and proliferation of microorganisms and particulates. High surface roughness or the presence of seams can provide hiding places for contaminants, increasing cleaning difficulty and affecting the cleanroom environment.

· Testing Method: Surface roughness is measured using a surface roughness meter to detect microscopic undulations on the surface. Alternatively, wipe tests can be performed by wiping the door surface with a specific type of cloth and observing the residues on the cloth to assess the ease of surface cleaning.

· Standard Requirements: The surface roughness should generally be below 0.8μm (Ra value), and the material should possess antibacterial and antifungal properties. For example, stainless steel materials used should meet certain surface treatment standards to inhibit microbial growth.

3. Particle Emission

· Indicator Description: The door materials and seals may emit particles during operation, which can enter the cleanroom and affect product quality and cleanliness. Excessive particle emission can lead to elevated particle concentrations in the cleanroom air, disrupting the clean environment.

· Testing Method: In a simulated cleanroom environment, particle counters are used to measure particle concentrations during door operation, recording the number of particles of different sizes. Alternatively, wipe methods can be used to collect particles from the door surface by wiping it and analyzing the wipe solution.

· Standard Requirements: Compliance with cleanroom level requirements is necessary (e.g., in ISO 5 or lower environments, particle concentrations must be below 3,520 particles/m³ for particles ≥0.5μm). For critical areas, such as filling zones in biopharmaceuticals, particle control requirements are even stricter.

4. Material Compatibility

· Indicator Description: Door materials must be compatible with the chemicals (such as disinfectants, solvents) present in the cleanroom to avoid corrosion, dissolution, or the release of harmful substances upon contact, which could contaminate the cleanroom environment.

· Testing Method: Chemical compatibility tests involve exposing the door material to specific chemicals for a certain period and then assessing changes in its physical and chemical properties, such as appearance, strength, and weight. Immersion tests can also be conducted to observe the material's reaction in the chemicals.

· Standard Requirements: Materials must comply with cleanroom material standards (such as ASTM G21 or ISO 10993) to ensure they are non-toxic and non-corrosive, and will not contaminate or damage products in the cleanroom.

5. Sealing System Performance

· Indicator Description: The compression resilience, wear resistance, and aging resistance of seals directly impact long-term airtightness. Poor seal performance can lead to gaps when the door is closed, affecting airtightness and disrupting the cleanroom environment.

· Testing Method: Compression set tests measure the recovery of seals after being compressed for a certain time and released. Wear tests simulate the friction seals experience during actual use to assess wear. Aging tests expose seals to high temperature, humidity, and other environments for a specified period to observe performance changes.

· Standard Requirements: Seals must comply with relevant industry standards (such as EN 12426) to ensure they maintain sealing effectiveness over long-term use, such as achieving a certain compression resilience percentage and meeting wear resistance and aging resistance requirements for the intended service life.

6. Electrostatic Control

· Indicator Description: The door surface must possess electrostatic dissipation properties to prevent the adsorption of particles due to static electricity, which can contaminate the cleanroom. Electrostatically adsorbed particles are difficult to remove and can affect product quality and production efficiency in the cleanroom.

· Testing Method: Surface resistance is measured using a surface resistance meter by placing the meter's electrodes on the door surface and reading the resistance value. Alternatively, friction charging tests can be performed by rubbing the door surface to observe static electricity generation and its intensity.

· Standard Requirements: The surface resistance should typically be between 10⁶ and 10⁹Ω, complying with ESD S20.20 standards, to ensure the door surface does not generate excessive static electricity and prevent particle adsorption.

7. Operational Stability

· Indicator Description: The smoothness and sealing effectiveness of the door during operation should prevent particle generation due to vibration or friction. Unstable operation can cause noise and particle generation, affecting the cleanroom environment and product quality.

· Testing Method: Long-term operation tests observe whether the door exhibits jitter, abnormal sounds, or sealing failure during operation. Vibration test meters can also measure the amplitude and frequency of door vibrations during operation.

· Standard Requirements: Compliance with cleanroom equipment operational stability standards is necessary to ensure consistent performance over long-term use, such as keeping door operating speed and acceleration within specified ranges and maintaining sealing effectiveness during operation.

8. Maintainability

· Indicator Description: The ease of maintaining the door and sealing system directly affects the sustained cleanliness performance. Difficult maintenance can lead to delays, impacting the door's lifespan and cleanliness performance.

· Assessment Method: Check if the door structure is easy to disassemble, clean, and replace seals. Observe if maintenance access is unobstructed and if maintenance tools are easy to operate.

· Standard Requirements: Compliance with cleanroom equipment maintenance standards is required to ensure rapid and dust-free maintenance, such as door designs facilitating personnel operations and minimizing interference with the cleanroom environment during maintenance.

9. Antibacterial Properties

· Indicator Description: The door surface should possess certain antibacterial capabilities to inhibit the growth and proliferation of microorganisms such as bacteria and molds, preventing microbial contamination of the cleanroom environment.

· Testing Method: Antibacterial tests involve exposing the door material to specific microorganisms for a certain period, then culturing the microorganisms and observing their growth to calculate the antibacterial rate.

· Standard Requirements: The antibacterial rate should meet certain standards, such as being greater than 90% against common bacteria, to ensure the door surface does not become a breeding ground for microorganisms.

10. Corrosion Resistance

· Indicator Description: The door should have good corrosion resistance to withstand erosion from chemicals, humidity, and other factors in the cleanroom, maintaining its performance and appearance.

· Testing Method: Salt spray tests, acid-base corrosion tests, etc., are conducted by exposing the door material to simulated corrosive environments and observing its corrosion.

· Standard Requirements: Depending on the cleanroom's operating environment and chemical substances, the door material's corrosion resistance level should be determined to ensure it does not deteriorate due to corrosion over long-term use.