Washing equipment that meets the microbial standards specified in WS/T508

According to the requirements of WS/T 508, "Technical Specification for Washing and Disinfection of Medical Textiles in Hospitals," medical textile washing must meet the following key points and be analyzed in conjunction with equipment characteristics:
I. Core Requirements of WS/T 508
Building zoning
Strict physical separation: The contaminated area (for receiving, sorting, and washing soiled textiles) must be completely separated from the clean area (for drying, ironing, and storage). Airflow should flow from clean to contaminated areas to prevent cross-contamination.
Personnel and Logistics Management: Staff and fabrics must flow in a unidirectional manner, and reverse crossings are prohibited.
Microbiological indicators
Medical textiles that have been washed and disinfected must meet the following standards:
Total bacterial colony count ≤ 200 CFU/100 cm²;
Pathogenic microorganisms such as coliforms and Staphylococcus aureus must not be detected.
II. Key Considerations for Selecting Washing Equipment
Washing equipment that meets WS/T 508 requirements must have:
Physically isolated design
Contaminated and clean areas must be physically separated through equipment design or process engineering, such as by using double-door designs or segmented isolation.
Effective disinfection capability
Thermal disinfection: High-temperature washing (≥75℃, ≥30 minutes) or equivalent parameters;
Chemical Disinfection: Use chlorine-based disinfectants or other compliant disinfectants, ensuring that the concentration and contact time meet the required standards.
Cross-contamination prevention measures
The airflow and water flow inside the equipment must be controllable to prevent direct connection between contaminated and clean areas.
III. Analysis of the Applicability of Tunnel-Type Continuous Washing Systems
1. A tunnel-type system that is connected to the atmosphere at both ends and is internally贯通.
Potential risks:
If both ends are open and internally connected, contamination could occur due to the free circulation of air, leading to cross-contamination between contaminated and clean areas—for example, air from the contaminated area could carry microorganisms into the clean area.
If fabrics are not properly segregated during transportation, secondary contamination may occur.
Compliance Improvement Recommendations:
Airflow control: Establish a negative pressure gradient or an air barrier between contaminated and clean areas to ensure unidirectional airflow from clean to contaminated zones.
Segmented Isolation: Use physical barriers (such as sealed doors and air showers) to separate different areas of the tunnel.
Automated process: Fully enclosed loading/unloading design to prevent contamination caused by human intervention.
2. Alternative: Double-door washing equipment
Advantage: The dual-door design directs one door toward the contaminated area and the other toward the clean area, ensuring that the washing process remains fully enclosed and meets physical isolation requirements, thereby reducing risks.
IV. Conclusion
Tunnel-type systems must meet additional requirements: If both ends are open and the interior is fully贯通, the risk of cross-contamination must be addressed through negative-pressure control, segmented isolation, and automated process design, and microbial indicators must be verified to meet the specified standards.
Recommended solution: Prioritize equipment featuring a physically isolated design (such as a double-door type) or a closed tunnel system (with segmented negative-pressure control) to ensure compliance with WS/T 508 requirements.
Verification steps: It is recommended to conduct third-party testing to confirm that the microbial indicators and airflow direction after washing meet the standards.
For further guidance on equipment selection, refer to the appendix of WS/T 508 or consult a medical disinfection technology institution.
4. When comparing the research findings of Deep Seep with the requirements of WS/T508 standard, three significant differences are observed:
1. Differences in Tunnel System Specifications
It explicitly requires that open-tunnel systems must be equipped with a triple set of measures: negative-pressure control, physical isolation, and automated processes, and microbial indicators must be verified. In contrast, the current WS/T508 does not include any “improvement requirements” and does not specify any particular technical standards.
2. Disagreement on Equipment Selection Recommendations
The recommended priority solutions include two types: dual-door physical isolation and enclosed tunnel systems. However, current standards remain silent on tunnel systems that are neither enclosed nor equipped with negative-pressure control, tacitly allowing the use of substandard equipment.
3. Contradictions in the selection of implementation paths
The study points out that technological improvements can significantly reduce the risk of infection—but standard-setting organizations have failed to incorporate mature technological solutions into mandatory regulations. This misalignment between lagging technical standards and the risk of limited accessibility essentially shifts the risk of hospital-acquired infections—risks that could have been averted through technological upgrades—onto patients themselves. In effect, patients are footing the bill for “saving on improvement costs” by bearing the health risks associated with these infections.