[Research on efficient ventilation protection measures for organic solvent in composite materials impregnation room].

<b>Objective:</b> To explore highly efficient ventilation protection technology for large-space workplaces adapted to the production process in composite material impregnation. <b>Methods:</b> A composite material impregnation room was selected as the research subject from August to December 2023. Occupational health investigation, on-site detection, and physical simulation of air distribution were used to analyze the distribution of the xylene concentrations in the impregnation room. In addition, the causes for excessive concentrations were analyzed, and the combination ventilation design of enclosed negative pressure cabinets and jet directional supply of fresh air was proposed. The concentration of xylene, the capture velocity and the differential pressure of ventilation facilities before and after the transformation were tested on the spot. The rationality of the airflow organization was determined through smoke testing, and the ventilation protection effects before and after the transformation were analyzed. <b>Results:</b> The time-weighted average allowable concentration (<i>C</i>(TWA)) of xylene was reduced from 41.73 mg/m(3) to 7.78 mg/m(3), and the <i>C</i>(TWA) of xylene were reduced by 81.4%. The values of capture velocity at all areas were higer than 0.5 m/s, and the values of velocity unevenness in all regions were lower than or equal to 0.25. The differential pressure between the enclosed cabinet and the impregnation room corridor was -2 to -1 Pa. The overall velocity distribution at all areas was relatively uniform, the airflow organization was reasonable, and negative pressure was formed inside the enclosed cabinet. <b>Conclusion:</b> The combination ventilation design of xylene, the capture velocity and the differential pressure of ventilation facilities effectively reducing the xylene concentration in the workplace, and provide a reference for ventilation protection of xylene workplace.