Analysis of Capture Velocity in the Case of Local Exhaust Ventilation.

This article presents a study on the capture velocity of local exhaust ventilation (LEV) using a specially designed workstation within a laboratory setting. The workstation featured a worktop with dimensions of 90 cm width and 45 cm depth, and the exhaust duct was positioned near the pollutant source, considering the intended operation of the LEV system. The worktop was divided into squares for precise documentation and remeasurement. A supply duct above the worktop provided controlled fresh airflow. Smoke was used to visualize airflow patterns. The measurements focused on air velocity and turbulence intensity, aiming to understand flow structures and vortices. Various capture rates were tested at specific measurement points. The study revealed that the central capture lines yielded the highest efficiency. To address air extraction from behind the exhaust duct, a back sheet panel was introduced. The results showed that installing a back sheet enhanced capture velocities. The findings contribute to understanding LEV efficiency and the importance of proper design and adjustments for effective containment of contaminants in the occupational environment. [ABSTRACT FROM AUTHOR]