OPTIMIZING FUME EXTRACTION: AN EMPIRICAL STUDY ON THE PERFORMANCE OF LOCAL EXHAUST VENTILATION (LEV) FOR WELDING IN TECHNICAL VOCATIONAL LABORATORIES

Povzetek

This study evaluates the performance of the Local Exhaust Ventilation (LEV) system at the Welding and Metal Fabrication Laboratory, Faculty of Technical and Vocational Education (FPTV), Universiti Tun Hussein Onn Malaysia (UTHM). The objectives were to measure velocity pressure (VP), static pressure (SP), and total pressure (TP) along the duct system, assess air velocity at duct and hood locations, analyze performance variation by duct size, and identify underperforming extraction points. Data were collected at sixteen locations (six ducts and ten hoods) using a digital anemometer, following the Department of Occupational Safety and Health (DOSH, 2008) guidelines. The results showed duct velocities ranging from 14.54 to 21.96 m/s and hood velocities from 1.94 to 3.27 m/s. Two hoods (Hood 9 and Hood 10) recorded velocities below the 2.0 m/s minimum recommended by ACGIH, indicating reduced extraction efficiency. The performance drop was attributed to extended duct length, dust accumulation, and pressure losses due to multiple bends. Optimization strategies were proposed, including regular duct cleaning, airflow balancing, fan performance assessment, and redesigning long ducts or installing booster fans. Implementing these measures can enhance airflow uniformity, improve capture efficiency, and ensure compliance with ACGIH and DOSH standards. The findings provide practical insights for maintaining effective LEV systems and improving occupational safety in Technical and Vocational Education and Training (TVET) welding laboratories.