طراحی و ارزیابی عملکرد سامانۀ تهویۀ مکشی موضعی بر روی مشعل جوشکاری

Background and aims: The welders' health threat due to exposure to welding fume is an important issue, so effective exhaust of fumes are needful for to be assured from the workers safety in exposured to such proccess. In this study, was evaluated prototype operation of local exhaust ventilation on-gun in bench scale. Methods: duct velocity Average was determined by using traverse points method and calculated flow rate by hood using ACGIH standard method. Also capture velocity close in contaminant source (Arc Point) was measured using thermal anemometer. Then in order to determine total particles concentration and capture efficiency created by system, Was used NIOSH 7200 standard method. Results: the results show that, duct velocity average and created flow rate by evaluated system was obtained respectively 6296.1±92.50 fpm and 34.06±0/50 scfm. Also capture velocity in close the weld point was obtained 140 fpm. Sampling results shows averaged total particles concentration in off and on positions of system, respectively 75±7 mg/m3 and 16.7±4 mg/m3. As a result achieved containment efficiency 77% by this system. Conclusion: The local exhaust ventilation used in this study was a low cust prototype and according to acheived results, it lead to reduce total particles concentration (T.P) in breathing zone aproximately to 22%.