Abstract:
Objective To investigate the current status of local exhaust ventilation facilities in workplaces, providing a basis for strengthening the management of local exhaust ventilation facilities in the manufacturing industry and preventing occupational diseases.
Methods A survey and inspection were conducted on 52 ventilators and 49 local exhaust hoods in 27 enterprises in a district of Shanghai, and the results were analyzed and evaluated.
Results Among the 49 local exhaust hoods, 46.9% (23 hoods) had an expansion angle > 90°, 42.9% (21 hoods) had a control distance greater than the equivalent diameter of the hood, and 38.8% (19 hoods) had a control wind speed < 0.25 m/s. Among 52 ventilators, 51.9% (27 ventilators) had more than 10 connected hood openings, 51.9% (27 ventilators) had an actual air volume to rated air volume ratio ≤ 0.7, and 32.7% (17 ventilators) had no inspection holes on the ducts in front of the ventilator.
Conclusions The surveyed enterprises had issues such as excessive expansion angles of exhaust hoods, excessive control distances, and insufficient control wind speeds. Additionally, there were problems with too many connected hood openings on ventilators, excessive system resistance leading to reduced exhaust volume, and low opening rates of inspection holes in front of the ventilators. It is recommended to strengthen the training of designers of occupational hazard protection facilities and to implement regular commissioning and maintenance actions for local exhaust ventilation facilities.
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