An evaluation of a local exhaust ventilation control system for a foundry casting-cleaning operation

Area of Science:

• Industrial Hygiene
• Occupational Safety
• Environmental Engineering

Background:

• Foundry casting-cleaning operations pose significant respiratory health risks due to airborne contaminants.
• Previous ventilation systems in place had inadequate exposure controls for respirable silica.
• Time-weighted average exposures to respirable silica ranged from 124 to 160 µg/m³ with the original system.

Purpose of the Study:

• To evaluate the effectiveness of a newly installed local exhaust ventilation (LEV) system.
• To quantify the reduction in respirable aerosol exposure for a worker performing casting cleaning.
• To compare exposure levels before and after the implementation of the LEV system.

Main Methods:

• A downdraft booth with a turntable was implemented as the new LEV system.
• Direct-reading instruments measured respirable aerosol exposure concentrations.
• Exposure measurements were taken before and after the LEV system installation for the same worker.
• Videotaping documented worker activities to correlate exposures with specific tools.

Main Results:

• The new local exhaust ventilation system reduced respirable aerosol exposures by 59% to 79%.
• Exposure reductions varied depending on the specific chipping and grinding tools used.
• The observed reductions in exposure were statistically significant.

Conclusions:

• The evaluated local exhaust ventilation system is effective in reducing worker exposure to respirable silica in foundry casting-cleaning operations.
• Implementing improved ventilation controls is crucial for mitigating occupational health risks in industrial settings.
• The downdraft booth design offers a significant improvement over previous ventilation configurations.