Local Exhaust Ventilation System

A local exhaust ventilation system includes a vacuum. The vacuum should have the following features:

• A sufficient flow rate to capture the dust and transport it to the vacuum source
• A HEPA filter to reduce the chances of releasing silica dust from the vacuum back into the worksite
• A pre-filter or cyclone that will increase the length of service of the HEPA filter
• A filter replacement indicator
• The ability to clean and replace filters and collection bowls or bags without exposing the operators to dust
• A motor that draws at least 10 amps

Next, the hose should have a diameter of 1.5 or 2 inches, a relatively smooth and interior, and a length of no more than 15 feet to provide for adequate air flow.

Finally, the type of shroud to be used depends on the task being performed. After testing different types of shrouds, NIOSH determined that all were equally effective, and reduced dust exposure by at least 90 percent.

Local exhaust ventilation systems offer several benefits, as follows:

• A reduction in worker exposure to hazardous dust
• A reduction in the need for protective respiratory protection
• A reduction in cleanup time
• A reduction in worker exposures during cleanup

To learn more about Silica Safety visit our General & Maritime Silica Safety Online Training web page.