How does work activity duration affect estimated dust exposure level?

The Silica Control Tool^TM estimates the average level of RCS exposure over the entire silica process. If there are more hours of cumulative exposure, more RCS will be inhaled. If there are less hours of cumulative exposure, less RCS will be inhaled.

The longer you are exposed to RCS the lower the exposure limit will need to be adjusted to ensure that shift or task length does not negatively impact worker health. For shift lengths greater than 8 hours, the allowable occupational exposure limit for RCS is less than the exposure limit of 0.05 mg/m³. This Concentration Equivalent (Ceq) is calculated using the following formula:

For related information, see Silica Control Tool Exposure Level Exposure Limit