In June 2016, the Occupational Safety and Health Administration, OSHA, reduced the Permissible Exposure Limit (PEL) for respirable crystalline silica (RCS) by half and will require engineering controls to help mitigate employee exposure. In June 2018, the new RCS PEL of 0.05 mg/m3 averaged over an 8-hour period applied to hydraulic fracturing and most other industries, and engineering control obligations will commence in June 2021. This update also created an Action Level (AL) which is half of the new standard and triggers other, new compliance areas if employee exposure is greater.
With millions of pounds of silica sand used in every horizontal well completion, crystalline silica is a major component of hydraulic fracturing. Multiple proppant transfer points can generate high concentrations of airborne dust, from offloading trucks to pumping sand down hole. Engineering controls can be used to mitigate exposure.
A study was conducted at multiple hydraulic fracturing sites to determine if RCS concentrations could be reduced below OSHA’s new PEL using chemically engineering controls that do not have an onsite footprint, like Covia’s DustShield. During the study, 10 mm nylon Dorr-Oliver (DO) cyclones were used to measure the amount of RCS produced with and without DustShield. The results showed significant reductions in RCS in both personal and area sampling.
These results show that DustShield is an effective engineering control with no on site footprint. It can help mitigate occupational exposures below the revised PEL and often below the Action Level.

Primary Author / Conference Presenter:
Lia Sedillos
VP Technical Sales
Houston, Texas, USA

Natalie Eglinton, Covia Corp, The Woodlands, TX