CALL US TOLL-FREE: 844.425.3642

Part One - Why frac sand exhaust ventilation engineering controls can't contain all respirable crystalline silica

Fri, 02/14/2014 - 14:46 -- Donny Beaver

Part I – Physical Reasons Why Engineering Controls Cannot Provide 100% Containment of all Crystalline Silica

  1. Respirable Crystalline Silica (RCS) is nearly as light as air, invisible, and migrates with the prevailing air currents both inside and outside any areas of containment.
    1. RCS has a very slow settling rate even in a controlled environment.  Recent studies show it takes as long as 57 minutes for RCS to settle inside an enclosed chamber after agitation.
    2. There are approximately 35.3 million RCS particles per cubic meter of air at current OSHA Permissible Exposure Limit  of 0.1 mg/m3.
  1. The currently available engineering controls are not manufactured to be “air tight” and create a false containment condition.
    1. Several engineering controls, such as shrouds, vacuum systems, exhaust plenums, are manufactured as sheet metal retrofits.
    2. The nature of retrofitting, and the standard tolerances used in sheet metal fabrication, create multiple gaps/holes/crevices between the pieces of equipment being retrofitted.
    3. The process of welding components together is not usually viable due to the mobility requirements of the industry.  Most engineering controls need to be designed for removal and relocation.
    4. The majority of these retrofits systems do not utilize proper gasketing techniques and/or clamping components necessary to create an air tight condition.
    5. Most sheet metal retrofits use the weight of the system and/or standard bolt/nut fastening to join the equipment together.  This leaves hundreds to gaps in the perimeter of the equipment through which RCS will always escape.
    7. We have also seen companies promote a basic system of “Tarps and Magnets” to contain certain areas of sand moving equipment.

jordan shoes for sale outlet orange