Selected Answers

From virani jagdish of MHI on April 29, 2014:
Non-visible dust can be detected by using a dust-l ...read more Non-visible dust can be detected by using a dust-level tape test.

From David Cobbett of B-Rite Coating Inspections on April 24, 2014:
When I was overseeing a dousing tank at a nuclear ...read more When I was overseeing a dousing tank at a nuclear site, I was looking at the previous coating failure and found as many as 5 coats could be distinguished, with a fine crystal-like film between each coat. So there was contamination from start to finish.  Fine airborne particles from other parts of the plant were driven upward because of the heat to the top of the reactor where the dousing tank was located. To overcome this problem, we fabricated dust walls using 2-inch PVC pipe and 40-mil plastic sheets, then sealed the walls with tape once an area was squared off, forming an inclosure. Two holes are necessary on both outer walls with two air-moving units. The intake runs at 70%, the outtake at 100%, creating a negative air space of about 3 atmosphere and achieving a dust-free environment.

From Warren Brand of Chicago Corrosion Group on April 8, 2014:
Of course, the details of the materials being proc ...read more Of course, the details of the materials being processed are critical. We worked at a large facility on a  flour silo. In that case, we took normal precautions for dust and isolated the work area. I think I would focus on isolating the work area. Testing or identifying contaminants would depend on the specific facility and materials involved. In another case, we worked at a facility that made powdered detergent. The dust was so incredibly fine that it was impossible to see. It was just luck that one of the blasters noticed a slight sheen on his blasted surface, which made us  realize that this invisible dust had contaminated the substrate.