Dust Control Handbook for Industrial Minerals Mining and Processing

minimal improvement in the cab's air quality. In fact, similar filtration and pressurizationsystems were installed on the rotary drill and front-end loader listed as items 1 and 3 inTable 9.2, with the PF varying from 2.8 to 10. One notable difference between these twosystems was that a small amount of pressurization was achieved in the front-end loader, whereasit was not possible to achieve any pressurization in the rotary drill. It should also be noted thatlow outside dust concentrations may have a negative impact on the PF.Another critical factor was the quality and effectiveness of the filtration system. The variousstudies presented in Table 9.2 indicated substantial improvement in the interior air quality fromeffectively removing the dust particles from the outside air and delivering this clean filtered airinto the enclosed cab. When sufficient pressurization was achieved along with an effectivefiltration system, very good air quality was obtained in these cabs as indicated by significant PFs.Laboratory StudyFrom these various field studies, a number of different factors emerged that were relevant to theeffectiveness of filtration and pressurization systems. In an effort to evaluate this area, acontrolled laboratory experiment was performed to systematically examine multiple cab designs.Figure 9.2 shows the cab filtration system setup used for this controlled laboratory study and thevarious parameters evaluated [NIOSH 2008b; Organiscak and Cecala 2008].Figure 9.2. Laboratory test setup to evaluate various operational parameterson a filtration and pressurization system for an enclosed cab.228 Operator Booths, Control Rooms, and Enclosed Cabs