Transcript Slide 1
HIGH-FLOW PERSONAL SAMPLER TO MONITOR EXPOSURE TO RESPIRABLE CRYSTALLINE SILICA AT NEW LOWER TLV Saulius Trakumas, Eddie Salter SKC Inc., Eighty Four, United States SKC Ltd., Blandford Forum, United Kingdom Crystalline Silica Crystalline silica is a basic component of soil, sand, granite, and many other minerals. Hazards of Crystalline Silica Exposure to silica is a serious threat to million of workers, including workers in high risk jobs such as abrasive blasting, foundry work, stonecutting, rock drilling, quarry work, and tunneling. Hazards of Crystalline Silica Occupational exposure to respirable crystalline silica is associated with the development of silicosis, lung cancer, and other pulmonary diseases. Hazards of Crystalline Silica Exposures to silica may also be related to the development of autoimmune disorders and other adverse health effects. Permissible Exposure Limits Recent studies have demonstrated that lifetime exposure to respirable crystalline silica at 0.05 mg/m3 is not low enough to eliminate the risk of developing chronic lung diseases. Permissible Exposure Limits The American Conference of Governmental Industrial Hygienists has lowered the 8-hour timeweighted average threshold limit value to 0.025 mg/m3 for quartz and cristobalite. Sampling and Analytical Methods Current sampling and analytical methods used to evaluate occupational exposure to respirable crystalline silica do not meet the accuracy criterion needed to quantify exposures at concentrations below 0.05 mg/m3. There is need for new, more sensitive, and more accurate methods to monitor occupational exposure to crystalline silica. Sampling Crystalline Silica Cyclone is used to remove larger particles. Respirable fraction is collected on PVC filter. www.osha.gov The objective of this study was to develop and test a personal respirable sampler that: Operates at a flow rate 2 to 3 times higher than currently available respirable samplers Follows respirable convention accurately Performance of Six Respirable Cyclones Dorr-Oliver GS-3 100 100 100 Sampling Efficiency, E, % DOP Glass Spheres Coal Mine Dust 50 25 DOP Glass Spheres Coal Mine Dust 75 50 25 2 4 6 8 2 4 6 8 0 10 50 25 Test Aerosol: DOP Glass Spheres Coal Mine Dust 75 50 25 Respirable Convention Aerodynamic Particle Diameter, da, m DOP Glass Spheres Coal Mine Dust 50 25 Respirable Convention 0 0 8 10 10 Test Aerosol: 75 Respirable Convention 0 8 SIMPED Cyclone, QS=2.2 L/min Sampling Efficiency, E, % Sampling Efficiency, E, % DOP Glass Spheres Coal Mine Dust 6 100 BGI-4CP Cyclone, QS=2.2 L/min Test Aerosol: 6 4 SIMPED 100 Aluminum Cyclone, QS=2.5 L/min 4 2 Aerodynamic Particle Diameter, da, m BGI-4CP 100 2 25 Aerodynamic Particle Diameter, da, m Aluminum 0 50 0 0 10 Aerodynamic Particle Diameter, da, m 75 DOP Glass Spheres Coal Mine Dust Respirable Convention 0 0 0 Test Aerosol: 75 Respirable Convention Respirable Convention Sampling Efficiency, E, % Sampling Efficiency, E, % Test Aerosol: Test Aerosol: 75 GS-1 Cyclone, QS=2.0 L/min GS-3 Cyclone, QS=2.75 L/min Dorr-Oliver Cyclone, QS=1.7 L/min Sampling Efficiency, E, % GS-1 0 2 4 6 8 Aerodynamic Particle Diameter, da, m 10 0 2 4 6 8 Aerodynamic Particle Diameter, da, m 10 Simulation of Respirable Curve Using Impactors 100 Six impactors: d50=7.1, 5.4, 4.4, 3.7, 3.0, and 1.8 m Penetration, P, % 75 Four impactors: d50=6.6, 4.6, 3.5, and 2.2 m Two impactors: d50=5.6, and 2.9 m 50 25 Respirable Convention Single Impactor: d50=4.0 m 0 0 2 4 6 8 Aerodynamic Particle Diameter, da, m 10 Performance of SKC Parallel Particle Impactor 100 Penetration, P, % 75 50 PPI, QS=2.0 L/min 25 Respirable Convention HD Cyclone, QS=2.2 L/min 0 0 2 4 6 8 10 Aerodynamic Particle Diameter, da, m 12 Performance of Individual Impactors of High Flow PPI Performance of High Flow Parallel Particle Impactor Aerosol Generator Clean Air (50 Lpm) Charge Neutralizer Virtual Impactor Experimental Setup Turbulence Generators Clear Plexiglass Cylinder (D=12”, H=48”) Honeycomb Flow Straightener Test Device Access Port Sampling Lines Foam To Filter Ball Valve Makeup Flow Aerodynamic Particle Sizer (APS 3320) CDown (d ) E (d ) 100% CUp (d ) SKC Parallel Particle Impactor Inlet Impaction Plate Exhaust SKC High Flow PPI Conclusions o High flow personal respirable sampler was developed and shown to match the entire ACGIH/CEN/ISO respirable curve closely. o The newly developed respirable sampler in conjunction with a high flow personal sample pump can be used to accurately measure occupational exposure to respirable crystalline silica when new lower exposure limits need to be met. Thank You!