53 A portable dust generation system for calibrating real time RCS measuring instruments

Aim The research was aimed at enhancing in-field calibration of portable Respirable Crystalline Silica (RCS) instrument. Problem There are challenges with calibrating instruments designed for near-real time RCS measurement at the workplace, in that, historical methods of calibration of laboratory instrumentation are not appropriate as they are based on short collection times of a standard material on filters from a generated dust cloud of short duration, not real time RCS dust clouds. Method This involved the development and validation of a small portable, low cost, dust generation system, for the generation of reproducible dust clouds and consequently standard RCS concentrations allowing near-real time instruments to be calibrated against known concentration of RCS standard in a dust cloud of significant duration. Results Preliminary laboratory data has shown that reproducible dust clouds of any dust can be generated including the Australian RCS standard material (A9950 Aust. No.1). Testing has shown that the physical characteristics of a dust can influence the generated concentration, and measures were found to improve the dust generation process for materials that may adhere to the dust generator drum’s surface. Four different ways of controlling the amount of dust generated and sampled out of the dust generator were determined, enabling increased dust input to the real time instrument, thus improving their means of calibration. Conclusion The dust generation system has potential to improve calibration of portable analytical instruments for RCS analysis. Further research may provide a means of estimating the “dustiness” of workplace materials before sampling.