Determination of asbestos content in the gasket material using thin section petrography and x-ray diffraction techniques

Gaskets are used as static seal or filler between two stationery material surfaces, which in this case are flange gaskets of mechanic assembly that contains certain fluids. Prior to more stringent regulations for asbestos usage, gaskets commonly contained asbestos due to its properties such as heat resistance (refractory) and electricity insulator, and relatively cheap. OSHA (Occupational Safety and Health Administration) regulation i.e. 29 CFR 1910.1001 defines that ACM (Asbestos-containing material) means any material containing more than 1 % asbestos. Therefore, determination on the content of asbestos in previously made gaskets was undertaken, since they may contain asbestos more than the regulation. In this observation, the techniques used to detect and characterize asbestos in gasket are Thin Section Petrography (TSP) and X-Ray Diffractometer (XRD) analysis because they are quite effective and easy to carry out. Three gasket samples and one sample as standard of comparison have been analyzed, and the results show that one of the three samples positively contains asbestos more than 1 wt %. Based on morphology characteristic on petrographic observation and peak pattern on XRD spectra, the asbestos is identified as orthochrysotile serpentine. These characteristics are similar to that of standard of comparison sample that contains clinochrysotile serpentine. (author)