This method is a good combination of stereo-microscope and Polarized Light Microscope (PLM) to detect and identify asbestos fibers. All samples should be examined initially through stereo-microscope, and then suspicious fibers will be mounted on a slide with appropriate refractive index liquid and then analyzed with the Polarized Light Microscope. PLM analysis is the most commonly accepted technique for analyzing bulk samples for asbestos. Identification of asbestos is based on the determination of various optical properties exhibited when the sample is treated with appropriate dispersion staining liquid.
X-ray diffraction (XRD) is a rapid analytical technique primarily used for phase identification of a crystalline material and can provide information on unit cell dimensions. The analyzed material is finely ground and homogenized. X-ray diffract instrument consists of three basic elements: an X-ray tube, a sample holder, and an X-ray detector. X-rays are generated in a cathode ray tube by heating a filament to produce electrons, accelerating the electrons toward a target by applying a voltage, and bombarding the target material with electrons. When electrons have sufficient energy to dislodge inner shell electrons of the target material, characteristic X-ray spectra are produced.
3. Scanning Electron Microscope (SEM)
The Scanning Electron Microscope (SEM) uses a focused beam of high-energy electrons to generate a variety of signals at the surface of solid specimens. The signals that derive from electron-sample interactions reveal information about the sample including external morphology (texture), chemical composition, and crystalline structure and orientation of materials making up the sample. The SEM is also capable of performing analyses of selected point locations on the sample, and this approach is especially useful in qualitatively or semi-quantitatively determining chemical compositions.
4. Phase Contrast Microscope (PCM)
This method is used to estimate the airborne concentration of asbestos and other non-asbestos fibers. The PCM technique has the advantage of fast turnaround time and low cost. The PCM air sampling is used for environmental monitoring, personnel monitoring, and clearance testing for minor abatement projects. However, fibers