Thesis--Technical University of Denmark. / Bibliography: p. 157-[159].

Orientador: Ines Joekes / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Quimica / Made available in DSpace on 2018-07-27T02:19:21Z (GMT). No. of bitstreams: 1 Filloy_PaulaHanao_M.pdf: 3876859 bytes, checksum: 183c36162f02aba1f8df16cbb2ed3a26 (MD5) Previous issue date: 2000 / Mestrado

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The Asbestos Hazard Emergency Response Act (AHERA) requires public schools to manage asbestos containing materials. Twenty five years after AHERA was enacted public schools continue to struggle with documenting and managing asbestos containing material assets. In addition, the manufacturing of lead based paint (LBP) was banned over thirty years ago yet public schools continue to have to manage LBP assets with no guidelines specific to public schools. When compared to current civil infrastructure asset management systems, AHERA and the HUD guidelines lack a rating system based on visual inspection data. The development of a condition index algorithm and risk of failure model would provide school planners an efficient management tool to predict the future condition of asbestos containing material and lead based paint assets. As a result, school planners would be able to prioritize maintenance, repair, and abatement projects based on the risk to the indoor air quality of their facilities and more efficiently utilize their limited resources to mitigate such risks. This paper presents initial work toward the development of a visual condition index algorithm and a risk of failure model to support prioritization of maintenance, repair, and abatement projects. The condition assessment categories provided by AHERA and HUD were adapted and incorporated in an evaluation form created to assist in rating the various stages of accessibility, deterioration, and detection of typical ACM and LBP building components. The evaluation form can be utilized by inspection and school personnel when reclassifying ACM and LBP components during semi-annual inspections of their facilities and also ensure the repeatability of the condition assessment and risk of failure methodologies. A risk of failure model was developed utilizing the FMEA process, specifically the calculation of a risk priority number (RPN). Three schools were selected for a field pilot study to develop the accessibility, deterioration, detection, and RPN algorithms and evaluate for repeatability. The algorithms will provide a quantitative and consistent means for documenting the condition and RPN of asbestos containing material and lead based paint assets and allow the condition of these assets to be monitored and reclassified over a period of time. / Ph. D.

ABSTRACT Asbestos has been extensively used to insulate boilers and associated heated pipe work throughout the world. Managing human health risks posed by asbestos during the removal of lagging poses many challenges. For this reason, acquiring a better understanding of factors that lead work tasks to produce high airborne fibre concentrations is important for the development of improved control methods. Aim: The aim of this study was to link observed work tasks and work practices with measured airborne concentrations of fibres in order to identify those factors contributing to high airborne concentrations generated during boiler de-lagging. The investigation was based on a study of two employees working on a boiler de-lagging contract lasting twenty-one days and resulting in a total of 79 measurements of airborne asbestos fibres. The primary form of asbestos dust control for the duration of the contract was the application of non-amended water. Objectives: To definitively identify the presence and type of asbestos lagging as well as quantify airborne fibre concentrations for two work tasks i.e. Stripping (removing lagging) and Bagging (placing removed lagging into bags as well as cleaning spills), in order to demonstrate how they may influence airborne fibre concentrations. Methodology: The type of asbestos was confirmed by Scanning Electron Microscopy. Phase Contrast Microscopy (PCM) was selected as the primary measure of airborne asbestos fibres. A Work Practice Checklist was developed to link observed daily Work Tasks and Work Practices with the concurrent airborne fibre concentrations. The geometric mean was a useful measure of central tendency for the data since it was highly skewed to the right (positively skewed). However, for public health purposes the arithmetic mean was also considered because it provides some idea of health risk where the human respiratory system is assumed to accumulate fibres linearly with concentration. Results: Bulk sample analysis confirmed the presence of both chrysotile and amosite asbestos lagging. Work Practices such as Wetting, Stripping and Bagging asbestos, were undertaken in a relatively uncontrolled manner during the first three days of the project resulting in mean airborne fibre concentrations of 1.171 f/ml for the Stripper, ranging from 0.612 to 1.236 f/ml and 0.315 f/ml for the Bagger, ranging from 0.107 to 0.631f/ml. These means were 4.5 times and 2.3 times respectively, greater than the means calculated for the entire project. The overall mean fibre concentration was approximately five times greater for personal samples, 0.198 f/ml (± 1.647) than for the concurrent static samples, 0.039 f/ml (± 0.129). The analysis of log transformed data revealed several strong tendencies for airborne fibre concentrations when related to Work Tasks and Work Practices. The difference between stripping asbestos in small manageable as opposed to larger unmanageable pieces was highly significant (p < 0.001). Smaller manageable pieces resulted in much lowerconcentrations. The manner with which asbestos was bagged was also highly significant (p < 0.001). Bagging in an uncontrolled manner resulted in much higher airborne concentrations. Surprisingly, the degree of wetting was not as important as expected: working dry did not generate significantly more fibres than working with saturated insulation but did generate significantly more fibres (p < 0.005) than working with partially wet insulation (which lead to the highest concentrations). A limitation to interpreting the Wetting work practice was the low number of samples taken within the dry category (n = 5). The difference in mean sample concentrations between personal and static samples for this study demonstrates the importance of spatial and temporal proximity as a determinant for airborne fibre concentrations. It also showed clear associations between what can be described as rushed, reckless Work Practices, and the resulting high levels of airborne fibre concentrations (exceeding the OEL). Within the context of this project, these findings demonstrate the utmost importance of providing the appropriate training and supervision of employees, not only for protecting themselves against airborne asbestos fibres, but for removing asbestos in manner that results in the generation of the least amount of airborne fibres possible

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No description available.

Examination of Chrysotile Asbestos from the Eastern Townships of Quebec using optical and electron microscopic methods has shown that Chrysotile fibres are intimately associated with minute particles of magnetite. / Measurements were made using a fluxgate magnetometer of the remnant magnetic fields of bulk commercial fibres and of airborne total dust and of the respirable fraction of airborne dust collected in Quebec asbestos mines and mills using a Hexhlet horizontal eleutriator. The validity of the Hexhlet horizontal eleutriator for respirable fibre collection in the mill environment was determined. It was observed that the remnant magnetic field intensities of airborne dust in laboratory generated dust clouds, and in the work places were related in a meaningful way to the magnetite content of the dust and to the total mass and respirable mass fractions of airborne dust, and also, to the concentrations of fibre greater than 5 micrometre length (aspect ratio > 3:1) measured using phase contrast microscopy. Calibration curves were developed for each of 9 Quebec mills. Repeat calibrations showed the lines to be reproducible within (+OR-) 10 percent. The accuracy of the method for mass dust determination was dependent on sample size with errors as low as (+OR-) 7.5 percent for samples larger than 3 milligrams, and as large as (+OR-) 40 percent for samples of mass smaller than 0.5 milligrams. The relationships between fibre concentrations and remnant magnetic fields were less reproducible and the lower detection limit was limited by the sensitivity of the fluxgate magnetometer. Although the measured remnant magnetic field varied as the magnetite content varied between different mills and commercial fibre products, magnetite to chrysotile ratio remained constant for a given mill and commercial product. Measurements of the remnant magnetic fields of airborne dusts collected in mill environments can thus provide the possibility of the rapid determination of airborne chrysotile fibre concentrations both in terms of mass and number of fibres per litre of air sampled as well as their iron content. / Measurement of the magnetic content of specimens of autopsied lung tissue from asbestos exposed workers indicated that the residual estimated fibre content measured by electron microscopy was less than estimated using magnetic field measurements. . . . (Author's abstract exceeds stipulated maximum length. Discontinued here with permission of author.) UMI