The effectiveness of asbestos stabilizers during abrasion of asbestos-cement sheets

The effectiveness of different organic stabilizers in stabilizing asbestos in fiber cement was evaluated using brush-abrasion tests on asbestos-cement (AC) sheets and counting the number of released respirable fibers using phase-contrast microscopy (PCM). All asbestos fibers released from the abraded sheets were identified as chrysotile. The binding effectiveness of the stabilizers varied from 35% (bitumen-based) to >90% (polyurethane resin (PUR), acrylic paint, flexible coating). Stabilizers with low binding efficiency, i.e., <80%, should not be used for coating. The 80% binding efficiency limit is suggested based on the performance of PUR stabilizer applied to the surfaces of AC sheets that were primarily in good condition. With very deteriorated surfaces, even the best performing stabilizers will not prevent fiber release on a scale comparable to that from unprotected sheets in good condition. The greatest effectiveness in binding asbestos fibers is achieved by applying stabilizers that combine a hard coating (PUR), high degree of flexibility (flexible coating) and adhesiveness (acrylic dispersion paint). A simple brush-abrasion test is recommended as an inexpensive, fast and reliable method for evaluating the performance of stabilizers. The brush-abrasion test can reveal invisible deterioration of the cement matrix weakening asbestos-fiber attachment to AC sheets

Comparison of the effects of use, protection, improper renovation and removal of asbestos products on the example of typical old office buildings in Poland

Abstract The study focused on old, German building types “LIPSK” and “BERLIN” used in Poland, since the 1960s in Eastern Europe. The different operations on buildings were analysed: protection and maintenance of asbestos products, asbestos removal and inadvertent damage to asbestos as a result of building renovation. Measurements of respirable (countable) asbestos fibres in the air were carried out using the PCOM + PLM method and SEM–EDS. In the case of the accidental destruction of products, initial contamination was ≈7000 f/m3. After 16 weeks from the end of the activity and 20 days of extreme ventilation, contamination decreased to about 500 f/m3. At the same time, in similar rooms, without extreme ventilation, the pollution was above 4000 f/m3. The average increase in pollution in a dozen or so similar buildings, after asbestos removal in places beyond the work zones, ranged from ≈ 1700–2700 f/m3 and lasted for one or two years. These buildings, used without ACM destruction or after product impregnation, have maintained low asbestos contamination < 300 f/m3 for more than 10–20 years. So, due to the easy release of asbestos that occurs with any ACM removal and the increased risk of occupant exposure, these works are often inappropriate for the buildings in question