What actually is asbestos?
Everyone has heard of asbestos and everyone knows that you don’t want it in your house. But what is asbestos and what should you do if you suspect it is in the plaster?
Asbestos is the term for naturally occurring, fibrous minerals that have a specific particle diameter in the range of 0.1µm and 2µm.
The chemical properties of asbestos include low flammability and good thermal insulation, which is why it was used as a building material in many different ways.
Asbestos fibers were used in house insulation, in cement or as a sealant, especially in the 1960s. Although it had long been known that asbestos causes health problems, its use was not banned in Germany until 1993.
Health risk from asbestos
Due to their small size, asbestos fibers can easily enter the lungs via the respiratory tract and cause serious damage. The fibers irritate the lung tissue and lead to inflammation and scarring. Prolonged exposure to asbestos can lead to the development of asbestosis (“asbestosis lung”). The damage to the lung tissue means that less oxygen can be absorbed, resulting in shortness of breath, tissue discoloration and pain in the chest.
Occurrence of asbestos in buildings
Due to its durable chemical properties, asbestos was used in many areas. For example, it was incorporated into facade paints and fillers. Tile adhesives, sealants and plaster containing asbestos were also commonly used.
Plaster is a wall coating that creates a smooth surface. This often involves large areas and these are usually renewed in their entirety. Due to the chemical properties described, asbestos in plaster is still a current problem in buildings built up to 1995.
Why are asbestos fiber measurements important?
Although asbestos has been banned since 1993, exposure can occur through the use of (contaminated) stored goods. For this reason, mandatory testing is considered appropriate for buildings built up to 1995.
Exposure can be measured for various reasons:
- Operation/use
- Refurbishment/maintenance
- Dismantling/demolition
- Valuation
Compared to other areas where asbestos is used, the problem with plaster containing asbestos is its inconspicuousness. It is not possible to detect contamination simply by visual inspection. In order to obtain certainty about asbestos contamination, it makes sense to take a material sample.
There are various concepts for measurement depending on the findings. Orienting Technical Investigation (OTE, standard case) is briefly explained here as an example. The basic assumption of this method is a uniform distribution of asbestos in the sample material (here: wall), so that targeted random samples provide a representative image. Guideline VDI 3866, which regulates the sample size, provides orientation for this.
Asbestos determination according to VDI 3866, Sheet 5, Appendix B
If it is necessary to check whether asbestos is present in the plaster, an asbestos determination according to VDI 3866, Sheet 5, Annex B (“concentration method”) is often used.
It will only be briefly explained here. This is an evaluation of fibre measurements of asbestos.
The individual samples are homogenized (ground) and combined in aliquots (approx. 200-250 mg) and also homogenized. The sample mixture is then ashed and taken up with HCl (hydrochloric acid, 10%), washed and diluted. An aliquot of the suspension is then removed and filtered through a core pore filter. The sample is then analyzed in accordance with the VDI 3492 guideline.
According to Annex B of VDI 3866, Sheet 5, taking into account the reference fibers specified there, the detection limit for such samples is 0.001% by mass of asbestos or respirable AMF.
If the presence of asbestos is measurable, the individual samples can be measured. These can be used to narrow down the findings so that the infestation can be limited in terms of area.
Occupational safety must always be taken into account when taking samples. If work with asbestos-containing material is unavoidable, appropriate protective clothing must always be worn and safety measures applied.
Sources:
[1]: Source Featured image: © animaflorapicsstock / 123RF.com
[2]: https://www.bvs-ev.de/presse/pressemitteilungen/pressedetail/?tx_ttnews%5Btt_news%5D=826&cHash=93142f3e263973c13d624bccbf4af835
[3]: https://wohnmedizin.eu/files/asbesthaltige_wand-_und_deckenbekleidungen.pdf
[4]: http://www.gesamtverband-schadstoff.de/files/z04-diskussionspapier_asbest_web_2015_06_16.pdf
[5]: https://www.crb-gmbh.com/pdf/allgemeine-informationen/VDI-3866-Blatt-5-2017-06-anmerkungen.pdf
[6]: https://www.db-bauzeitung.de/db-metamorphose/schwachstellen-aus-bauschaeden-lernen/asbesthaltige-spachtel-kleber-und-putze/
[7]: https://www.git-labor.de/forschung/umwelt/asbest-eine-gesellschaftliche-und-analytische-bestandsaufnahme
[8]: https://www.schadstoff-kompass.de/gebaeudeschadstoffe-innenraumluft/download/asbestexposition-auf-baustellen/ xml-ph-0008@deepl