Asbestos and fibre analysis

Examination according to VDI-3866, sheet 5 (fracture edge, target preparation; estimated detection limit ≈ 1 wt.%)

Examination according to VDI-3866, sheet 5 (scatter preparation; estimated detection limit ≈ 0.1 wt.%), as well as Examination according to VDI-3866, sheet 5, appendix B (suspension or
filter preparation; estimated detection limit ≈ 0.001 wt.%)

Quantitative determination of low mass fractions of asbestos in road asphalts, raw materials and construction waste

In Lower Saxony, the exact determination of the mass fraction of asbestos is mandatory for the processing, disposal and possible reuse of bituminous road pavements. This results from the fact that, in addition to other mixture components, mineral raw materials were frequently used as fillers here, which may contain small natural proportions of asbestos minerals (basic magmatites such as gabbro, diabase, basalt). Asbestos was therefore not used because of its technical properties. Rather, it represents only a technically irrelevant secondary aggregate of the fillers used. In contrast to the technical products, asbestos mostly occurs as minerals of the amphibole group: Tremolite, Actinolite, Amosite and Anthophyllite.

For disposal as non-asbestos-containing waste or for possible reuse of the material, the limit value of 0.1% by weight specified in the Ordinance on Hazardous Substances must be undercut.

Furthermore, road surfaces with a mass fraction of respirable asbestos fibers of 0.008% or more may only be processed under special protective measures (e.g. chiseling, milling)

The analyses required for this are carried out on our premises according to the following test method:

IFA workbook 7487: (limit value for disposal: 0.1 wt.%)
Method for the analytical determination of low mass contents of asbestos fibers in powders, powder and dusts with SEM/EDX ("BIA method").

In this method, the samples are prepared and homogenized by freezing and crushing, depending on the condition of delivery. A representative portion is annealed at 400 °C to remove organic components that interfere with the analysis. The annealing residue is ground to a particle size of < 100 µm. A portion (20 mg) of the powder is placed in suspension and this is filtered onto a core pore filter (nominal pore diameter 0.2 µm) vaporized with gold. The filter surface is then examined for asbestos fibers.

If the material is to be examined with regard to falling below the limit value of 0.1 wt.% for landfilling or reuse, all fibers with a length of > 5 µm and a length/thickness ratio > 3 are evaluated.

If the limit value of 0.008 wt.% of respirable fibers is to be investigated with regard to occupational health and safety, the requirements of the following guideline also apply:

Technical rules for hazardous substances TRGS 517: (limit value for occupational health and safety: 0.008 wt.%)
Activities with potentially asbestos-containing mineral raw materials and mixtures and products made from them Detailed information on the analysis methods can be found here.

Here, only fibers with a diameter D < 3 µm (WHO fibers) are considered for the calculation of the measurement result.

For the analysis, the samples can be offered in different forms and quantities: As cores, broken up, pre-crushed granules, in powder form. The customer is requested to ensure that the sample handed over to BIOLAB is representative of the total quantity to be processed. We will be pleased to advise you on this, or to carry out the sampling for you.

After prior preparation, qualitative detection of asbestos can be carried out on all sample materials. In the case of subsequent quantification, the costs for preparation are charged

The described methods can also be applied to other materials with expected low asbestos contents, should a question arise in this regard: Plasters, fillers, screeds, bituminous roofing membranes, construction debris.

The quantitative content of artificial mineral fibers as defined by the WHO can also be determined on all sample materials using the above methods.

In principle, these analysis methods can also be applied to all materials with low asbstos contents (e.g, plasters, etc.).

We ask you to use plastic bags with a zip/pressure seal (Fig. 01) as small as possible for your material samples, adapted to the contents. Carefully tightened/pressed is usually sufficient to transport the sample safely. Further gluing of the closure is only necessary in rare cases. In this case, however, a repacking of the bag to secure the contents can also help.

The use of glass containers, for example, leads to potential contamination of the workplace and samples, as the sample must be transferred from the glass container into a plastic bag by our staff for archiving. In addition, glass may shatter during transport. Suitable plastic bags are more resistant and allow a safe transport.

The required sample quantity can be found in the asbestos product information. However, these only apply if you order the asbestos analysis only. If other analysis parameters are added, we ask you to send more sample material accordingly (see Analyses and their sample quantities).

To avoid cross-contamination of samples, samples should generally be packed individually.

Here is an example:
You would like to have a pipe sheathing made of gypsum and an attached insulation wool (Fig. 02) tested for asbestos and artificial mineral fibers (AMF) according to the WHO definition. If you were to store both materials together in a bag (Fig. 03, 04), both samples would contaminate each other. As a result, it would not be possible to make a clear statement as to whether the gypsum coating also originally contains AMF or only as a result of contamination.
In case of mineral construction materials (e.g. plaster, tile adhesives, fillers, etc.), it is possible to have up to five similar materials tested in one mixed sample. However, we ask you to pack each sample individually so that the mixed sample is prepared properly in the laboratory. This ensures that each sample is tested in equal proportions and that a meaningful result can be delivered. In addition, in the event of a positive result, each sample can be examined again individually to find out exactly which one contains asbestos.

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Figure 01: Sample bags with zip/print closure in different sizes.	Figure 02: Pipe sheathing made of gypsum with AMF insulation
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Figure 03: Different samples packed together. This is an unfavorable variant of packaging, as the samples contaminate each other.	Figure 04: Different samples packed individually. This is the correct variant of packing samples.