Asbestos: Comparison of test methods

In the first blog in our series, we looked at the topics of asbestos in general, the fields of application, the dangers of asbestos and the risks.

In the following, the various test procedures for detecting asbestos will be examined in particular and their advantages and disadvantages outlined. The primary objective here is to provide an overview of which test procedures are most suitable if you suspect the presence of asbestos and what should be done if asbestos is identified.

Which asbestos tests are suitable for which application

Testing for asbestos is worthwhile for both private individuals and business people, but for different reasons.

Asbestos testing for individuals

For private individuals, the test is usually of interest if there is a suspicion of asbestos in their own home and for identifying the general exposure potential of an area. There are two types of test that are directly suitable.

Asbestos test on the ambient air

As a rule, a dust sample is taken from a surface and sent to a specialist laboratory to have the sample tested for asbestos exposure.

The dust test is particularly useful if one of the following criteria applies

• The material properties are uncertain due to the age of the premises (construction before 1999)
• Construction work has just been carried out, during which dust was released
• Respiratory problems are identified after construction work
• Respiratory problems are identified after moving into a new home

With the latter phenomena in particular, you should not only carry out a test, but also consult a doctor to protect your own health. In most cases, dust samples are available cheaply from various suppliers as an indicative test for asbestos exposure.

An asbestos test of the ambient air also makes sense if you experience problems with your airways in a new working environment that you did not notice before and is money well invested at this point, as you can reduce risks for colleagues and your employer by identifying the problem in good time.

If an ambient air test is to be carried out by an expert, a measuring device is set up, which filters 1 m³ of air precisely. The sample is then tested in the laboratory for the presence and concentration of asbestos fibres.

Asbestos testing of general materials

An asbestos test of general materials or building materials is particularly useful if you are planning extensive conversion measures in a house or apartment, or if renovation work is to be carried out and the property was built before 1999.

Common materials that can be tested here are:

• Asbestos test on roof elements
• Asbestos test on insulation elements in buildings, ovens and electrical appliances
• Asbestos test on cement
• Asbestos test on sealant
• Asbestos in fireproof clothing

In particular, roofing elements such as roofing felt, fibre cement sheets and roof tiles often contain asbestos in properties built before 1999 and are easily forgotten. "Asbestos roofs" are a major issue throughout the country, as they can involve unexpected dangers and costs during renovation work.

It is important to exercise extreme caution during sampling and, in case of doubt, seek expert advice, as improper sampling may cause contamination of the environment.

Asbestos testing for business people and traders

Testing for exposure to asbestos is often essential and legally binding for business people and traders, as improper handling of material contaminated with asbestos can result in severe penalties and pose a risk to the health of employees or colleagues.

A before-and-after test procedure is often prescribed here, in which the material to be processed is tested before starting work and a dust sample is carried out after the work to prove that there is no remaining asbestos contamination.

This ensures that there is no risk to the environment and residents after the construction measures. Similarly, a laboratory result can increase customer confidence in your company if it can be certified that there are no harmful asbestos exposures.

The before-and-after test method also avoids lengthy legal proceedings that cost lots of time and money. In severe cases, people can even assert intangible damage claims due to psychological stress; so professional testing is often a cost-effective safeguard.

Care should be taken to ensure that the analysis is carried out by qualified laboratories that meet DIN standards for asbestos test procedures; this ensures that the results are reliable for customers, authorities and, if necessary, even courts.

The dust sample in the condition after the work is complete is all the more valuable if asbestos was disposed of as part of construction measures and an asbestos-free condition of the living space and environment must therefore be documented.

Unfortunately, improper handling of asbestos is still frequently making headlines today. From neglecting precautions to gross negligence in due diligence, avoidable errors occur time and again when working with asbestos.

Since statutory accident insurance does not pay out to business people in the event of a gross violation of the regulations, asbestos tests should be part of the standard repertoire of any professional company in order to protect itself and its own employees.

It is therefore worthwhile for companies to contact providers of asbestos tests, as discounts can often be agreed as part of larger test recordings and both customers and authorities can receive proof of clean work.

What technical asbestos testing methods and evidence are available?

Roughly speaking, there are two test procedures:

• the so-called PLM procedure (polarisation of microscopic analysis), in which the examination is carried out using a light microscope
• the SEM procedure in which the sample is examined under a scanning electron microscope (SEM for short).

The sample that can be provided is crucial above all. As a rule, more sample material is better for detecting and analysing asbestos. But from a dust collection to a small fragment from a wall, any material in any quantity can be used as proof – there is no need to send whole asbestos sheets or fibre cement sheets to the lab. However, the test procedure is particularly important in the case of smaller samples.

The test procedures at a glance

PLM and REM test procedures at a glance

Asbestos test: PLM test procedure

Although the PLM process is simpler and more cost-effective, it is also much less accurate. While a good light microscope offers 50x magnification, it is significantly lower than the 300,000x magnification of a scanning electron microscope.

This is an older test method, which was often used in the past until it was replaced in modern laboratories with the REM method for detecting asbestos. Since the REM test procedure has a significantly higher resolution, offers reliable results and, unlike the PLM procedure, can detect even the smallest traces of asbestos, the PLM procedure can also be described as outdated.

Similarly, the PLM procedure is strongly inferior to the REM test method if only small sample quantities can be taken. Small-fibre traces of asbestos cannot be reliably detected with the PLM method due to the lower magnification factor.

In particular if a legally compliant result is required, REM analysis is preferable by far, as it records reliable and accurate analysis results that would remain invisible and undetected in the PLM test procedure.

In case of doubt, a sample would therefore have to be reanalysed using the REM procedure, which can lead to additional costs. However, the price difference between the two methods is only £15–25 for simple samples for professional analysis in a certified laboratory.

Considered objectively, it is therefore advisable to have asbestos samples processed directly with the REM test procedure to save time and costs on the one hand and to ensure legal certainty and reliability on the other.

Asbestos test: REM test procedure

The REM test procedure can be regarded as the gold standard in a modern asbestos test. Since the scanning electron microscope allows 300,000x magnification, it is able to detect the smallest asbestos fibres.

This is an enormous advantage of this test method, as the concentration cannot be equated with the fibre size in the case of asbestos exposure, which is of particular importance when analysing blue and brown asbestos. A high concentration of small asbestos fibres is extremely hazardous to health and can often not be detected in the PLM test procedure, as the necessary magnification is not possible.

Since the computer-generated image must be interpreted when using the REM test procedure, the images must be viewed by trained specialists in a certified laboratory or by a laboratory group.

As can be seen from the example of the University of Constance, the interpretation of the analysis result can be clear, but a trained eye is necessary to be able to decide in case of doubt whether or not the sample in question is a material contaminated with asbestos.

Because misinterpretation can have enormous financial and legal consequences, it is essential to seek the expertise of a renowned laboratory.

Nevertheless, the REM method is often regarded and preferred as a standard procedure, as it offers the option of detecting very small traces through its higher resolution and precise accuracy. Conversely, compliance with the guide value can also be reliably demonstrated after renovation and refurbishment work.

Qualitative and quantitative analysis, what is the difference?

Providers often refer to qualitative analyses and quantitative analyses. This can be confusing for laypeople in particular if the advertising terminology also refers to high-quality analyses testing quantity.

Two things can be tested:

1. a) What type of asbestos is present? (Qualitative analysis)
2. b) How much asbestos is present? (Quantitative analysis)

For an initial test, it is usually sufficient to perform a qualitative analysis. If the result is positive, an expert should be contacted to discuss the further course of action.

In most cases, a quantitative analysis is required if it is necessary to determine whether the asbestos fibre content in the air is too high and the associated risk is determined. It is also carried out if the absence of asbestos must be determined in order to document that the guide values are not exceeded in a legally compliant manner.

Positive test result: What should I do?

If you have sent in a sample and the test result comes back positive, the first thing to remember is: Keep calm.

As asbestos is naturally occurring, there will always be a low level of exposure. According to the Federal Institute for Research on Building, Urban Affairs and Spatial Development, the natural exposure is around 100 fibres/m³ air. Within a building, a guideline value of 200-500 fibres / m³ of air is considered conspicuous and requires further investigation. If the asbestos guideline value is exceeded, there is a hazardous situation that must be dealt with immediately.

It is important that you do not attempt to dispose of or remove asbestos yourself, either as a private person or as a non-specialist business person. As asbestos is a first-class hazardous substance due to the associated high risk of cancer, the special guidelines of TRGS 519 apply to handling, transport and disposal in order to place as little strain on the environment and other people as possible.

For this area of application, there are various specialist companies that specialise in the topic of asbestos removal and can also dispose of asbestos without violating guidelines or laws. Although there are costs associated with using these specialist companies, it is the safest alternative to the consequences of improper handling. The specialist companies are also able to implement TRGS 519, which must be observed in order to protect employees and other persons when handling asbestos.

This is also relevant as the processes vary depending on the material and require special handling. For this reason, there is a so-called "Directive for the Evaluation and Renovation of Weakly Bound Asbestos Products in Buildings" in place, which is published by the trade supervisory authority in the individual federal states and specifies what is to be carried out in which case.

Legal certainty in test procedures

The legal certainty of test procedures is a constant major topic, which has already been addressed in this blog.

It is particularly important that the context plays a primary role here. For example, a dust sample can prove the presence of asbestos in the dust, but does not say anything about the volume of asbestos fibres/m³ of air.

However, the test can be used as a basis to determine whether further measures and tests are necessary. If there is a positive result from an unknown source, it is advisable to consult an expert or appraiser in order to determine the further course of action.

However, exposure to asbestos in material samples sent in, such as roofing felt, fibre cement sheets, fibre cement, etc., can be used as a legal basis if a decision has to be made on the correct refurbishment and disposal of the material concerned.

The same applies to the sending in of samples for unusual materials (fireproof materials/insulation materials or similar). Here too, the result can be used as the legal basis for the further course of action.