Vinyl asbestos panel
Vinyl asbestos panels (also known as floor flex or flex panels ) are a floor covering that was very often used in the 1950s to 1970s. Visually, it is very difficult to distinguish it from linoleum or PVC floor coverings that are common today. Due to its material properties, this product was only offered as tiles. By far the greatest problem is the lack of knowledge about the use of asbestos in this product and the lack of sensitivity in its removal and disposal.
General
From the 1950s and 1960s, plastic floor coverings in a wide variety of designs came into fashion. They may have looked attractive for the time, but most importantly, they were affordable to virtually everyone. A large number of beneficial properties spoke in favor of these floor and wall coverings. They were largely resistant to a wide range of influencing media, such as oils, fats, acids or other chemicals. Thanks to the dense, homogeneous and closed surface, the ingress of dust and dirt could be avoided.
Another aspect was hygiene. Due to the extremely smooth surface, these floor coverings could be cleaned and kept clean very well and easily, which promoted their use in heavily frequented buildings such as schools, administrative buildings or hospitals.
In an effort to continuously develop new types of properties for such floor and wall coverings, asbestos was increasingly used in their manufacture from around the 1960s.
There are basically two types of asbestos-containing coverings. On the one hand, there were the so-called “Floor-Flex” panels, in which asbestos is firmly integrated as a filler into the matrix of the covering material (e.g. based on PVC, but also as linoleum).
On the other hand, there were also multi-layer coverings in which the upper wear layer - usually made of PVC - was connected to a lower carrier layer made of asbestos. This asbestos-containing carrier layer, often referred to as the backing of the covering, has the smallest amounts of binding agent, so it consists of almost pure asbestos based on chrysotile (white asbestos) and its structure is comparable to a thin asbestos cardboard. These coverings were called "cushion vinyl" coverings, or CV coverings for short, as the asbestos backing had a cushioning effect.
The following table shows a comparison of the two types of asbestos-containing floor coverings, based on the most important asbestos-specific material properties.
| "Floor-Flex" | "Cushion vinyl" | |
|---|---|---|
| Asbestos content | approx. 20% (wt.%) | approx. 40-98% (wt.%) |
| Asbestos occurrence | firmly bound in PVC matrix | weakly bound in cardboard as a carrier material |
Asbestos content in various floor coverings
processing
The production or laying of asbestos-containing floor and wall coverings, but above all cushion vinyl coverings (CV coverings), was particularly strongly promoted in the 1960s and 1970s. Information in the relevant specialist literature shows that in the reference year 1975 in what was then the Federal Republic of Germany, floor coverings accounted for 7% of the total asbestos use.
| Asbestos product group | Share of total asbestos use 1975 |
|---|---|
| Asbestos cement | 65% |
| Friction linings | 7% |
| Floor coverings | 7% |
| Asbestos cardboard and seals | 7% |
| Asbestos textiles | 4% |
| Others | 10% |
Asbestos use
The following table shows the form in which the consumption or production of asbestos-containing floor coverings, separated into vinyl asbestos panels and CV coverings, developed in Germany in the early 1970s. What is striking in these years is the decline in vinyl asbestos panels compared with an enormous increase in CV coverings.
| 1972 | 1973 | 1974 | 1975 | |
|---|---|---|---|---|
| Consumption of vinyl asbestos panels in million m² | 14.9 | 14.5 | 12.7 | 7.2 |
| Production of CV coverings in million m² | 5.1 | 9.1 | 13.6 | 14.9 |
Volume development
If one assumes that a floor covering has a lifespan of 20 to 40 years, especially in the private sector, depending on the intensity of its use, then one can see from these figures that this problem is very topical into the 21st century.
Brown-black bitumen adhesives were often used to bond vinyl asbestos panels. These adhesives often also contain asbestos. Ultimately, only a material analysis can provide certainty about the asbestos content of such an adhesive. If the bitumen adhesive layer, which may contain asbestos, is to be removed in addition to the panels, protective measures must be taken as for weakly bound asbestos products.
construction
In terms of their structure, vinyl asbestos coverings are homogeneous, smooth coverings that have the following components:
- approx. 20% PVC / PVA copolymer as an organic binder
- approx. 20% chrysotile (white asbestos)
- approx 50% limestone powder as a filler as well
- approx. 10% pigments
The mixture of the first three components was gelled in a kneader at approx. 160 ° Celsius and then drawn out as a pasty mass in the calender to form sheets approx. 1.5 mm to 2.0 mm thick. During this process, the pigment substances were also incorporated into the mass, which resulted in the marbling pattern characteristic of the vinyl asbestos panels. During the hardening process, the vinyl asbestos panels lost their plasticity and finally solidified into hard, brittle panels that tended to break even if only slightly bent. Because of this property of being easily brittle, vinyl asbestos panels were marketed as tiles and not as continuous sheets.
Purpose of asbestos use
Only chrysotile or white asbestos was used for vinyl asbestos panels. Foreign ions can be stored and adsorptively bound in the tubes and spirals of the elementary fibrils of the chrysotile, which in increased numbers result in the parallel fiber bundles . This property plays an essential role in the use of asbestos as a filler in polymers, such as PVC in vinyl asbestos panels. This achieved extremely high dimensional stability and abrasion resistance. Another reason for the use of asbestos as a filler was the improvement in the processability of the raw product and, last but not least, the considerable saving in the proportion of PVC of up to 20% by weight.
Fiber emissions during use and processing
As already described, vinyl asbestos panels have a homogeneous structure, with the asbestos firmly integrated into the matrix of the covering. Since the density of the material of the vinyl asbestos panels is over 1 g / cm³, it is a firmly bound product containing asbestos. In principle, asbestos fibers can be released not only during processing, but in principle also during use and finally also during dismantling of the vinyl asbestos panels.
When laying, the panels were naturally cut in order to adapt them to the spatial conditions. A number of specific tools were used for this purpose, such as special knives, shears , etc. With these tools, both shearing and crushing stress was exerted on the covering material, which naturally had the possibility of releasing asbestos fibers.
Another aspect to be mentioned is the dismantling of these vinyl asbestos panels. Due to extreme mechanical stress, which causes the plates to break, fibers can be torn out of the previously stable matrix bond.
Finally, the usual use of the vinyl asbestos covering can also lead to a release of fibers, if this also requires relatively extreme conditions of use. For example, small stones and grains of sand, but also other sharp particles (e.g. shavings) that may have entered the soles of shoes, cause a scratching and shearing effect on the surface when walking through them.
In the course of a research project carried out by the Battelle Institute in 1978 on behalf of the Federal Environment Agency in Berlin, the emission of asbestos fibers from vinyl asbestos panels due to various stresses was examined using measurements. The measurement and evaluation method used was a scanning electron microscope method, for which there was apparently no standardized method at that time. Only so many image fields were evaluated in each case that 44 respirable asbestos fibers, which could also be identified as such by means of energy-dispersive X-ray microanalysis, were found, but at least 20 image fields.
The following table summarizes the emission values determined by the Batelle Institute, with the specified fibers / l being converted to fibers / m³.
| Type of stress | Measurement result (lAF / m³) | |
|---|---|---|
| Natural running wear | Blank sample (without air movement) | <1,000 |
| Plates covered | <1,000 | |
| freshly laid slabs | <1,000 | |
| Simulated running wear | with sandpaper | 60,000 |
| with sole leather and sand | 10,000 | |
| Machining | Cutting up with shears | 30,000 |
| Dismantling | Tear off with pliers | 1,000,000 |
| Scraping | 25,000 | |
| Sanding down | undetectable | |
Product examples for vinyl asbestos panels
On the basis of excerpts from a so-called “floor newspaper” from 1978, the following table summarizes typical product examples for vinyl asbestos panels including supplementary product information.
| Manufacturer | Trade name | Underlayer | particularities | design |
|---|---|---|---|---|
| Armstrong Cork International GmbH | Excelon Travertex | Vinyl asbestos | marbled | |
| Woodtone | Vinyl asbestos | Wood character | marbled | |
| Tidestone | Vinyl asbestos | Stone character | marbled | |
| Parquet | Vinyl asbestos | Relief structure, deep embossing | Parquet character | |
| Travertines | Vinyl asbestos | Relief structure, deep embossing | Original travertine pattern | |
| Tavarra | Vinyl asbestos | Relief structure, deep embossing | Marble character | |
| Armaplast | Vinyl asbestos with a higher PVC content | "Flexible" asbestos tile | marbled | |
| DLW Aktiengesellschaft | Deliflex | Vinyl asbestos | cloudy | |
| Dunloplan GmbH | Pastel polyflex | Vinyl asbestos | marbled | |
| Forbo GmbH | Colovinyl | Vinyl asbestos | flamed, jaspered | |
| Pegulan-Werke AG | Flex plates | Vinyl asbestos | directed |
Manufacturers and Products
Removal / disposal
initial situation
The current practice of removing and disposing of asbestos-containing floor and wall coverings is ostensibly influenced by the fact that the vast majority of building and apartment owners, but also relevant tradespeople (e.g. floorers, tilers, painters and upholsterers, etc.) ) awareness of the asbestos-specific problem is either not at all or is insufficient.
In addition, the difficulty of identifying floor and wall coverings containing asbestos is a given above all for those affected and that the problem, if at all, only becomes apparent - in the truest sense of the word - when z. B. in the case of cushion vinyl coverings, the asbestos cardboard is already exposed. But even then, only a laboratory analysis of the material can provide absolute certainty.
Because of the almost complete decline in the installation of such coverings at the beginning of the 1980s, even the employees in the relevant occupational groups practically only have knowledge of it if they have been working in this field since the late 1970s or longer.
Another influencing factor for the current removal practice is that many of those affected are put off by the costs of proper removal and often accept the risk of damage to health as a lesser evil, especially since any consequences do not appear almost immediately due to the long incubation period.
The main removal methods used are either
- in a conventional removal of such coverings without any personal protective measures, often in the course of replacing an old and / or damaged covering, or
- in an asbestos removal in compliance with all the prescribed precautions, whereby simplifications are often used under certain conditions and at the discretion of the disposer.
The normal case will generally be conventional removal.
According to the result of the study "Disposal of asbestos-containing floor and wall coverings" by the Austrian Federal Ministry of Agriculture and Forestry, a survey of 20 floor layers found that
- 15 respondents were completely ignorant and had never heard of asbestos in floor coverings,
- 3 respondents have heard of it, but don't care
- 1 respondent knew very specifically about the asbestos problem, but wanted to appease the inquirer and talk about proper removal with reference to the costs and
- Finally, 1 respondent showed the only correct reaction by referring the inquirer to a specialist asbestos disposal company before attempting to lay the new surface.
Although this was not a scientifically based opinion poll, the reality is likely to have been represented relatively well.
It is to be feared that many of those floor layers who have still worked with CV floor coverings themselves may not have the appropriate sensitivity or do not want to acknowledge this problem due to a self-protection mechanism that is perhaps understandable. On the other hand, the younger generation may not have come into contact with this material at all and for this reason may either no longer know about it or be no longer able to identify it.
The result of the survey is undoubtedly thought-provoking and shows that there is likely to be a major lack of information and sensitivity in the most important professional group in this area.
Conventional removal
The conventional removal of vinyl asbestos panels is usually carried out with large, possibly electric spatula tools. The vinyl asbestos panel breaks due to its brittle material properties, whereby the asbestos fibers bound in the PVC matrix can be released. According to the investigations of the Batelle Institute, "tearing off with a pair of pliers" causes an emission in the order of 1,000,000 lAF / m³ despite its character as a firmly bonded product containing asbestos; it is still due to the scraping of the vinyl asbestos sheet always about 25,000 lAF / m³.
The surface treatment after the vinyl asbestos plate has already been completely removed can no longer cause asbestos fiber emissions, which has also been confirmed by the Batelle Institute.
Removal according to IFA (DGUV Information 201-012, formerly BGI 664)
The Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA) - formerly the Federal Cooperative Institute for Occupational Safety and Health - maintains a directory of tested work processes with low asbestos fiber exposure in accordance with TRGS 519 ( technical rules for hazardous substances). This also includes one for removing vinyl asbestos panels. A precise regulation stipulates which requirements a process must meet in order to be considered tested. To be read in DGUV Information 201-012 (formerly BG Information BGI 664).
The work steps are described as follows:
- Removal of all movable equipment, such as furniture, carpets, curtains, murals and the like
- Immovable furnishings, e.g. B. radiators, built-in furniture, cover with foil or mask off
- Close doors / windows
- Attach safety signs with entry ban
- Moisten the floor in sections, lift off the panels with a hand spatula as smoothly as possible and spray under relaxed water while lifting (misting)
- Do not use strippers or floor-laying scrapers
- Collect the dismantled panels in a plastic bag (thickness> 0.2 mm), place the bag in the labeled cardboard box for double packaging
- Do not make packaging weights greater than 25 kg
- Remove adhesive residues with a hand spatula, vacuum up loose residues
- Clean the tool with a damp cloth, put the cloth in the rubbish bag, then clean the tool again outdoors with water
- Seal the rubbish sack and cardboard box so that they are dust-proof with adhesive tape, store the packed rubbish in transport containers (e.g. containers, big bags )
- Vacuum the floor after superficial drying with a K1 vacuum cleaner; Vacuum or wipe other surfaces with a damp cloth
- Then coat the floor with adhesive dispersion to bind the remaining fibers
Using suitable technical aids, it is possible to remove the asbestos-containing adhesive on the panels directly from the floor using a grinding machine. All safety measures for materials containing asbestos must be observed. The grinding machine must be able to extract the asbestos-containing dust directly, and the room must also be appropriately sealed. The procedures permitted for this are listed as BT 17 procedures in DGUV Information 201-012.
disposal
Decisive for the disposal of asbestos and asbestos-containing products are the requirements of TRGS 519, the AbfAblV , the LAGA- Merkblatt 23 and the AVV : Fixed or treated asbestos-containing waste (waste code 17 06 05 * "Asbestos-containing building materials") is placed in landfills or landfill areas of classes I or II, packed e.g. B. in so-called big bags, deposited. There is currently no recycling option in Germany.
swell
- Disposal of asbestos-containing floor and wall coverings. Austrian Federal Ministry for Agriculture, Forestry, Environment and Water Management (BMSK)
- Institute for Occupational Safety and Health of the German Social Accident Insurance (IFA), asbestos removal (BGI 664)
- BAuA - Federal Institute for Occupational Safety and Health, TRGS 519