Silicate special coating for asbestos cement and fibre cement boards PREMIUM is our Standard.

Transcription

1 KEIM Teknosil Silicate special coating for asbestos cement and fibre cement boards PREMIUM is our Standard.

2 Asbestos cement heritage with problems Asbestos a very delicate topic Hardly any material has caught so much attention over the past years and decades as asbestos. Originally, asbestos was built into countless buildings due to its versatile applicability. Concerns against the up to then highly praised material came up for the first time in the sixties of last century. Even though the health risks have been already known for a long time, asbestos was used continuously as a building material through the 1970 s and 1980 s. Because of increased incidences in cases of illness and death led in 1993 finally to a total ban of use in Germany. This ban had already been effective for using asbestos in walls and ceilings since January 1st, The best way would be undoubtedly the removal or replacement of asbestoscontaining building materials, but, in many cases this cannot be realized because of economic reasons and sometimes it is not always urgently necessary from a technical point of view. Such buildings should be renovated in a useful and responsible way within the framework of economic possibilities and technical requirements also considering health and environmental aspects. Working with asbestos-containing materials, however, is subject to a series of directives and regulations which have to be strictly observed, because only marginal quantities of asbestos fibres pose considerable health risks. Today we are confronted with the numerous buildings where asbestoscontaining building materials were used. According to estimates the existing surface of asbestos cement is amounting to approx. 900 million m² in the old federal countries of Germany and to approx. 500 million m² in the new federal countries (SCHMIDT-SIEBETH 1993) 1 demanding a huge field for renovation, refurbishment and maintenance activities for all market participants, namely building owners, their representatives and handicrafts. 1 See: LfU (Bavarian State Office of the Environment), environmental knowledge about asbestos, 2010, page 6 2

3 Hazardous substance asbestos Poorly bound asbestos is particularly dangerous Asbestos (Old Greek: ásbestos, everlasting ) is a collective term for naturally occurring fibre-shaped minerals which are embedded in many places in the earth s crust. Asbestos is very strong, heat- and acid-resistant, has good insulating properties and can be easily woven. This is the reason why asbestos has found its place in the shipping, insulation, construction and car tire industry.² On the other hand, asbestos cement products are the so-called strongly bound products whose fibre content has maximum 15 percent by weight and with a bulk density higher than 1,400 kg/m³. In many buildings asbestos cement is installed in form of roof and wall coverings 4. The panels are mostly harmless as long as they remain intact, do not weather and are not mechanically treated. Chrysotile, also known as white asbestos, found its widest technical application mostly as reinforcement fibre in asbestos cement. While working with asbestos-containing materials asbestos fibres are released. The fine, sharpedged fibres reach the alveoli of the lungs and can cause the so-called asbestosis and malignant tumors. The critical fibre geometry is the reason that asbestos fibres are so hazardous to health. Particularly dangerous are products with poorly bound asbestos which have a fibre content of 50% and more and, which release the dangerous fibres easily ³. The bulk density of such materials is normally less than 1,000 kg/m³. Typical for those are spray and soft asbestos. Picture (SEM): Amphibole asbestos fibres 2 Compare: Wikipedia, definition of asbestos. 3 Anke Jordan-Gerkens: Disposal of asbestos waste by mechanic fibre destruction. Published by: Cuvillier Verlag, Göttingen/Germany in 2005, ISBN X, page 3 and 4. 4 Typical trademarks: Eternit, Fulgurit.. 3

4 Recognizing asbestos cement Only as of 1991 guaranteed asbestos-free Asbestos is not really visible. A definite determination is only possible under the electron microscope. However, a help would be, to know how old the panels are meaning, in which year they were manufactured. In principle, asbestos has to be expected in Germany to be part of fibre cement boards built before But it needs to be mentioned that starting in the 1980 s also panels with substitute fibres were used. Panels used before 1983 contain probably asbestos fibres and from the year 1991 and later (production and installation in Germany) they are classified as asbestos-free. Particular caution must be taken for boards installed between 1983 and Poorly bound asbestos products Strongly bound asbestos products Fibre content > 50 % Bulk density < 1,000 kg/m 3 Fibre content < 15 % Bulk density > 1,400 kg/m 3 Typical application Soft asbestos Spray asbestos Asbestos-containing lightweigt mortar or lightweight panels Asbestos mats or cords Floor coverings with a paper felt-like asbestos underlay (CV-coverings) Air ventilation ducts Fire dampers and fillings in fire protection doors Protection curtains Pipe clamp inlays Typical application Panels, claddings, pipes or moulded parts made from asbestos cement for: Roofing Facade claddings Ventilation pipes and exhaust stacks Garden articles like flower boxes 5 5 Reference: BGBau, Medien, Asbestos (BG BAU= German trade association for the construction industry) 4

5 What asbestos always need to be considered? Despite a ban of use, asbestos fibre cement panels do not have necessarily to be removed. The fibres are not dangerous as long as they are not exposed. Only exposure and the danger of inhalation cause the health risk. Any contact with asbestos-containing materials requires a high degree of protective measures which are stipulated in the following laws and instructions: German Hazardous Substances Ordinance (GefStoffV), particularly the German Technical Regulations for Hazardous Substances, TRGS 519 German Water Resources Act (WHG) Accident Prevention Regulations (UVV) The Hazardous Substances Ordinance restricts the so-called DRM-works (demolition, redevelopment and maintenance) in a way that cleaning and renovation works with uncoated asbestos cement roofs and wall claddings are generally prohibited. 6 A whole series of conditions according to the German Technical Regulations for Hazardous Substances, (TRGS 519) is connected for DRM-works (demolition, redevelopment and maintenance) with uncoated asbestos cement panels which have to be strictly observed. These conditions are for example a certificate regarding the contact with asbestos and the associated risks (so-called certificate of knowledge) and also proof that the performing workshop has the corresponding equipment. Moreover, if dimensions are greater than 100 m² the proper authorities must be informed in time, i.e. at least seven days before the beginning of work, so that possible objections could be done. This notification entails a whole series of information. For works up to 100 m² the workshop has to notify the authorities that he generally performs such activities. Orders less than 100 m² do not need to be reported in individual cases. Plus, a general employment prohibition is applied for pregnant women and young people. Only a competent, qualified workshop with well-trained employees combined with highest processing and product quality provides sufficient security for humans and environment and protects the craftsmen from unpredictable risks. Expertise is imperative 6 Compare: Annex II to article 16 (2) of the regulation recasting the Hazardous Substances Ordinance dated November 26,

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7 A lot of questions one answer: Facade panels made from asbestos cement what must be considered when coating? Coating of facade panels made from asbestos cement which product is suitable and why? Facade panels made from asbestos cement is there a reasonable alternative other than removal? Coating of facade panels made from asbestos cement what is the proper procedure? KEIM Teknosil The coating solution for asbestos cement! 7

8 KEIM Teknosil : Advantages and benefits 1. Protection against coating damages and panel deformation 2. Protection against chalking and colour shade change 3. Fibre-binding effect One of the most important quality criterions when coating asbestos cement panels is to reach a maximum of permeability to avoid moisture behind the panels. If moisture cannot be released towards the outside there will be a risk of deformation of panels which at the end result in replacement or removal and, spalling of the paint coat. Front and back of the panels need a functioning diffusion balance. By coating only the front side this balance can be considerably disturbed. In this sense, diffusion-inhibiting coating structures must be absolutely avoided. KEIM Teknosil with a diffusion resistance rate of < 0.02 m is highly permeable and does not affect the moisture diffusion through the fibre cement panel. Over time UV radiation causes disintegration for almost all organic pigments and binders. The result is binder decomposition, early chalking and colour changes. KEIM Teknosil is a silicate paint according to European Standard EN 1062 with only inorganic pigments. The mineral, special waterglass as binder and the pure, inorganic pigments stand for highest UV resistance and thus for weathering protection and a colour shade durability of grade A1! Over the years, weather influences affect the surfaces of asbestos cement panels and plates and can impair the binding of the fibres. A coating with fibre-binding properties provides here an increased protection for humans and environment. KEIM Teknosil has an excellent fibrebinding effect. The silicate binder waterglass binds possibly exposed fibre ingredients chemically into the matrix of the paint coat and provides therefore a higher degree of safety. 8

9 4. Unbeatable in terms of economy Any common coating system which can be used for the difficult application case on asbestos cement requires a coating structure with three coats and, depending on the panel type, various products for priming and various coatings materials. KEIM Teknosil, however, captivates by the simplicity. No priming and only one single coating material. That means: Two coats Ready! You cannot find a more economical solution. 9

10 Coating of fibre cement panels 1. Construction inspection 2. Identification of the installed fibre cement boards 3. Notification of DRM-works The construction and the condition of the façade cladding must be absolutely inspected. Attention has to be paid to a sufficient rear ventilation, sound substructure (stability proof) and professional installation of the panels. In case of concerns regarding the construction the customer is recommended to have an expert inspect the façade cladding (corresponds to separate performance) 7. The removal is necessary in case of deficiencies. Plus, it is mandatory to replace defective panels. Specific panel types are available for that purpose. First it should be found out with absolute certainty if there are any asbestos fibres. Precondition: Panels as of 1991 or electron microscopic analysis. If asbestos fibres are assumed it needs to be examined if the asbestos cement panels are coated or uncoated. Panels are considered as coated if they are factoryprecoated (acrylate or silicate [=> Glasal, Fulgural]) or if they were coated afterwards. Prior to work start, in Germany the planned activities have to be reported in written to the responsible authorities, normally to the trade supervisory authority and the professional association. A supervisor with expertise certificate (as per TRGS 519 German Technical Regulations for Hazardous Substances ) has to be appointed for each construction site. Moreover, all the prescribed measures (as per TRGS 519) have to be observed. Types of asbestos cement panels Untreated Grey, with partly high absorbency Steam-hardened Grey with dense surface Factory-precoated with dispersion coating Factory-precoated with mineral coating Factory-precoated with mineral coating Coloured, smooth and/or textured, with a relatively dense surface White cement with dense surface Glasal, mostly coloured, with a very dense, smooth surface 7 Compare: BFS-Technical Information 15, section 3, page 6 10

11 4. Cleaning 5. Coating If asbestos cement facades have to be cleaned as part of coating works, the cleaning has to be accomplished only with water without any pressure and soft tools, e.g. sponge. Cleaning agents can be added. The cleaning water must be collected and can be discharged into the public sewer system if there is no other official regulation. Abrasive methods are not allowed in general. This applies also for high pressure or low pressure water jetting, brushing or grinding. Only exception would be low-emission procedures which are acknowledged by the authorities or the trade associations. The regulations of the TRGS 519 have to be always strictly observed. Soiling, contamination and possible growth of microorganisms must be thoroughly removed as per TRGS 519. The surfaces require an additional treatment by applying KEIM Algicid-Plus after cleaning for disinfection in case of microbial growth. The painting works can be performed after a thorough cleaning of the panel surfaces, disinfection where necessary and, sufficient drying time The coating structure is based on a base and a top coat. If necessary, the base coat can be diluted with approx. 10 % KEIM Teknosil-DL. The finish coat application is always undiluted. Substrate Priming Coating Binding of residual fibres of asbestos-containing parts to be removed like wall panels and plates and the substructure. Asbestos cement façade panels with intact polymer resin coating Asbestos cement façade panels with intact old dispersion coating Intact Glasal or Fulgural panels New, untreated, asbestos-free fibre cement panels On all sides, fibre-binding, apply Teknosil-DL 1x liberally to bind the fibres not applicable not applicable not applicable not applicable not applicable 2 x Teknosil 2 x Teknosil 2 x Teknosil 2 x Teknosil 11

12 KEIM Teknosil Surface coating for asbestos-containing fibre cement panels Silicate Highly open to diffusion UV-stable Protection for health and environment by fibre-binding effect KEIM Teknosil provides the solution for the difficult application of coating asbestos cement. Safe competent sustainable KEIMFARBEN GmbH Keimstraße 16 D Diedorf Fon +49 (821) Fax +49 (821) Frederik-Ipsen-Straße 6 D Luckau Fon +49 (35456) Fax +49 (35456) KEIMFARBEN consistently mineral Stand 04/2014 engl. info@keimfarben.de