KEIM TEKnosIl Silicate Special coating for aSbeStoS cement – and fibre cement boardS

®

„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 applica-bility.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, 1991.

today we are confronted with the numerous buildings where asbestos-containing 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 fede-ral countries (ScHmidt-SiebetH 1993)1 – demanding a huge field for reno-vation, refurbishment and maintenance activities for all market participants, namely building owners, their represen-tatives and handicrafts.

the best way would be undoubtedly the removal or replacement of asbestos-containing building materials, but, in many cases this cannot be realized because of economic reasons and some-times it is not always urgently necessary from a technical point of view.

Such buildings should be renovated in a useful and responsible way within 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.

1 See: LfU (Bavarian State Office of the Environment), environmental knowledge about asbestos, 2010, page 6

Asbestos cement – heritage with problems

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Poorly bound asbestos is particularly dangerous

asbestos (old greek: ásbestos, „ever-lasting”) 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

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, sharp-edged 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.

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 coverings4. the panels are mostly harmless as long as they remain intact, do not weather and are not mechanic-ally treated.

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 3-8653-7414-X, page 3 and 4.4 Typical trademarks: Eternit, Fulgurit..

picture (Sem): amphibole asbestos fibres

Hazardous substance asbestos

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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 1991. 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 1991.

5 Reference: BGBau, Medien, Asbestos (BG BAU= German trade association for the construction industry)

Recognizing asbestos cement

Poorly bound asbestos products

Strongly bound asbestos products

fibre content > 50 %bulk density < 1,000 kg/m3

fibre content < 15 %bulk density > 1,400 kg/m3

Typical application 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

panels, claddings, pipes or moulded parts made from asbestos cement for:

roofing

facade claddings

Ventilation pipes and exhaust stacks

garden articles like flower boxes

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Expertise is imperative

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 corres-ponding 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.

6 Compare: Annex II to article 16 (2) of the regulation recasting the Hazardous Substances Ordinance dated November 26, 2010.

What has to be considered?

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A lot of questions – one answer:

KEIM Teknosil® The coating solution for asbestos cement!

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?

coating of facade panels made from asbestos cement – what is the proper

procedure?

facade panels made from asbestos cement –

is there a reasonable alternative other than

removal?

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KEIM Teknosil®: Advantages and benefits

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• deformationofpanelswhichatthe end result in replacement or removal and, • spallingofthepaintcoat.

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 fibre-binding effect. the silicate binder water-glass binds possibly exposed fibre ingredients chemically into the matrix of the paint coat and provides therefore a higher degree of safety.

1. Protection against coating damages and panel deformation

2. Protection against chalking and colour shade change

3. Fibre-binding effect

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any common coating system which can be used for 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.

4. Unbeatable in terms of economy

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Coating of fibre cement panels

the construction and the condition of the façade cladding must be carefullyinspected. attention has to be paid to a sufficient rear ventilation, sound substruc-ture (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 factory-precoated (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.

1. Construction inspection 2. Identification of the installed fibre cement boards

3. Notification of DRM-works

7 Compare: BFS-Technical Information 15, section 3, page 6

Types of asbestos cement panels

Untreated grey, with partly high absorbency

Steam-hardened grey with dense surface

factory-precoated with dispersion coating

coloured, smooth and/or textured,with a relatively dense surface

factory-precoated with mineral coating

White cement with dense surface

factory-precoated with mineral coating

“glasal”, mostly coloured, witha very dense, smooth surface

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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 sanding. 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.

4. Cleaning 5. Coating

Substrate Priming Coating

binding of residual fibres of asbestos-containing parts to be removed like wall panels and plates and the substructure.

on all sides,fibre-binding,apply teknosil-dl 1x liberally to bind the fibres

not applicable

asbestos cement façade panels with intact polymer resin coating

not applicable 2 x teknosil

asbestos cement façade panels with intact old dispersion coating

not applicable 2 x teknosil

intact glasal® or fulgural® panels

not applicable 2 x teknosil

new, untreated, asbestos-free fibre cement panels

not applicable 2 x teknosil

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KEIM. ColoURs FoR EVER.

KEIMFARBEn GMBh Keimstraße 16/ 86420 Diedorf /Tel. +49 (0)821 4802-0/ Fax +49 (0)821 4802-210 Frederik-Ipsen-Straße 6 / 15926 Luckau / Tel. +49 (0)35456 676-0/ Fax +49 (0)35456 676-38 www.keim.com/info@keimfarben.de