Release of asbestos fibers from fiber cement boards

Fiber cement boards that are traded and installed today are generally considered to be harmless to health, as they are made of modern substitute materials and are free of carcinogenic asbestos fibers. However, for houses built from the mid-1960s to the 1990s, it is often suspected that the fiber cement panels installed still contain the asbestos fibers that were previously mixed in and are harmful to health. These can be released with increasing weathering during renovation or refurbishment.

Wonder building material asbestos – use of fiber cement containing asbestos

From the 1960s onwards, asbestos, which was considered a miracle product at the time, was widely used in house construction, smaller outbuildings and numerous other industrial products due to its positive insulating and resistant properties.

Fiber cement boards generally consist of cement and bonded fibers. The Austrian Ludwig Hatscheck developed this building material at the end of the 19th century. He mixed 90 % cement with 10 % asbestos fibers. His invention was patented with the trademark and process“Eternit” and later produced and sold in factories worldwide. By adding asbestos fibers to the fiber cement at the time, the cement remained malleable and durable. It was therefore mainly used for roof construction and cladding facades. It had good sealing properties, was fireproof, cold-insulating, easy to process and also inexpensive. For roofs, the strongly bound asbestos was used as asbestos cement, corrugated asbestos (with an admixture of about 10 to 15 percent bonded asbestos) or in the form of asbestos corrugated sheets is used.

Fiber cement boards and Eternit

Due to the high profile of fiber cement under the Eternit brand, it was increasingly used as a synonym for the building material fiber cement. Fiber cement with asbestos or Eternit was mixed with asbestos fibers until around autumn 1990, although from 1985 substitutes were already being marketed as Eternit in some cases instead of the asbestos fiber admixture. After 1990, all Eternit building construction products were converted to an asbestos-free material. Under the new Etex Germany Exteriors GmbH, only asbestos-free products with artificial mineral fibers or organic fibers were then manufactured. This also includes the asbestos-free fiber cement boards. However, the trade was still allowed to sell the remaining stock until the end of 1991 , so that even fiber cement boards purchased in 1991 were not undoubtedly asbestos. In general, there was a Germany-wide ban on products containing asbestos from 1993, and from 2005 the ban on the manufacture and sale of asbestos also applies throughout the EU.

More than 30 years have now passed and the risk of asbestos fibers being released in older houses still exists, mainly due to many years of weathering.

Release of asbestos fibers from old fiber cement boards

Asbestos – the versatile miracle product for building materials and industrial products

Gradual weathering in particular can cause the previously bound asbestos to dissolve from the fiber cement panels of old buildings. In the process, the previous binding agents become brittle and release the finest and respirable asbestos fibers. These can also be released during fires.

Asbestos is a fibrous silicate mineral which, like its name derived from “asbestos”, was considered almost imperishable. The outstanding properties of asbestos are its resistance to cold, heat and fire. In addition, asbestos was easy to process with other materials and was also inexpensive. It was only a few decades ago that asbestos fibers were proven to be a health hazard . In addition to causing allergies, these very fine fibers can cause cancer in the lungs and abdominal and chest areas after prolonged exposure. They spread rapidly, particularly through mechanical activities such as drilling, breaking and cutting. For this reason, roof panels made of asbestos-containing material, for example, must not be cleaned with a high-pressure cleaner. According to the Technical Rules for Hazardous Substances (TRGS 519), demolition, renovation and maintenance work should only be carried out by competent persons.

Substitutes for fiber cement made from asbestos fibers

Since the ban on producing fiber cement or Eternit with asbestos fibers in 1990 , substitute materials have been used as additives for the fiber cement.

Today’s fiber cement boards are enriched with these substitute mixtures in order to achieve similar effects for stability as was previously possible with asbestos fibers. These new substitutes include fibers made from organic polymers (fiber cement) or fiberglass-reinforced concrete, which no longer pose a health hazard because their fibers cannot penetrate deep into the lungs to cause damage. The new replacement products are similar in shape to asbestos fibers and therefore cannot be clearly distinguished from the previous asbestos-containing panels. It should therefore be checked, especially in buildings constructed before 1990, whether they are already asbestos-free building materials.

AF marking – asbestos-free fiber cement boards and Eternit

Nowadays, there are labels indicating that materials such as Eternit and fiber cement boards are asbestos-free after packaging. These then bear the abbreviation “AF” for asbestos-free. This AF marking is prescribed in the GefStoffV , which specifies a certain dimension of 5 cm x 2.5 cm. This size must have a white “a” on a black backgroundtogether with a text on a black or red background. As this designation is only to be shown on the packaging, the individual plates within the packaging marked in this way do not have to bear the designation with AF.

Due to this fact that individual fiber cement boards do not have to have the AF “mandatory” marking , it is advisable to have an asbestos measurement to ensure that the panels installed on your roof or as façade cladding or other building material are free of asbestos fibers .

To this end, the GSA Messgerätebau through its GSA measuring devices online store offers specialized measuring devices that are specially designed for measuring asbestos fibers and sample the indoor air for the concentration of harmful asbestos fibers in order to subsequently analyze them via a testing laboratory such as the GSA Schadstoffanalytik to analyze them.

Asbestos measurement with the GSA measuring devices SG12

For professional asbestos measurement of asbestos fibers in accordance with VDI 3492, the GSA measuring devices SG12 is suitable for indoor air measurement in indoor areas. In these areas, the inhalation of asbestos fibers is particularly harmful to health. The SG12 can be used to take samples of inorganic fibrous particles in accordance with VDI 3492 and ISO 14966 as well as asbestos or KMF. According to VDI 3492 , eight hours of sampling are sufficient. For a measurement at the workplace according to DGUV 213-546, a measurement duration of two hours is possible.

Sources:

www.baua.de/DE/Angebote/Publikationen/Kooperation/Asbesterkundung.html

www.bgbau.de/fileadmin/Medien-Objekte/Medien/Broschuere_Flyer/asbest.pdf

www.baustoffwissen.de/baustoffe/baustoffknowhow/fassade_und_massivbau/asbest-asbestfrei-faserzement/

www.geo.de/wissen/gesundheit/so-erkennen-sie–ob-ihr-eternit-asbest-enthaelt-31743412.html

www.haus.de/bauen/enthaelt-ihr-eternit-asbest-28675

www.haus.de/bauen/faserzementplatten-fuer-fassade-und-dach-besser-als-ihr-ruf-22236

www.umweltbundesamt.de/themen/abfall-ressourcen/abfallwirtschaft/abfallarten/gefaehrliche-abfaelle/asbesthaltige-abfaelle