Sheep wool as insulation
| Sheep wool | |
|---|---|
|
|
| origin | |
| raw materials | Sheep wool |
| Primary energy consumption (production) | 70-80 kWh / m 3 |
| Material properties | |
| Thermal conductivity λ | 0.040 W / (m K) |
| Specific heat capacity c | 1300 J / (kg K) |
| Bulk density ρ | 20-25 kg / m 3 |
| Vapor diffusion resistance μ | 1-2 |
| commitment | |
| Areas of application | between rafters / structural timbers; Cavities, pipes, joints; Impact sound insulation |
| material costs | approx. 75–100 € / m 3 for U-value = 0.2 W / (m 2 · K) |
In addition to being used for textiles , sheep's wool can also be used as a natural insulation material . In this role she is z. B. used in New Zealand and has meanwhile also established itself in German-speaking countries, with a market share of less than 0.5%.
Manufacturing
For the production of insulation materials in the German-speaking area, only European and preferably regional sheep wool is currently used; they are made from virgin sheep's wool in the form of mats or darning wool. After the initial preparation by washing, degreasing and neutralizing the pH value, the wool is mixed in the fine opener and cleaned of foreign matter. Finally it is carded , the resulting fleece is placed crosswise on top of each other, mechanically needled in the needling machine and then cut to size. Cutting waste is recycled.
In New Zealand, and recently also in Switzerland / Germany, polyester fibers are added during production to support the fabric .
Since sheep's wool is susceptible to attack by clothes moths , it must be treated to protect against them. On the one hand, this can be done with sodium borate , which also has the advantage of being flame-retardant. However, since these lose themselves from the material after a few years, it was also fixed to the wool with natural rubber for a while . However, due to the categorization of borates as toxic to reproduction, their use is now being discontinued. As an alternative, it was possible until around 2005 to treat the wool with sulcofuron (trade name Mitin FF) before delivery, and for some years also with Thorlan IW. However, both products no longer have European approval as "moth protection" and are therefore no longer available for insulation manufacturers. Therefore, permethrin is often used again - also in Germany - as a moth protection, although the use of this substance, which is also classified by the Institute for Risk Research "as a neurotoxin and yet classified as safe for wool carpets", is very controversial, especially in an "ecological building material". The international environmental label " natureplus ", for example, rejects the use of such biocides (substance bans).
As an alternative, a biocide-free finish is also offered, whereby the wool is modified to prevent it from eating and thus protected.
Technical characteristics
Sheep wool has a WLG value of 0.040, similar to wood fiber , cellulose , rock wool or polystyrene . With a heat capacity of 1300 J / (kg · K) it stores heat well. The vapor diffusion resistance is comparatively low at 1 to 2. It is classified in building material class B2 or E, so it is normally flammable, the ignition temperature is between 580 and 600 ° C, the high nitrogen content has a flame-retardant effect.
The pollutant-cleaning effect of sheep's wool as an insulating material is unusual . Due to its origin and fiber structure, sheep's wool is a medium for breaking down formaldehyde and an efficient sorbent for long-term binding of numerous other aldehydes and other harmful substances such as B. toluene from the room air.
Due to these properties, sheep's wool is now increasingly used preventively in new buildings for general room air improvement.
Sheep wool is extremely elastic and only breaks when it is bent over 20,000 times. It can absorb a great deal of moisture and only reduces its insulating properties when the water content exceeds 16 percent by weight.
Areas of application
When building a house, you can insulate the roof, walls and ceiling as well as the facade with sheep's wool. It is also particularly suitable for insulating technical systems such as cooling, air conditioning and ventilation systems. In the case of the former, it is used especially for thermal insulation, in the case of the latter it is more of a sound insulation. It is also suitable for the insulation of moving or regularly loaded parts because the fibers are flexible. However, like other natural insulation materials, sheep's wool is unsuitable for perimeter insulation.
Market importance
Sheep wool has established itself as a thermal insulation material in Germany, but the market share in the insulation material market is less than 0.5%. Due to the special combination of structural properties, which limit their area of application as insulation material to special cases, and the competition from its use as a raw material for textiles, the market share will in all probability barely exceed 1% in the future. In the market segment of insulating materials made from renewable raw materials, it has a market share of 4%. With material costs of around € 75–100 / m 3 with a heat transfer coefficient of 0.2 W / (m 2 · K), sheep's wool is also more expensive than conventional insulation materials or natural insulation materials with the same insulation effect.
Web links
- Brochure insulation materials made from renewable raw materials , Federal Ministry of Food, Agriculture and Consumer Protection and Agency for Renewable Raw Materials e. V., PDF file, accessed February 2016
- Sheep wool - the insulation material - information on moth protection 2016 ,
- Sheep wool as a reactive sorbent for air pollutants in the interior Robert Sweredjuk, Gabriele Wortmann, Gerd Zwiener, Fritz Doppelmayer - Study by the German Wool Research Institute at RWTH Aachen University
Individual evidence
- ↑ a b Entry of sheep's wool insulation materials in: WECOBIS - Ecological Building Material Information System at the Federal Ministry of Transport, Building and Urban Development, Online ( Memento of the original from October 1, 2010 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , Accessed February 14, 2009
- ^ A b c d Lutz Dorsch, Christian Kaiser, Werner Niklasch, Hamlet Schöpgens, Josef Spritzendorfer: Insulation materials from renewable raw materials , Fachagentur Nachwachsende Rohstoffe e. V. (Ed.), 2016, p. 38 ff., [1]
- ↑ a b c W. Eicke-Hennig: Insulation materials made from waste paper or natural fibers - (not) an alternative? In: Bauthema Naturdämmstoffe, 2006, ISBN 3-8167-6916-0 , pp. 16–30.
- ↑ http://www.isolena.at/ueber-uns/unsere-wolle
- ↑ B. Mühlethaler, S. Haas: Strengths, hurdles and opportunities of natural insulation materials In: Bauthema Naturdämmstoffe, 2006, ISBN 3-8167-6916-0 , pp. 9-10.
- ↑ a b Ingo Gabriel and Heinz Ladener (eds.), 2008: From old buildings to low-energy and passive houses. Ökobuch-Verlag. Pp. 74-75, ISBN 978-3-9368-9632-9 .
- ↑ Robert Sweredjuk, Gabriele Wortmann, Gerd Zwiener, Fritz Doppelmayer: Sheep wool as a reactive sorbent for air pollutants in the interior - Part 1 Aldehydes , study by the German Wool Research Institute at RWTH Aachen University , PDF Online .
- ↑ Stefan Thomé: Investigations into the sorption of indoor air pollutants by wool , dissertation, 2006, PDF online .
- ↑ Pollution remediation and prevention with sheep's wool
- ↑ Michael Carus et al .: Study on the market and competitive situation for natural fibers and natural fiber materials (Germany and EU). Gülzower Expert Discussions Volume 26, Fachagentur Nachwachsende Rohstoffe e. V. 2008, p. 180.
