Materials Based On Animal Products

Basic info is found in Chapter 11.

Climatic materials obtained from animals are primarily hair, wool and hide (Table 14.10). Animal fibres are high quality thermal insulators and very good moisture regulators. Reindeer skins have been widely used as thermal insulation, especially amongst the Lapps. The most widespread use of animal products today is as ingredients for wool-based building papers and thermal matting. A slightly more peripheral product is crushed mussel shells providing thermal insulation and cappillar breaking layer in slab-on-ground foundations.

Woollen matting can contain varying quantities of recycled wool. The product often contain borates (approximately 1% by weight) against insect attack. In some cases biocides such as pyrethrin and chlorinated compounds like sulcofuron are added for additional protection against

Table 14.10 Climatising qualities of animal products

Material

Composition

Areas of use

Mussels

Shell

Thermal insulation, capillary barrier

Wool, loose fill

Wool, possibly partly recycled; biocides

Thermal insulation, sound insulation, moisture buffering, sealing of joints

Wool, matting and felt

Wool, possibly partly recycled; glued with polyesters (melting fibres), biocides

Thermal insulation, sound insulation, moisture buffering, sealing of joints

Wool, building paper Wool, possibly with cellulose (recycled) or Sound insulation (impact noise)

bitumen added

Wool, building paper Wool, possibly with cellulose (recycled) or Sound insulation (impact noise)

bitumen added moths. As a binder, fibres of polyester (e.g. polyethylene terephthalate) are melted in, in amounts around 10% by weight, but the product are also produced by needle-punching (see Figure 14.23).

Woollen felt is used as a sound insulation between floor joists and as a thermal insulation around water pipes. Felt strips are also often used for sealing gaps between windows, doors and the building fabric. Woven sealing strips are used in windows. They become hard when painted, and damp can cause them to shrink and loosen from their position.

Wool-based building paper consists of a good deal of recycled paper, but the woollen content must not be lower than 15%. Wool building paper is soft and porous and is often used as step sound insulation.

Wool is broken down at a temperature of over 100 °C and by fat, rust, petroleum, alkalis and oil. The material does not burn easily, but smoulders when exposed to fire.

The raw material for most woollen products is rejected wool from abattoirs, which would otherwise be thrown away. If sheep farming were to be done solely for wool, then the environmental impact, especially associated with growing of their fodder and emissions of the greenhouse gas methane from digestive processes, would be high - however, seen largely as a by-product, the equation looks more favourable.

Animal products can be considered problem-free in the user phase. Additionally, woollen products help to even out moisture changes in the indoor air as well as within construction. However, the use of toxic additives makes it necessary to dump the waste at special tips. Pure products of wool can and should be composted. This should take place at controlled sites since normal dumping will lead to increased nutrients seeping into the ground water from the tip.

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