Sustainable Design Materials: Wool Industry Analysis

Introduction

The design of environmentally friendly buildings and materials is currently one of the most pertinent issues in the design industry. The reasons for environmental design revolve around human health, the quality of air, water and soil. With common materials, like low-cost synthetics, little to no regard has been made for the environment because of high energy consumption for extraction, transport, and production. Common materials also add chemicals that are not in the interest of human health to enhance aesthetic or technical characteristics. Currently, the demand for increasingly sustainable materials has transitioned the consumer’s personal choice to industry requirements in order to improve areas such as environmental behavior of infrastructures and buildings. New approaches to energy-saving and sustainable building designs focus on decreasing energy use, but also in the application of natural and/or local materials. This shows not only the importance of reducing energy use, but more importantly, being environmentally conscious through smart design. The purpose of this report is to illuminate how the wool industry processes, which shows much less adverse effects to the environment than synthetics, could be a sustainable answer for the commercial design materials, like insulation or sound absorbers. This shows even more possibilities for environmentally friendly steps in the building industry.

Wool Properties

Natural Part of the Carbon Cycle

Wool hairs are grown directly from sheep’s skin and is a fully natural protein fibre. Sheep produce new fleece or hairs annually from the consumption of grass and other pasture plants. This is a natural process and part of the carbon cycle, making wool a renewable source of fibre. Pure organic carbon makes up fifty percent of wool weight​, therefore, a​t the end of its use, wool decomposes easily. Wool releases nutrients back into the soil, unlike most synthetics.

Inherent Properties

Wool has physical properties without the use synthetic additives. Its fibres are hygroscopic, meaning it absorbs and dispenses water vapour. This makes wool an effective insulator as heat is generated through water absorption. The material is breathable as it can take in thirty percent of its weight in water and release it. The same goes for absorbing and releasing sweat, preventing bacteria from developing and producing odour. This moisture retention prevents a high build-up of static electricity and attracting airborne lint or dust. The high water content in wool combined with nitrogen also makes it flame-retardant and self-extinguishing with a high ignition threshold. This prevents melting and sticking to areas, like skin and produces less noxious fumes. Wool fibres are resilient and can bend back on themselves over 20,000 times. Its crimped structure makes it naturally elastic. It can stretch and return to its natural shape, preventing most of wrinkling and sagging in its use. The wool hair structure is also unique because of its hydrophilic core and hydrophobic outer layer. The water attracting centre dyes richly and is colourfast, without synthetic treatment. The water repellent and waxy coating makes it naturally stain and UV resistant.

Wool Processing

Four major steps are involved in wool processing. The process begins with shearing, followed by sorting and grading, spinning yarn and, lastly, weaving fabric. To remove impurities, like sand and dust, the wool is washed, dried, then carded. Carding is the stage of untangling wool through wire-toothed rollers and arrange the product into a sheet called a web.

Wool applications

Wool Interiors

Sheep wool as a natural material has been traditionally used in the textile industry for the manufacture of conventional woolen products, such as carpets, garments, curtains, covers and bedding. Recently, the use of natural and renewable materials with similar properties to those of conventional materials has become more important. Wool is great example of this. As mentioned, its natural properties make it adaptable to many uses, especially for the interiors of buildings. As we spend more time indoors, our exposure to volatile organic compounds are increased. VOCs are vaporous off gasses from chemical materials that can be easily inhaled. They are common products from the home, like solvents, paints and thinners. Other causes of VOC off-gassing are cleaners, disinfectants, air fresheners, copy machines, printers, building materials and furnishings. Conventional thermal insulation and limited ventilation in modern buildings leads to the deterioration of indoor air quality. Concentrations of VOCs may be two to five times higher indoors.

This can result in feeling ill inside these living spaces, which is classified as Sick Building Syndrome. These VOCs can be absorbed and neutralized by wool. The used of wool around the home, like in furniture, carpets, clothing, or insulation, can be an eco-friendly solution to the issue of indoor contaminants and improving indoor air quality. Wool can also be an added protection from gas, smoke, and toxic fumes, all unfortunately common contributors for fatalities in house fires with fatalities that are more likely to occur in rooms with soft furnishings. Wool is more flame resistant than commonly used textiles (e.g. cotton, rayon, polyester, acrylic and nylon). As previously mentioned, wool does not melt or stick to skin, unlike polyester and nylon. When burns it forms an insulating char, this is especially useful for large amounts of wool inside the home, like blankets and carpets. This can help stop the spread of flames to other materials. It also produces less smoke and fewer fumes than other synthetic alternatives.

2. Building Materials

The need for environmentally friendly building materials, especially from renewable sources, is growing fast. In reference to the current progress and attitudes in science and technology, it can be said that thermal insulators made from organic materials are likely to become a suitable alternative to those made from different synthetic materials (mineral wool, polystyrene or polyurethane). Even though sheep wool insulation is a relatively well developed market in Western Europe, there is no producer in Canada. Based on the fact that sheep’s natural properties, including inherent thermal insulation, moisture management, and sound absorption, insulation from organic fibres can match the functions of common insulating boards and sound absorbers from synthetics. Wool performs better than other fibers under average weather conditions because of its abilities to absorb and desorb moisture from the air. This ability helps the building breathe and stay cool in summer and create heat through evaporating moisture in the winter. Using natural building materials supports human health. For example, expanded polystyrene (EPS) is a common building material for insulation. Its use has been linked to significant safety, environmental and health issues because of its flammability and production of toxic fumes. The demand for more environmental regulations in the construction industry and the initiation of green building certification like Leading Energy and Environmental Design (LEED), US Green Building Council and Building Environmental Standards (BOMA BESt) have generated a market for sustainable materials. In regard to these attitudes, wool insulation shows real potential as a viable substitute of others more aggressive to the environment.

Considerations

Life Cycle Assessment

The life cycle assessment (LCA) is a tool that can be used to understand wool’s environmental impact, also known as the “cradle-to-grave” assessment. Its life cycle starts with the farm and then on to production, use, reuse and recycling. As a part of the agricultural industry, the main concerns revolve around land, energy and water use, along with emissions of greenhouse gases and other chemicals. The main greenhouse gas emissions from wool production are carbon dioxide, methane and nitrous oxide. It is important to note that there is no singular life cycle assessment for every wool product. For example, as a long lasting and valuable material, wool is more likely to be re-sold, donated to charities or passed on for sentiment. These extend the life cycle for wool and without involving the impacts and resource use for reprocessing.

Fossil Fuels

Fossil fuel, a non-renewable energy, contributes to climate change and is widely regarded as one of the largest current environmental issues. It is also related to human health risks and deterioration of air quality. Fuel use is fairly low for wool production compared to alternative fibres. However, with larger farming systems, heavy metals from high fertiliser use on feed crops can contribute to human health, like cancer.

Water Consumption

Fresh water use is based on the amount withdrawn and not returned to catchments and environmental effects varies based on locational availability. The main contributors to water consumption are the in-use phase (eg. washing garments) and the on-farm phase. On-farm is water used to produce fertilisers and freshwater consumption from sheep. Additionally, garment mills may also be high users of water.

Climate Change

The major contribution to the climate change of wool products is methane. Methane is produced in the digestive process of sheep and the production of fertilisers. These are large sources of on-farm greenhouse gas emissions. Carbon dioxide emissions from from fossil fuel use in electricity and transportation also emit greenhouse gasses that contribute climate change. 5. Land Occupation This impact category represents the damage to ecosystems linked to human use over a certain period of time. Changes between forest, grassland and cropland can result in large changes in carbon levels in the carbon system. This is relevant to forests cleared for sheep pasture or a change from grassland to croplands for feed. There is currently insufficient data on historic land use and uncertainties in attributing changes to natural or man-made factors. There is also a variety of land management practices across farms.

Conclusions & Recommendations

Sheep wool is a renewable and sustainable material with amazing natural properties. A future well-organized collection and clean production of sheep wool products, including alternative uses, could create a positive environmental effect. Sustainable materials, like sheep wool, offers a green solution for contemporary architecture as proper materials for insulation and energy saving in buildings. Insulation from sheep wool provides comparable characteristics with conventional materials, and in some applications, even performs better. Importing and exporting wool overseas for manufacturing and re-purchasing is not beneficial from a business or environmental standpoint. However, research on the manufacturing process from these overseas locations, like Western Europe is needed.

Further research is also needed on the wool life cycle, especially for alternative products like insulation. It is also apparent that a global guideline for wool life cycle assessments needs to be developed. This includes providing even more information and perspectives on the impacts that are tied with agricultural wool production, notably greenhouse gas emissions. An environmental strategy for the wool industry should include sustainable production and consumption. The consumption of raw materials and energy in wool production creates waste and emissions, but crafting sheep wool building materials has high possibilities in positive environmental impact - especially with the use of waste wool. It is essential that standardized and sustainable procedures are thoroughly followed in all stages to create an ethical practice.