Improvements give new life to old building material
Wood wool cement board (WWCB) is a versatile building material made from finely shredded wood fibre embedded in cement. Although it provides rapid and durable low cost constructions, its manufacture was declining in Europe because of hazards in WWCB manufacture and competition from resin bonded board and thermoplastics. A Craft project enabled both the process and the product to be improved. The new manufacturing equipment is already selling well, and the process has been freed from environmental and safety problems. The decline in the WWCB industry in Europe has been reversed, safeguarding employment, and providing exports to developing countries.
WWCB is resistant to fire, wet and dry rot, frost and vermin and it provides excellent thermal and acoustic insulation. It accepts a wide range of finishes and can be used to construct entire buildings. Widely used in Europe in the 1950s, WWCB now has to compete with resin bonded boards and thermoplastics made from less environmentally friendly materials. A major drawback of WWCB is the hazardous nature of its production. Traditional wood shredding machines are dangerous and noisy to operate. The dust they produce is damaging to health, flammable and explosive.
An improved production process
A new company, Eltomation, was formed to re-invigorate the WWCB market. Two innovations were required – a modern wood shredder, and an improved board-forming machine that would make medium density WWCB with a closer and smoother surface on both sides of the board.
Eltomation joined with other small companies in an EC-supported project that has achieved both objectives and led to commercial success.
The project’s core development is a completely new automated wood shredder, which produces thinner and longer fibres of wood wool than before, thus improving the strength of the new WWCB product ‘EltoBoard’. Innovative cutting blades produce less wood waste and less dust. Patents have been issued for the shredder, the knives and for EltoBoard. The technology is also suitable for upgrading existing plant and the new Eltomation manufacturing equipment can also be used to make conventional WWCB, providing flexibility in production and marketing.
EltoBoard contains wood strands, ordinary Portland cement and water. It contains no toxic or hazardous substances, nor does the production process emit any toxic or environmentally harmful byproducts. It is strong and durable, suitable for exterior walls and roofing as well as partitions and floors, and can be made into complete fabricated houses and permanent shuttering for concrete-forming systems.
A business trend reversed
A new EltoBoard plant has less than half the setup costs of a conventional plant of the same output, one reason why Eltomation has now sold six of the new rotary shredders in Europe worth a total of about €3 million, and nine associated distributing machines worth €1.4 million – safeguarding employment by ensuring the continuation of the WWCB industry in developed countries.
Board makers, such as project partner Tepro Byggmaterial AB (now Träullit), are benefiting from reduced energy consumption and more output per worker. Each machine pays for itself within three years and then adds €170 000 to profits every year. Furthermore, the new products with finer fibres have opened a market for attractive ceiling boards.
There are interested customers for this technology worldwide because, even where wage-costs are low and safety rules less strict, manufacturers tend to prefer the most advanced technology. This machine can keep the industry competitive, allowing manufacturers to survive and recover some of the market from competing products such as polyurethane.
The environment benefits, too
The conventional WWCB machines are dangerous to operate, and dust and noise may harm the operator’s health. They will soon be banned under new EC regulations. The new automatic shredder does not need an operator and consumes 50% less energy. It is also dust-free, making for greater safety in the working environment. It uses a renewable material, wood, rather than thermoplastic derived from fossil fuels; and it makes productive use of wood that would otherwise be burned –with virtually no waste.
Since the end of the project, a major effort has been made into developing further the capacity of the prototype shredder. It can now handle non-standard wood – different qualities and hard knots in the wood – and can operate in conditions of greater humidity. This was made possible by the innovative shredder blade design.