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Methods of preserving bamboo
There are many techniques of extending the life of bamboo under use is through preservation treatments. These techniques include non-chemical and chemical methods. Full training on the most useful and economical methods are will be conducted at Kitil farm. Why preserve bamboos? Bamboos are a natural material and under natural conditions will gradually decay. If they are used as structural components they will need to be replaced after a period of time. The costs of this may prove prohibitive and the status of the bamboo will need constant monitoring to determine when it needs to be replaced. Preserving bamboos extends their life, reduces costs in the long run and improves safety of the structures they are used to form. What are sap displacement preservation methods? Sap displacement methods replace the sap in the vessels of a fresh bamboo culm with preservative. The culms are then left to stand for two weeks in order that the preservative can diffuse into the surrounding tissues and the preserving salts can be fixed in the cells. Sap displacement can be done by using natural capillary action or by one of a small range of simple pressurised techniques. What is the role of a sap displacement preservation unit in rural development? The unit itself offers employment opportunities to its employees and to many people in its forward and backward linkages. The unit can only treat freshly harvested bamboos and so a source of bamboos near to the unit is required. Local bamboo plantations can be established to supply the unit and create further income generating opportunities. Bamboos can be intercropped with food plants and the plantations can thereby increase the food security of the rural people that manage them. How do I establish a sap displacement unit? A sap displacement preservation unit can be established very cheaply. The only requirements are a supply of freshly harvested bamboos, labour and information from the secondary processors of their requirements. If a pressurised unit is to be established then a source of energy for the compressor will be needed. A pressurised unit capable of treating 50 bamboos per day can be established for USD $500, including a compressor, and non-pressurised units can be established for considerably less. http://www.inbar.int/totems/bamboo-preservation-by-sap-displacement/ How to treat bamboo? Preservation treatment methods of bamboo are of 2 types: the traditional or non-chemical methods and chemical methods. Others alternatives methods are rarely used, Chalet & Bamboo has developed on 100% eco-friendly method. The choice of treatment method will depend on the state of bamboo, whether it is green or dry, whether whole cane or split, its future application, quantity to be treated and the time available. Traditional or non-chemical methods These are ancient methods widely used for centuries by villagers and artisans in countries where bamboo grows, and often the skills are passed on from generation to generation. The most commonly methods used are smoking, white-washing, storage in water. Smoking: Smoking is carried out in chambers. Heat and toxic agents produced by smoke destroy the starch in bamboo making it immune to insect attack and also blackens the culms. There are, in Japan, bamboo houses older than 100 years. The smoke from the kitchen (fireplace without chimney) spreads throughout the house and thus preserves the bamboo structure from any attack. Baking over open fire Baking over fire after applying oil on the surface of green round bamboos. This causes rapid drying of the outer shell and induces partial charring and decomposition of starch and other sugars. This method is very useful for simultaneous straightening of bamboos in round form. White washing Bamboo culms are painted with slaked lime, thereby prolonging their lifespan by delaying and reducing the absorption of moisture while being a repellent against insects. Soaking in water: Freshly cut bamboo is stored either in water ponds or in running water for 3-4 weeks to leach out starch. This process protects the bamboo against insects. When stored in water basins, water must be changed frequently to avoid fouling. Although traditionally treated bamboo shows increased resistance to insects and fungi attack compare to the freshly cut culms, these methods do not however provide complete satisfaction in the long term. Chemical treatment methods Chemical preservatives are used to protect bamboo products from degradation. These are well established methods providing good protection even in adverse conditions. Tanalised method - chromated copper arsenate (CCA) As for wood, bamboo products are often tanalised, impregnatedunder pressure or by boiling with highly toxic substances such as chromated copper arsenate (CCA)to protect against rot. TheCCA has been very effective but very toxic and carcinogenic. Other products are used as "ammoniacal copper arsenate" or ACA. Ammoniac facilitating penetration in bamboo or wood makes this product effective against fungi, bacteria and insects. Ammoniac and copper components are highly and eco-toxic non-degradable. They therefore pose problems in end of life of the product. Due to these toxins, it is advised that not to burn tanalised products, since arsenic (which is a poison) is immediately released into the ambient atmosphere. Since the 1990s, this product is prohibited gradually increasing number of countries and a growing number of uses. Unfortunately, these products are still widely used in some bamboo factories without much consideration. Treatment with Boric acid / Borax The preservative used is a mixture of boric acid and borax which result in the formation of disodium octaborate, which is easily soluble in water. Boron salts are effective against borers, termites and fungi (except soft rot fungi), and is widely recognized to be environmentally acceptable and safe for the mammals. These boron salts are dissolved in water. After treatment, the water evaporates leaving the salts inside the bamboo. Boron salt is non-fixing type, that is, the preservative is leachable. Therefore this process is recommended for bamboo culms that would not be exposed to water or rain. Borax/boric acid seem to be non toxic to the environment, but is highly saline, and little is known environmental toxicity. However, as it hasafungicideandinsecticideaction thatsuggestsit would not beenvironmentally neutralin caseofmajor pollution. It is mildly toxic to humans. Simple exposure can cause respiratory and skin irritation; ingestion may cause gastrointestinal distress including nausea, persistent vomiting, abdominal pain, and diarrhea. There are various way methods of treatment of bamboo. |