Diesel Water Fuel Emulsion

Wood preservation

History
A modern wharf piling bored by bivalves known as "jokes."
As suggested by Richardson, treatment of wood has been practiced for almost as long as the use of the wood itself. Some accounts date back to the beginnings of recorded history. For example the Bible in Genesis 6:13-14 God told Noah th … Make yourself an ark of gopher wood, make rooms in the ark, and the tone will do inside and out with pitch. There are also records conservation of wood that dates back to ancient Greece, during the reign of Alexander the Great, where bridge wood was soaked in olive oil. The Romans protected their hulls of boats on the planing of wood tar. During the wood preservation Industrial Revolution became a cornerstone of the transformation timber industry. The inventors and scientists such as Bethell, Boucherie, Burnett and Kyan made historic developments in wood preservation, with solutions conservation and processes. commercial pressure treatment was started in the second half of the 1800s with the protection of railroad ties with creosote. Treated wood is used primarily for industrial, agricultural and utility, which is still used, until its use was considerably increased (at least in the U.S.) in 1970 as homeowners began to build decks and backyard projects.
Hazards
Industrial wood pressure treated with an approved preservative pose a limited risk to the public, but must be disposed of properly. On December 31, 2003, the industry of wood treatment was stopped treating wood Residential arsenic and chromium (chromated copper arsenate, CCA). This was a voluntary agreement with the U.S. Environmental Protection Agency. ECP was replaced by Pesticides based on copper, with exceptions for certain industrial uses. Industrial chemicals for wood preservation are not generally available to the public and can be directly require special authorization to import or purchase depending on the product and the jurisdiction where it is used. In most countries, industrial operations conservation of wood are notifiable industrial activities that require licensing by regulatory authorities such as the EPA or its equivalent. Presentation reporting and licensing conditions vary widely depending on the chemicals used and especially the country of use.
Although pesticides are used to treat wood, wood preservation protects natural resources, allowing timber products last longer. Previous bad practices in the industry have left legacies of contaminated soil and water around the wood treatment sites in some cases. However, currently approved industry practices and controls regulators, as applied in Europe, North America, Australia, New Zealand, Japan and elsewhere, the environmental impact of these operations should be minimal.
Wood treated with modern preservatives is generally safe to handle the management given appropriate precautions and personal protective measures. However, treated wood may present certain hazards in some circumstances, such as during combustion, or loose particles of wood dust or other toxic wastes are generated fine or treated wood comes into direct contact with food and agriculture.
Material data sheets and safety guidelines for safe handling are required by law to charge suppliers of wood preservative chemicals and treated wood products. This information should be obtained and reviewed before handling and use of chemicals wood preservatives and treated wood products.
Chemical preservatives
Wood or wood treated with a preservative generally have applied through a vacuum and / or pressure treatment. The preservatives used to pressure treat lumber are classified as pesticides. The wood treatment provides a long-endurance term for organisms that cause spoilage. If implemented correctly, it extends the productive life of wood five to ten times. If left untreated, wood that is exposed to moisture or soil for long periods of time are weakened by several types of fungi, bacteria or insects.
Chemical preservatives can be classified into three Categories: Preservatives waterborne, preservatives transmission oil and light organic solvent preservative (LOSPs). This is discussed more detailed below.
waterborne preservatives
Water is the most common carrier solvent in formulas for conservation because of its availability and low cost. waterborne systems however, have the disadvantage that wood swell, which leads to increased torque, the division and control than other alternatives.
Chromated copper arsenate (CCA)
Main article: chromated copper arsenate
. In the CCA treatment, copper is the main fungicide, arsenic is a secondary fungicide and an insecticide, and chromium is a fixative which also provides ultraviolet (UV) light resistance. Recognized for the greenish tint given to the Wood, CEC is a preservative that was common for many decades.
In the process of pressure treatment, an aqueous solution of CCA is applied using a vacuum and pressure cycle, and the treated wood is stacked for drying (see application process below.) During the process, the mixed oxide reacts to form insoluble compounds, help with problems of leaching. If the process is done correctly, very little preservative remaining on the surface of the wood, and the safety hazard of toxins to minimize the surface.
The process can apply different amounts of preservatives in different pressure levels to protect wood against increasing levels of attack. increasing protection can be applied (in increasing order of attack and treatment) for: exposure to the atmosphere, the implementation on the ground, or inclusion in a marine environment.
In the last decade, concerns were raised that the chemicals can leach from the wood into surrounding soil, resulting in concentrations above natural background levels. One study cited in Forest Products Journal found 1213% of chromated copper arsenate leachate from treated wood buried in compost for a period of 12 months. Once these chemicals have leached from the wood, it is likely that bind to the particles soil, especially clay soils or soils that are more alkaline than neutral. In the United States to the powerful U.S. Consumer Product Safety Commission issued a report in 2002 stating that exposure to arsenic in direct human contact with CCA-treated wood may be higher than previously thought. On January 1, 2004, Protection Agency Environmental (EPA) in a voluntary agreement with industry began to restrict the use of CCA treated wood in residential and commercial construction, with the exception of the Beats and shingles, permanent wood foundations, and some commercial applications. This was an effort to reduce the use of arsenic and improve the safety of the environment, although EPA were careful to note that not concluded that the structures of CCA-treated wood in service that pose an unacceptable risk to the community. The EPA does not calling for the removal or dismantling of the structures of CCA-treated wood.
In Australia, the Australian Pesticides and Veterinary Drugs Authority (NRA) restricted condom use CCA for treating wood used in certain applications since March 2006. CCA can not be used to treat wood used in "close contact human applications such as playground equipment, furniture, floors and residential handrailing. Use low contact residential, commercial and industrial remains unrestricted as well as its use in all other situations. NRA's decision to restrict the use of CCA in Australia was a precautionary measure, although the report found no evidence showing CCA-treated wood poses unreasonable risks to humans under normal conditions of use. As in the U.S. EPA, the NRA did not recommend removal or the elimination of the existing structures of CCA-treated wood.
In Europe, Directive 2003/2/EC restricts the marketing and use of arsenic, including treatment ACC wood. CCA-treated wood is not permitted to be used in residential or domestic. It allows its use in various industrial and public works, such as bridges, fences, road safety, power transmission and telecommunications poles.
Alkaline copper quaternary
Alkaline copper quaternary (ACQ) is a preservative made of copper, a fungicide, and a quaternary ammonium compound (quat), an insecticide which also increases the fungicide treatment is a wood preservative has come into widespread use in the U.S., Europe, Japan and Australia following restrictions on CCA. Its use is governed by national and international standards, which determine the volume of condom use needed to capture the wood specific purpose.
Because it contains high levels of copper, wood treated with ACQ is five times more corrosive to common steel, according to test results. It is necessary to use double-galvanized steel fasteners in wood or stainless ACQ. The use of fasteners that meet or exceed the requirements of ASTM A 153 Class D meets the requirements for added durability bra. U.S. began mandating the use of non-arsenic containing preservatives wood for practically all the wood for residential use in 2004.
Modern versions have been developed to provide a better performance of the above. It noted that the American Wood Protection Association (AWPA) standards require retention ACQ 0.25 pounds per cubic foot (PCF) for above ground use and 0.40 pcf for contact with the ground.
Specialty Chemicals, Inc. (CSI now Viance) received the U.S. Presidential Environmental Protection Agency's Green Chemistry Challenge Award in 2002 for the commercial introduction of ACQ. Its widespread use has removed greater amounts of arsenic and chromium in CCA previously reported.
Copper azole
Copper azole preservative (identified as CA-B, and C-CA under the American Wood Protection Association (AWPA)) is a wood preservative copper-based major has entered in widespread use in the U.S., Europe, Japan and Australia following restrictions on CCA. Its use is governed by national and international standards, which determine the amount of uptake conservation necessary for a specific end use of wood.
Copper azole is similar to ACQ with the difference that condoms dissolved copper is enhanced by a co-azoles biocide rather than quat biocides used in ACQ. The azoles co-produce a copper azole biocide product that is effective at much lower retention than required for equivalent performance ACQ.
It is marketed widely in the context of "Wolmanized" brand in the U.S., and Tanalith "brand in Europe and other international markets.
AWPA Retention CA-B standard is 0.10 pounds per cubic foot (PCF) for applications above ground and 0.21 pcf for ground contact applications. azoles Copper Type C, known as CA-C, has been introduced under the brand Wolmanized. AWPA retention standard for CA-C is 0.06 pounds per cubic foot (PCF) for terrestrial applications above and 15 pcf for applications in contact with the ground.
Copper azole preservative incorporates organic triazoles such as tebuconazole or propiconazole as the co-biocide also used to protect food crops. The general aspect of wood treated with copper azole preservatives is similar to the CEC with a green tint.
Other copper compounds
These include copper HDO (CuHDO), copper chromate, copper citrate, acid copper chromate, ammoniacal copper arsenate of zinc (ACZA). Treatment CuHDO is an alternative to CCA, ACQ and CA used in Europe and in stages of approval from the United States and Canada. ACZA is generally used for marine applications.
technology micronized copper
Particulate (micronized or dispersed) preservative copper technology recently introduced in the U.S. and Europe. In these systems, copper, has been micro-sized particles suspended in the water instead of being dissolved in a chemical reaction as is the case with other products such as ACQ and copper azole for copper. Currently there are two systems of particles of copper production. One system uses a quat biocide system (known as PEM) is a takeoff of ACQ. The other uses a biocidal azoles (known as MCA or CA C-) and is a takeoff of copper azole.
Proponents of the copper particles systems make the case that the particles copper work as well or better than dissolved copper systems as a wood preservative. None of the copper particle systems have been submitted to the protection of American Wood Association (AWPA) for evaluation, so the particle systems should not be used in applications where AWPA standards are required. However, all copper particle systems have been tested and approved for building code requirements by the International Code Council (ICC). Particle systems Copper provides a lighter color than dissolved copper systems such as ACQ or copper azole.
Two sets of particles of copper, a position as MicroPro and the other as Wolmanized through the development of CA-C, have achieved Environmentally Preferable Product certification. The EPP "Certificate was issued by Scientific Certification Systems (SCS), and is based on a comparison of the life cycle impact assessment with an industry standard.
The size of the copper particles used in the products micronized copper ranges from 1 to 700 nm with an average of less than 300 nm. Larger particles do not adequately penetrate the cell walls of wood. It is claimed by defenders micronized copper products copper nanoparticles to escape from the timber easily attaches to organic matter and become biologically inactive.
Borate preservatives
Boric acid, oxides and salts (borates) are effective wood preservatives and are offered under several brands around the world. borate-treated wood is of low toxicity to humans and do not contain copper or other heavy metals. However, unlike most of the preservative compounds borate did not look at the wood and can be easily leached. Therefore should not be used in will be exposed to rain, water or contact with the ground. The recent interest by the low toxicity wood for residential use, together with new regulations restricting certain preservatives of wood, has resulted in a resurgence of use treated wood for the floor beams and borate internal structural elements.
Sodium silicate-based preservatives
Sodium silicate is produced by the fusion of sodium sand or heat both ingredients under pressure. He has been in use since 1800. It can be a deterrent against attacks by insects and possesses lower flame resistant, however, it is easy to wash wood by moisture, forming a layer of scales as in the top of the wood. One company, Wood treatment Technology, LLC, has been found to merge wood with a chemical solution containing sodium silicate with a specific energy level applied timber yields that not only offers multi-layered flakes of wood, or washing as others have done in the past, and provides the processed wood that received a Class A rating fire. His paintings also processed wood and new wood stains do. TTT, LLC, sells these products under the name TimberSIL. Other uses such as fixing of pigments in paints and printing material, and for the preservation of eggs.
Potassium silicate-based preservatives
There are a number of European of "natural" paint manufacturers have developed potassium silicate (waterglass potassium) based preservatives. They often include boron compounds, cellulose, lignin and other plant extracts. They are a surface application with a minimum of impregnation for internal use.
Bifenthrin spray preservatives
In Australia, a water-based preservative bifenthrin has been developed to improve resistance to insects of wood. As this preservative is applied by spraying only the outside enters 2 mm cross-section of wood. Concerns have been raised about whether this thin envelope system that provides protection against insects in the long term, especially when exposed to sunlight for prolonged periods.
fire retardant treated
This treated wood contains a fire retardant chemical that remains stable in environments high temperature and does not increase the aggressiveness of metal hardware in contact with the wood.
transmission oil preservatives
These include pentachlorophenol and creosote. They are toxic, have an unpleasant odor and are not widely used in consumer products.
Coal tar creosote
Creosote is a tar base preservative has been used for telephone poles and railroad ties. Creosote is a wood preservative oldest and was originally derived from a distillate wood. Today almost all Creosote is a product of the distillation of coal tar. Often accumulates in chimneys and can cause a fire hazard. Creosote is regulated as a pesticide and is not usually sold to the general public. It is still used for railroad ties (also called railway sleepers and ties) and utility poles.
Linseed oil
In recent years in Australia and New Zealand, Linseed has been incorporated into the formulas of conservation, endowment as a gift solvent and water repellent to the 'wood. This involves treating the outer 5mm of the cross section of a member of such timber, with preservative permethrin 25:75, leaving the core untreated. Although not as effective as CCA or LOSP methods, treatment of housing are much cheaper because they use much less conservative. The leading manufacturers of preservative or add a blue tint to the treatments on red. Blue timber is for use south of the Tropic of Capricorn and red for other places. The tint also indicates that the wood is treated to the resistance to termites / white ants. There is an ongoing promotional campaign in Australia for this type treatment. Flaxseed oil is used to preserve wooden fences, log cabins and wooden furniture. (Timber as the willow, pine, oak, exc.) Role of Oil Flaxseed as a preservative is believed to be related to its action as a water repellent and drying agent rather than a direct biocidal activity. Several European companies have developed natural treatments oil-based only, no synthetic preservatives such as permethrin is added. Menz Holz OHT using autoclave impregnation with linseed, sunflower and rapeseed oil for 6-8 hours.
Other emulsions
Light organic solvent preservatives (LOSP)
This kind of wood treatments alcohol use White as a solvent carrier to deliver in a wood preservative compounds. synthetic pyrethroids are used as an insecticide such as permethrin, deltamethrin and bifenthrin. In Australia and New Zealand, the most common formulations for use as an insecticide permethrin and tebuconazole Propaconazole and fungicides. While still use a chemical preservative, This formulation does not contain heavy metal compounds.
With the introduction of stringent volatile organic compound (VOC) laws in the European Union LOSPs disadvantages due to high costs and long processing times associated with vapor recovery systems. LOSPs been emulsified in water-based solvents. While this reduces VOC emissions significantly, wood swells during the treatment, eliminating many of the advantages of LOSP formulations.
New technologies
Wood acetylation
Chemical modification of wood at the molecular level has been used to improve their performance properties. Many chemical reaction systems for the modification of wood, especially those using different types of anhydrides have been published, however, the reaction of wood with acetic anhydride has been the most studied.
The physical properties of any material are determined by their chemical structure. The wood contains an abundance of chemical groups called "free hydroxyl. Songs hydroxyl groups readily absorb and release water according to changes in climatic conditions to which are exposed. This is the main reason why the size of timber stability is affected by swelling and contraction. It is also believed that digestion timber by the enzymes start at the sites of hydroxyl free – which is a major reason why the wood is likely to decay.
Acetylation effectively changes free hydroxyl groups in the wood in acetyl groups. This is done by the reaction of wood with acetic anhydride, which comes from acetic acid (known as vinegar when diluted form). When free hydroxyl groups are transformed into acetyl groups, the ability of wood to absorb water is greatly reduced, making the wood more dimensionally stable and, because it is not digestible, extremely durable. In general, softwoods naturally have an acetyl content from 0.5 to 1.5% and the most stable woods between 2 to 4.5%. Wood acetylation is well beyond these levels with corresponding benefits. These include a extended life coatings due to the acetylated wood as a more stable substrate for paints and clear coats. Acetylated wood is not toxic and does not have environmental issues associated with traditional conservation techniques.
The acetylation of wood was first held in Germany in 1928 by Fuchs. In 1946, Tarkow, Stamm and Erickson first described the use of wood acetylation to stabilize wood from swelling in water. Since 1940, many laboratories around the world have studied the acetylation of many different types of forest and agricultural resources.
Despite the tremendous amount of research on changes wood chemistry, and, more specifically, the acetylation of wood, the marketing was not easy. The first patent on the acetylation of wood was by Suida in Austria in 1930. Later, in 1947, Stamm and Tarkow filed a patent on the acetylation of wood and boards with pyridine as catalyst. In 1961, the Koppers Company issued a technical bulletin on the acetylation of wood without the use of catalysis, but with an organic cosolvent in 1977 in Russia Otlesnov Nikitina and was about marketing, but the process was suspended presumably because the cost can not be achieved. In 2007 a company based in London, with production facilities in the Netherlands, reached the profitable marketing and began mass production of acetylated wood.
Natural preservatives
Naturally rot resistant wood
These species are resistant to decay in its natural state, due to high levels of organic chemicals called "extracts", mainly polyphenols. Excerpts are chemicals that are deposited in the heartwood of some species of trees and transform wood sapwood and heartwood. Huon Pine (Lagarostrobos) Merbau (bijuga Intsia), Ironbark (Eucalyptus spp.) TTARA (Podocarpus totara), puriri (Vitex lucens), Kauri (Agathis australis), and many cypress trees, as Coast Redwood (Sequoia sempervirens) and western red cedar (Thuja plicata), fall into this category. However, many of these species tend to be prohibitively expensive for general construction applications.
Huon pine was used for the hulls of ships in the 19th century, but over-harvesting and Huon Pine extremely slow growth rate makes this a special wood now. Huon pine is so rot resistant that fallen trees many years ago, continue to be of great commercial value.
Merbau timber decking remains a popular and has a long life above ground applications, but is recorded in an unsustainable manner (see illegal logging) and is too hard and brittle for general use. Ironbark is a good choice when available. It is harvested from both middle-aged and plantations in Australia and is highly resistant to rot and termites. It is most commonly used for fence posts and house stumps.
Eastern Red Cedar (Juniperus virginiana) and Black against locust (Robinia pseudoacacia) have long been used for fence posts resistant to rot and the rails in eastern U.S., Black locust is also planted in modern times in Europe. Redwood Coast is commonly used for similar applications in the western United States.
Puriri TTARA and were widely used in New Zealand Europe during the colonial era when native forests were "mined", even as fence posts many of whom still work. TTARA was used by to build large Maori waka (canoe). Today is special woods because of their scarcity, declining stocks are making available degree Good gardening.
Kauri is an excellent wood for the construction of the hulls and decks of ships. He too is now a specialty timber and logs old (more than 3000 years) that have been extracted from the marshes are used by wood turners and furniture makers.
Be aware that the durability natural or rot and insect resistance of wood species is always based on the heartwood (or truewood). The sapwood of all species of wood must be considered as not sustainable without preservative treatment.
Tung oil
Tung oil has been known for hundreds of years in China, where it is used as a preservative for wooden ships. Oil penetrates the wood, then hardens to form a hydrophobic layer waterproof up to 5 mm into the wood. As conservation land is effective for exterior work above and below, but thin layer makes it less useful in practice. Not available as a pressure treatment. Some manufacturers recommend tung oil as a stabilizer for the CCA.
Heat treatments
There is ongoing research as to whether heat treatments can be used to make the wood more durable. By heating the wood at a temperature determined, it may be possible that the wood fiber of less palatable to insects. Although unlikely to be as effective as chemical preservatives, anecdotal evidence suggests Some consumers prefer non-chemical methods of wood preservation.
Heat treatment can also improve the properties of wood with respect to water: lower the equilibrium moisture content, less moisture deflection and resistance to weathering. It is weatherproof to allow their use without protection, on the facades or kitchen tables, where you expect to get wet.
There are three similar heat treatments in Europe: Retiwood, developed in France, Thermowood, developed in Finland by VTT, and Platowood developed in the Netherlands. These processes of wood treated in autoclave, under pressure and heat, along with nitrogen or steam of water to control the drying process treatment stages from 24 to 48 hours at temperatures from 180 to 230C depending on the timber. These processes of increased durability, dimensional stability and hardness of treated wood at least one class, however, the treated wood is dark in color, and there are changes in certain mechanical properties: specifically, the modulus increases to 10%, and modulus of rupture was reduced by 5% to 20%, so that treated timber requires removal of nails avoid splitting the wood. Some of these processes result in a lower impact than others in their mechanical effects on the treated wood. Wood treated with this process is often used for coating or covering, flooring, furniture and windows.
Sludge treatment
Wood and bamboo can be buried in the mud to help protect it from insects and decay. This practice is widely used in Vietnam to build houses consisting of a wooden frame structure, a structure of bamboo roof bamboo with mud mixed with rice straw for the walls. While the wood in contact with the ground in general, decay more rapidly than wood in contact with the soil, may predominantly clay soils prevalent in Vietnam provides a degree of mechanical protection against insect attack which compensates the rapid pace decomposition.
In addition, since wood is subject to bacterial decomposition under conditions of temperature and specific ranges of moisture content, submerging in water saturated with mud can slow down the decomposition by saturation of the inner cells of the wood beyond the range of moisture decay.
Application processes
Introduction and History
Probably the first attempts to protect wood against decay and insect attack was preservatives in brush or rub the surface of treated wood. Through trial and error the most effective preservatives and implementation of processes that gradually determined. In the Industrial Revolution, demands for such things as telegraph poles and railroad ties helped fuel an explosion of new techniques that emerged in the 19th century. The largest increase in inventions took place between 1830 and 1840, when Bethell, Boucherie, Burnett and Kyan were doing wood preservatives in history. Since then, many processes have been introduced or improved existing processes. The aim of the modern wood preserving days is to ensure deep penetration and uniform with a reasonable cost, without compromising the environment. Wider application processes today are those that use artificial pressure through which many forests are still an effective treatment, but several species (such as fir, Douglas fir, larch, spruce and pine) are very resistant to impregnation. With the use of incision, treatment of these forests has had some success, but with a higher cost and results not always satisfactory. You can split the wood preservatives in any broadly methods of process without pressure or pressure processes.
No pressure processes
There are many processes without pressure treating wood which vary mainly in its proceedings. The most common of these treatments include application of the condom by brushing or spraying, dipping, soaking, soaking or through a hot bath and cold. There are a variety of additional methods involving the carbonization, the application of preservatives in drilling, the diffusion processes and the sap of displacement.
Brush and spray treatments
Brushing condom is a method long practiced and often used today carpentry workshops. Through the evolution of technology is also possible to spray preservative on the wood surface. Some of the liquid is drawn in wood as a result of capillary action, but this penetration is negligible and not suitable for long-term weather. By using the method of spraying, tar creosote coal, oil and solutions by water-borne salts (so far) can also be applied. A thorough brush or spray treatment with coal tar creosote can add 1-3 years to the life of poles or posts. Two or more coats provide better protection than one, but the layers Successive should not be applied until the previous layer has dried or soaked into the wood. The wood must be experienced before treatment.
Immersion
Immersion is simply to immerse the wood in a bath of creosote or other preservatives for a few seconds or minutes. insights similar to that of brushing and spraying processes have been achieved. It has the advantage of minimizing labor. It requires more equipment and larger quantities of preservatives and is not suitable for the treatment of small lots of wood. In general, the immersion process is useful in the treatment of window sashes and doors. Protective treatment with the copper salt is no longer allowed with this method.
Soaking
In this process the wood is submerged in a tank mixture of water-conservative, and allowed to soak for a longer period of time (Several days or weeks). This process was developed in the 19th century by John Kyan. The depth and retention depends on factors such as species, wood moisture conservation and enjoyment of life. Most absorption takes place during the first two or three days, but continue at a slower pace during a period undefined. As a result, the longer the wood can be left in the solution, the best treatment you receive. When the wood treatment experienced both water and salt to penetrate into the wood preservative, which is necessary to season the wood a second time. Posts and poles can be treated directly in the endangered areas extinction, but must be treated at least 30 cm (0.98 feet) above ground level future.
The depth obtained during regular soaking varies 5 to 10 mm (1 / 8 to 1 / 3 inches) to 30 mm (1.2 inches) of pine sap. Due to the low absorption power of the solution should be somewhat stronger than in the process of pressure, around 5% for dry wood and 10% of green wood (because the concentration slowly decreases as the chemicals spread on wood). The power of the solution should be monitored continuously and, if necessary, be corrected with the salt additive. After the wood is removed from the treatment tank, the chemical continue to expand into the wood if you have sufficient moisture content. The wood must be weighed and stacked so that the solution can reach all surfaces. (Adhesive materials must be placed between each layer sawn board.) This process is minimal use despite its former popularity in continental Europe and Great Britain.
Kyanizing
Named after John Howard Kyan, who patented the process in England in 1832, consists of Kyanizing soak the wood in a chloride 0.67% mercury preservative solution.
Cold and hot bath
CA Seeley patented this process reaches a dip treatment of dry wood in bathrooms successive hot and cold preservatives. During the hot baths, the air expands in the woods. When the timber is changed to the cold bath (also condoms be changed) a partial vacuum is created within the lumen of the cells, making the preservative to be prepared in the wood. Some penetration occurs during hot baths, but most occurs during the cold baths. This cycle is repeated with a significant time reduction in comparison with other processes soaking. Every bathroom can last 4-8 hours or sometimes longer. The temperature of the preservative in the water bath should be between 60-110 C (140-230 F) and 30 40 ° C (86-104 º F) in the cold bath (depending treespecies preservative). The mean penetration depth achieved with this process ranges from 30 mm to 50 mm (1 to 12 / 3 inches). Both preservative oils and water-soluble salts can be used with this treatment. Because of the longer treatment periods, this method finds little use in the industry of commercial wood preservation today.
Pressure processes
Pressure processes are the most permanent around today in preserving the life of the wood. Pressure processes are those in which treatment takes place in closed bottle with applied pressure and / or vacuum. These processes have a number of advantages over the methods of non-pressure. In most cases, a deeper penetration and more uniform greater absorption of conservation is achieved. Another advantage is that processing conditions can be controlled so that the retention and penetration can be varied. These pressure processes can be adapted to mass production. The high initial costs for equipment and energy costs are the major drawbacks. These methods treatment are used to protect links, posts and structural beams and find use throughout the world today. Different pressure processes are used today days differ in details, but the method is general in all cases the same. The treatment takes place in the bottle. The timber was loaded onto special rail cars, the IUGG, and cylinder. These cylinders are placed under pressure often with the addition of a higher temperature. As a final treatment, the vacuum is often used to Conservatives remove excess. These cycles can be repeated to achieve better penetration.
LOSP treatments often use a vacuum impregnation process. Namely possible due to the lower viscosity of the company used white spirit.
Full-cell process
In the entire process of cells, the intention is to maintain the greatest amount of liquid absorbed by the wood during the pressure as possible, thus leaving the maximum concentration of preservatives in the treated area. In general, solutions of salts from water preservatives are used with this process, but it is also possible to impregnate the wood with oil. Retention desired by changing the strength of the solution. William Burnett patented this development in 1838 of Full-cell impregnation with aqueous solutions. The patent covers the use of chloride water-based zinc, also known as Burnettizing. Cell entire process oils was patented in 1838 by John Bethell. His patent describes the production of tar and oils in the wood by applying pressure in closed cylinders. This process is still used today with some improvements.
Fluctuation of process pressure
Contrary to the full Tatic Cell and Empty Cell "process, the fluctuation of the process is a process ynamic. Through this process the pressure inside the cylinder impregnation of the changes between the pressure and vacuum in seconds. There have been inconsistent claims that through this process, it is possible to reverse the pit closure by Spruce. However, the best results have been achieved with this process do not exceed Spruce deeper penetration of 10 mm (1/3in.). Specialized equipment is necessary and therefore higher investment costs are.
Boucherie process
Developed by Dr. Boucherie of France in 1838, this approach was to put a bag or container of preservative solution to a foot or a freshly cut tree with bark, branches, and leaves still attached, so that the injection fluid in the sap of the current. Through transpiration of moisture from the leaves is extracted condom upward through the sapwood of the tree trunk.
The process of amending Boucherie involves placing freshly cut, unpeeled wood on skates in decline, with the stump slightly elevated, then sealing lids covering or drilling a series of holes in the ends, and insertion of a copper sulfate solution or other preservative in water-borne caps or holes of a container high. Preservative oils tend not to penetrate satisfactorily by this method. The hydrostatic pressure forces fluid along and through conservation of the sapwood, thus pushing the sap at the other end of the wood. After a few days, the sapwood is completely impregnated, the penetration unfortunately has little or nothing out in the heartwood. Only the green wood can be treated this way. This process has found considerable use to impregnate poles and trees also higher in Europe and North America, and has experienced a resurgence of the use of bamboo to impregnate in countries like Costa Rica, Bangladesh, India and the state of Hawaii.
High pressure sap displacement system
Developed in the Philippines, this method (abbreviated HPSD) consists of a cylinder pressure cap from a 3 mm thick steel sweet secured with 8 sets of screws, a 2-HP diesel engine, and a pressure regulator with capacity of 1.4 kg / m 2 14. The cover is placed over the stump of a pole, tree conservation or bamboo and is bound to the timber with the pressure of the engine.
The incision
First tested and patented by Kolossvary, Haltenberger and Berdenich of Austria in 1911 and 1912 (U.S. 1,012,207 and 1,018,624 palmaditas.) with some improvements in OPM Goss, DW Edwards and JH Mansfield, among others, this process consists of making shallow holes, slit, as in the penetration material surfaces to be treated, so that more and more uniform preventive measures are available. The term "incision" incidere perforation comes from America, a compound within and caedere (cut). This process can also be used to ensure long life of food through its packaging. The air exchange can be guaranteed with laser cut holes in the package are so fine that moisture can not escape. The incisions made in the cut material are generally parallel to the grain of the wood. This process is common in North America (1950), where Douglas fir and the butts of their products poles of various species are prepared before treatment. It is most useful for logs that are resistant to penetration by hand, but allow the transport of conservation along the grain. In the region in which it is produced, it is common practice to influence all Douglas fir lumber 3 inches or more thick before treatment.
Unfortunately, the impregnation of Spruce, the most important structural timber large areas in Europe has shown that unsatisfactory treatment depths have been achieved impregnation. The maximum penetration of 2 mm (1 / 12 inch) is not sufficient to protect the wood in the gradient positions. The machines today incision days consist essentially of four rotating cylinders with teeth or needles or lasers that burn the incisions in the wood. Preservatives can be spread over grain up to 20 mm (5 / 6 inches) in the radial and up to 2 mm (1 / 12 in.) tangential and radial direction.
In North America, where small dimensions wood are common, deep incision of 4-6 mm (1 / 6 to 1 / 4 inches) have become standard. In Europe, where large is widespread, the depth of incision of 10-12 mm (1 / 2 inches) are required. The incisions are visible and often seen as wooden error. Laser incisions are significantly lower than those of rays or needles. The costs for each type of process is about speaking and conventional all-incision of 0.50 m laser incision of 3.60 meters incision and the needle 1.00 m. (These figures originate from the year 1998 and may vary from the prices of our days.)
Microwaving
An alternative method to increase the permeability of wood involves the use of microwave technology. Ongoing research in this area is carried out by the Centre Cooperative Research of the University of Melbourne, Australia.
See also
Sodium silicate # timber treatment
Koppers
References
^ Richardson, BA Wood preservation. Landcaster: construction, 1978.
^ USEPA web http://www.epa.gov/oppad001/reregistration/cca/sealant_qa.htm
^ Http: / / www.apvma.gov.au/
^ Http://www.apvma.gov.au/chemrev/arsenic.shtml
^ (Rowell et al., 2008)
^ Roger M. Rowell, Kattenbroek Bert, Ratering Peter Ferry Bongers, Francesco Leichen, and Hal Stebbins, roduction of dimensional stability and decay-resistant wood-based components acetylation, submitted at the International Conference on the durability of building materials and components. Istanbul, Turkey, 2008
^ Goldstein et al. 1961, Dreher et al. 1964
^ Spencer, Sally. "Accoya of the blocks." Timber Trades Journal May 31, 2007. <http://www.ttjonline.com/story.asp?storycode=49809>.
Links External
No CCA wood preservatives
No CCA wood preservatives: Selected Resource Guide – The National Pesticide Information
Arsenate
Case Studies in Environmental Medicine – Arsenic Toxicity
CPSC Test coatings to reduce arsenic emissions from pressure-treated wood
Borate
Borate treated wood in modern applications
Analysis of borate as an insecticide in Madera
Sodium silicate
Brief loss of the Columbia Encyclopedia
The mineral Albite
Others
FAQ Forest Products Laboratory U.S. Forest Service
U.S. Information Environmental Protection Agency
The American Wood Protection Association (AWPA, formerly the American Association of Wood Preservatives)
Username: Baruns7/Wooden Facade Project
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