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Engineered wood, also called composite wood, man-made wood, or manufactured board; includes a range of derivative wood products which are manufactured by binding or fixing the strands, particles, fibers, or veneers or boards of wood, together with adhesives, or other methods of fixation〔http://www.dataholz.com/cgi-bin/WebObjects/dataholz.woa/wa/baustoff?baustoff=Brettsperrholz&language=en〕 to form composite materials. These products are engineered to precise design specifications which are tested to meet national or international standards. Engineered wood products are used in a variety of applications, from home construction to commercial buildings to industrial products.〔(A Guide To Engineered Wood Products, Form C800 ). Apawood.org. Retrieved on 2012-02-10.〕 The products can be used for joists and beams that replace steel in many building projects.〔(Naturally:wood Engineered wood ). Naturallywood.com. Retrieved on 2012-02-10.〕 Typically, engineered wood products are made from the same hardwoods and softwoods used to manufacture lumber. Sawmill scraps and other wood waste can be used for engineered wood composed of wood particles or fibers, but whole logs are usually used for veneers, such as plywood, MDF or particle board. Some engineered wood products, like oriented strand board (OSB), can use trees from the poplar family, a common but non-structural species. Alternatively, it is also possible to manufacture similar engineered bamboo from bamboo; and similar engineered cellulosic products from other lignin-containing materials such as rye straw, wheat straw, rice straw, hemp stalks, kenaf stalks, or sugar cane residue, in which case they contain no actual wood but rather vegetable fibers. Flat pack furniture is typically made out of man-made wood due to its low manufacturing costs and its low weight, making it easy to transport. ==Types of products== * Plywood, wood structural panel, is sometimes called the original engineered wood product.〔("Milestones in the History of Plywood" ), APA – The Engineered Wood Association. Accessed October 22, 2007.〕 Plywood is manufactured from sheets of cross-laminated veneer and bonded under heat and pressure with durable, moisture-resistant adhesives. By alternating the grain direction of the veneers from layer to layer, or “cross-orienting”, panel strength and stiffness in both directions are maximized. Other structural wood panels include oriented strand board and structural composite panels.〔(APA A glossary of Engineered Wood Terms ). Apawood.org. Retrieved on 2012-02-10.〕 * Medium-density fibreboard, is made by breaking down hardwood or softwood residuals into wood fibres, combining it with wax and a resin binder, and forming panels by applying high temperature and pressure. 〔Corky Binggeli. (2013), "Materials for Interior Environments".〕 * Oriented strand board (OSB) is a wood structural panel manufactured from rectangular-shaped strands of wood that are oriented lengthwise and then arranged in layers, laid up into mats, and bonded together with moisture-resistant, heat-cured adhesives. The individual layers are cross-oriented to provide strength and stiffness to the panel. Produced in huge, continuous mats, OSB is a solid panel product of consistent quality with no laps, gaps or voids.〔(Oriented Strand Board Product Guide, Form W410 ). Apawood.org. Retrieved on 2012-02-10.〕 * Glued laminated timber (glulam) is composed of several layers of dimensional timber glued together with moisture-resistant adhesives, creating a large, strong, structural member that can be used as vertical columns or horizontal beams. Glulam can also be produced in curved shapes, offering extensive design flexibility. * Laminated veneer lumber (LVL) is produced by bonding thin wood veneers together in a large billet. The grain of all veneers in the LVL billet is parallel to the long direction. The resulting product features enhanced mechanical properties and dimensional stability that offer a broader range in product width, depth and length than conventional lumber. LVL is a member of the structural composite lumber (SCL) family of engineered wood products that are commonly used in the same structural applications as conventional sawn lumber and timber, including rafters, headers, beams, joists, rim boards, studs and columns.〔(APA – The Engineered Wood Association ). Apawood.org. Retrieved on 2012-02-10.〕 *Cross-Laminated Timber (CLT) is a versatile multi-layered panel made of lumber. Each layer of boards is placed cross-wise to adjacent layers for increased rigidity and strength. CLT can be used for long spans and all assemblies, e.g. floors, walls or roofs.〔(FPInnovations Cross-Laminated Timber: A Primer ). (PDF) . Retrieved on 2012-02-10.〕 CLT has the advantage of faster construction times as the panels are manufactured and finished off site and supplied ready to fit and screw together as a flat pack assembly project.〔()〕 * Parallel strand lumber (PSL) consists of long veneer strands laid in parallel formation and bonded together with an adhesive to form the finished structural section. A strong, consistent material, it has a high load carrying ability and is resistant to seasoning stresses so it is well suited for use as beams and columns for post and beam construction, and for beams, headers, and lintels for light framing construction.〔 PSL is a member of the structural composite lumber (SCL) family of engineered wood products.〔(APA Structural Composite Lumber: A Practical Alternative ). Apawood.org. Retrieved on 2012-02-10.〕 * Laminated strand lumber (LSL) and oriented strand lumber (OSL) are manufactured from flaked wood strands that have a high length-to-thickness ratio. Combined with an adhesive, the strands are oriented and formed into a large mat or billet and pressed. LSL and OSL offer good fastener-holding strength and mechanical connector performance and are commonly used in a variety of applications, such as beams, headers, studs, rim boards, and millwork components. These products are members of the structural composite lumber (SCL) family of engineered wood products.〔 LSL is manufactured from relatively short strands—typically about 1 foot long—compared to the 2 foot to 8 foot long strands used in PSL.〔 * Finger-jointed lumber is made up of short pieces of wood combined to form longer lengths and is used in doorjambs, mouldings and studs. It is also produced in long lengths and wide dimensions for floors. * I-joists and wood I-beams are ""-shaped structural members designed for use in floor and roof construction. An I-joist consists of top and bottom flanges of various widths united with webs of various depths. The flanges resist common bending stresses, and the web provides shear performance.〔(APA – The Engineered Wood Association ). Apawood.org. Retrieved on 2012-02-10.〕 I-joists are designed to carry heavy loads over long distances while using less lumber than a dimensional solid wood joist of a size necessary to do the same task (). As of 2005, approximately half of all wood light framed floors were framed using I-joists (). * Roof trusses and floor trusses are structural frames relying on a triangular arrangement of webs and chords to transfer loads to reaction points. For a given load, long wood trusses built from smaller pieces of lumber require less raw material and make it easier for AC contractors, plumbers, and electricians to do their work, compared to the long 2x10s and 2x12s traditionally used as rafters and floor joists.〔 Engineered wood products are used in a variety of ways, often in applications similar to solid wood products. Engineered wood products may be preferred over solid wood in some applications due to certain comparative advantages: * Because engineered wood is man-made, it can be designed to meet application-specific performance requirements. * Engineered wood products are versatile and available in a wide variety of thicknesses, sizes, grades, and exposure durability classifications, making the products ideal for use in unlimited construction, industrial and home project application.〔(Wood University ). Wood University. Retrieved on 2012-02-10.〕 * Engineered wood products are designed and manufactured to maximize the natural strength and stiffness characteristics of wood. The products are very stable and some offer greater structural strength than typical wood building materials.〔(Naturally:wood engineered wood ). Naturallywood.com. Retrieved on 2012-02-10.〕 Eight-storey Stadthaus, an apartment complex in London, England, was made with cross-laminated timber panels and is the tallest habitable timber building in the world.〔(Stradthaus, London, England )〕 *Glued laminated timber (glulam) has greater strength and stiffness than comparable dimensional lumber and, pound for pound, is stronger than steel.〔 Glulam products are also a better environmental choice than steel because they have less embodied energy.〔(FPInnovations A Synthesis of Research on Wood Products and Greenhouse Gas Impacts \P. 61 ). (PDF) . Retrieved on 2012-02-10.〕〔 * Some engineered wood products offer more design options without sacrificing structural requirements.〔(Hardwood Flooring PDX ). Engineered Wood vs Real Hardwood〕 * Engineered wood panels are easy to work with using ordinary tools and basic skills. They can be cut, drilled, routed, jointed, glued, and fastened. Plywood can be bent to form curved surfaces without loss of strength. And large panel size speeds construction by reducing the number of pieces to be handled and installed.〔 * Engineered wood products provide the natural warmth and beauty of wood. Many products are available in a variety of surface textures and treatments for nearly every aesthetic taste, from rustic to elegant. The products can be easily and beautifully finished with paints, stains, and varnishes.〔 * Engineered wood products make more efficient use of wood. They can be made from small pieces of wood, wood that has defects or underutilized species.〔(APA Engineered Wood and the Environment: Facts and Figures ). Apawood.org. Retrieved on 2012-02-10.〕 * Wooden trusses are competitive in many roof and floor applications, and their high strength-to-weight ratios permit long spans offering flexibility in floor layouts.〔(Naturally:wood Engineered wood ). Naturallywood.com. Retrieved on 2012-02-10.〕 * Sustainable design advocates recommend using engineered wood, which can be produced from relatively small trees, rather than large pieces of solid dimensional lumber, which requires cutting a large tree.〔 Mary McLeod et al. ("Guide to the single-family home rating" ). Austin Energy Green Building. p. 31-32. 〕 Engineered wood products also have some disadvantages: * Some products may burn more quickly than solid lumber. * They require more primary energy for their manufacture than solid lumber. * The adhesives used in some products may be toxic. A concern with some resins is the release of formaldehyde in the finished product, often seen with urea-formaldehyde bonded products. * Cutting and otherwise working with some products can expose workers to toxic compounds. * Some engineered wood products, such as those specified for interior use, may be weaker and more prone to humidity-induced warping than equivalent solid woods. Most particle and fiber-based boards are not appropriate for outdoor use because they readily soak up water. Plywood and OSB typically have a density of 35 to 40 pounds per cubic foot (550 to 650 kg per cubic meter). For example, 3/8" plywood sheathing or OSB sheathing typically has a weight of 1.0 to 1.2 pounds per square foot.〔 ("Weights of building materials -- pounds per square foot (PSF)" ). Boise Cascade: Engineered wood products. 2009. 〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「engineered wood」の詳細全文を読む スポンサード リンク
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