95-458: Shipwrights Way , so called because it traces in a fanciful way the route that might have been taken by timber from forest to warship , is a 50-mile long-distance footpath through Hampshire , England from Alice Holt Forest to Portsmouth : it passes through Bordon , Liphook , Liss , Petersfield , Queen Elizabeth Country Park , Staunton Country Park , Havant and Hayling Island en route. This Hampshire location article
190-424: A glass with no true melting point, can be used as a glass fiber for fiberglass but has the drawback that it must be worked at very high temperatures. In order to lower the necessary work temperature, other materials are introduced as "fluxing agents" (i.e., components to lower the melting point). Ordinary A-glass ("A" for "alkali-lime") or soda lime glass, crushed and ready to be remelted, as so-called cullet glass,
285-647: A rip saw is the most common method, because sawing allows logs of lower quality, with irregular grain and large knots, to be used and is more economical. There are various types of sawing: Dimensional lumber is lumber that is cut to standardized width and depth, often specified in millimetres or inches (but see below for information on nominal dimensions vs. actual dimensions). Carpenters extensively use dimensional lumber in framing wooden buildings. Common sizes include 2×4 (pictured) (also two-by-four and other variants, such as four-by-two in Australia, New Zealand, and
380-455: A "class 1 flame spread rating of 25 or less, when tested in accordance with ASTM standard E 84," which means it burns more slowly than almost all treated wood lumber. A timber mark is a code beaten on to cut wood by a specially made hammer to show the logging licence. The basic understanding of lumber, or "sawn planks", came about in North America in the seventeenth century. Lumber is
475-400: A 1-inch-thick (25 mm) board, 8/4 (eight quarter) is a 2-inch-thick (51 mm) board, etc. This "quarter" system is rarely used for softwood lumber; although softwood decking is sometimes sold as 5/4, even though it is actually one inch thick (from milling 1 ⁄ 8 in or 3.2 mm off each side in a motorized planing step of production). The "quarter" system of reference is
570-534: A 10-foot-long (3.0 m) 2×4 ( 1 + 1 ⁄ 2 by 3 + 1 ⁄ 2 in or 38 by 89 mm) into two 1×4s ( 3 ⁄ 4 by 3 + 1 ⁄ 2 in or 19 by 89 mm) of the same length is considered re-sawing. Structural lumber may also be produced from recycled plastic and new plastic stock. Its introduction has been strongly opposed by the forestry industry. Blending fiberglass in plastic lumber enhances its strength, durability, and fire resistance. Plastic fiberglass structural lumber can have
665-539: A 5 mg/m total limit. As of 2001, the Hazardous Substances Ordinance in Germany dictates a maximum occupational exposure limit of 86 mg/m . In certain concentrations, a potentially explosive mixture may occur. Further manufacture of GRP components (grinding, cutting, sawing) creates fine dust and chips containing glass filaments, as well as tacky dust, in quantities high enough to affect health and
760-602: A November, 2011 modification to its Proposition 65 listing to include only "Glass wool fibers (inhalable and biopersistent)." Therefore a cancer warning label for biosoluble fiber glass home and building insulation is no longer required under federal or California law. As of 2012, the North American Insulation Manufacturers Association stated that fiberglass is safe to manufacture, install and use when recommended work practices are followed to reduce temporary mechanical irritation. As of 2012,
855-439: A binder. It is typically processed using the hand lay-up technique, where sheets of material are placed on a mold and brushed with resin. Because the binder dissolves in resin, the material easily conforms to different shapes when wetted out. After the resin cures, the hardened product can be taken from the mold and finished. Using chopped strand mat gives the fiberglass isotropic in-plane material properties. A coating or primer
950-417: A chemical solution. The individual filaments are now bundled in large numbers to provide a roving . The diameter of the filaments, and the number of filaments in the roving, determine its weight , typically expressed in one of two measurement systems: These rovings are then either used directly in a composite application such as pultrusion , filament winding (pipe), gun roving (where an automated gun chops
1045-444: A chopped strand mat, or woven into glass cloth . The plastic matrix may be a thermoset polymer matrix —most often based on thermosetting polymers such as epoxy , polyester resin , or vinyl ester resin —or a thermoplastic . Cheaper and more flexible than carbon fiber , it is stronger than many metals by weight, non- magnetic , non- conductive , transparent to electromagnetic radiation , can be molded into complex shapes, and
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#17328514059441140-401: A combined stream from a chopper gun. Workers roll out the spray-up to compact the laminate. Wood, foam or other core material may then be added, and a secondary spray-up layer imbeds the core between the laminates. The part is then cured, cooled, and removed from the reusable mold. Pultrusion is a manufacturing method used to make strong, lightweight composite materials. In pultrusion, material
1235-467: A framer much time, because they are pre-cut by the manufacturer for use in 8-, 9-, and 10-foot ceiling applications, which means the manufacturer has removed a few inches or centimetres of the piece to allow for the sill plate and the double top plate with no additional sizing necessary. In the Americas, two-bys (2×4s, 2×6s, 2×8s, 2×10s, and 2×12s), named for traditional board thickness in inches, along with
1330-430: A liner to prevent gas leakage or as a barrier to protect the composite from the fluid to be stored. Filament winding is well suited to automation, and there are many applications, such as pipe and small pressure vessels that are wound and cured without any human intervention. The controlled variables for winding are fiber type, resin content, wind angle, tow or bandwidth and thickness of the fiber bundle. The angle at which
1425-913: A post-exposure recovery period." Historic reviews of the epidemiology studies had been conducted by Harvard's Medical and Public Health Schools in 1995, the National Academy of Sciences in 2000, the Agency for Toxic Substances and Disease Registry ("ATSDR") in 2004, and the National Toxicology Program in 2011. which reached the same conclusion as IARC that there is no evidence of increased risk from occupational exposure to glass wool fibers. Genetic and toxic effects are exerted through production of reactive oxygen species , which can damage DNA, and cause chromosomal aberrations , nuclear abnormalities, mutations, gene amplification in proto-oncogenes , and cell transformation in mammalian cells. There
1520-399: A relatively small set of specified lengths; in all cases hardwoods are sold to the consumer by the board-foot (144 cubic inches or 2,360 cubic centimetres), whereas that measure is not used for softwoods at the retailer (to the cognizance of the buyer). Also in North America, hardwood lumber is commonly sold in a "quarter" system, when referring to thickness; 4/4 (four quarter) refers to
1615-415: A thermoplastic inner tank which acts as a preform during construction. Much more reliable tanks are made using woven mat or filament wound fiber, with the fiber orientation at right angles to the hoop stress imposed in the sidewall by the contents. Such tanks tend to be used for chemical storage because the plastic liner (often polypropylene ) is resistant to a wide range of corrosive chemicals. Fiberglass
1710-449: A timber is referred to as one "timber" (材), and the dimensions of other structural components were quoted in multiples of "timber"; thus, as the width of the actual timber varied, the dimensions of other components were easily calculated, without resorting to specific figures for each scale. The dimensions of timbers in similar applications show a gradual diminution from the Sui dynasty (580–618) to
1805-443: A traditional North American lumber industry nomenclature used specifically to indicate the thickness of rough sawn hardwood lumber. In rough-sawn lumber it immediately clarifies that the lumber is not yet milled, avoiding confusion with milled dimension lumber which is measured as actual thickness after machining. Examples – 3 ⁄ 4 -inch, 19 mm, or 1x. In recent years architects, designers, and builders have begun to use
1900-426: A unit of dimensional lumber is limited by the height and girth of the tree it is milled from. In general the maximum length is 24 ft (7.32 m). Engineered wood products, manufactured by binding the strands, particles, fibers, or veneers of wood, together with adhesives, to form composite materials, offer more flexibility and greater structural strength than typical wood building materials. Pre-cut studs save
1995-489: Is a stub . You can help Misplaced Pages by expanding it . This British trail or long-distance path-related article is a stub . You can help Misplaced Pages by expanding it . Timber Lumber is wood that has been processed into uniform and useful sizes (dimensional lumber), including beams and planks or boards . Lumber is mainly used for construction framing , as well as finishing (floors, wall panels , window frames ). Lumber has many uses beyond home building. Lumber
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#17328514059442090-427: Is a fabrication technique mainly used for manufacturing open (cylinders) or closed-end structures (pressure vessels or tanks). The process involves winding filaments under tension over a male mandrel. The mandrel rotates while a wind eye on a carriage moves horizontally, laying down fibers in the desired pattern. The most common filaments are carbon or glass fiber and are coated with synthetic resin as they are wound. Once
2185-545: Is also indirect, inflammation-driven genotoxicity through reactive oxygen species by inflammatory cells . The longer and thinner as well as the more durable (biopersistent) fibers were, the more potent they were in damage. In the US, fine mineral fiber emissions have been regulated by the EPA , but respirable fibers (“particulates not otherwise regulated”) are regulated by Occupational Safety and Health Administration (OSHA); OSHA has set
2280-432: Is also used for septic tanks . Glass-reinforced plastics are also used to produce house building components such as roofing laminate, door surrounds, over-door canopies, window canopies and dormers, chimneys, coping systems, and heads with keystones and sills. The material's reduced weight and easier handling, compared to wood or metal, allows faster installation. Mass-produced fiberglass brick-effect panels can be used in
2375-401: Is applied to the chosen mold to allow the finished product to be cleanly removed from the mold. Resin—typically a 2-part thermoset polyester, vinyl, or epoxy—is mixed with its hardener and applied to the surface. Sheets of fiberglass matting are laid into the mold, then more resin mixture is added using a brush or roller. The material must conform to the mold, and air must not be trapped between
2470-479: Is applied to the roving to help protect the glass filaments for processing and manipulation and to ensure proper bonding to the resin matrix, thus allowing for the transfer of shear loads from the glass fibers to the thermoset plastic. Without this bonding, the fibers can 'slip' in the matrix causing localized failure. An individual structural glass fiber is both stiff and strong in tension and compression —that is, along its axis. Although it might be assumed that
2565-419: Is available in many species, including hardwoods and softwoods , such as white pine and red pine , because of their low cost. Finished lumber is supplied in standard sizes, mostly for the construction industry – primarily softwood , from coniferous species, including pine , fir and spruce (collectively spruce-pine-fir ), cedar , and hemlock , but also some hardwood, for high-grade flooring. It
2660-483: Is called pultrusion . The manufacturing process for glass fibers suitable for reinforcement uses large furnaces to gradually melt the silica sand, limestone , kaolin clay , fluorspar , colemanite , dolomite and other minerals until a liquid forms. It is then extruded through bushings ( spinneret ), which are bundles of very small orifices (typically 5–25 micrometres in diameter for E-Glass, 9 micrometres for S-Glass). These filaments are then sized (coated) with
2755-478: Is chemically inert under many circumstances. Applications include aircraft, boats, automobiles, bath tubs and enclosures, swimming pools , hot tubs , septic tanks , water tanks , roofing, pipes, cladding, orthopedic casts , surfboards , and external door skins. Other common names for fiberglass are glass-reinforced plastic ( GRP ), glass-fiber reinforced plastic ( GFRP ) or GFK (from German : Glasfaserverstärkter Kunststoff ). Because glass fiber itself
2850-579: Is credited with producing the first composite boat in 1937 but did not proceed further at the time because of the brittle nature of the plastic used. In 1939 Russia was reported to have constructed a passenger boat of plastic materials, and the United States a fuselage and wings of an aircraft. The first car to have a fiberglass body was a 1946 prototype of the Stout Scarab , but the model did not enter production. Unlike glass fibers used for insulation, for
2945-543: Is critical, such as trusses , rafters , laminating stock, I-beams and web joints. Machine grading measures a characteristic such as stiffness or density that correlates with the structural properties of interest, such as bending strength . The result is a more precise understanding of the strength of each piece of lumber than is possible with visually graded lumber, which allows designers to use full-design strength and avoid overbuilding. In Europe, strength grading of rectangular sawn lumber/timber (both softwood and hardwood)
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3040-633: Is done according to EN-14081 and commonly sorted into classes defined by EN-338. For softwoods, the common classes are (in increasing strength) C16, C18, C24, and C30. There are also classes specifically for hardwoods and those in most common use (in increasing strength) are D24, D30, D40, D50, D60, and D70. For these classes, the number refers to the required 5th percentile bending strength in newtons per square millimetre. There are other strength classes, including T-classes based on tension intended for use in glulam . Grading rules for African and South American sawn lumber have been developed by ATIBT according to
3135-401: Is essentially an entire two-dimensional plane; with woven fabrics or unidirectional layers, directionality of stiffness and strength can be more precisely controlled within the plane. A fiberglass component is typically of a thin "shell" construction, sometimes filled on the inside with structural foam, as in the case of surfboards. The component may be of nearly arbitrary shape, limited only by
3230-406: Is minimally 1 + 1 ⁄ 2 by 3 + 1 ⁄ 2 inches (38 mm × 89 mm). As previously noted, less wood is needed to produce a given finished size than when standards called for the green lumber to be the full nominal dimension. However, even the dimensions for finished lumber of a given nominal size have changed over time. In 1910, a typical finished 1-inch (25 mm) board
3325-551: Is more commonly made from softwood than hardwoods, and 80% of lumber comes from softwood. In the United States and Canada, milled boards are called lumber , while timber describes standing or felled trees. In contrast, in Britain, and some other Commonwealth nations and Ireland, the term timber is used in both senses. (In the UK, the word lumber is rarely used in relation to wood and has several other meanings.) Re-manufactured lumber
3420-513: Is pulled through forming machinery using either a hand-over-hand method or a continuous-roller method (as opposed to extrusion , where the material is pushed through dies). In fiberglass pultrusion, fibers (the glass material) are pulled from spools through a device that coats them with a resin. They are then typically heat-treated and cut to length. Fiberglass produced this way can be made in a variety of shapes and cross-sections, such as W or S cross-sections. People can be exposed to fiberglass in
3515-552: Is referred to as timber in the United Kingdom, Europe, Australia, and New Zealand, while in other parts of the world (mainly the United States and Canada) the term timber refers specifically to unprocessed wood fiber , such as cut logs or standing trees that have yet to be cut. Lumber may be supplied either rough- sawn , or surfaced on one or more of its faces. Rough lumber is the raw material for furniture-making, and manufacture of other items requiring cutting and shaping. It
3610-639: Is required, such as equipment cabinets and steel support structures, due to the ease with which it can be molded and painted to blend with existing structures and surfaces. Other uses include sheet-form electrical insulators and structural components commonly found in power-industry products. Because of fiberglass's lightweight and durability, it is often used in protective equipment such as helmets. Many sports use fiberglass protective gear, such as goaltenders' and catchers' masks. Storage tanks can be made of fiberglass with capacities up to about 300 tonnes . Smaller tanks can be made with chopped strand mat cast over
3705-591: Is required. Under the prescription of the Method of Construction (營造法式) issued by the Song dynasty government in the early twelfth century, timbers were standardized to eight cross-sectional dimensions. Regardless of the actual dimensions of the timber, the ratio between width and height was maintained at 1:1.5. Units are in Song dynasty inches (31.2 mm). Timber smaller than the 8th class were called "unclassed" (等外). The width of
3800-459: Is smaller than the nominal dimensions because modern technology makes it possible to use the logs more efficiently. For example, a "2×4" board historically started out as a green, rough board actually 2 by 4 inches (51 mm × 102 mm). After drying and planing, it would be smaller by a nonstandard amount. Today, a "2×4" board starts out as something smaller than 2 inches by 4 inches and not specified by standards, and after drying and planing
3895-505: Is sometimes referred to as "fiberglass", the composite is also called fiberglass-reinforced plastic ( FRP ). This article uses "fiberglass" to refer to the complete fiber-reinforced composite material, rather than only to the glass fiber within it. Glass fibers have been produced for centuries, but the earliest patent was awarded to the Prussian inventor Hermann Hammesfahr (1845–1914) in the U.S. in 1880. Mass production of glass strands
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3990-422: Is still continued in some places. Otherwise, logs were sawn using a two-person whipsaw, or pit-saw, using saddleblocks to hold the log, and a pit for the pitman who worked below. In 1420 the island of Madeira – an archipelago comprising four islands off the northwest coast of Africa and an autonomous region of Portugal – was discovered. King Henry VI sent settlers to Madeira and
4085-402: Is that the resins used are subject to contraction during the curing process. For polyester this contraction is often 5–6%; for epoxy, about 2%. Because the fibers do not contract, this differential can create changes in the shape of the part during curing. Distortions can appear hours, days, or weeks after the resin has set. While this distortion can be minimized by symmetric use of the fibers in
4180-437: Is the result of secondary or tertiary processing of previously milled lumber. Specifically, it refers to lumber cut for industrial or wood-packaging use. Lumber is cut by ripsaw or resaw to create dimensions that are not usually processed by a primary sawmill . Re-sawing is the splitting of 1-to-12-inch (25–305 mm) hardwood or softwood lumber into two or more thinner pieces of full-length boards. For example, splitting
4275-460: Is used when tensile strength (high modulus) is important and is thus an important building and aircraft epoxy composite (it is called R-glass, "R" for "reinforcement" in Europe). C-glass ("C" for "chemical resistance") and T-glass ("T" is for "thermal insulator"—a North American variant of C-glass) are resistant to chemical attack; both are often found in insulation-grades of blown fiberglass. Fiberglass
4370-433: Is versatile because it is lightweight, strong, weather-resistant, and can have a variety of surface textures. During World War II, fiberglass was developed as a replacement for the molded plywood used in aircraft radomes (fiberglass being transparent to microwaves ). Its first main civilian application was for the building of boats and sports car bodies, where it gained acceptance in the 1950s. Its use has broadened to
4465-605: Is well utilised in the construction industry. Attempts to maintain lumber quality over time have been challenged by historical changes in the timber resources of the United States – from the slow-growing virgin forests common over a century ago to the fast-growing plantations now common in today's commercial forests. Resulting declines in lumber quality have been of concern to both the lumber industry and consumers and have caused increased use of alternative construction products. Machine stress-rated and machine-evaluated lumber are readily available for end-uses where high strength
4560-503: The American Lumber Standard Committee , appointed by the U.S. Secretary of Commerce . Design values for most species and grades of visually graded structural products are determined in accordance with ASTM standards, which consider the effect of strength reducing characteristics, load duration, safety, and other influencing factors. The applicable standards are based on results of tests conducted in cooperation with
4655-702: The American colonies began in 1607 when the Jamestown settlers cut timber to build the first settlement in the new world. America's first sawmill was built at the Falls of Piscatauqua , on the line between the Province of Maine and the Province of New Hampshire , in 1634. Unauthenticated records, however, claim that as early as 1633 several mills were operating in New Netherland . The American colonies were essential to England in
4750-564: The International Agency for Research on Cancer (IARC) as "not classifiable as to carcinogenicity to humans" ( IARC group 3 ). "Epidemiologic studies published during the 15 years since the previous IARC monographs review of these fibers in 1988 provide no evidence of increased risks of lung cancer or mesothelioma (cancer of the lining of the body cavities) from occupational exposures during the manufacture of these materials, and inadequate evidence overall of any cancer risk." In June 2011,
4845-539: The USDA Forest Products Laboratory. Design Values for Wood Construction, which is a supplement to the ANSI/AF&;PA National Design Specification® for Wood Construction, provides these lumber design values, which are recognized by the model building codes. Canada has grading rules that maintain a standard among mills manufacturing similar woods to assure customers of uniform quality. Grades standardize
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#17328514059444940-404: The "quarter" system in specifications as a vogue of insider knowledge, though the materials being specified are finished lumber, thus conflating the separate systems and causing confusion. Hardwoods cut for furniture are cut in the fall and winter, after the sap has stopped running in the trees. If hardwoods are cut in the spring or summer the sap ruins the natural color of the lumber and decreases
5035-409: The 4×4 (89 mm × 89 mm), are common lumber sizes used in modern construction. They are the basic building blocks for such common structures as balloon-frame or platform-frame housing. Dimensional lumber made from softwood is typically used for construction, while hardwood boards are more commonly used for making cabinets or furniture. Lumber's nominal dimensions are larger than
5130-539: The European Union and Germany have classified synthetic glass fibers as possibly or probably carcinogenic, but fibers can be exempt from this classification if they pass specific tests. A 2012 health hazard review for the European Commission stated that inhalation of fiberglass at concentrations of 3, 16 and 30 mg/m3 "did not induce fibrosis nor tumours except transient lung inflammation that disappeared after
5225-825: The UK), 2×6 , and 4×4 . The length of a board is usually specified separately from the width and depth. It is thus possible to find 2×4s that are four, eight, and twelve feet in length. In Canada and the United States, the standard lengths of lumber are 6, 8, 10, 12, 14, 16, 18, 20, 22 and 24 feet (1.8, 2.4, 3.0, 3.7, 4.3, 4.9, 5.5, 6.1, 6.7 and 7.3 m). For wall framing, precut "stud" lengths are available, and are commonly used. For ceilings heights of 8, 9 or 10 feet (2.4, 2.7 or 3.0 m), studs are available in 92 + 5 ⁄ 8 inches (2.35 m), 104 + 5 ⁄ 8 inches (2.66 m), and 116 + 5 ⁄ 8 inches (2.96 m). The length of
5320-553: The US National Toxicology Program (NTP) removed from its Report on Carcinogens all biosoluble glass wool used in home and building insulation and for non-insulation products. However, NTP still considers fibrous glass dust to be "reasonably anticipated [as] a human carcinogen (Certain Glass Wool Fibers (Inhalable))". Similarly, California's Office of Environmental Health Hazard Assessment (OEHHA) published
5415-499: The United States began with the publication of the American Lumber Standard in 1924, which set specifications for lumber dimensions, grade, and moisture content; it also developed inspection and accreditation programs. These standards have changed over the years to meet the changing needs of manufacturers and distributors, with the goal of keeping lumber competitive with other construction products. Current standards are set by
5510-422: The actual standard dimensions of finished lumber. Historically, the nominal dimensions were the size of the green (not dried), rough (unfinished) boards that eventually became smaller finished lumber through drying and planing (to smooth the wood). Today, the standards specify the final finished dimensions and the mill cuts the logs to whatever size it needs to achieve those final dimensions. Typically, that rough cut
5605-458: The air near manufacturing facilities or when they are near building fires or implosions . The American Lung Association advises that fiberglass insulation should never be left exposed in an occupied area. Since work practices are not always followed, and fiberglass is often left exposed in basements that later become occupied, people can get exposed. No readily usable biological or clinical indices of exposure exist. Fiberglass will irritate
5700-403: The amount of oxygen is inadequate. Fungi lumber/timber defects: Following are the insects and molluscs which are usually responsible for the decay of timber/lumber: Fiberglass Fiberglass ( American English ) or fibreglass ( Commonwealth English ) is a common type of fiber-reinforced plastic using glass fiber . The fibers may be randomly arranged, flattened into a sheet called
5795-599: The automotive and sport equipment sectors. In the production of some products, such as aircraft, carbon fiber is now used instead of fiberglass, which is stronger by volume and weight. Advanced manufacturing techniques such as pre-pregs and fiber rovings extend fiberglass's applications and the tensile strength possible with fiber-reinforced plastics. Fiberglass is also used in the telecommunications industry for shrouding antennas , due to its RF permeability and low signal attenuation properties. It may also be used to conceal other equipment where no signal permeability
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#17328514059445890-550: The complexity and tolerances of the mold used for manufacturing the shell. The mechanical functionality of materials is heavily reliant on the combined performances of both the resin (AKA matrix) and fibers. For example, in severe temperature conditions (over 180 °C), the resin component of the composite may lose its functionality, partially due to bond deterioration of resin and fiber. However, GFRPs can still show significant residual strength after experiencing high temperatures (200 °C). One notable feature of fiberglass
5985-412: The construction of composite housing, and can include insulation to reduce heat loss. In rod pumping applications, fiberglass rods are often used for their high tensile strength to weight ratio. Fiberglass rods provide an advantage over steel rods because they stretch more elastically (lower Young's modulus ) than steel for a given weight, meaning more oil can be lifted from the hydrocarbon reservoir to
6080-402: The conversion of log timber into planks 30 times faster than previously. The circular saw, as used in modern sawmills, was invented by an Englishman named Miller in 1777. It was not until the nineteenth century, however, that it was generally applied, and its great work belongs to that period. The first insertable teeth for this saw were invented by W. Kendal, an American, in 1826. Logging in
6175-408: The countries with significant sawmilling industries. Historical wood-frame home building regions are: Europe, North America, Japan. Different areas of the world are recognized as significant timber suppliers; however, these areas (Indonesia, Sarawak, New Guinea, etc.) are exporters of raw logs and do not have a significant domestic lumber producing industry. The largest lumber manufacturing regions in
6270-973: The design, a certain amount of internal stress is created; and if it becomes too great, cracks form. The most common types of glass fiber used in fiberglass is E-glass , which is alumino-borosilicate glass with less than 1% w/w alkali oxides, mainly used for glass-reinforced plastics. Other types of glass used are A-glass ( A lkali-lime glass with little or no boron oxide), E-CR-glass ( E lectrical/ C hemical R esistance; alumino-lime silicate with less than 1% w/w alkali oxides, with high acid resistance), C-glass (alkali-lime glass with high boron oxide content, used for glass staple fibers and insulation), D-glass (borosilicate glass, named for its low D ielectric constant), R-glass (alumino silicate glass without MgO and CaO with high mechanical requirements as R einforcement), and S-glass (alumino silicate glass without CaO but with high MgO content with high tensile strength). Pure silica (silicon dioxide), when cooled as fused quartz into
6365-433: The early 1940s, and many sailing vessels made after 1950 were built using the fiberglass lay-up process . As of 2022, boats continue to be made with fiberglass, though more advanced techniques such as vacuum bag moulding are used in the construction process. Though most bullet-resistant armours are made using different textiles, fiberglass composites have been shown to be effective as ballistic armor. Filament winding
6460-562: The eyes, skin, and the respiratory system. Hence, symptoms can include itchy eyes, skin, nose, sore throat, hoarseness, dyspnea (breathing difficulty) and cough. Peak alveolar deposition was observed in rodents and humans for fibers with diameters of 1 to 2 μm. In animal experiments, adverse lung effects such as lung inflammation and lung fibrosis have occurred, and increased incidences of mesothelioma , pleural sarcoma , and lung carcinoma had been found with intrapleural or intratracheal instillations in rats. As of 2001, in humans only
6555-563: The fiber has an effect on the properties of the final product. A high angle "hoop" will provide circumferential or "burst" strength, while lower angle patterns (polar or helical) will provide greater longitudinal tensile strength. Products currently being produced using this technique range from pipes, golf clubs, Reverse Osmosis Membrane Housings, oars, bicycle forks, bicycle rims, power and transmission poles, pressure vessels to missile casings, aircraft fuselages and lamp posts and yacht masts. A release agent, usually in either wax or liquid form,
6650-434: The fiber is weak in compression, it is actually only the long aspect ratio of the fiber which makes it seem so; i.e., because a typical fiber is long and narrow, it buckles easily. On the other hand, the glass fiber is weak in shear—that is, across its axis. Therefore, if a collection of fibers can be arranged permanently in a preferred direction within a material, and if they can be prevented from buckling in compression,
6745-415: The fiberglass and the mold. Additional resin is applied and possibly additional sheets of fiberglass. Hand pressure, vacuum or rollers are used to be sure the resin saturates and fully wets all layers, and that any air pockets are removed. The work must be done quickly before the resin starts to cure unless high-temperature resins are used which will not cure until the part is warmed in an oven. In some cases,
6840-420: The final structure to be strong, the fiber's surfaces must be almost entirely free of defects, as this permits the fibers to reach gigapascal tensile strengths . If a bulk piece of glass were defect-free, it would be as strong as glass fibers; however, it is generally impractical to produce and maintain bulk material in a defect-free state outside of laboratory conditions. The process of manufacturing fiberglass
6935-459: The gas content of the material was replaced by plastic. This reduced the insulation properties to values typical of the plastic, but now for the first time, the composite showed great strength and promise as a structural and building material. Many glass fiber composites continued to be called "fiberglass" (as a generic name) and the name was also used for the low-density glass wool product containing gas instead of plastic. Ray Greene of Owens Corning
7030-473: The glass into short lengths and drops it into a jet of resin, projected onto the surface of a mold), or in an intermediary step, to manufacture fabrics such as chopped strand mat (CSM) (made of randomly oriented small cut lengths of fiber all bonded together), woven fabrics, knit fabrics or unidirectional fabrics. Chopped strand mat (CSM) is a form of reinforcement used in fiberglass. It consists of glass fibers laid randomly across each other and held together by
7125-441: The legal limit ( permissible exposure limit ) for fiberglass exposure in the workplace as 15 mg/m total and 5 mg/m in respiratory exposure over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 3 fibers/cm (less than 3.5 micrometers in diameter and greater than 10 micrometers in length) as a time-weighted average over an 8-hour workday, and
7220-413: The mandrel is completely covered to the desired thickness, the resin is cured; often the mandrel is placed in an oven to achieve this, though sometimes radiant heaters are used with the mandrel still turning in the machine. Once the resin has cured, the mandrel is removed, leaving the hollow final product. For some products such as gas bottles, the 'mandrel' is a permanent part of the finished product forming
7315-449: The material will be preferentially strong in that direction. Furthermore, by laying multiple layers of fiber on top of one another, with each layer oriented in various preferred directions, the material's overall stiffness and strength can be efficiently controlled. In fiberglass, it is the plastic matrix which permanently constrains the structural glass fibers to directions chosen by the designer. With chopped strand mat, this directionality
7410-543: The modern era; a 1st class timber during the Sui was reconstructed as 15×10 (Sui dynasty inches, or 29.4 mm). Defects occurring in lumber are grouped into the following four divisions: During the process of converting timber to commercial forms of lumber the following defects may occur: Fungi attack wood (both timber and lumber) when these conditions are all present: Wood with less than 25% moisture (dry weight basis) can remain free of decay for centuries. Similarly, wood submerged in water may not be attacked by fungi if
7505-586: The more biopersistent materials like ceramic fibres, which are used industrially as insulation in high-temperature environments such as blast furnaces , and certain special-purpose glass wools not used as insulating materials remain classified as possible carcinogens ( IARC Group 2B ). The more commonly used glass fibre wools including insulation glass wool , rock wool and slag wool are considered not classifiable as to carcinogenicity to humans ( IARC Group 3 ). In October 2001, all fiberglass wools commonly used for thermal and acoustical insulation were reclassified by
7600-491: The most common and widely used method of sawing logs. Plain sawn lumber is produced by making the first cut on a tangent to the circumference of the log. Each additional cut is then made parallel to the one before. This method produces the widest possible boards with the least amount of log waste. Lumber manufacturing globally is determined by the preferred style of building; areas with a "wood building culture" (homes were built from wood rather than other materials like brick) are
7695-505: The quality of lumber at different levels and are based on moisture content, size, and manufacture at the time of grading, shipping, and unloading by the buyer. The National Lumber Grades Authority (NLGA) is responsible for writing, interpreting and maintaining Canadian lumber grading rules and standards. The Canadian Lumber Standards Accreditation Board (CLSAB) monitors the quality of Canada's lumber grading and identification system. Their common grade abbrievation, CLS, Canadian Lumber Standard
7790-653: The role of supplier of lumber for the British fleet. By the 1790s, New England was exporting 36 million feet of pine boards and at least 300 ship masts per year to the British Empire. The timber supply began to dwindle at the start of the twentieth century due to significant harvest volumes, so the logging industry was forced to seek timber elsewhere; hence, the expansion into the American West. Logs are converted into lumber by being sawn, hewn , or split . Sawing with
7885-511: The rules of the Sciages Avivés Tropicaux Africains (SATA) and is based on clear cuttings – established by the percentage of the clear surface. In North America, market practices for dimensional lumber made from hardwoods varies significantly from the regularized standardized ' dimension lumber ' sizes used for sales and specification of softwoods – hardwood boards are often sold totally rough cut, or machine planed only on
7980-446: The settlers started clearing the huge expanses of forest in order to grow crops. Felled trees were made into planks by water-powered mills and the timber (cedar and yew) was shipped to Portugal and Spain. About 1427, the first sawmill in Germany was built. Cornelis Corneliszoon (or Krelis Lootjes) was a Dutch windmill owner from Uitgeest who invented the first mechanical sawmill, which was wind-powered, on 15 December 1593. This made
8075-628: The surface with each stroke, all while reducing the load on the pumping unit. Fiberglass rods must be kept in tension, however, as they frequently part if placed in even a small amount of compression. The buoyancy of the rods within a fluid amplifies this tendency. GRP and GRE pipe can be used in a variety of above- and below-ground systems, including those for desalination, water treatment, water distribution networks, chemical process plants, water used for firefighting, hot and cold drinking water, wastewater/sewage, municipal waste and liquified petroleum gas . Fiberglass composite boats have been made since
8170-453: The two (broader) face sides. When hardwood boards are also supplied with planed faces, it is usually both by random widths of a specified thickness (normally matching milling of softwood dimensional lumber) and somewhat random lengths. But besides those older (traditional and normal) situations, in recent years some product lines have been widened to also market boards in standard stock sizes; these usually retail in big-box stores and using only
8265-459: The value of the wood for furniture. Engineered lumber is lumber created by a manufacturer and designed for a certain structural purpose. The main categories of engineered lumber are: In the United States, pilings are mainly cut from southern yellow pines and Douglas-fir . Treated pilings are available in chromated copper arsenate retentions of 0.60, 0.80 and 2.50 pounds per cubic foot (9.6, 12.8 and 40.0 kg/m ) if treatment
8360-482: The work is covered with plastic sheets and vacuum is drawn on the work to remove air bubbles and press the fiberglass to the shape of the mold. The fiberglass spray lay-up process is similar to the hand lay-up process but differs in the application of the fiber and resin to the mold. Spray-up is an open-molding composites fabrication process where resin and reinforcements are sprayed onto a mold. The resin and glass may be applied separately or simultaneously "chopped" in
8455-415: The workplace during its fabrication, installation or removal, by breathing it in, by skin contact, or by eye contact. Furthermore, in the manufacturing process of fiberglass, styrene vapors are released while the resins are cured. These are also irritating to mucous membranes and respiratory tract. The general population can get exposed to fibreglass from insulation and building materials or from fibers in
8550-424: The world are: China (18%); United States (17%); Canada (10%); Russia (9%); Germany (5%); Sweden (4%). In early periods of society, to make wood for building, the trunks of trees were split with wedges into as many and as thin pieces as possible. If it was necessary to have them still thinner, they were hewn, by some sharp instrument, on both sides, to the proper size. This simple but wasteful manner of making boards
8645-514: Was 13 ⁄ 16 in (21 mm). In 1928, that was reduced by 4%, and yet again by 4% in 1956. In 1961, at a meeting in Scottsdale, Arizona, the Committee on Grade Simplification and Standardization agreed to what is now the current U.S. standard: in part, the dressed size of a 1-inch (nominal) board was fixed at 3 ⁄ 4 inch; while the dressed size of 2 inch (nominal) lumber
8740-490: Was accidentally discovered in 1932 when Games Slayter , a researcher at Owens-Illinois , directed a jet of compressed air at a stream of molten glass and produced fibers. A patent for this method of producing glass wool was first applied for in 1933. Owens joined with the Corning company in 1935 and the method was adapted by Owens Corning to produce its patented "Fiberglas" (spelled with one "s") in 1936. Originally, Fiberglas
8835-516: Was reduced from 1 + 5 ⁄ 8 inch to the current 1 + 1 ⁄ 2 inch. Dimensional lumber is available in green, unfinished state, and for that kind of lumber, the nominal dimensions are the actual dimensions. Individual pieces of lumber exhibit a wide range in quality and appearance with respect to knots, slope of grain, shakes and other natural characteristics. Therefore, they vary considerably in strength, utility, and value. The move to set national standards for lumber in
8930-425: Was a glass wool with fibers entrapping a great deal of gas, making it useful as an insulator, especially at high temperatures. A suitable resin for combining the fiberglass with a plastic to produce a composite material was developed in 1936 by DuPont . The first ancestor of modern polyester resins is Cyanamid 's resin of 1942. Peroxide curing systems were used by then. With the combination of fiberglass and resin
9025-443: Was the first type of glass used for fiberglass. E-glass ("E" because of initial Electrical application), is alkali-free and was the first glass formulation used for continuous filament formation. It now makes up most of the fiberglass production in the world, and also is the single largest consumer of boron minerals globally. It is susceptible to chloride ion attack and is a poor choice for marine applications. S-glass ("S" for "stiff")
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