Laminated veneer lumber (LVL) is an engineered wood product that uses multiple layers of thin wood assembled with adhesives . It is typically used for headers , beams , rimboard , and edge-forming material. LVL offers several advantages over typical milled lumber : Made in a factory under controlled specifications, it is stronger, straighter, and more uniform. Due to its composite nature, it is much less likely than conventional lumber to warp, twist, bow, or shrink. LVL is a type of structural composite lumber, comparable to glued laminated timber (glulam) but with a higher allowable stress. A high performance more sustainable alternative to lumber, Laminated Veneer Lumber (LVL) beams, headers and columns are used in structural applications to carry heavy loads with minimum weight.
29-514: LVL may refer to: Laminated veneer lumber LVL (artist) , an industrial/electronic artist from New York "LVL", a song by American rapper ASAP Rocky from his 2013 debut album Long. Live. ASAP LVL, ISO 4217 currency code for Latvian lats , the former currency of Latvia See also [ edit ] Laval, Quebec , a city in Quebec, Canada Level (disambiguation) Topics referred to by
58-422: A step-growth polymerization reaction that can be either acid - or base -catalysed. Since formaldehyde exists predominantly in solution as a dynamic equilibrium of methylene glycol oligomers , the concentration of the reactive form of formaldehyde depends on temperature and pH. Phenol reacts with formaldehyde at the ortho and para sites (sites 2, 4 and 6) allowing up to 3 units of formaldehyde to attach to
87-400: A thermosetting network polymer , while the other restricts the formaldehyde to produce a prepolymer known as novolac which can be moulded and then cured with the addition of more formaldehyde and heat. There are many variations in both production and input materials that are used to produce a wide variety of resins for special purposes. Phenol-formaldehyde resins, as a group, are formed by
116-489: A combination of I-joists and LVL in floor and roof assemblies. Because it is specifically sized to be compatible with I-joist floor framing, residential builders and building designers like the combination of I-joist and LVL floor and roof assemblies. LVL is considered to be a highly reliable building material that provides many of the same attributes associated with large sized timbers. LVL can also be used in combination with gluelam as an outer gluelam tension lam to increase
145-424: A cross linker unlike novolacs, a "two step" resin. Resoles are major polymeric resin materials widely used for gluing and bonding building materials. Exterior plywood, oriented strand boards (OSB), engineered high-pressure laminate are typical applications. When the molar ratio of formaldehyde:phenol reaches one, in theory every phenol is linked together via methylene bridges, generating one single molecule, and
174-580: Is delocalised over the aromatic ring , activating sites 2, 4 and 6, which then react with the formaldehyde. Being thermosets , hydroxymethyl phenols will crosslink on heating to around 120 °C to form methylene and methyl ether bridges through the elimination of water molecules. At this point the resin is a 3-dimensional network, which is typical of polymerised phenolic resins. The high crosslinking gives this type of phenolic resin its hardness, good thermal stability, and chemical imperviousness. Resoles are referred to as "one step" resins as they cure without
203-645: Is also made from strands rather than veneer, although the strands are shorter and aligned with less precision than PSL and is created as billets that are like a thick version of oriented strand board . Billets of PSL and LVL are very similar although their sizes are different. Billets of PSL can be as large as 12 inches (300 mm) wide and 60 feet (18 m) long while LVL can range up to 4 feet (1.2 m) wide and 80 feet (24 m) long. Phenol formaldehyde resin Phenol formaldehyde resins (PF) ( phenolic resins or phenoplasts ) are synthetic polymers obtained by
232-597: Is an important monomer in the production of epoxy resins . Bisphenol-F can further link generating tri- and tetra-and higher phenol oligomers. Novolaks (or novolacs) are phenol-formaldehyde resins with a formaldehyde to phenol molar ratio of less than one. In place of phenol itself, they are often produced from cresols (methylphenols). The polymerization is brought to completion using acid-catalysis such as sulfuric acid , oxalic acid , hydrochloric acid and rarely, sulfonic acids. The phenolic units are mainly linked by methylene and/or ether groups. The molecular weights are in
261-413: Is different from Wikidata All article disambiguation pages All disambiguation pages Laminated veneer lumber Structural composite lumber products, including LVL, are a relatively recent innovation. They are the result of new technology and economic pressure to make use of new species and smaller trees that cannot be used to make solid sawn lumber. While plywood became widespread by
290-553: Is used as a binder in loudspeaker driver suspension components which are made of cloth . Higher end billiard balls are made from phenolic resins, as opposed to the polyesters used in less expensive sets. Sometimes people select fibre reinforced phenolic resin parts because their coefficient of thermal expansion closely matches that of the aluminium used for other parts of a system, as in early computer systems and Duramold . The Dutch painting forger Han van Meegeren mixed phenol formaldehyde with his oil paints before baking
319-456: Is used to make countertops. Another use of phenolic resins is the making of duroplast , famously used in Trabant automobiles. Phenolic resins are also used for making exterior plywood commonly known as weather and boil proof (WBP) plywood because phenolic resins have no melting point but only a decomposing point in the temperature zone of 220 °C (428 °F) and above. Phenolic resin
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#1732793072873348-579: The thermoset polymer matrix . The base material choice depends on the intended application of the finished product. Paper phenolics are used in manufacturing electrical components such as punch-through boards, in household laminates, and in paper composite panels . Glass phenolics are particularly well suited for use in the high speed bearing market. Phenolic micro-balloons are used for density control. The binding agent in normal (organic) brake pads, brake shoes, and clutch discs are phenolic resin. Synthetic resin bonded paper , made from phenolic resin and paper,
377-566: The United States. In 1942, an increased demand for wood caused a sudden timber shortage. The war industry utilized a panel material developed by the Homasote Company of Trenton, New Jersey, made of wood pulp and ground newspaper, to be used in place of siding and sheathing for buildings. The invention of laminated veneer lumber as known today can be attributed to Arthur Troutner. While glue laminated wood veneers were in use since
406-424: The category of engineered wood called structural composite lumber. Other members of this category are parallel strand lumber (PSL) and laminated strand lumber (LSL). All members of this category are strong and predictable, and are thus interchangeable for some applications. PSL is made from veneers that are cut up into long strands and oriented parallel to its length before being compressed into its final shape. LSL
435-500: The creation of LVL is often proprietary and thus its make-up is largely dependent on individual manufacturers, in general one cubic meter of North American lumber is composed of 97.54% wood, 2.41% of phenol formaldehyde resin , 0.02% of phenol-resorcinol-formaldehyde resin, and 0.03% fillers. LVL is commonly manufactured in North America by companies that also manufacture I-joists . LVL is manufactured to sizes compatible with
464-543: The curing agent is a source of formaldehyde which provides bridges between novolac chains, eventually completely crosslinking the system. Novolacs have multiple uses as tire tackifier , high temperature resin, binder for carbon bonded refractories, carbon brakes, photoresists and as a curing agent for epoxy resins . Base-catalysed phenol-formaldehyde resins are made with a formaldehyde to phenol ratio of greater than one (usually around 1.5). These resins are called resoles. Phenol, formaldehyde, water and catalyst are mixed in
493-486: The depth of I-joist framing members for use as beams and headers. Additionally, some manufacturers further cut LVL into sizes for use as chord-members on I-joists. In 2012, North American LVL manufacturers produced more than 1.2 million cubic metres (43.4 million cubic feet) of LVL in 18 different facilities, and in 2013 the production increased by more than 14%. It is not coincidental that LVL mills are often co-located with I-joist manufacturing facilities as many builders use
522-462: The desired amount, depending on the resin to be formed, and are then heated. The first part of the reaction, at around 70 °C, forms a thick reddish-brown tacky material, which is rich in hydroxymethyl and benzylic ether groups. The rate of the base-catalysed reaction initially increases with pH , and reaches a maximum at about pH = 10. The reactive species is the phenoxide anion (C 6 H 5 O ) formed by deprotonation of phenol. The negative charge
551-453: The early 20th century, the invention of LVL was not until the 1980s after the invention of oriented strand board. The American Wood Council 's National Design Specification for Wood Construction is generally updated on a 3- to 5-year cycle. The 1991 release is the first release which mentions LVL. LVL is mentioned as a subcategory of structural glued laminated timber. The first explorations into engineered lumber happened during World War II in
580-464: The finished canvas, in order to fake the drying out of the paint over the centuries. Atmospheric re-entry spacecraft use phenol formaldehyde resin as a key component in ablative heat shields (e.g. AVCOAT on the Apollo modules). As the heat shield skin temperature can reach 1000-2000 °C, the resin pyrolizes due to aerodynamic heating. This reaction absorbs significant thermal energy, insulating
609-408: The low thousands, corresponding to about 10–20 phenol units. Obtained polymer is thermoplastic and require a curing agent or hardener to form a thermoset . Hexamethylenetetramine is a hardener added to crosslink novolac. At a temperature greater than 90 °C, it forms methylene and dimethylene amino bridges. Resoles can also be used as a curing agent (hardener) for novolac resins. In either case,
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#1732793072873638-406: The middle of the 19th century on a small scale for furniture and pianos, Troutner was the first to develop a laminated veneer lumber of a scale large enough to be used in construction. In 1971 "Micro=Lam LVL" was introduced. "Micro=Lam LVL" consisted of laminated veneer lumber billets 4 feet (1.2 m) wide, 3 + 1 ⁄ 2 inches (89 mm) thick, and 80 feet (24 m) long. Troutner proved
667-612: The reaction of phenol or substituted phenol with formaldehyde . Used as the basis for Bakelite , PFs were the first commercial synthetic resins. They have been widely used for the production of molded products including billiard balls , laboratory countertops, and as coatings and adhesives . They were at one time the primary material used for the production of circuit boards but have been largely replaced with epoxy resins and fiberglass cloth, as with fire-resistant FR-4 circuit board materials. There are two main production methods. One reacts phenol and formaldehyde directly to produce
696-415: The ring. The initial reaction in all cases involves the formation of a hydroxymethyl phenol: The hydroxymethyl group is capable of reacting with either another free ortho or para site, or with another hydroxymethyl group. The first reaction gives a methylene bridge , and the second forms an ether bridge: The diphenol (HOC 6 H 4 ) 2 CH 2 (sometimes called a "dimer") is called bisphenol F , which
725-402: The same term [REDACTED] This disambiguation page lists articles associated with the title LVL . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=LVL&oldid=792241548 " Category : Disambiguation pages Hidden categories: Short description
754-610: The strength of the gluelam beam. However, due to the fact that the assembly adhesives limit the penetration of chemicals typically used to treat outdoor-rated lumber, LVL may not be suitable for outdoor load-bearing use — rotten LVL joists were blamed for the Berkeley balcony collapse which killed 7 people. The breakdown of LVL end uses in North America is 33% new single family residential construction, 25% residential renovations and upkeep, 8% new non-residential construction and 34% manufacturing furniture and other products. LVL belongs to
783-500: The structural capabilities of his Micro=Lam product by building a house in Hagerman, Idaho, using beams made of Micro=Lam. Most corporations considered Troutner's invention to be a niche product and it was not until the mid-1980s when logging became an environmental concern and corporations moved toward engineered lumber that LVL became widespread in use. Laminated veneer lumber is similar in appearance to plywood , although in plywood
812-520: The system is entirely crosslinked. This is why novolacs (F:P <1) do not harden without the addition of a crosslinking agents, and why resoles with the formula F:P >1 will. Phenolic resins are found in myriad industrial products. Phenolic laminates are made by impregnating one or more layers of a base material such as paper, fiberglass , or cotton with phenolic resin and laminating the resin-saturated base material under heat and pressure. The resin fully polymerizes (cures) during this process forming
841-683: The veneers switch direction while stacking and in LVL the veneers all stack in the same direction. In LVL, the direction of the wood grain is always parallel to the length of the billet. The stacking of these veneers into a complete board, called a billet, creates a single piece of LVL sharing a common direction of wood grain. LVL is typically rated by the manufacturer for elastic modulus and allowable bending stress. Common elastic moduli are 12, 13 and 14 GPa (1,700,000, 1,900,000 and 2,000,000 psi), and common allowable bending stress values are 19 and 21 MPa (2,800 and 3,000 psi). Although
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