Oriented strand board OSB is a type of engineered wood similar to particle boardformed by adding adhesives and then compressing layers of wood strands flakes in specific orientations. It was invented by Armin Elmendorf in California in Though it may seem intuitive to assume that the term "chipboard" refers to oriented strand board based on its appearance, and to contrast it against particle boardthe two terms are treated as synonyms by the industry, with the "chips" in chipboard being of a size that a lay person would readily judge to be "particles".
OSB is a material with favorable mechanical properties that make it particularly suitable for load-bearing applications in construction. For exterior wall applications, panels are available with a radiant-barrier layer laminated to one side; this eases installation and increases energy performance of the osb eller golvspån envelope.
OSB is also used in furniture production. Oriented strand board is manufactured in wide mats from cross-oriented layers of thin, rectangular wooden strips compressed and bonded together with wax and synthetic resin adhesives. The adhesive resins types used include: urea-formaldehyde OSB type 1, nonstructural, nonwaterproof ; isocyanate -based glue or PMDI poly- methylene diphenyl diisocyanate based in inner regions with melamine - urea-formaldehyde or phenol formaldehyde resin glues at surface OSB type 2, structural, water resistant on face ; phenol formaldehyde resin throughout OSB types 3 and 4, structural, for use in damp and outside environments.
The layers are created by shredding the wood into strips, which are sifted and then oriented on a belt or wire-mesh caul a heated, ventilated support and coated with the resin. Individual layers can also vary in thickness to give different finished panel thicknesses typically, a 15 cm 5.
The mat is placed in a thermal press to compress the flakes and bond them by heat activation and curing of the resin that has been coated on the flakes. Individual panels are then cut from the mats into finished sizes. Materials other than wood have been used to produce products similar to OSB.
Oriented structural straw board is an engineered board made by splitting straw and formed by adding P-MDI adhesives and then hot compressing layers of straw in specific orientations. Adjustments to the manufacturing process can affect thickness, panel size, strengthand rigidity.
OSB panels have no internal gaps or voids, and can be water-resistant, although they do require additional membranes to achieve impermeability to water and are not recommended for exterior use. The finished product has properties similar to plywoodbut is uniform and cheaper.
When tested to failure, OSB has a greater load-bearing capacity than milled wood panels. While OSB does not have a continuous grain like a natural wood, it does have Diverse frågor strength on its long axis because more of the component grains are oriented in this direction.
This can be seen by observing the alignment of the surface wood chips. All wood-based structural use panels can be cut and installed with the same types of equipment as for solid wood. The resins used to create OSB have raised questions regarding the potential for OSB to emit volatile organic compounds such as formaldehyde.
Urea-formaldehyde is more toxic and should be avoided in home use. Phenol-formaldehyde products are considered to be relatively hazard-free. Some newer types of OSB, so-called "new-generation" OSB panels, use isocyanate resins that do not contain formaldehyde and are considered nonvolatile when cured.
Some manufacturers treat the wood chips with various borate compounds that are toxic to termiteswood-boring beetlesmoldsand fungibut not mammals in applied doses. Five grades of OSB are defined in EN in terms of their mechanical performance and relative resistance to moisture: [2].