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| Essay:OSB - A research project in exterior sheathingOriented strandboard (OSB), as well as other types of particle panel boards, is gaining wide acceptance and usage in construction since 1980's in North America and is being marketed to other regions of the world such as Japan and Europe. The continued popularity of OSB depends both on the (perceived) suitability of OSB and social-economical-market forces and trends in the construction industry.
OSB and composite wood panels Composite wood panels have been recognized and used as alternatives to lumber for their resource oriented process and enriched properties through manufacturing. Particle panel boards (particleboard, waferboard and oriented strandboard) are manufactured using residue of woodmill or small-diameter logs that are previously under-utilized. They have a viable potential in time of curtailed timber supplies due to reducing forest, demand from conservation groups and public for saving the environment, and more stringent logging regulations. They are widely used in North America and are gaining popularity in Japan, Europe and other countries [R-654] Oriented strandboard (OSB) is a newer type of the particleboard that are made from relatively large flakes or shavings. Since its first production in 1964 in Canada, it had a rapid growth in 1980s that still has a strong momentum today. Figure 1 shows the recent trend of OSB production in US and Canada. The majority of OSB application is in the construction industry, especially in the residential sector. The social-economic trends and housing market will affect the market of the OSB. To market in other countries where wood and wood products are not traditional construction material or local construction methods, persuasions in addition to technology and economy advantages of OSB will be necessary. However, technical understanding and proved suitability of OSB in construction can strengthen the driving force of the current upward momentum in North America, and provide strong support for opening up new market in other regions of the world.
Building envelope and use of OSB The use of OSB in new residential construction is mainly in floor system, exterior wall sheathing, roof sheathing, and exterior siding. It also finds its use as I-joist webstock and as components in other engineered wood products. As a building envelope component, OSB should be subjected to the examination similar to other materials. Building envelope is currently under concerted collaborative assessment by the industry and research community. Among other problems, uncontrolled moisture transport and accumulation have been identified to be the most important factor that reduces the structural integrity of its components through mechanical, chemical and biological degradation. The hygrothermal process in building envelope is very complex and involves coupled heat, air and moisture transfer through the envelope as a results of the interaction within the width of the envelope and with the outdoor and indoor environments. For cold climate, for example, high thermal insulation and moisture migration from indoor to outdoor and interstitial condensation have been recognized as one of the main causes of moisture building-up in the building envelope.
[By J. Rao, 1999]
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