- Количество слайдов: 12
Wood Utilization—Wood Industry in North America
How much wood is used in building a house? For a 2000 ft 2 wood-framed house • 16, 2000 board ft. (1 bf = 1’ x 1”) Lumber or 1, 350 ft 3 or 20. 5 m 3 or 20 pine trees (30” DBH) • Plus 9, 500 ft 2 (based on 0. 5” thick) Structural Panels or 400 ft 3 or 300 4’ x 8’ x 0. 5” sheets of Plywood, OSB, or Hardboard for sheathing, decking & siding • Wood for decks and non-structural panels are extra
Lumber • Solid lumber is good but subjects to availability and variability in physical properties • Can be substitutes by engineered wood products, such as Parallel Strand L, I-joist, Laminated Veneer L and Laminated Strand L Plus Glue-laminated Timber Glulam PSL I-Joist LVL LSL
Advantages of Engineered Products • Value-added and conservative These products made from materials of lower grades and processing residues • Predictable physical properties and performances
Disadvantages • Wood is good but needs to be protected from many enemies Fires destroy houses And billions of dollars Property lose annually Along with 12, 200 fatalities
Enemies of Wood • Termites also destroy houses Annual property lose: 250 M$ Costs 125 M$/yr in Corrective measures.
Wood Decays Millions are spent annually to repair houses due to decay Bath room leakage causes decay A brown-rot fungus is eating up the wood My Pella window decayed Only because of inproper installation!
The wood industry is proud to be environmentally friendly • A survey was conducted in 1996 by the Forest Products Laboratory to identify Top Ten Most Significant Forest Products Technologies
Here They Are #1 Development of wood preservative treatments to extend the service life of wood --How many trees saved? #2 Oriented Strand Board manufacturing --Use low-value species and milling residues
#3 Manufacturing paper from hardwood and wood wastes --Again, saving more valuable softwoods #4 Technology for plywood production from Southern pine --Saved many big Douglas fir and larch trees
#5 Methods to utilize alternative/low-value species #6 Methods of processing small logs --Computer technologies make it possible #7 Development of composite products from waste or low-value woods/fibers including hardboard, particleboard, medium density fiberboard, wood/plastic composites
#8 Development of recycling technologies for paper, wastewood and agricultural fibers #9 Development of non-toxic wood preservatives #10 Technology transfer to the forest products industry