MasterFormat Division 6 correct answers Wood, Plastics, and Composites
Tree Structure correct answers Bark: Outermost protective layer (A: dead, B: living)
Cambium layer (C): Source of new cells
Sapwood (D): Living cells that store and transport nutrients
Heartwood (E): Dead cells that contri...
COSC 253 EXAM 2 (Simms) || All Correct.
MasterFormat Division 6 correct answers Wood, Plastics, and Composites
Tree Structure correct answers Bark: Outermost protective layer (A: dead, B: living)
Cambium layer (C): Source of new cells
Sapwood (D): Living cells that store and transport nutrients
Heartwood (E): Dead cells that contribute to structural strength
Pith (F): Innermost, first year's growth
Annual growth rings (G): Result from differences in rate of tree growth and density of cells,
from spring to summer
Softwoods correct answers - from cone-bearing (coniferous) trees
- simple cell structure
- generally, plain grain structure (or figure) - pattern of grain and surface features
- primarily originate from North American forests
- fast-growing, plentiful, relatively in-expensive
- generally soft, easy worked
- used for structural wood products, finish trim, shingles, siding, flooring
- note: not all softwoods are soft! For example, Douglas Fir is harder than some hardwoods
Hardwoods correct answers - from broad-leaf (deciduous) trees
- more complex cell structure
- often more interesting grain structure/figure
- harvested from around the world
- slower growing, generally more expensive than softwoods
- denser, with greater variety of color and figure
- for fine trim, paneling, flooring, fine cabinet work, furniture
Environmentally Certified Wood correct answers - comes from largest forests that are managed
to meet certain standards
- Forest Stewardship Council (FSC) certification program
-- Chain of Custody Certification
-- FSC Controlled Wood (less stringent)
- Chain of Custody Certified Wood eligible for points in the LEED rating system
Sustainability of Wood correct answers - wood is the only major structural material that is
renewable
- in North America, annual tree growth exceeds the volume of harvested trees
- manufactured wood products efficiently use waste (chips, strands,
sawdust, scraps, etc.)
- if the wood frame of a building is kept dry, it can last indefinitely
Sawing correct answers - plainsawn: growth rings roughly parallel to wider face of board
- quartersawn: growth rings close to perpendicular to wider face of board
, Plainsawn Lumber correct answers - most economical sawing method
- produces maximum yield of useful pieces
- lumber experiences greater distortion (crook, bow, cup, twist) during drying process
Quartersawn Lumber correct answers - requires more handling of the log during sawing
- not as efficient, generates more waste
- lumber is more dimensionally stable
- produces more pleasing grain figure
Seasoning correct answers - after lumber is sawn, it is seasoned (dried), either in air or in kilns
- kiln drying usually preferred over air drying
- kiln drying uses more energy but is faster and produces more stable, uniform lumber
- seasoned lumber is lighter, stronger, and stiffer than green (unseasoned) lumber
Seasoning (moisture content) correct answers - Moisture Content (MC) - amount of water
present in wood
- Determining MC = (Wet Wt. - Dry Wt.)/Dry Wt. x 100
- standard framing lumber is seasoned to MC 19 at the mill
- decay causing fungi cannot survive in wood with a moisture content (MC) below ~20%
- MC of growing wood can vary from 30 percent to 200 percent
Seasoning (shrinkage) correct answers - wood does not shrink/swell uniformly with changes in
MC
- shrinkage along the length of the log (longitudinal) is minimal
- radial shrinkage is larger
- tangential shrinkage is larger again by half or more and causes radial cracks called checks
- Difference between rates of tangential and radial shrinkage cause distortions in shape,
especially in plainsawn lumber
- as wood dries below approximately 30 percent MC, it shrinks, mostly in cross section, and only
slightly in length
- wood eventually dries to equilibrium with the surrounding air, reaching its equilibrium
moisture content (EMC)
-- EMC for exterior uses: ~ 12%
-- EMC for interior uses: ~ 8%
Surfacing correct answers - lumber is surfaced to make it smooth and more dimensionally
precise
- Framing lumber: usually surfaced four sides (S4S)
- Finish lumber: may be S4S, or surfaced two sides (S2S), the other
sides to be sawn and surfaced by the woodworker
- Surfacing after seasoning (S-DRY) most common: removes some drying distortions
- Surfacing before seasoning (S-GRN): sometimes more economical; best for wood species that
don't distort excessively as they dry
- Construction planking: unsurfaced; Plank is stronger (no material has been removed) and more
slip-resistant
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller FullyFocus. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R199,94. You're not tied to anything after your purchase.
