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Types
Average-quality plywood with show veneer
High-quality concrete pouring plate in plywood
Different varieties of plywood exist for different applications:-
[edit]Softwood plywood
Softwood panel is usually made either ofcedar, Douglas firorspruce, pine, and fir(collectively known as spruce-pine-
firor SPF) orredwood and is typically used for construction and industrial purposes.[1]
The most common varieties of softwood plywood come in three, five or seven plies with a metric dimension of 1.2 m 2.4
m or the slightly larger imperial dimension of 4 feet 8 feet. Plies vary in thickness from 1/10" through 1/6" depending on
the panel thickness. Roofing can use the thinner 5/8-inch plywood. Subfloors are at least 3/4-inch thick, the thickness
depending on the distance between floorjoists. Plywood for flooring applications is often tongue and groove; the mating
edge will have a "groove" notched into it to fit with the adjacent "tongue" that protrudes from the next board. This prevents
one board from moving up or down relative to its neighbour, so providing a solid feeling floor when the joints do not lie
over joists. Tongue & groove flooring plywood is typically 1" in thickness.
[edit]Hardwood plywood
Used for demanding end uses. Birch plywood is characterised by its excellent strength, stiffness and resistance to creep.It has a high planar shear strength and impact resistance, which make it especially suitable for heavy-duty floor and wall
structures. Oriented plywood construction has a high wheel-carrying capacity. Birch plywood has excellent surface
hardness, and damage- and wear-resistance.[2]
[edit]Tropical plywood
Tropical plywood is always made of mixed species of tropical wood in the Asian region. Tropical plywood boasts its
superiority over softwood plywood due to its density, strength, evenness of layers, and high quality. It is usually sold at a
premium in many markets if manufactured with high standards. Tropical plywood is widely used in UK, Japan, Taiwan,
Korea, Dubai, and other major cities worldwide. It is the most preferred choice for construction purposes in many regions.
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The
hesies
sed i
l
dhave
jecomea
oi
t ofconcern. Bothrea formaldehydeand
henol formaldehydeare
carcinogenic inveryhighconcentrations. Asaresult, manymanufacturersare turning to low formaldehyde-emittingglue
systems, denotedj yan k Ek ratingl
k Em
k
ossessing the lowest formaldehydeemissions). Plywood
roduced tok Em
k has
effectively zero formaldehydeemissions.[ n ]
Inaddition to thegluesj eingj rought to the forefront, thewoodresources themselvesare j ecoming the focusof
manufacturers, due in
art toenergyconservation, aswell asconcern forournatural resources. Thereareseveral
certificationsavailable tomanufacturerswho
artici
ate in these
rograms. o orest Stewardshi
Councill
oSC), Leadershi
in Energyand Environmental
esignl
LEE
),Sustainableo
orestry Initiativel
SoI), and
Greenguardareall certification
rograms that ensure that
roductionandconstruction
racticesaresustainable. Manyof
these
rogramsoffer taxbenefits toboth themanufacturerand theenduser.[ ]
[edit]Sizes
Themost commonlyused thicknessrange is fromm
.
in.l
.
cm.) to
.
m
in.l
7
mm.). Thesizesof themost commonly
used
lywoodsheetsare
ft.l
.
m.)wideby
ft.
l
.
m.)or
ft.
l m
.9 m.)by
ft.l
.
m.). Widthand lengthmayvary in
ft.l
m
.
m.) in increments.
In
S, themost commlyusedsize is: ft by ft or
ft by
ft [z
]
[edit]Grades
Gradingrulesdifferaccording to thecountryoforigin. Most
opularstandard is the British Standardl
BS)and American
Standardl
ASTM).{oyce
l
97
m
), however, list somegeneral indicationofgradingrules:[ | ]
Grade Description
A Face and back veneers practically free from all defects.
A/B Face veneers practically free from all defects. Reverse veneers with only a few small knots or discolorations.
A/BB Face as A but reverse side permitting jointed veneers, large knots, plugs, etc.
B Both side as reverse of A/B
B/BB Face as reverse of A/B. Reverse side as reverse of A/BB
BB Both sides as reverse of B/BB
WG Guaranteed well glued only. All broken knots plugged.
X Knots, knot-holes, cracks, and all other defects permitted.
[edit]Applications
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Plywood isused inmanyapplications that needhigh-quality, high-strengthsheet material. Quality in thiscontext means
resistance tocracking, breaking, shrinkage, twistingandwarping.
Exteriorgluedplywood issuitable foroutdooruse, but becausemoistureaffects thestrengthofwood, optimal
performance isachieved inenduseswhere thewood'smoisturecontent remainsrelatively low.}
n theotherhand,
subzeroconditionsdon't affect plywood'sdimensional orstrengthproperties, whichmakessomespecial applications
possible.
Plywood isalsousedasanengineeringmaterial forstressed-skinapplications. It hasbeenused formarineandaviation
applicationssince WWII. Most notable is the British~
eavilland Mosquitobomber, whichwasprimarilymadeout of
wood. Plywood iscurrentlysuccessfullyused instressed-skinapplications.[citation needed]
. The American
designersCharlesand ay Eamesare famous fortheirplywood-based furniture, whilePhil Bolger is famous for
designingawiderangeofboatsbuilt primarilyofplywood.
[edit]S l appli ati ns
Typical endusesofspruceplywoodare:
loors, wallsandroofs inhouseconstructions
Windbracingpanels
Vehicle internal bodywork
Packagesandboxes
encing
Therearecoatingsolutionsavailable that mask theprominent grainstructureofspruceplywood.orthesecoated
plywoods therearesomeenduseswherereasonablestrength isneededbut the lightnessofspruce isabenefit e.g.:
Concreteshutteringpanels
eady-to-paint surfaces forconstructions[edit]Birchpl applicati ns
Coatedspecial birchplywood is typicallyusedasaready-to-install component e.g.:
Panels inconcrete formworksystems
loors, wallsandroofs in transport vehicles
Containerfloors,
loorssubjected toheavywearinvariousbuildingsand factories,
Scaffoldingmaterials
Birchplywood isusedasastructural material inspecial applicationse.g.:
Wind turbineblades
Insulationboxes forLiquefied Natural GasLNG)carriers
Smoothsurfaceandaccurate thicknesscombinedwith thedurabilityof thematerial makesbirchplywooda favourable
material formanyspecial endusese.g.:
ie-cuttingboards
Supportingstructure forparquet
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Playgroundequipment
urniture
Signsand fences fordemandingoutdooradvertising
Musical instruments
Sportsequipment
[edit]Tropical pl oodapplications
Tropical plywood iswidelyavailable from the South-East Asiaregion, mainly from Malaysiaand Indonesia. Tropical
plywoodboastspremiumquality, andstrength.ependingonmachinery, tropical plywoodcanbemadewithhigh
accuracy in thickness, and isahighlypreferablechoice in America,
apan, Middle East, Korea, andotherregionsaround
theworld.
Commonplywood
Concretepanel
loorbase
Structurepanel
Containerflooring
Laminboard
Laminated VeneerLumber
LVL)