Ttypes of Plywood

8/6/2019 Ttypes of Plywood

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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)

Documents

Ttypes of Plywood