Plywood Knowledge and Grading Rules

DIFFERENT COUNTRIES AND MARKETS ,PLYWOOD STANDARD AND GRADE

Plywood Standard And Grade

BSI Standard and Grade
Russian GOST_3916-96
JPIC Standard and Grade
BS1088 Standard
Russian Birch Grade
SFS Birch Grade
Indonesian Plywood Grade
IHPA standard of Hardwood Face Grade
HPVA standard Grade
ANSI Face And Back Grade
South East Asian Plywood Grading Rules
China Plywood Grade

EXOTIC PLYWOOD GRADE RULES

Indonesian/Malaysian Grade Rules
FD Grade Free-Of-Defect, very similar characteristics to an ANSI/HPVA “A” Grade.
BB Grade Smooth, tight cut, full length veneer. Natural characteristics of the wood such as pin knots, sound burls, color streaks and spots are allowed. Dead knots, stain and mineral streaks, decay, open splits, rough cut, torn grain, symmetrical patches are not allowed.
CC Grade Natural characteristics of the wood are allowed. However, in comparison to the “BB Grade” the following characteristics ARE permitted: Color, dead knots and rough cut (if well puttied), and hairline splits (max. 6”).
OVL Grade Overlay and Better Grade. In addition to BB and CC grade, OVL may contain dead knots and knot holes (if well puttied), stain and mineral streak, hairline splits (max. 12”), rough cut and torn grain.
Industrial Allows open defects such as splits and gaps at the veneer joint as well as all the natural characteristics of the wood specie.
Note: The BB and CC grades are usually combined and marketed as a BB/CC panel.
Chinese Grade Rules
B/C or B/2 Grade Fairly uniform in color with slight contrasts allowed. Small conspicuous burls and pin knots allowed with a minimum number of scattered sound or repaired knots. Both faces are typically sanded smooth. The “C” back grade is typically more on the C minus to D plus grade or compatible to a #1 and #2 mix back grade on ANSI/HPVA standards.
C/D or C/2 Grade A larger color contrast is allowed. There are a unlimited number of conspicuous burls and pin knots and greater quantity of scattered sound and repaired knots allowed. “Blended Repaired” is allowed whereby splits in the veneer will be repaired with color matched putty. The “D” back grade is typically more on the D minus grade or compatible to a #2 and #3 mix back grade on ANSI/HPVA standards.
D/E or D/3 Grade All defects not permitted by C grade will generally be allowed on D grade. More sound and dark pin knots, repaired knot holes, longer putty repaired veneer splits will be allowed, but the number of knot holes is the major determining factor. The “E” back grade borders in grade and similarity to the #4 or reject back grade on ANSI/HPVA standards.
Note: The majority of these panels are laid up on a Chinese Poplar core. IT IS VERY IMPORTANT TO UNDERSTAND THE APPLICATION OF THE PANEL. B Grade: often used for upper-end cabinetry, architectural millwork, and furniture. C Grade: used primarily on paint grade type applications, in lower-end casework, and for cabinet interiors in upper-end cabinetry. D Grade: used for non-visible cabinet parts.
Russian (Baltic) Birch Grade Rules
B Grade One piece sanded face with even color. No patches, voids or mineral streaks allowed.
BB Grade One piece sanded face with generally even color. Slight pin knots and mineral streaks allowed. Open knots and defects are cut out and replaced with oval patches.
CP Grade This is a fall down from BB with more patches on the face that may not always be matched for color. Splits less that 0.5 mm are allowed.
C Grade Un-sanded face that allows patches, open knots and veneer splits.
Note: Russian Birch panels are a consistent specie throughout the panel (core and face and back veneer).

WHAT THESE “VENEER CONSTRUCTION ” JARGON MEANS ?FOR NEW FRESH PLYWOODMAN TO LEARN

Veneer Construction
P/S = Plain Sliced
WPF = Whole Piece Face
SPF = SPF = Sliced Piece Face
QSF = Quarter Sawn Face
1/2 PF = Maximum 2 Piece on Face
3/4 PF = Maximum 4 Piece on Face
Shop = Down Fall from any above
grade due to manufacturing
flaws. Still allows for 85%
usable surface.

WHAT IS CROSSGRAINVENEER SHEET ?

CrossgrainVeneer sheet in which the grain of the wood runs in the 4′ direction. This is denoted as 8’x4′. Width is the measurement across the grain, while length is the measurement with the grain. The first number is always the width and the second is the length.

MANY CHINESE SALES PEOPLE ASKED ME THE DEFINITION & CHARACTERISTICS OF MDO PLYWOOD AND HDO PLYWOOD

“MDO” plywood (Medium Density Overlay) is constructed of a core of overlapping veneers of wood, but with a surface layer of medium density fiber. The resulting product has a smooth surface. MDO plywood can be used once as a concrete form material, but should not be re-used for that purpose.

“HDO” (High Density Overlay) plywood is similar to MDO Plywood described just above. HDO plywood also is constructed wit a core of overlapping wood veneers, but instead of using a medium density fiber for its external surfaces, HDO plywood uses a high-density fiber exterior. HDO plywood products, having a harder exterior surface, can be re-used several time for concrete forms.

GLOSSARY OF THE PLYWOOD ,CERTIFICATES AND INDUSTRY STANDARD FROM DIFFERENT COUNTRIES AND MARKETS

BS British Standard
IHPA International Hardwood Products Association
IPS Indonesian Plywood Standard
JAS Japanese Agricultural Standard
JPIC Japan Plywood Inspection Corporation
 
Plywood Uses
Type I Exterior
Type II Interior
 
Glue Type
Type I/WBP WBP (Water and Boil Proof) using phenolic resin
Type I/MEL Melamine resin
Type II/MR MR (Moisture Resistant) using urea resin
 
Glue Emission Level 
LFE Low Formaldehyde Emission
New JAS
F**** Formaldehyde Emission – average 0.3 mg/L, maximum value 0.4 mg/L
F*** Formaldehyde Emission – average 0.5 mg/L, maximum value 0.7 mg/L
F** Formaldehyde Emission – average 1.5 mg/L, maximum value 2.1 mg/L
F* Formaldehyde Emission – average 5.0 mg/L, maximum value 7.0 mg/L
 
Grade of Veneers
Face Grades BB
  CC
  Overlay
  Utility
 
  JAS Grade-1
  JAS Grade-2

TIGHT SIDE AND LOOSE SIDE OF THE FACE VENEER ?

TIGHT SIDE AND LOOSE SIDE

There are two faces to each sheet of veneer, and on each sheet one face will be the “loose” side, and the other will be the “tight” side.

When you bend a sheet of veneer with the grain, it will bend further and more easily on the loose side than on the tight side.

The difference between each side is caused by the action of the veneer slicing blade upon the cells of the wood. The blade tends to open up and tear the cells on the loose side, while closing and compressing the cells on the tight side.

now the white birch plywood is really complicated ,so many grades created by buyers and manufacturers according to the market changes .

B ,C ,C+,C-,D+,D,D-,E+ ,E- or E …F ….

Even the fancy plywood started to use more complicated rules and groups …

So ,for the foreign buyers ,not easy to understand the exact rules now ,even for our QC not easy to understand if just looking the prices if not go to check the plywood quality in personal on site .

so ,when the foreign improters received quotation from the chinese plywood suppliers,make sure the quality are exactly what you are looking for and the prices matched ,or ,prices are nothing and quality are nothing …

even the same manufactuers ,their customers have different grading rules and qulaity requirements ,how you can recognize the quality ?

Plywood Abbreviations
   • FC: Fiber Core
• G1S: Good 1-Side
• G2S: Good 2-Sides
• HDF: High Density Fiber– to 58 lbs./cu. ft.
• HDO: High Density Overlay
• LC: Lumber Core
• MDF: Medium Density Fiber– to 48 lbs./cu.ft.
• MDO: Density Overlay
• OES: Oiled/Edge Sealed
• OC: On Center
   • PC: Particle Core
• PF1: Prefinished 1-side
• PF2: Prefinished 2-Sides
• PS: Plain Sliced
• PTS: Plugged/Touch Sanded
• S,M&N: Sequence,Matched/Numbered
• T/G: Tongue/Grooved
• VC: Veneer Core
• WPF: Whole Piece Face

DEFINITIONS OF THE DIFFERENT VENEER CUTTINGS

Definitions of the Different Veneer Cuttings:
rotary cut
R/C ROTARY CUT:  The log is centrally mounted on a computerized, hydraulic lathe and turned at a high speed against a special knife, which peels the veneer in a long continuous sheet, similar to unwinding a roll of paper.  A wide variegated grain pattern is often the result.  Rotary cut veneer is either left as a whole piece veneer, or is cut into narrower widths to be assembled later into a spliced veneer face.
plain slice
P/S PLAIN SLICED:  The log is cut into half lengthwise.   The half log is then moved back and forth against a stationary knife, producing parallel slices through the center of the log.  This produces narrow strips of veneer that closely match that of flat sawn lumber.  The narrow strips of veneer are assembled later to form the veneer face.
rift cut
RIFT SLICED:  Rift sliced veneer is produced in much the same way as plain sliced veneer except that the log is cut into quarters lengthwise.  The log is then sliced at a 90 degree angle to the grain.  This produces narrow strips of veneer with a straight vertical grain.  The narrow strips of veneer are assembled later to form the veneer face.
quarter slice
QUARTER SLICED:  Quarter sliced veneer is produced in the same way as rift sawn veneer.
Veneer Matching
SLIP MATCH
WHOLE PIECE
PLEASING MATCH
BOOK MATCH
RANDOM MATCH
slip match
whole piece match
pleasing match
book match
random match
Adjacent veneer sheets are joined side by side, same sides up, for a uniform grain pattern. One single piece of veneer is used, with continuous grain characteristics running across the sheet. Veneers are matched by color or similarity, not necessarily by grain characteristics. Every other piece of adjacent veneer is turned over, resulting
in identical, but
opposing patterns.
Veneers intentionally do not match at the joints, providing a casual effect.

 

DOMESTIC PLYWOOD GRADE RULES

Face Grades A Grade B Grade C Grade D Grade
Birch, Ash, Maple and Poplar: Rotary-Cut, Plain-Sliced
Pin Knots and Small Burls, Comb. Avg. ANSI 10- 4 to 1/4″ 16- 8 to 1/4″ No Limit No Limit
Conspicuous Burls, Max. ANSI 3/8″ 1/2″ No Limit No Limit
Sound and Repaired Knots in Comb ANSI No 4 8 10
Repaired Knots ANSI No 4 to 1/8″ 4 to 1/2″ 5 to 3/4″
Mineral Streaks ANSI Slight Slight Yes Yes
Vine ANSI Slight Yes Yes Yes
Rough Cut ANSI No Slight Two 8″ Areas 5% of Panel
Blended Repaired Tapering Hairline Splits ANSI Two 1/16″ x 6″ Four 1/8″ x 8″ Four 3/16″ x 8″ Six 1/4″ x 10″
Face Grades A Grade B Grade C Grade
Red and White Oak: Rotary-Cut, Quarter-Cut, Plain-Sliced
Pin Knots and Small Burls, Comb. Avg. ANSI 12- 10 to 1/4″ 24- 16 to 1/4″ No Limit
Sound and Repaired Knots in Comb ANSI No 4 8
Repaired Knots ANSI No 4 to 1/8″ 4 to 1/2″
Mineral Streaks ANSI Slight Few to 8″ Yes to 12″
Sap ANSI 5% Up to 20% Yes
Blended Repaired Tapering Hairline Splits ANSI Two 1/16″ x 6″ Four 1/8″ x 8″ Four 3/16″ x 8″
Back Grades 1 Back 2 Back 3 Back 4 Back
Sound Tight Knots ANSI 16 to 3/8″ 16 to 3/4″ Max 16 1/2″-1 1/2 Yes
Knotholes ANSI No All Repaired All 3/8″ 10 to 1 Up to 4″
Repaired Knots ANSI No 8 to 1/2″ Not No
Sound Tight Burls ANSI Yes Yes Yes Yes
Mineral/Sap ANSI Yes/Yes Yes/Yes Yes/Yes Yes/Yes
Rough Cut ANSI Two 8″ Dia. Areas Yes Yes Yes
Joints or Splits ANSI Six 1/8″ x 12″ Rep’rd Six 3/16″ x 12” Rep’rd 3/8″ x 1/4″ LOP 1″ to 1/4 LOP, 1/2″ to 1/2 LOP, 1/4″ to Full LOP

 

Indonesian/Malaysian Grade Rules
FD Grade Free-Of-Defect, very similar characteristics to an ANSI/HPVA “A” Grade.
BB Grade Smooth, tight cut, full length veneer. Natural characteristics of the wood such as pin knots, sound burls, color streaks and spots are allowed. Dead knots, stain and mineral streaks, decay, open splits, rough cut, torn grain, symmetrical patches are not allowed.
CC Grade Natural characteristics of the wood are allowed. However, in comparison to the “BB Grade” the following characteristics ARE permitted: Color, dead knots and rough cut (if well puttied), and hairline splits (max. 6″).
OVL Grade Overlay and Better Grade. In addition to BB and CC grade, OVL may contain dead knots and knot holes (if well puttied), stain and mineral streak, hairline split (max. 12″), rough cut and torn grain.
Industrial Allows open defects such as splits and gaps at the veneer joint as well as all the natural characteristics of the wood specie.
NOTE: The BB and CC grades are usually combined and marketed as a BB/CC panel.

 

Chinese Grade Rules
B/C or B/2 Grade Fairly uniform in color with slight contrasts allowed. Small conspicuous burls and pin knots allowed with a minimum number of scattered sound or repaired knots. Both faces are typically sanded smooth.The “C” back grade is typically more on the C minus to D plus grade or compatible to a #1 and #2 mix back grade on ANSI/HPVA standards.
C/D or C/2 Grade A larger color contrast is allowed. There are a unlimited number of conspicuous burls and pin knots and greater quantity of scattered sound and repaired knots allowed. “Blended Repaired” is allowed whereby splits in the veneer will be repaired with color matched putty. The “D” back grade is typically more on the D minus grade or compatible to a #2 and #3 mix back grade on ANSI/HPVA standards.
D/E or D/3 Grade All defects not permitted by C grade will generally be allowed on D grade. More sound and dark pin knots, repaired knot holes, longer putty repaired veneer splits will be allowed, but the number of knot holes is the major determining factor. The “E” back grade borders in grade and similarity to the #4 or reject back grade on ANSI/HPVA standards.
NOTE: The majority of these panels are laid up on a Chinese Poplar core. IT IS VERY IMPORTANT TO UNDERSTAND THE APPLICATION OF THE PANEL.
B Grade: often used for upper-end cabinetry, architectural millwork, and furniture.
C Grade: used primarily on paint grade type applications, in lower-end case work, and for cabinet interiors in upper-end cabinetry.
D Grade: used for non-visible cabinet parts.

 

Russian (Baltic) Birch Grade Rules
B Grade One piece sanded face with even color. No patches, voids or mineral streaks allowed.
BB Grade One piece sanded face with generally even color. Slight pin knots and mineral streaks allowed. Open knots and defects are cut out and replaced with oval patches.
CP Grade This is a fall down from BB with more patches on the face that may not always be matched for color. Splits less that 0.5 mm are allowed.
C Grade Un-sanded face that allows patches, open knots and veneer splits.
NOTE: Russian Birch panels are a consistent specie throughout the panel (core and face and back veneer).

VENEER GRADES – HPVA ,ACCEPTED FACE GRADES AS ESTABLISHED BY THE HPVA

VENEER GRADES – HPVA

 

 

Following are the accepted face grades as established by the HPVA.

Source : http://www.veneernet.com/grades.html

GRADE AA -The veneer shall be smooth, tight cut and full length. When the face consists of more than one veneer component or piece, the edges shall appear parallel and be edge matched as described for the various species in 200-S-9. Rotary cut faces may be whole piece or multipiece with edge joints tight and no sharp color contrasts at the joints. Species specified for natural color will allow color contrasts, but must be book matched or conform to the type of matching specified. The components of plain sliced (flat cut) faces will be book matched, unless otherwise specified, and arranged, at the option of the woodworker, with a running, balanced, or center match, unless otherwise specified. Plain sliced faces will consist of two or more components and rotary faces will consist of one or more components with no component less than 152 mm (6″) wide except for outside components which may be less than 152 mm (6″) to allow for certain types matching or panel edge trim loss. No plain sliced components will have a split heart. No full quarter cut is allowed in plain sliced faces. The width of any single component in quartercut rift cut or comb grain faces shall not be less than 76 mm (3″) except for outside components which may be less than 76 mm (3″) to allow for matching and edge trimming.

Hardwood veneer faces from species not covered in 200-S-9 may contain small burls and occasional pin knots not to exceed 6 mm (1/4″) in total diameter and 3 mm (1/8″) in diameter of the dark pin knot centers. Color streaks or spots: two repaired, tapering hairline splits not to exceed 1.5 mm (1/16″) by 152 mm (6″); and small inconspicuous repairs are also permitted. Unfilled wormholes. rough cut veneer. knots (other than pin knots), shake, and doze and other forms of decay will not be permitted.

GRADE A – The veneer shall be smooth. tight cut and full length. When the face consists of more than one veneer component or piece, the edges shall appear parrel and be edge matched as described for the various species in 200-S-9. Rotary cut faces may be whole piece or multipiece with tight edgejoints; however, no sharp colorcontrasts are permitted at the joints and the face will provide a good general appearance. Species specified for natural color will allow color contrasts, but must be book matched or conform to the type of matching specified. The components of plain sliced (flat cut) faces will be book matched, unless otherwise specified, and arranged, at the option of the woodworker, with a running, balanced, or center match, unless otherwise specified. Plain sliced faces will consist of two or more components and rotary faces will consist of one or more components, with no component less than 127 mm (5″) wide except for outside components which may be less than 127 mm (5″) to allow for certain types matching or panel edge trim loss. Split heart is permitted if manufactured cathedral is achieved. No full quarter cut is allowed in plain sliced faces. The width of any single component in quarter cut, rift cut or comb grain faces shall not be less than 76 mm (3″) except for outside components which mav be less than 76 mm (3″) to allow for matching and edge trimming. In some species sapwood is permitted: in other species it may be permitted bv agreement between buyer and seller.

Hardwood veneer faces from species not covered in 200-S-9 may contain small burls and occasional pin knots not to exceed 6 mm (1/4″) in total diameter and 3 mm (1/8″) in diameter of the dark pin knot centers. Color streaks or spots, two repaired, tapering hairline splits not to exceed 1.5 mm (1/16″) by 152 mm (6″); and small inconspicuous repairs are also permitted. Unfilled wormholes. rough cut veneer, knots (other than pin knots), shake, and doze and other forms of decay will not be permitted.

GRADE B – The veneer shall be smooth, tight cut and full length. Slip or book matched veneers are available if specified bv the buver. If not specified. multipiece faces will be pleasingly matched. Sharp color contrasts at the joints are not permitted. and natural variations in grain and color will be blended to the extent possible. Species specified for natural color will allow color contrasts, but must be pleasing matched or conform to the type of matching specified. Plain sliced faces will consist of two or more components with no component less than 76 mm (3″) wide and rotary faces will consist of one or more components with no component less than 102 mm (4″). Outside components may be less than 76 mm (3″) for plain sliced faces and 102 mm (4″) for rotary faces to allow for certain types of matching or panel edge trim loss. Some full quartercut is permitted in plain sliced faces. For some species unlimited sapwood is allowed, and in other species a percentage of sapwood is allowed.

Hardwood veneer faces from species not covered in Section 2OO may contain small burls and occasional pin knots not to exceed 6 mm (1/4″) in total diameter and 3 mm (1/8″) in diameter of the dark pin knot centers. Color streaks or spots, two repaired, tapering hairline splits not to exceed 3 mm (1/8″) by 203 mm (8″); and small inconspicuous repairs are also permitted. Unfilled wormholes, rough cut veneer, knots (other than pin knots), shake, and doze and other forms of decay will not be permitted.

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