10.55-71 Grade B Grade BB Grade CP Grade C
3916.1-96 Grade I Grade II Grade III Grade IV
Pin knots Not more than 3 per square meter Allowed Allowed Allowed
Sound intergrown knots Allowed with diameter not more than 15 mm Allowed with diameter not more than 25 Allowed with cracks not wider than 1,5 mm Allowed
Other knots Allowed with maximum diameter 6 mm Allowed with maximum diameter 6 mm Allowed with maximum diameter 6 mm Allowed with maximum diameter 40 mm
Closed splits Maximum length 200 mm Maximum length 200 mm Allowed Allowed
Open splits Not allowed Allowed with maximum size 200*2 mm Allowed with maximum size 300*2 mm Allowed with maximum width 10 mm
Light discoloration Allowed not more than 5% of the surface Allowed Allowed Allowed
Heavy discoloration Not allowed Not allowed Not allowed Allowed
Glue penetration (through faces) Not allowed Allowed not more than 2% of the surface of the panel Allowed not more than 5% of the surface of the panel Allowed
Veneer overlapping Not allowed Allowed with maximum length 100 mm Allowed with maximum length 200 mm Allowed
Repairing by plugs Not allowed Allowed with single plugs Allowed with double plugs Allowed with double plugs
Sanding through faces Not allowed Not allowed Not allowed Allowed
Chinese Birch plywood 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.