Plywood grade descriptions

Birch Plywood is subdivided by the following grades depending on face veneer quality:

 


Plywood grade is marked by face and back veneer quality (face/back). For example:
Е/В ( E/I ), В/В ( I/I ), I/II, II/II, II/III, II/IV, III/III, III/IV, IV/IV etc.



Grade "E" (Elite): Perfect grade


Grade E

Categories of defects

Permissible amount of defects

Pin knots

Permitted

Irregularities in the structure of wood

Permitted, but slight

Coloured streaks

Permitted accosionally




Grade "B" ( I ): Almost without deffects intended for natural finish. For furniture construction and decoration.


Grade B

Categories of defects

Permissible amount of defects

Pin knots

Permitted up to 3 per 1 m²

Other knots and patched holes:

sound knots


unsound (falling) knots


Permitted up to an individual maximum diameter of 15 mm in amount of 5 per 1 m²

Permitted up to an individual maximum diameter of 6 mm in amount of 3 per 1 m²

Knots and knotholes repairement

Not Permitted

Irregularities in the structure of wood

Permitted

Hearth and discoloration

Not more than 5% of surface

Closed splits and checks, patched

Permitted for an individual maximum length up to 200 mm in amount of 2 per 1 m width of sheet

Open splits

Not Permitted

Discolouration and coloured streaks

Permitted, but slight

Defects at the edges due to sanding or sawing

Allowed up to 2 mm from the edge

Glue penetration

Not Permitted

Sanding through

Not Permitted




Grade "S": Almost without defects, Occasional small sound tight knots are allowed and up to 2 patches are allowed per one sheet. Used for varnishing and painting in furniture construction, decoration and lamination of various kind of wood.


Grade S

Categories of defects

Permissible amount of defects

Pin knots

Permitted (diameter to 3mm)

Sound intergrown knots light/dark

"Allowed up to an individual maximum diameter of 20 mm with total quantity not more than 2,5 per m2 (or total diameter up to 50mm/m2 of the panel square) 0,5"

Partly intergrown, open knots, knotholes, worm tracks

Allowed up to an individual maximum diameter of 10 mm with total quantity not more than 2,5 per m2 (or total diameter up to 25mm/m2 of the panel square) 0,5

Knots and knotholes repairement

Not Permitted

Irregularities in the structure of wood

Permitted

Hearth and discoloration

Not more than 5% of surface

Closed splits and checks, patched

Permitted for an individual maximum length up to 200 mm in amount of 2 per 1 m width of sheet

Irregularities in the structure of the wood

Allowed cross grain, curly grain and burls

Hearth and discoloration

Not more than 20% of surface

Defects at the edges due to sanding or sawing

Allowed up to 5 mm from the edge

Glue penetration

Allowed not more than, 1% of the panel surface

Sanding through

Not Permitted




Grade "BB" ( II ): For furniture construction and for covering with decorative materials.

Grade BB

Categories of defects

Permissible amount of defects

Pin knots

Permitted

Sound knots

Permitted up to an individual maximum diameter of 25 mm in amount of 10 per 1 m²

Other knots and patched holes:

unsound (falling) knots

Permitted up to an individual maximum diameter of 6 mm in amount of 6 per 1 m²

Irregularities in the structure of wood

Permitted, but slight

Open splits and patched holes

Permitted for an individual maximum length up to 200 mm and width up to 2 mm in amount of 2 per 1 m width of sheet

Closed splits and checks, patched

Permitted for an individual maximum length up to 200 mm in amount of 2 per 1 m width of sheet

Discolouration and coloured streaks

Not more than 30% of surface

Repaired defects (inserts)

Permitted up to 8 per m²

Double inserts

Not Permitted

Sanding through

Not allowed

Glue penetration

Permitted up to 2% of surface

Defects on the edges due to sanding or sawing

Admitted up to 5 mm from the edge





Grade "CP": Suitable for construction, which are not observed and for special packaging. And also calibration allows to use this plywood for decorating with valuable veneer.

Grade CP

Categories of defects

Permissible amount of defects

Pin knots

Permitted

Sound knots

Permitted along with cracks for width up to 1,5 mm

Other knots and patched holes

Permitted up to an individual maximum diameter of 6 mm in amount of 10 per 1 m²

Repaired defects (inserts)

Allowed

Double inserts

Allowed

Irregularities in the structure of the wood

Allowed

Discolouration and coloured streaks

Permitted

Open splits

Permitted for an individual maximum length up to 300 mm and width up to 5 mm in amount of 5 per 1 m length of sheet

Closed splits and checks

Permitted

Hearth and discoloration

Permitted

Open joints, patched

Permitted for an individual maximum width up to 2 mm and length of 200 mm, no more than 1 per metre of sheet width

Overlaps

Permitted for a maximum length of 200 mm and no more than 1 per metre of sheet width

Hollows, bumps and imprints

Permitted, but slight

Roughness

Permitted, but slight

Inserts

Unlimited number permitted

Sanding through

Permitted up to an extent of 10 cm²

Glue penetration

Permitted up to an extent of 5% of the surface of sheet

Defects on the edges due to sanding or sawing

Admitted up to 4 mm from the edge




Grade "WG": Suitable for construction, which are not observed and for special packaging.

Grade WG

Categories of defects

Permissible amount of defects

Sound intergrown knots

Allowed up to an individual maximum diameter of 65 mm

Other knots and knot holes

Allowed up to an individual maximum diameter of 15 mm with total quantity not more than 10 per m2

Repaired defects (inserts)

Allowed

Double inserts

Allowed

Irregularities in the structure of the wood

Allowed

Open splits

Permitted for an individual maximum length up to 300 mm and width up to 4 mm in amount of 2 per 1 m length of sheet

Closed splits

Permitted

Hearth and discoloration

Permitted

Open joints, patched

Permitted for an individual maximum width up to 2 mm and length of 200 mm, no more than 1 per metre of sheet width

Overlaps

Permitted

Hollows, bumps and imprints

Permitted, but slight

Inserts

Unlimited number permitted

Sanding through

Permitted up to 5% of surface

Glue penetration

Permitted up to an extent of 5% of the surface of sheet

Defects on the edges due to sanding or sawing

Admitted up to 5 mm from the edge





Grade "C" (IV): All defects are allowed. Plywood has good gluing. For firm packaging and construction.

Grade C

Categories of defects

Permissible amount of defects

Pin knots

Permitted

Sound knots

Permitted

Other knots:

unsound knots

Permitted up to an individual maximum diameter of 40 mm in unlimited amount

Discolouration and coloured streaks

Permitted

Open splits and checks

Permitted for an individual maximum width up to 10 mm in unlimited length and amount

Closed splits and checks

Permitted

Discolouration and coloured streaks

Permitted

Open joints

Permitted for an individual maximum width up to 3 mm

Overlap

Permitted for a maximum length of 500 mm and no more than 2 per metre of sheet width

Hollows, bumps and imprints

Permitted, some

Roughness

Permitted

Inserts

Unlimited number permitted

Glue penetration

Permitted

Defects on the edges due to sawing

Admitted up to 5 mm from the edge