Birch Plywood is subdivided by the following grades depending on face veneer quality:
Е (Elite)
B(I)
S
ВВ ( II )
СР ( III )
WG
С ( IV )
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 | |
| Categories of defects | Permissible amount of defects |
| Pin knots | Permitted |
| Irregularities in the structure of wood | Permitted, but slight |
| Coloured streaks | Permitted accosionally |
| 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 “B” ( I ): Almost without deffects intended for natural finish. For furniture construction and decoration. | |
| Grade “S”: Almost without defects, Occasional small sound tight knots are allowed and up to 2 patches are allowed per m2. Used for varnishing and painting in furniture construction, decoration and lamination of various kind of wood. | |
| 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. | |
| 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. | |
| 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”: Suitable for construction, which are not observed and for special packaging. | |
| 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. | |
| 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 |
