Appearance of Birch Plywood

UPM's standard birch plywood classification is by the grades of the face veneers in accordance with SFS 2413 standard. 

 

Grade B

 

 ​ Recommended for surfaces to be lacquered. A few pin knots with a diameter of up to 6 mm are permitted as is slight variation in colour. In standard sizes up to a panel size 1250 x 2500 mm the outer ply shall be of one veneer. Does not contain plugs.​
  

Grade S 

 ​ Recommended for surfaces to be painted with non-transparent paint. A good, uniform grade. Some sound knots with a diameter of up to 20 mm and a limited number of other knots with a diameter of up to 10 mm are permitted. Discolouration is permitted.
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Grade BB

 ​ A grade most used in structures. Minor surfaces defects are repaired with synthetic filler. A few sound knots with a diameter of up to 25 mm and other knots with a diameter of up to 6 mm are permitted.
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Grade WG 

 ​ Suitable for constructional purposes where appearance is not important. Open splits, knot holes and other defects permitted.
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