SFS GRADES OF FINNISH BIRCH FACE VENEERS IN ACCORDANCE WITH SFS 2413

· B (I)

Pin knots permitted. Other knots and holes permitted up to 6 mm diameter, limited to a cumulative diameter of 12 mm per m2. Closed splits and checks permitted up to an individual length of 100 mm and one per metre of panel width. Slight discoloration and streaks permitted. Other defects strictly limited.

· S (II)

Pin knots permitted. Sound intergrown knots permitted up to an individual diameter of 20 mm , limited to a cumulative diameter of 50 mm per m2. Other knots and repaired holes permitted up to 10 mm diameter, limited to a cumulative diameter of 25 mm per m2. Repaired splits and checks up to 2 mm width, length 200 mm limited to one per metre of panel width. Closed splits and checks permitted up to 200 mm length and two per metre of panel width. Discoloration and coloured streaks permitted. One wooden patch/m2 permitted.

· BB (III)

Pin knots permitted. Sound knots permitted up to 25 mm diameter, limited to a cumulative diameter of 60 mm per m2. Other knots and holes permitted up to 6 mm diameter, limited to a cumulative diameter of 25 mm per m2. Open splits and checks, repaired, permitted up to 2 mm wide and 200 mm long not exceeding 1 per metre of panel width. Discoloration, roughness and sanding through permitted if all slight. Wooden patches permitted up to 3 % of area. Glue penetration limited to 5 % of panel surface.

· WG (IV)

Pin knots and sound knots permitted up to 65 mm diameter, limited to a cumulative diameter of 600 mm per m2. Other knots and holes up to 15 mm diameter limited to a cumulative diameter of 100 mm per m2. Open splits and checks up to 4 mm wide and 2 per metre width of panel. Discoloration, streaks, roughness, slight sanding through, glue penetration and patches are permitted.