EN 635-1: 1995 (confirmed 2014)
Plywood – Classification by surface appearance – General
Part 1 establishes rules for the classification of plywood by its surface appearance. Five appearance classes are distinguished – E, I, II, III and IV. The classification is made according to the number and extent of certain natural characteristics of wood and the defects that may arise from the manufacturing process.
Natural classification and manufacturing defects used to classify plywood by its appearance
Natural Characteristics Inherent in Wood |
Manufacturing Defects |
|
|---|---|---|
Knots:
|
Open joints | |
| Splits & checks | Overlaps | |
| Abnormalities due to insect, marine borers & parasitic plants | Roughness, other than that due to irregularities in the structure of the wood | |
| Resin pockets, Resin streaks & inbark | Blisters | |
| Irregularities in the structure of the wood | Hollows, imprints & bumps | |
| Discolouration which is not wood-destroying | Sanding through | |
| Fungal decay which is wood-destroying | Glue penetration | |
| Other characteristics | Foreign particles – metal, mineral | |
| Repairs – patches, shims, synthetic filler | ||
| Defects at panel edges – sanding and sanding defects, missing wood | ||
| Other defects |