Quality is determined by the conformity of geometrical, visual, mechanical and physical parameters. For curvininear wood flooring, interior finishes, skirting boards and other timber intended for indoor use, there are 3 main quality classes:
CLASS A
Top quality class.
The moisture of wood is 8-12%.
Timber is without branches or their quantity and size are not important.
Fallen branches are not allowed.
Cracks not exceeding 50 mm in length are permitted if they don't go fully trough
Non-essential resin openings (up to 10 mm in length) are allowed for pine timber.
CLASS I
Slightly lower quality class.
The moisture of wood is 8-12%.
Branches are allowed- the size of live branches is not limited, black branches are allowed up to 15 mm.
There may be fallen branches not exceeding 8 mm in size.
Cracks that don't go fully though are allowed.
Resin openings (up to 25 mm in length) are allowed for pine timber.
CLASS II
Lowest quality class.
The moisture of wood is 8-12%.
Timber with unlimited size branches (black branches as well as fallen branches) are allowed.
Cracks that don't go fully through are allowed.
Cracks (up to 300 mm in length) that go though are allowed.
Resin openings (without limited sizes) are allowed for pine timber.
For external finishing boards and other timber intended for outdoor use, there are 2 main quality classes:
CLASS AB
The moisture of wood is 18-20%.
Branches are allowed- the size of live branches is not limited, black branches are allowed up to 20 mm.
There may be fallen branches not exceeding 10 mm in size.
Cracks that don't go fully though are allowed.
Resin hole length can be up to 50 mm.
CLASS C
The moisture of wood is 8-12%.
Timber with unlimited size branches (black branches as well as fallen branches) are allowed.
Cracks that don't go fully through (up to 300 mm in length) are allowed.
Resin openings (without limited sizes) are allowed.
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