EN 635 – 1 : 1994

Plywood
Classification by surface appearance

Part 1: General

3. Classification by surface appearance

1. 1Classification of plywood by surface appearance is made according to both the
   

number and the extent of certain natural characteristics of wood and the
manufacturer defects.
Five appearance classes are distinguished, indentified with the following classes:
E, I, II, III, IV

1. 2Characteristics and defects to be taken into consederation.
   

Determination of the appearance class, based on the appearance of the panel surface, shall taken into account the categories of characteristics given in 3.2.1 and defects given in 3.2.2

1. 2.1Table : Natural characteristics of wood
   

Natural characteristics of wood

Category	Type
3.2.1.1  Pin knots
3.2.1.2  Sound intergrown knots
3.2.1.3   a) Unsound knots               b) Non-adhering knots and partially adhering knots               c) Holes except those due to insects, borers and parasitic plantes	1.Dog holes 2.Knot holes
3.2.1.4  a) Splits              b) Cheks	1.Open 2.Closed
3.2.1.5   Abnormalities due to insects, marine borers and parasitic plants	1.Small worm holes 2.Large worm holes 3.Marine borers holes 4.Marks from parasitic plants
3.2.1.6  a) Resin pockets b)Resin streaks c)nbark
3.2.1.7  Irregularities in the structure of the wood	1.Angle grain 2.Curly grain 3.Interlocked grain 4.Spiral grain
3.2.1.8  Discolouration which is not wood-destroying	1.Blue stain, mould and fungal discolouration 2.Coloured sapstains 3.False heartwood 4.Other discolouration such as chemical stain and colour streaks
3.2.1.9  Fungal decay which is wood-destroyed	1. Rot

1. 2.2Table : manufacturing defects
   

Manufacturing defects

Category	Type
3.2.2.1  Open joinsts
3.2.2.2  Overlapss
3.2.2.3  Blisters
3.2.2.4  a) Hollows             b)Imprints             c)Bumps
3.2.2.5  Rougness, after than that due to irregulations in the structure of the wood
3.2.2.6  Sanding through
3.2.2.7  Glue penetration
3.2.2.8  Foreign defects	Metal, mineral, etc
3.2.2.9  Repairs	1.Patches 2.Shims 3.Synthetic fillers
3.2.2.10  Defects at the edges of the panel	1.Sanding defects 2.Sawing defects 3.Missing wood

EN 635 – 2 : 1995

Plywood
Classification by surface appearance

Part 2: Hardwoods

3. Classification by surface appearance

1. 3Appearance classes
   

Asessment of characteristics and defects for determination of the appearance shall be carried out in accordance with EN 635-1.
Surface classification shall be based on the permissable characteristics and defects within each appearance class as specified in 3.2

1. 4Permissable characteristics and defects
   

Each surface shall be assigned to one of the appearance classes ( E, I, II, III, IV ) as defined in
Table 1 and 2

1. 4.1Table 1 : natural characterics
   

Classification according to natural characteristicks

Characteristick	Appearance class
	E	I	II	III	IV
3.2.1.1 Pin knots*	Few or none	3 per m2permitted	permitted
3.2.1.2  Sound intergrown knots		Permitted up to individal diametr			Permitted (cf. note below)
		of 15 mm provided their cumulative diametr does not exceed 30 mm/m2	35 mm	of 50 mm
		such knots may have splits provided they are:
		very slight	slight
3.2.1.3  Unsound knots, non-adhering knots and knots holes		Permitted up to individal diametr of			Permitted (cf. note below)
		6 mm if filled and up to a number of 2 per m2	5 mm if unrepai-red; 10 mm if filled and up to a number of 3 per m2	40 mm
3.2.1.4   Splits               Open               Closed		Permitted if less than
		1/10	1/5	1/3	Permitted (cf. note below)
		of panel length up to individual width of
		3mm	5 mm	20 mm
		and up to a number of
		3 per m.	3 per m.	3 per m.
		of panel width, if properly filled
				if unrepaired or unlimited if all filled
		Permitted
3.2.1.5   Abnormalities due to insects, marine borers and parasitic plants	Nor permitted		Marks of parasitic plants not permitted. Insects and marine borers holes permitted up to		Permitted (cf. note below)
			Diametr of 3 mm vertically to the plane of the panel up to a number of 10 per m2	Width of 15 mm and a length of 60 mm, up to a number of 3 per m2
3.2.1.6                Inbark	Nor permitted		Permitted up to a width of		Permitted (cf. Note below)
			4 mm if properly filled	25 mm
3.2.1.7   Irregularities in the structure of the wood	Few or none	Permitted if		permitted
		very slight	slight
3.2.1.8  Discolouration which is not wood-destroying		Permitted if of low contrast		permitted
3..2.1.9  Fungal decay which is wood-destroyed	Not permitted
3.2.1.10   Other characteristic	Few or none	To be considered under the category which they most closely resemble

* Pin knots: sound intergrown knots of no more than 3 mm diametr.

NOTE: Natural characteristicks are permitted provided that they do not impair the service ability of the panel.

EN 635 – 3 : 1995

Plywood
Classification by surface appearance

Part 2: Softwoods

3. Classification by surface appearance

1. 5Appearance classes
   

Asessment of characteristics and defects for determination of the appearance shall be carried out in accordance with EN 635-1.
Surface classification shall be based on the permissable characteristics and defects within each appearance class as specified in 3.2

1. 6Permissable characteristics and defects
   

Each surface shall be assigned to one of the appearance classes ( E, I, II, III, IV ) as defined in Table 1 and 2

1. 6.1Table 1 : natural characterics
   

Classification according to natural characteristicks

Characteristick	Appearance class
	E	I	II	III	IV
3.2.1.1  Pin knots*	Few or none	3 per m2 permitted	permitted
3.2.1.2   Sound intergrown knots		Permitted up to individual diametr of			Permitted (cf. note below)
		of 15 mm	of 50 mm	of 60 mm
		Provided their cumulative diametr does not exceed 30 mm/m2
		such knots may have splits provided they are:
		very slight	slight
3.2.1.3  Unsound knots, non-adhering knots and knots holes		Permitted up to individal diametr of			Permitted (cf. note below)
		6 mm if filled and up to a number of 2 per m2	5 mm if unrepai-red; 25 mm if filled and up to a num-mber of 6 per m2	40 mm
3.2.1.4   Splits              Open               Closed	Few or none	Permitted if less than
		1/10	1/3	1/2	length unlimited
		of panel length up to individual width of
		3mm	10 mm	15 mm	25 mm
		and up to a number of panel width
		3 per m. if properly filled	3 per m. all splits greather than 2mm in width to be filled	3 per m.	unlimited
		Permitted
3.2.1.5   Abnormalities due to insects, marine borers and parasitic plants	Not permitted		Marks of parasitic plants not permitted. Insects and marine borers holes permitted up to		Permitted (cf. note below)
			Diametr of 3 mm vertically to the plane of the panel up to a number of 10 per m2	Width of 15 mm and a length of 60 mm, up to a number of 3 per m2
3.2.1.6   Resin pockets and inbark Resin streak	Not permitted		Permitted up to a width of		Permitted (cf. note below)
			6 mm if properly filled	40 mm
			permitted if slight	permitted
3.2.1.7   Irregularities in the structure of the wood	Few or none	permitted if		permitted
		very slight	slight
3.2.1.8  Discolouration which is not wood-destroying		Permitted if of low contrast		permitted
3..2.1.9  Fungal decay which is wood-destroyed	Not permitted
3.2.1.10   Other characteristic	Practi-cally absent	to be considered under the category which they most closely resemble

* Pin knots: sound intergrown knots of no more than 3 mm diametr.

NOTE: Natural characteristicks are permitted provided that they do not impair the service ability of the panel.