Description and limitations of plywood defects

Description and limitations of plywood defects

 

Description of deficts as per GOST 30427 E grade

plywood face veneers

I grade plywood face veneers II grade plywood face veneers II grade plywood face veneers IV grade plywood face veneers
1.Pin knots Not allowed Max 3 per M2 allowed Allowed Allowed Allowed
 

2.Sound lights and/or dark knots

 

 

Not allowed

Up to 5 per M2 max, 15mm diam. cracks no more than 0,5mm wide Up to 10 per M2 max, 25mm diam. cracks no more than 1mm wide  

Allow cracks not more than 1,5mm wide

 

Allow cracks not more than 1,5mm wide

3.Loose knots or with/without knot holes, worn holes in cluster or scattered  

 

Not allowed

 

Up to 3 with max 6mm diam.

 

Up to 6 with max 6mm diam.

 

Up to 6 with max 6mm diam.

 

No limits with max 40 mm diam.

 

4.Tight cracks/splits

 

Not allowed

Up to 2 per 1M of plywood, max 200mm long Up to 2 per 1M of plywood, max 200mm long  

Allowed

 

Allowed

 

 

5.Wide cracks/splits

 

 

 

Not allowed

 

 

 

Not allowed

 

Up to 2 per 1M of plywood filled with putty max 200mm long

Up to 2 per 1M of plywood filled with putty max 600mm long and 5 mm wide  

 

Allowed with limitations

6.Light Mold Not allowed Allowed Allowed Allowed Allowed
 

 

7.Dark mold

 

 

Not allowed

 

 

Not allowed

General number allowed as per item 2 of present table General number allowed as per item 2 of present table  

 

Allowed

8.Deviation in wood structure Allowed very insignificant,incidental disposition Allowed Allowed Allowed Allowed
 

9.Light color variation

 

Not allowed

Allowed, no more than 5% of the sheet surface  

Allowed

 

Allowed

 

Allowed

10.Strong color variation Not allowed Not allowed Not allowed Not allowed Allowed
11.Decay Not allowed Not allowed Not allowed Not allowed Not allowed
 

 

12.Pinholes

 

 

Not allowed

General number allowed as per item 3 of present table General number allowed as per item 3 of present table General number allowed as per item 3 of present table General number allowed as per item 3 of present table
 

 

13.Veneer overlap

 

 

 

Not allowed

 

 

 

Not allowed

Allowed no more than 100mm in quantity of no more than 1 piece for 1m of panel width Allowed no more than 200mm in quantity of no more than 2 pieces for 1m of panel width  

 

 

Allowed

14.Lack of veneer, defects of panel edges due to sanding or squaring  

 

Not allowed

Allowed with a width of no more than 2mm Allowed with a width of no more than 4mm Allowed with a width of no more than 4mm Allowed with a width of no more than 5mm
15.Presense of glue tape  

Not allowed

 

Not allowed

Allowed in non-sanded plywood Allowed in non-sanded plywood Allowed in non-sanded plywood
 

16.Glue bleed through

 

Not allowed

 

Not allowed

Allowed no more than 2% of panel surface Allowed no more than 5% of panel surface  

Allowed

17.Scratches Not allowed Not allowed Allowed Allowed Allowed
 

18.Indentations or imprints

 

 

Not allowed

 

 

Not allowed

Allowed if depth/height is in range of thickness variance Allowed if depth/height is in range of thickness variance  

 

Allowed

 

19.Torn Grain, Brashy Fibers

 

Not allowed

 

Not allowed

Allowed no more than 5% of panel surface Allowed no more than 15% of panel surface  

Allowed

20.Grinding Not allowed Not allowed Not allowed Not allowed Allowed
 

21.Warp and twist

Does not apply to thickness under 6,5mm. If over 6,5mm then allowed with sag of no more than 15mm over 1M panel’s diagonal length Does not apply to thickness under 6,5mm. If over 6,5mm then allowed with sag of no more than 15mm over 1M panel’s diagonal length Does not apply to thickness under 6,5mm. If over 6,5mm then allowed with sag of no more than 15mm over 1M panel’s diagonal length Does not apply to thickness under 6,5mm. If over 6,5mm then allowed with sag of no more than 15mm over 1M panel’s diagonal length Does not apply to thickness under 6,5mm. If over 6,5mm then allowed with sag of no more than 15mm over 1M panel’s diagonal length
22.Metal inclusions  

Not allowed

 

Not allowed

 

Not allowed

Color metal staples are allowed Color metal staples are allowed
 

 

23.Gap in slice joint

 

 

Not allowed

 

 

Not allowed

Allowed with width of no more than 1mm in 1 piece for 1M of panel sheet Allowed with width of no more than 2 mm in 1 piece for 1M of panel sheet  

 

Allowed

24.Delamination, bubbles, etc Not allowed Not allowed Not allowed Not allowed Not allowed
25.Waviness(for sanded plywood), charter marks  

Not allowed

 

Not allowed

 

Not allowed

 

Allowed

 

Allowed

 

 

 

26.Rough or torn grain

 

Roughness parameter(Rm) is per GOST 7016; 100 for

sanded plywood and 200 for non-sanded

Roughness parameter(Rm) is per GOST 7016; 100 for

sanded plywood and 200 for non- sanded

Roughness parameter(Rm) is per GOST 7016; 100 for

sanded plywood and 200 for non- sanded

Roughness parameter(Rm) is per GOST 7016; 100 for

sanded plywood and 200 for non- sanded

Roughness parameter(Rm) is per GOST 7016; 100 for

sanded plywood and 200 for non- sanded

 

27.Wooden plugs

 

Not allowed

 

Not allowed

Allowed in repair up to 8 pieces for 1m2 of panel  

Allowed with no limits

 

Allowed with no limits

 

28.Overlapped plugs

 

Not allowed

 

Not allowed

Allowed no more than 2 pieces per 1m2 of panel  

Allowed

 

Allowed

 

Note:
1. Norm of manufacturing defects “lack of veneer” refers both to outer and core lines.
2. Wood and manufacturing defects which are not mentioned in Table 3 are not allowed.

 

TABLE 4

 

Grade of Face Veneer Maximum amount of permitted defects for wood and manufacturing (in pieces)
E No visible defects
I 3
II 6
III 9
IV Amount of wood and manufacturing defects is unlimited. Limits on dimensions is in accordance with items 3,5,11,12,14,24 of Table 3

 

APPENDIX A
COMPARATIVE CHART OF GRADE MARKING IN THIS GOST, IN GOST 10.55-71
AND GOST 3916.1-89
GRADES

 

GOST 3916.1-96 GOST 10.55-71 GOST 3916.1-89
E A
I B AB
II BB B
III CP BB
IV C C

 

 

TABLE 5

 

 

Index

 

Thickness(mm)

Gluebond  

Birch

AlderBeech Pine Larch FirSilverfir Cedar LimeAspPoplar
Moisure content 3-30 FSF FK 5-10 5-10 5-10 5-10
Shear strenght (MPa) not less than
after boiling in water for 1 hour  

 

3-30

FSF 1,5 1,2 1,0 0,6
after soaking in water for 24 hours FK 1,5 1,0 1,0 0,6
Static bending strength of fibres (MPa) not less than  

9-30

FSF 60 50 40 30
FK 55,0 45,0 35,0 25,0
Tensile strengh 3-6,5 FSF 40,0 40,0 40,0 40,0
along fibers, MPa, no less than   FK 30,0 30,0 30,0 30,0

 

Note: Shear strength along glue line of 1.2. Mpa is permitted in accordance with terms of a sales contract.

 

TABLE 6

 

Glue Emission Class Formaldehyde content in 100 grams of dry plywood mass, in mg.
E1 Up to 10
E2 From 10 to 30

 

 

TABLE 7

 

 

Volume for the lot

Index of control on the items below(in panels)
3.2.1.; 3.2.3; 3.2.3; 4.1.2; 4.1.6; 4.1.7; 4.3
Selection Volume Number for Acceptance Selection Volume Number for Acceptance
Up to 500 8 1 13 1
501 to 1200 13 1 20 2
1201 to 3200 13 1 32 3
3201 to 10000 20 2 32  

 

如无特殊说明,文章均为本站原创,转载请注明出处。If there are no special instructions, the articles are original, if you want to use or reproduce, please indicate the original source www.plywoodinspection.com,If you find that our article infringes on your rights and interests, please email us in time and we will delete it at the first time.

Check Also

British Standard 1088 (Joubert Okoume & Hydrotek Marine Meranti) GRADING RULES

British Standard 1088 (Joubert Okoume & Hydrotek Marine Meranti) GRADING RULES B.S. 1088 : 1966 …

Leave a Reply

Your email address will not be published. Required fields are marked *