INTERGOVERNMENTAL STANDARDGOST 3916.1-96Plywood with faces in hardwood veneer for general use.
1. DESCRIPTION - GENERAL USE PLYWOOD
This standard covers general use plywood with hardwood face veneer.
This standard is not applicable to specialty or decorative plywood.
Minimal requirements relating to the formaldehyde emission of plywood are covered in 4.3 and 6.8.
3. CLASSIFICATION AND DIMENSIONS
3.1. Plywood is subdivided into grades based on the following: appearance of face veneers, glue bond, the degree of moisture resistance of the bond,and if sanded or not.
3.1.1. The plywood is subdivided into 5 grades, based on the appearance of the face veneers: E (elite), I, II, III and IV. Descriptions of the face grades of the plywood are specified in Supplement A.
3.1.2. The degree of moisture resistance of the plywood bond is specified by the following marks:
- FSF - water proof plywood (WBP)
- FK - water resistant plywood (MR)
3.1.3. The sanding if the plywood is specified as follows:
- Not sanded (NS)
- Sanded one side (S1)
- Sanded two sides (S2)
3.2.1. The dimensions and the number of plies in the plywood sheets must correspond to tables 1 and 2.
Table 1. Dimensions (millimeters)
Note: Production of plywood is allowed in other dimensions corresponding with the terms of a contract.
|Lengt(width) of the plywood sheets||Min(Max)Tolerance in mm|
Table 2. Thickness (millimeters)
Note: Production of plywood is allowed in other thickness and construction (number of plies) corresponding with the terms of a contract. The minimum and maximum variances may be determined by the following formula.
|Nominal thickness of plywood||Number of plies||Sanded Plywood Tolerance Min/Max(mm)||Sanded Plywood Thickness Variance(mm)||Unsanded Plywood Tolerance Min/Max (mm)||Unsanded Plywood Thickness Variance(mm)|
|3,0 mm||3-ply||+0,3/-0,4|| ||+0,4/-0,3|| |
|4,0 mm||3-ply||+0,3/-0,5|| ||+0,8/-0,4|| |
|6,5 mm||5-ply||+0,4/-0,5|| ||+0,9/-0,4||1,0|
|9,0 mm||7-ply||+0,4/-0,6|| ||+1,0/-0,5|| |
|12,0 mm||9-ply||+0,5/-0,7||0,6||+1,1/-0,6|| |
|15,0 mm||11-ply||+0,6/-0,8|| ||+1,2/-0,7|| |
|18,0 mm||13-ply||+0,7/-0,9|| ||+1,3/-0,8|| |
|21,0 mm||15-ply||+0,8/-1,0|| ||+1,4/-0,9||1,5|
|24,0 mm||17-ply||+0,9/-1,1|| ||+1,5/-1,0|| |
|30,0 mm||21-ply||+1,1/-1,3|| ||+1,7/-1,2|| |
Sanded Plywood - maximum/minimum tolerance:
- Maximum: Thick * 0.03 mm + 0.2 mm (12 mm*0.03 mm + 0.2 mm)=12 mm + 0.5 mm
- Minimum: Thick * 0.03 mm + 0.4 mm (12 mm*0.03 mm + 0.4 mm)=12 mm - 0.7 mm
Unsanded Plywood - maximum/minimum tolerance:
- Maximum: Thick * 0.03 mm + 0.8 mm (12 mm*0.03 mm + 0.8 mm)=12 mm + 1.1 mm
- Minimum: Thick * 0.03 mm + 0.4 mm (12 mm*0.03 mm + 0.3 mm)=12 mm - 0.6 mm
3.2.2. Plywood panels must be cut at a right angle. Deviation must not exceed 2 mm per 1 lineal meter.
3.2.3. Deviation from square edges can not exceed 2mm per 1 lineal meter.
3.3. Making if plywood must include:
- Name of product
- Woos species of the face and core veneers
- Glue Bond marks
- Veneer grades for face and core
- Formaldehyde emission classification
- Type of surface treatment
- Applicable GOST standard
Below is an example of markings in plywood. Birch plywood with core plies of birch veneer, water resistant, with a combination of face and core veneers I/III, with an emission class of E1, sanded in both sides, in 2440 mm long, 1220 mm wide and 9 mm thick is marked: Birch plywood/birch, FK, I/III, E1, S2, 2440*1220*9 GOST 3916.1-96
4. TECHNICAL REQUIREMENTS
4.1.1. To produce face veneers for plywood, the following species can be used for the face veneer: birch, alder, maple, elm, beech, asp, poplar,lime. For core veneers, in addition to the ones just mentioned, the following can be used: pine, spruce, fir, larch and cedar.
The timber used to make veneers fir plywood determines the species of the plywood.
The plywood can be made of one or more than one species of wood, therefore it is either "homogeneous" or "combined".
If the number of veneer plies is even, the direction of fibers (grain) of the two middle plies must be parallel.
Veneers, located symmetrically within the thickness of plywood, must be the same species and thickness.
The thickness of the veneer used for the faces must not exceed 3,5 mm. And for the thickness if core veneers must nit exceed 4 mm.
4.1.2. Wood and manufacturing defects exceeding limits stated in Table 3, are not allowed in face veneers.
4.1.3. Wood and manufacturing defects, exceeding the limits stated in Table 3, are allowed in core veneers, as long as they do not influence its integrity and dimensions. The requirements for quality and dimensions are specified in this standard.
4.1.4. The maximum amount of wood and manufacturing defects allowed in face veneers is indicated in Table 4.
4.1.5. The combination of face veneer grades is indicated in GOST 30427.
4.1.6. The face veneer of E grade can consist of 2 components with one splice joint in the middle of the panel. This applies only to widths up to 1525 mm.
If the width is over 1525 mm, the face veneer if E grade can consist of 3 components of equal width. The face veneer of I and II grades can be made from an unlimited number of veneer components.
For grades E, I, II veneer joints must be parallel to plywood edges.Veneers must be matched for color.
4.1.7. Plugs must be even with the surface, firmly bonded, must match the color of the face of the panel. The grain must also be parallel to the direction of the wood fibers (grain) on face veneer. For grades I and II the plugs must match the color of the wood.
Putty fills or reapirs must match the color of the wood of a given grade. In addition, they must provide easy gluing, retain its color during plywood treatment and not crack while bending.
4.2. Strength and mechanical indices are stated in Table 5.
4.3. Formaldehyde content in plywood, depending in emission class, must meet the limits stated in Table 6.
4.4. The plywood is measured in either square meters or cubic meters.The volume of one panel is determined with a precision of up to 0.00001 m3. The volume of a few panels is determined with the precision of up to 0.5 m3. The squareness of a panel is measured with the precision of up to 0.01 m2. The squareness of a few panels in measured with a precision of up to 0.5 m2.
4.5. The marking is stamped with indelible paint on the back side of every panel stating plywood grade and inspector's number.
Marks of bundles or crates of plywood contain:
- Name if the country plywood-producer
- Name of mill-producer or its trade mark
- Conventional plywood marking
- Number of panels in the bundle
- National mark of conformity for certified production
- Transportation marking is in accordance with GOST 14192.
4.6.1. Plywood must be packed in bundles weighting no more than 1500 kgs. It has to be separated according to species, glue bond, grades, glue emission classes, types of surface treatments and dimensions.
If parties mutually agree and in accordance with a sales contract,plywood can be packed in bundles or other weights.
4.6.2. If plywood id to be shipped to regions in the Extreme North or other difficult-to-reach regions, it has to be packed according to 4.6.1.and GOST 15848.
5. RULES OF ACCEPTANCE
5.1. Plywood is accepted in lots.
A lot consists of plywood of one species, one glue bond, one sort,one glue emission class one type of surface treatment and panel dimensions.
There should be one document for each lot, specifying quality and containing:
- Name of the country-producer
- Name of the mill-producer and (or) its trade mark
- Conventional plywood marking
- Volume or square meters of panels in lot
- Stamp of technical control
- National mark of conformity for a certified production
5.2. Quality and dimensions of panels are subject to random inspection.If specified in a sales contract (agreement), specific lots may be subject to full inspection.
In a random inspection, sheets are selected indiscriminately in accordance with GOST 18324 and confirming the quantities, mentioned in Table 7.
5.3. Shear, tensile and static bending strengths are checked fir plywood of every species, glue bond and number of plies at least once month. In accordance with sales contracts (agreements), it is permitted to select 0.1 % of sheets in every lot, but not less than one sheet.
5.4. Formaldehyde emission is checked every 30 days for FSF plywood mark and every 15 days for FK plywood mark. In accordance with terms of sales contract, a check may be done every 7 days.
5.5. A lot is considered to meet the requirement of the current standard and is accepted, if in the random inspection the following is confirmed:
- number of plywood sheets which are not meeting the requirements of the current standard due to dimensions, out of square, linear edges, wood and manufacturing defects is LESS or EQUAL to the accepted amount, which is stated in Table 7.
- all sheets of plywood must have no bubbles, no delamination and no trace of bark
- formaldehyde emission corresponds to the norms defined in Table 6
6. CONTROL METHODS
6.1. Selection of samples for strength and mechanical tests are done in accordance with GOST 9620. Selection of samples for formaldehyde emission tests are done in accordance with GOST 27678.
6.2. The length and width is measured at two points in the same panel,which are parallel to the edges and are located at least 100 mm from the edges. The measurements are done with a metal tape, which has an index error of 1 mm or less in accordance with GOST 7502. Measurements have to be taken twice and the actual length (width) of the sheet would be their average.
6.3. Thickness is measured at a distance of at least 100 mm from the edges. Thickness also has to be measured at the middle of each side of the panel with a caliper as per GOST 11358, or with a micrometer with a scale division of at least 0.1 mm in accordance with GOST 6507.
Measurements of thickness have to be taken 4 times and the actual thickness would be an average of those 4 measurements.
The difference in thickness in one panel of plywood is determined as a difference between the maximum and minimum thickness from these 4 measurements.
6.4. Moisture content is determined in accordance with GOST 9621.
6.5. Shear strength along the glue line is determined in accordance with GOST 9624.
6.6. Static bending strength is determined in accordance with GOST 9625
6.7. Tensile strength is determined in accordance with GOST 9662
6.8. Formaldehyde emission is determined in accordance with GOST 27678
6.9. Roughness of the surface is determined in accordance with GOST 15612
6.10. Wood and manufacturing defects are measured in accordance with GOST 30427
6.11. Deviation from linear edges of plywood panel is determined by measurements of the maximum gap between the panel edge and metallic square edge in accordance with GOST 8925 and within an index error of 0,2 mm.
6.12. Measurements for squareness are determined in accordance with GOST 30427.
7. TRANSPORTATION AND STORAGE
7.1. Plywood is transported in covered vehicles, in accordance with the transportation consignment rules for each given vehicle.
7.2. Transportation and storage of plywood, which is to be shipped to the Extreme North or difficult-to-access regions are done in accordance with GOST 15846.
7.3. Plywood is stored in horizontally stacked bundles, on pallets or on wooden pallets. The temperature of closed premises, in which the plywood is stored, should be between -400C to +50C. The humidity should not exceed 80%
8. PRODUCERS GUARANTEE
Producers guarantee that the plywood conforms with the current GOST, as well as with transportation and storage conditions.
FK plywood has a guarantee of 3 years and FSF plywood has a guarantee of 5 years from the day it was shipped.
Table 3. 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|
- 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.
|Grade of Face Veneer||Maximum amount of permitted defects for wood and manufacturing (in pieces)|
|E||No visible defects|
|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|
Comparative chart of grade marking in this gost, in gost 10.55-71 and gost 3916.1-89
|GOST 3916.1-96||GOST 10.55-71||GOST 3916.1-89|
|Index||Thickness(mm)||Glue bond||Birch||Alder Beech||Pine Larch Fir Silverfir Cedar||Lime Asp Poplar|
|Moisure content||3-30||FSF |
|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|
|Tensile strengh along fibers, MPa, no less than||3-6,5||FSF||40,0||40,0||40,0||40,0|
Note: Shear strength along glue line of 1.2. Mpa is permitted in accordance with terms of a sales contract.
|Glue Emission Class||Formaldehyde content in 100 grams of dry plywood mass, in mg.|
|E1||Up to 10|
|E2||From 10 to 30|
|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||3|