GOST 26002-83

 

Rough lumber of coniferous species.
Interpretation of Russian export grading rules in accordance to GOST 26002-83

1. Dimensions:

1.1 Sawn lumber is subdivided:

By thickness: Thin 16 – 22 mm
Medium 25 – 44 mm
Thick 50 – 100 mm
By width: Narrow 75 – 125 mm
Wide 150 mm and wider
By length: Short 450 – 2400 mm
Long 2700 – 6300 mm

1.2. Nominal thickness and width are guided by standard GOST 24454-80, where thickness of the lumber shall not exceed 100 mm.

1.3. Lengths of lumber are ranged:
from 1500 mm and up with a step of 300 mm;
from 450 mm up to 1350 mm with a step of 150 mm;
Lumber with length from 450 mm up to 1350 mm is manufactured by an order of State foreign trade organization.

1.4. Nominal dimensions of lumber are established for the wood of MC (moisture content) 20%. With MC of more or less than 20%, actual thickness and width of lumber shall be more or less than nominal dimensions in correlation with shrinkage value according to standard GOST 6782.1-75.

1.5. Limiting deviations from nominal dimensions of lumber shall not exceed in mm:

By length 

+ 25 

– 12

By width

+ 3 

– 2 

By thickness:

 

 

   thickness less than 50 mm

+ 2 

– 1 

   thickness 50 mm und up

+ 3 

– 2 

Volume of lumber with maximum admitted deviations shall not exceed 25% of total volume of lumber.

2. Technical Requirements

2.1. Lumber shall be manufactured in accordance to the requirements of the present technology standard for the wood of Pine, Spruce, Fir and Larch species.

2.2. Lumber is subdivided by quality of the wood and by its machining into 1, 2, 3, 4 and 5 grades.

2.3. Lumber is arranged:
By dimensions;
By species;
By grades:

U/S Unsorted (combining 1, 2, 3 grades together, the percentage correlation of which shall correspond to the natural recovery of lumber while sawing);

            4 grade separately;

            5 grade separately;

            Up to 15% of Fir is admitted in a load of Spruce lumber. 

2.4. MC moisture content of lumber shall not exceed 22%. Variation of the moisture content is admitted by custom orders.

2.5. Antiseptic treatment of lumber is per standard GOST 10950-78.

2.6. Quality of the wood and manufacture of lumber shall correspond to the requirements specified in tables 1-3.

Pine and Larch Lumber                                                                                                                         
Table 1

Wood defects Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
1. Knots
1.1. Intergrown knots
1.1.1. Round and Oval
1.1.1.1.
Face 		 

Admitted on outside face in dimensions in mm and number in pieces on average per 1000 mm of length of lumber.

In thick wide sawn lumber

13-17 1 18-27 1 28-38 2 Admitted

over 38
up to 50

 1
In thick narrow lumber
10-14 1  15-24  1  25 2 Admitted

over 25
up to 38

2

In medium wide lumber

10-14 

1 

 15-18  1  19-25 3 Admitted

over 25
up to 38

1
In medium narrow lumber
10-14  1  15-18  1  19-25 3 Admitted
over 25
up to 32 		1
In thin lumber
10-14  1  15-18  1  19-22 2 Admitted

over 22
up to32

1

In lumber of 75 mm wide knots shall not exceed:
1/4 1/3 1/2 2/3 Admitted
of face width

Number of knots on the inside face of lumber of 1 & 2 grades is admitted twice more and in 
3 grade one and a half times more than for outside face.

1.1.1.2.
Edge & corner

 Admitted on each edge with dimensions in mm and number in pieces for entire length of a piece:
In thick lumber:
up to 6 3-4 7-12 3-5 13-16 5-8 Admitted
13-19 3-5 over
16
up to 25		 3-5
over
25
up to 32		 3
In medium lumber:
up to 6 2-3 7-12 2-4 13-16 2-4 Admitted
13-19 2-3 over
16
up to
3/4 of
thickness		 2-4
In thin lumber:
up to 6 1-2 7-10 1-2 up to
2/3 of
thickness		 2 Admitted

1.1.1.3. End

 Admitted on each end with dimensions in mm and number in pieces:
Not admitted 25 1 Admitted
1.1.2. Spike, branchy including appeared on corners, and edge

Admitted on the inside face of sawn timber (lumber) in total number of intergrown round and oval knots with dimensions and amount as per paragraphs 1.1.1.1.; 1.1.1.2.

Dimension of knots in mm by maximum diameter is admitted of not more than:
38 50 admitted
Appearing of knots on edges:
Admitted with appearing on edge of not more than:
Not admitted 1/4 
of the
thickness		 1/3 
of the
thickness		 Admitted
Wood defects Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number

1.2. Encased sound, unsound, decayed, rotten
1.2.1. Face

Admitted on the outside face within the amount of intergrown sound knots with dimensions in mm and number in pieces in average per 1000 mm of the length of lumber:

In thick wide sawn timber lumber
Not admitted 25 1 63 1 Admitted

Knot holes shall not exceed 32 mm in narrow and 38 mm in wide sawn timber (lumber)

Through the board unsound, decayed and rotten
Not admitted 25 1
In thick narrow lumber
Not admitted 19 1 50 1
Through the board unsound, decayed and rotten
Not admitted 25 1
In medium wide lumber
Not admitted 19 1 50 1
Through the board unsound, decayed and rotten
Not admitted 19 1
In medium narrow lumber
Not admitted 13 1 38 1
Through the board unsound, decayed and rotten
Not admitted 19 1
In thin lumber
Not admitted Only sound
13 1 38 1
Through the board unsound, decayed and rotten 
19 1
In lumber of 75 mm wide of all thickness the knot’s sizes shall not
exceed:
Not admitted 1/3 1/2 2/3
Of width of face

1.2.2. Edge and corner, including knot
holes

 Admitted on each edge with dimensions in mm and by number in pieces on
the entire length of lumber.
In thick lumber
Not admitted 13 1-2 38 2-4 Admitted
In medium lumber
Sound only
Not admitted 10 1-2 32 2-4 Admitted
In thin lumber
Sound only
Not admitted 6 1-2 25 2-4 Admitted
Knot holes not more than:
Not admitted Admitted with depth not more than: Admitted
In thick – 1/4 thickness of lumber with showing on outside face
not more than 2,0 mm 		Admitted
In medium – 1/3
In thin – 1/2
Of thickness of lumber
Wood defects Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number

1.2.3. End

Not admitted

 Admitted
2. Checks
2.1. Side checks
2.1.1. Face checks
2.1.1.1. Non through

Admitted with extent of not more
than:

 Admitted by conditions of integrity of lumber
1/3 1/2 2/3
Of the length of lumber
Without appearing on ends and edges

With appearing on one end up to 1/3 of thickness without exiting from end to edge.

2.1.1.2. Through
2.1.1.2.1. Through without appearing on the end, including ring shakes

Note:

Not admitted Admitted without exiting on edges from outside and inside faces with length of not more than: Admitted by conditions of integrity of lumber
In thick lumber
1/5 (1/2) 1/3 (2/3)
Of the length of a piece
In medium lumber
1/10 (1/4) 1/5 (1/3)
Of the length of lumber
In thin lumber
Not admitted
Check sizes, shown without brackets, relate to outside face; those in brackets relate to inside face.
2.1.1.2.2. Through appearing on end Admitted with extension from each end of not more than, mm:
30 40 50 Width of lumber 600
2.1.2. Edge checks Admitted:
Shallow, length not more than 40 mm Not crossing corners of edge Admitted
Wood defects Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
2.2. End checks ..
2.2.1. Heart checks Heart checks

Admitted in thick lumber on one end with length extent not more than 1/2 of width of a piece

Admitted
2.2.2. Ring shakes Not admitted

Admitted with diameter of not more than, mm:
In lumber with width

25 to 44mm  – 10
45 to 63mm  – 19
above 63mm – 25

 Admitted by conditions of integrity of lumber
3. Defects of wood structure
3.1. Slope of grain

Admitted, if grain deviation from straight direction per 300 mm of length of lumber compose not more than, mm:

Admitted
10 19 25
3.2. Compression wood Admitted without splits on ends Admitted
3.3. Pitch pockets

 

 

 

 

 

 

 

 

Note:

 On faces Admitted
In thick lumber
Admitted non through with width not more than, mm:
3 3 6
With length up to, mm:
75 100 200
On each face in amount in pieces of not more than:
2-3 4-6 8
In medium and thin lumber
Admitted non through with width not more than, mm:
3 3 6
With length up to, mm:
25 75 125
On each face in amount in pieces of not more than:
2-3 3-4 5
Without appearing on edges and ends –
Indicated amount of pitch pockets is admitted in less numbers
on outside face and more numbers on inside face.
On edges Admitted
Not admitted Admitted
1/2 of norm for outside face Width up to 3 mm;
length up to 100 mm in amount up to 4
pieces on each edge
On ends
Not admitted

Admitted in medium and thin lumber with width up to 3 mm
and length up to 1/3 of width of lumber
Wood defects Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
3.4. Pith

 

 

 

 

 

 

 

Note:

 Admitted in lumber of over 25 mm thick (without ring shakes and checks) Admitted Admitted
With extent up to 1/2 of length of lumber appearing on one end at distance not more than 1/6 of thickness of timber from inside face. With extent of total length of lumber appearing on one end at distance not more than 1/4 of thickness from inside face.
Admitted in lumber of 25 mm thick and thinner
Not admitted Admitted attached to inside face with appearing on outside face. Admitted
In a load of lumber of 3 grade not more than 30% of boxed heart is admitted
3.5.  In bark (Bark pockets) Not admitted

Admitted on faces non through not more than 25 mm wide in amount of 1 piece up to 75 mm long and up to 3 pieces with length up to 50 mm;
On edges 2 pieces up to 2 mm wide, not more than 15 mm long; not admitted on ends.

Admitted up to 50 mm wide;
In thick lumber on one face with no limit length.
In medium and thin lumber up to 175 mm long.

 

 Admitted
3.6. Pitch & Pitch Streaks Not admitted Admitted on faces and edges in form of spots and streaks Admitted
4. Fungal defects
4.1. Fungal heartwood stains (streaks) Not admitted

Admitted in thick lumber on face or edge without appearing on ends up to 1/5 of width and length of a piece.
Not admitted in medium and thin lumber

Admitted on faces and edges up to 1/2 of width and length of lumber, admitted showing on end with covering of not more than 10% of end’s area. Admitted
4.2. Light fungal sap stains and mold
4.2.1. Surface Not admitted Admitted on faces and edges up to 2 mm deep in shape of spots and streaks with total area of covering of not more than 15% of area of one face. Admitted on faces and edges in shape of spots and steaks. Admitted
4.2.2. Deep

Note:

Not admitted Admitted on faces and edges up to 2 mm deep in shape of spots and streaks with total area of covering of not more than 5% of area of one face. Admitted on faces and edges up to 2 mm deep in shape of spots and streaks with total area of covering of not more than 50% of area of one face and edges. With covering of not more than 10% of end area. Admitted

Volume of lumber with maximum admitted norm of deep fungal sap stains in a batch of 4 grade shall not exceed 25%.

Wood defects Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
4.3. Decay
4.3.1. Sap Decay
4.3.1.1. Firm Not admitted

In thick lumber is admitted on face or edge up to 1/5 of width and length without appearing on ends.
 Not admitted in medium and thin lumber

Admitted on faces and edges up to 1/2 of width and length of lumber without appearing on end. Admitted
4.3.1.2. Soft Not admitted
4.3.2. Heart Decay Not admitted

Brown checked not admitted.
Firm mottle honeycomb is admitted appearing on all sides in shape of streaks covering not more than 50% area of one face.
Decay shall not cover more than 20% of and area.

4.3.3. External rot Not admitted
5. Insect damages
5.1. Wormholes Not admitted External is admitted, caused by bark beetles

Spruce and Fir Lumber                                                                                                                         
Table 2   

Wood defects

Limiting norms of wood defects by grades

1 grade

 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
1. Knots

Admitted on outside face in dimensions in mm and amount in pieces on average per 1000 mm of lumber length.

1.1. Intergrown knots
1.1.1. Round & Oval
1.1.1.1. Face

In thick lumber
13 3 19-25 3 Admitted Admitted

Over
13
up to
19

1

Over
25
up to
38

2 70-75

1-2 
on entire
length

Over
19
up to
25

 1

Over
38
up to
50

1-2
on entire
length

With absence of unsound, decayed, rotten knots

With absence of enlisted unsound, decayed, rotten knots

In medium lumber
13 2 19-25 2 38-50 1 Admitted

Over
13
up to
19

1

Over
25
up to
37

 1

(over 50
up to
63)

1 – 2
on entire
length

With absence of unsound, decayed, rotten knots

In thin lumber
13-18 1 19-31 1-2 32 3 Admitted

(over 32
up to
38)

1

With absence of unsound, decayed, rotten knots

In lumber of 75 mm wide of all thickness size of knots shall not exceed:

1/3 of face width 1/3 of face width 1/2 of face width 2/3 of face width Admitted
Note:

1. Knots, dimensions of which are shown in brackets, admitted among recorded knots of smaller dimensions.
2. Quantity of knots on inside face is admitted: in 1 grade – double, in 2 grade – one and a half, in 3 grade – one time correspondently to norm for outside face.

Wood defects

Limiting norms of wood defects by grades

1 grade

 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
1.1.1.2. Edge & Corner Admitted on each edge with dimensions in mm and number in pieces for entire length of lumber:
In thick lumber:
Up to 13 8 19-43 3-6 44-50 1-3 Admitted
Over 13
up to
16		 4
Over 16
up to
18		 1-3
In medium lumber
up to 13 2-3 From 14 up to 2/3 of thickness of timber 2-3 From 19 up to 3/4 of thickness of timber 3-5 Admitted

In thin lumber

Up to 6

 2-3 From 7 up to 12 1-2 From 13 up to thickness of timber 2-4 Admitted
1.1.1.3. End Admitted with dimensions in mm and number in pieces:
On one end 1 knot up to 25 On both ends 1 knot up to 25 25 1 Admitted
On each end
1.1.2. Spike, branchy including appeared on corners, and edge knots Admitted on the inside face of sawn timber (lumber) in total number of intergrown round and oval knots with dimensions and amount as per paragraphs 1.1.1.1.; 1.1.1.2. In sawn timber of 1 grade largest diameter of branchy knot shall not exceed 50 mm and it shall not cover more than 1/4 of thickness of an edge.
1.2. Encased sound, unsound, decaying, rotten Admitted on each face within the amount of intergrown sound knots with dimensions in mm and number in pieces for the entire length of lumber:
1.2.1. Face In thick lumber
Not admitted Up to 30 3-6 Over 
30
up to 50		 3-6 Admitted

Admitted. Knot holes shall not exceed 32 mm in narrow and 38 mm in wide lumber

Through the board unsound, decayed and rotten

Not admitted

Up to 38

 Admitted
In medium lumber
Not admitted Up to 20 2-4 Over 20 up to 25 2-4 Admitted
Through the board unsound, decayed and rotten Admitted
Not admitted Up to 25 Admitted
In thin lumber
Not admitted Up to 16 1-3 Over 16 up to 22 1-3 Admitted
Through the board unsound, decayed and rotten Admitted
Not admitted Up to 25 Admitted
In lumber with width of 75 mm and any thickness, dimension of knots shall not exceed:
Not admitted 1/3 of the face width 1/2 of the face width Admitted

Wood defects

Limiting norms of wood defects by grades

1 grade

 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
1.2.2.
Edge and corner, including knot holes

Admitted on each edge with dimensions in mm and number in pieces on the entire length of lumber

In thick lumber
Not admitted Up to 15 1-2 16-25 2-4 Admitted
In medium lumber
Not Admitted 13-19 1-3 Admitted
In thin lumber
Not admitted 6-10 1-2 Admitted
Knot holes on edges
Not admitted Admitted covering up to: Admitted
2/3 of thickness of lumber Entire thickness of lumber with appearing on outside face in extent of 2 mm
1.2.3. End Not admitted Admitted
2. Checks
2.1. Side Checks

2.1.1. Face
2.1.1.1. Non through

 

 

Admitted with extent of not more than:		 Admitted by conditions of integrity of lumber
1/3 2/3 3/4
of the length of lumber
Without appearing on ends and edges

with appearing on one end up to 1/2 of thickness without exiting from end to edge.

2.1.1.2. Trough
2.1.1.2.1. Through without appearing on the end, including ring shakes 		Not admitted Admitted on outside face and for ring shakes on inside face with length of not more than: Admitted by conditions of integrity of lumber
1/4 1/3
Of the length of lumber
2.1.1.2.2. Through appearing on end Admitted with extension from each end of not more than, mm:
50 75 100 Width of a piece 600
2.1.2. Edge checks Admitted, mm:
Shallow, length not more than 75 mm Not crossing corners of edge Admitted
2.2. End checks
2.2.1. Heart checks		 Not admitted


Admitted in thick sawn timber on one end with length extent not more than 3/4 of width of a piece

Admitted by conditions of integrity of lumber
2.2.2. Ring shakes Not admitted

Admitted with diameter of not more than, mm:
In sawn timber with width:
25 to 44mm  – 10
45 to 63mm  – 19
above 63mm – 25

Admitted by conditions of integrity of lumber

Wood defects

Limiting norms of wood defects by grades

1 grade

 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
3. Defects of wood structure
3.1. Slope of grain

Admitted, if grain deviation from straight direction per 300 mm of piece’s length compose not more than, mm:


Admitted
13 25 38
3.2 Compression wood Admitted without splits on ends Admitted
3.3 Pitch pockets On faces
Admitted on each face without appearing on edges and ends with width up to 3 mm and length not more than, mm:

Admitted not through up to 6 mm wide and up to 200 mm long in amount of 10 pcs. on each face

Admitted
75 150
In amount of not more than, pcs:
3 5
On edges
Admitted with dimensions and numbers not exceeding 1/2 of those stipulated for the face. Admitted
On ends
Not admitted

Admitted in medium and thick sawn timber with width up to 3 mm and length up to 1/3 of width of lumber

Admitted
3.4. Pith

Note:

In lumber of less than 22 mm thick:
Not admitted Admitted
In lumber of over 22 mm and up to 44 mm thick:
Admitted with extend of entire length of lumber with appearing on one or both ends not far from inside face than: Admitted
1/4 1/3 1/3
Of thickness of lumber without checks and shakes in 1 and 2 grades.
In lumber of over than 44 mm thick:

Admitted with extend of entire length of lumber far from inside face not less than 1/4 of thickness of lumber

Admitted
In a load of sawn timber of 3 grade not more than 30% of boxed heart is admitted
3.5. In bark (bark pockets) Not admitted

Admitted on faces non through in amount up to 4 pcs in lumber with thickness of 55 mm and up:
125 mm long and 25 mm wide;
in lumber with thickness of less than 55 mm:
63 mm long and 15 mm wide;
On edges 2 pieces up to 2 mm wide, not more than 20 mm long;

Admitted
3.6. Pitch & Pitch Streaks Not admitted Admitted on faces and edges in form of spots and streaks Admitted

Wood defects

Limiting norms of wood defects by grades

1 grade

 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
4. Fungal defects
4.1. Fungal heartwood stains (streaks)

Not admitted

Admitted on face or edge up to 1/4 of width and length of lumber

Admitted on faces and edges up to 1/2 of width and length of lumber, admitted showing on end with covering of not more than 10% of end’s area.



Admitted
4.2. Light fungal sap stains and mold

4.2.1. Surface

Not admitted

Admitted on faces and edges up to 2 mm deep in shape of spots and streaks with total area of covering of not more than 15% of area of one face

Admitted on faces and edges in shape of spots and steaks. Covering of not more than 10% of end’s area

Admitted
4.2.2. Deep

Note:

Not admitted

Admitted on faces and edges in shape of spots and streaks with total area of covering of not more than 5% of area of one face.

Admitted on faces and edges in shape of spots and streaks with total area of covering of not more than 50% of area of one face and edges. With covering of not more than 10% of end’s area.

Admitted

Volume of lumber with maximum admitted norm of deep fungal sap stains in a batch of 4 grade shall not exceed 25%.

4.3. Decay
4.3.1. Sap decay
4.3.1.1. Firm

Not admitted

Admitted on face or edge up to 1/4 of width and length of lumber

Admitted on faces and edges up to 1/2 of width and length of lumber without appearing on ends

Admitted
4.3.1.2. Soft Not admitted
4.3.2. Heart Decay Not admitted

Admitted firm non through with dimensions up to 1/5 of width and length of lumber without appearing on ends

Admitted firm on one face with dimensions up to 1/4 of width and 1/3 of length of lumber, slightly exiting on another face and edges

Brown checked not admitted.
Firm mottle honeycomb is admitted appearing on all sides in shape of streaks covering not more than 50% area of one face.
Decay shall not cover more than 25% of end’s area

4.3.3. External rot Not admitted
5. Insect damages
5.1. Wormholes
Not admitted
External is admitted, caused by bark beetles
Note: Table 1 & 2

1. Amount of knots for entire length of lumber, shown “from – to” means that less amount is admitted for short lumber and more – for long.
2. Knots with less dimensions than indicated are disregarded.
3. Intergrown knots could be knots fully intrgrown on one face and fully incased on another face or edge.
4. In U/S (1-3 grades together) lumber, simultaneous presence of incased knots, checks and fungus sapwood stains with maximum limits are not admitted.
 5. With absence of other limiting defects one defect is admitted exceeding 20% of parameters, except for blue stain and checks.

   Table 3  

Wood defects

 Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
1. Manufacturing defects
1.1. Wane		  
1.1.1. Obtuse Admitted on one edge with extension of not more than:

Admitted on both edges extended not more than 2/3 of the length of lumber

Admitted on both edges extended on entire length with covering of not more than 2/3 of thickness and width of lumber

1/5 1/4 1/3
Of the length of the lumber
On both edges:
1/10 1/5 1/4
Of the length of the lumber
Width of wane, calculated by maximum value of miss sawn part in mm, is admitted of not more than:
In lumber with thickness up to 25 mm:
1/4 1/3 1/2 2/3
Of thickness of lumber
In lumber with thickness over 25 mm:
1/5 1/4 1/3 2/3
Of thickness of lumber
 

Wane admitted on condition that sawn part of edge shall be not less than 1/2 of thickness of lumber

1.1.2. Sharp Not admitted

Admitted on one edge not more than 1/10 of length of lumber provided that nominal width of inside face shall be maintained

Note: The wane shall be free of bark and inner bark, in lumber of 5 grade inner bark may be present
1.2. Saw marks The depth of saw teeth marks shall not exceed 0,75 mm
1.3. Fringe Not admitted
1.4. Bevel cut Declinations from perpendicularity of end to face and to edge are admitted up to 3% of width and thickness of lumber correspondently.
1.5. Chipping Chipping due to mechanical damages, saw kerfs, knife marks caused by debarking machines on edge corners next to inside face are not admitted; on edge corners next to outside face are admitted  correspondently to wane limitations.
1.6. Waving The height of wave shall not exceed 0,75 mm
1.7. Torn grain On faces
Admitted not more than 0,75 mm deep without number limitations

Admitted up to 3 mm deep without number limitations

Admitted
On edges
Admitted not more than 3 mm deep without number limitations

Admitted not more than 5 mm deep without number limitations

Admitted
Note: Limits for waving and torn grain are indicated only for lumber recovered on “chip and saw” equipment
1.8. Foreign particles (nails, wire, metal debris and etc.) Not admitted

Wood defects

 Limiting norms of wood defects by grades
1 grade 2 grade 3 grade 4 grade 5 grade
size number size number size number size number size number
2. Warping  
2.1. Crook Admitted with deflection of not more than, %
0,10 0,10 0,15 0,20 admitted
Of the length of lumber
Note:

1. Volume of lumber with admitted crook warp shall not exceed 20% of the total volume of the said grade.
2. Values for crook warp for lumber of different length are given in reference Annex

2.2. Bow Admitted with deflection per each 1500 mm of the length of lumber of not more than, mm: Admitted
2 4 6 13
2.3. Cup Admitted with deflection of not more than, mm: Admitted
For wide lumber
3 3 6 10
For narrow lumber
1 1 3 6
2.4. Twist Admitted with deflection from sawing plain not more than 13 mm for entire length of lumber Admitted
Note: Volume of lumber with crook, bow and twist, provided p. 2.2-2.4 shall not exceed in U/S grade – 10%, in 4 grade – 20% of total volume.

 

3. Acceptance Rules and Methods of Control
3.1. Acceptance rules and methods of control – as per GOST 6564-84
3.2. Sizes of knots are determined by the smallest diameter. Measurement of spike,
branchy including appeared on corners and edge knots shall be taken on corner of lumber. Their
size to be accepted as per the norms of admitted knots on edges. Their depth of covering of edge
shall be measured by the distance between corner and tangent placed parallel to the corner.

 

  Values of crook warping for lumber by length and grades:

Length of lumber in mm

Crook warping by grades

Unsorted (U/S)

4 grade

%

mm

%

mm
1500 0,15 2,2 0,2 3,0
1800 0,15 2,7 0,2 3,6
2100 0,15 3,2 0,2 4,2
2400 0,15 3,6 0,2 4,8
2700 0,15 4,0 0,2 5,4
3000 0,15 4,5 0,2 6,0
3300 0,15 5,0 0,2 6,6
3600 0,15 5,4 0,2 7,2
3900 0,15 5,8 0,2 7,8
4200 0,15 6,3 0,2 8,4
4500 0,15 6,8 0,2 9,0
4800 0,15 7,2 0,2 9,6
5100 0,15 7,6 0,2 10,2
5400 0,15 8,1 0,2 10,8
5700 0,15 8,6 0,2 11,4
6000 0,15 9,0 0,2 12,0
6300 0,15 9,4 0,2 12,6
6600 0,15 9,9 0,2 13,2
6900 0,15 10,4 0,2 13,8
7200 0,15 10,8 0,2 14,4
7500 0,15 11,2 0,2 15,0