Technical conditions for valuable breeds. Assortment of boards - types of products, main parameters of structures Quality requirements for furniture boards

Real Technical conditions define: quality requirements for sawn timber and furniture boards for valuable wood species used in the trade turnover of the ORIS TRADE company.

Requirements for grade AA (grade 0).

Requirements for grade AB (grade 1).

UPPER PLATE
- requirements as for grade AA (grade 0).

LOWER PLATE
- one-sided blind healthy knots up to 12 mm in diameter are allowed, no more than two on one face of the board.
- Eyes (live light knots "in color" no more than 5 mm in diameter) except for group eyes ("cat's paw") without restrictions.
- Sapwood without limits

QUALITY REQUIREMENTS FOR BEECH LAMBERS

Requirements for grade "AA"

UPPER PLATE and LOWER PLATE (variety-determining defects):
- Presence of one mineral inclusion up to 7 mm per running meter
- Capturing a false kernel is NOT ALLOWED.

Requirements for grade "AB"

UPPER PLATE
- As in AA grade

LOWER PLATE
- False kernel allowed without restrictions
- No more than 3 live knots with a diameter of no more than 10 mm per face are allowed
- Dead and rotten edge, edge and end knots "for processing" are allowed (for trimming or trimming - at the butt or on the edge of the board)
- Mineral inclusions up to 10 mm are allowed 1 pc per running meter

Requirements for the grade "CC"

UPPER PLATE and LOWER PLATE (variety-determining defects):
- requirements as for grade B face

NOT ALLOWED on all grades
- core, rot in all forms (tobacco, etc.), rotten knots falling out, wormholes
- mushroom stains (bluish and colored sap stains), gasket stains

For beech boards, the following variety-forming characteristics are additionally distinguished:
- steamed beech - lumber that has undergone special processing ("steaming") and has a specific reddish color (the degree of color can vary from "pink" to "red" depending on the degree of steaming).
- Unsteamed beech - lumber that has not undergone special processing ("steaming"), and has a natural color characteristic of beech lumber (white).

QUALITY REQUIREMENTS FOR ASH LUMBERS

Requirements for grade "AA"

UPPER PLATE and LOWER PLATE (variety-determining defects):
- The presence of one unilateral live knot with a diameter of not more than 7 mm on one face
- Capturing the kernel is NOT ALLOWED.

Requirements for grade "AB"

UPPER PLATE
- As in AA grade
LOWER PLATE
- One-sided blind healthy knots up to 12 mm in diameter are allowed, no more than two on one face of the board.
- Dead and rotten edge, edge and end knots "for processing" are allowed (for trimming or trimming - at the butt or on the edge of the board)

Requirements for the grade "CC"

UPPER PLATE and LOWER PLATE (variety-determining defects):
- Unlimited kernel allowed
- No more than 2 live knots with a diameter of no more than 10 mm per face are allowed
- Dead and rotten edge, edge and end knots "for processing" are allowed (for trimming or trimming - at the butt or on the edge of the board)

NOT ALLOWED on all grades
- core, rot in all forms (tobacco, etc.), rotten knots falling out, wormholes
- mushroom stains (bluish and colored sap stains), gasket stains

Quality requirements for furniture boards

Definition of quality (grade):

For all types of furniture boards:

humidity not more than 8% +/- 2%;
dead (black) knots are not allowed;
lamella width 40-50mm
PVA glue D-4 (KLEIBERIT);
grinding at least 120 units;
thickness tolerance + 0.1mm; width tolerance +/- 1mm;
shrink wrapping.

Requirements for oak shields

AA - Both sides are clean, without sapwood (protein). On one face, knots no more than 2 mm in diameter are allowed, not through, ‛live‛ no more than 1 piece per linear meter Both faces are matched by texture (lamellas of radial and tangential sawing are glued into different panels) and color (no sharp color transitions on one face )
AB - The top face is clean, without sapwood, without knots. The lower (2nd layer) allowed the presence of sapwood (squirrel) without restrictions, as well as live knots in color with a diameter of no more than 20 mm. One face (front) matched to chromaticity (no sharp color transitions on one face)
CC On both seams, sapwood is allowed without restrictions, live knots up to 20 mm in diameter. Rotten knots, rot are not allowed. Matching by color and texture is not performed

Requirements for beech shields

AA - Both surfaces are clean, without the capture of a false nucleus. On one face, knots no more than 2 mm in diameter are allowed, not through, ‛live‛ no more than 1 piece per linear meter. Mineral inclusions are allowed up to 7 mm. Both faces are matched by texture (lamellas of radial and tangential sawing are glued into different panels) and color (no sharp color transitions on one face)
AB - The upper face is clean, without the capture of a false nucleus. On the upper (front) face, knots no more than 2 mm in diameter are allowed, not through, ‛live‛ no more than 1 piece per running meter. Mineral inclusions are allowed up to 7 mm. The lower (2nd layer) is allowed a false core without restrictions, as well as live knots "in color" with a diameter of no more than 20 mm, mineral inclusions up to 15 mm. One face (front) is matched by color (no sharp color transitions on one face)
CC On both seams, the capture of a false core is allowed without restrictions, live knots up to 20 mm in diameter, mineral inclusions up to 15 mm. Rotten knots, rot are not allowed. Color and texture matching is not performed.

All photos from the article

Assortment refers to the totality of types and sizes of a particular type of product, that is, as far as the board is concerned, the most important criteria are the grade and size range. It is by these factors that all products are subdivided. of this type, we will consider the basic information that every developer who selects lumber of the considered group should know.

Types of products

As for the main types of products shown in the diagram above, the following can be said about each of them:

Unedged board	This option is distinguished by the fact that only two sides are cut off, and the ends are not processed. Such elements are most often used for the construction of battens and other structures, where the appearance does not have of particular importance, the main advantage of this solution is its democratic price, which is why it is the most affordable
Semi-edged board	For this type of product, two sides and one of the ends are most often processed, but at the same time there may be bevels and remnants of bark on the edge. In general, this solution is of higher quality, but nevertheless it also cannot be used on visible structures, where aesthetic appeal is important.
Edged board	The highest quality type of product, in which all sides are processed, therefore the geometric parameters of the elements are the same, and the strength indicators are much higher. This group of products is used most often and is in demand among developers much more than other types

Important! According to the scientific definition, a board is a type of lumber, the thickness of which does not exceed 100 m, and the width is at least twice the thickness. Elements up to 32 mm thick in hardwood and up to 40 mm in conifers ah belong to thin board, other options - to the thick one.

Basic parameters of structures

Assortment wooden planks includes requirements for grade and size, we will consider the first criterion in more detail in the next section, and in the table below we denote the generally accepted sizes of elements:

As for the length, the generally accepted options vary in the range from 1 to 6 meters, upon agreement, other standard sizes can be produced.

Product grade

The type of edged board directly depends on the quality of the element and its strength characteristics, this parameter is applicable only to edged elements and is intended to simplify the choice of a specific type of product for certain works, we will consider the main options, and the photo below shows all the defects that must be taken into account when definition of the variety.

The correct choice of the type of edged board or edged bar has big influence not only on the quality of the final product, but also on its final price.

Legal framework

Currently, the criteria and indicators of the quality of sawn timber are regulated by the current state standards and take into account several factors:

In one article, we decided to briefly combine all the characteristics of lumber - this is what is important to understand and need to know for an ordinary consumer. We will tell you about the main factors and criteria affecting the grade, as well as the methods of their visual determination. Our methodology is based on the above state standards and is as close as possible to the concepts of sawn timber grade existing on the market today. Yes, indeed, some norms state standards, adopted in the 80s, today differ from the real properties of sawn timber offered for sale on the market. The main thing remains the fact that, in fact, lumber in its physical properties has not changed: pine and spruce are out of politics, despite the fact that years have passed since the adoption of GOSTs, and they can and should be used in general construction activities with confidence and without fear. Currently, there are unwritten standards on the market for determining the grade of coniferous wood, and in most of the regulated parameters they differ from the generally accepted GOST standards. Also, deviations from GOST can be according to the classification of natural defects, taking into account their biological characteristics, meaning knots - the shape and their number, the size of the wane part. Be sure to read the article Classification of wood defects, you will learn what is an important and unacceptable defect, and what is not important. Don't be fooled when buying lumber.

General technical requirements

Softwood lumber is made from spruce, fir, pine, cedar and larch. The most common and affordable is pine or spruce lumber. As a rule, for the manufacture of edged sawn timber, raw round timber is not sorted and spruce and pine are offered for sale in mixed form, since they also grow together in the forest. Sorting is economically unprofitable - in other words, sorting will lead to an increase in the cost of the final cost of the material, but at the same time it is important to understand: the quality of pine and spruce boards is the same in its own way. technical characteristics... That is, you can ignore this aspect - their physical characteristics are very close, and for solving most construction problems, the quality and strength characteristics of spruce and pine will be identical.

According to the quality of the structure and the quality of processing, the edged board can be of five varieties. Edged timber conifers have four varieties. The relative humidity of selected and 1-3 grades sawn timber cannot exceed 22%, as agreed with the customer, the indicators may change. The fourth grade has no moisture restrictions. The grade is assessed taking into account the condition of the edge or face, only the worst part... The surface roughness for selected and 1-3 grades should be less than 1250 microns, the fourth grade has no restrictions on this parameter. This is very important. Often, cheaper lumber is sold under the guise of a higher grade.

Edged timber, size according to GOST

The criterion for limiting natural defects of wood also affects the type of sawn timber, we will tell you about the general approaches of the standard to determining the class of wood. On our site there are many articles explaining narrow professional terms, techniques that do not say anything for an ordinary person. But, even after studying the materials, experience is needed, it is difficult for an average person to distinguish dozens of types of knots and violations of wood structure "by eye". Most The best way not to be a victim of fraud is to buy edged boards or edged beams, relying on a trusted supplier. Our company "Elka-Palka" is always ready to help you. We are honest about sorting. Let us briefly consider the main differences between the varieties of edged boards and edged beams. The criteria by which it is worth distinguishing the varieties and quality of boards and beams is the presence of defects or defects.

Norms and Limitations of Natural Vices

Selective grade. Healthy intergrown knots, bed, rib, edge and partially intergrown knots are allowed, the quantity is indicated in the tables of the standard. The presence of rotten and shriveled knots is prohibited. End cracks(deep and shallow) can be no more than 10% and 16%, respectively. All signs of the presence of fungal diseases of wood are prohibited, the warping and non-parallelism of the edges is set within 0.2-1.0%.
First grade board. This is lumber of the correct geometric shape, with dimensional tolerances within the framework of GOST. If you compare it with a select variety, then the following indicators will slightly change: the number of healthy knots increases different types, by about 10%, the number of shallow end cracks can reach 25%. Roll is allowed no more than 20% of the area of the face of the material. Mushroom heart spots (stripes), mushroom sap stains and mold are allowed with a total area of the lumber area - no more than 10%. Rot is not allowed. These indicators are typical for the summer period and do not affect the quality of lumber in any way, since they are natural and do not lead to the destruction of the wood structure. Look to understand the article Wood flaws on our website. Shedding is allowed blunt, on the edges and faces of the size in fractions of the width of the corresponding sides of the edged sawn timber without limitation in length, no more than 1/6. Such wane is also called "pencil" wane. Basically, 1 grade edged board is used for general construction work - installation roof systems roofs, bearing structures, building a house, beams and interfloor ceilings, rough hemming and rough floors, fences.

Board of the second grade. The advantage is mainly the low price. The main differences from grade 1 sawn timber - products can have large values of the inclination of the fibers, resin pockets are allowed. Lumber may have a larger, but slight, fungal stain and small bluish spots. Considerable wane is allowed. The main use of edged boards of the second grade is use in construction, in the manufacture of formwork, lathing on pitched roofs, it is also used for the manufacture of scaffolding.
Third grade. A significant roll is allowed, the presence of resin pockets, can increase up to 4 pcs / m. etc., double core is allowed. The eruption can only be one-sided, the number of heart spots can increase up to 20%. A wormhole is allowed anywhere. Rotten rotten and tobacco knots are allowed in the total number of partially accreted and non-accreted healthy knots of the same size and no more than half of their number. Plast and through cracks, including those coming to the end. In connection with the above listed features physical properties timber deteriorate sharply and it is possible to use such material in limited use - the construction of temporary buildings or sheds, the manufacture of containers and pallets.
Fourth grade. A wormhole is allowed up to 6 pcs / m. etc., rot can only be variegated sieve, total area rot - no more than 10% of the lumber area. It can have a blunt and sharp wane, transverse and longitudinal warping along the face and edge, including winging.

These are the "scientific" characteristics of lumber, depending on their class. Now we deem it necessary to give you practical advice, with the help of which lumber should be selected, for this you do not need to study the provisions of state standards

We deeply doubt that most buyers, before purchasing sawn timber, measure various defects and compare their appearance with an album of wood diseases and defects. It is for them that we will give several simple and understandable criteria for choosing high-quality wood.

The more annual rings are visible in a vertical section and the closer they are to each other, the more better quality lumber... If there are many rings, radial sawing was performed, and this is the most quality boards... The closer the rings are to each other - the less the annual growth of wood, the stronger it is, better withstand moisture, etc. This indicator largely depends on climatic zone growth of a tree, the colder the climate, the better the tree.

One more thing. It is very common to see the difference in the quality of wood different varieties even professionals cannot, these assessments are rather subjective. Nobody examines every board for hours. And in terms of price, the difference between them is significant. What are we driving at? Buy lumber from a trusted supplier and there will be no unpleasant "surprises". The Elka-Palka company always has edged timber and edged board best quality, which you can buy one call at a time. Such a purchase will allow you, without overpaying and without wasting time, to get the desired result. Buy edged board can be inexpensive and excellent appearance, with remarkable properties.